OCA 6

Started on Thursday, 16 January 2014, 11:28 PM

State Finished

Completed on Friday, 17 January 2014, 12:09 AM

Time taken 41 mins 5 secs

Marks 34.00/34.00

Grade 100.00 out of a maximum of 100.00

Question 178. How long did it take for oxygen to build up in the Earth's atmosphere to its present levels?Select one:a. 545 million yearsb. 4 billion years c. 2 billion yearsd. 360 million yearsFeedbackThe correct answer is: 4 billion years

Question 23. Stromatolites areSelect one:a. fossils of the first eukaryotesb. layers of sediment that once contained colonies of ancient microbes c. fossils of the first organisms to introduce oxygen into the atmosphered. fossils of the first multicellular organismsFeedbackThe correct answer is: layers of sediment that once contained colonies of ancient microbes

Question 312. The most common isotope of carbon isSelect one:a. carbon 12 b. carbon 13c. carbon 14d. carbon 11FeedbackThe correct answer is: carbon 12Question 479. The point in time at which oxygen started to build up in the Earth's atmosphere is referred to as theSelect one:a. great photosynthetic eventb. great oxygen crisis

c. great oxygenation eventd. great oxidation event FeedbackThe correct answer is: great oxidation event

Question 533. RNA catalysts are known asSelect one:a. ribozymes b. riboenzymesc. riboflavinsd. enzymesFeedbackThe correct answer is: ribozymes

Question 625. Life probably did not originate on the land surface becauseSelect one:a. there was no ozone layer to shield out harmful UV rays b. impacts would have destroyed any life that appearedc. organic materials were not present on the landd. water was not plentiful on landFeedbackThe correct answer is: there was no ozone layer to shield out harmful UV rays

Question 758. The very first living organisms on the Earth were probablySelect one:a. photoautotrophsb. chemoheterotrophsc. chemoautotrophs d. photoheterotrophsFeedbackThe correct answer is: chemoautotrophs

Question 837. The first molecules of RNA were probably madeSelect one:a. on the surfaces of clays or other mineralsb. in space and then transported to the Earth in meteorites c. in the atmosphered. deep within the earthFeedbackThe correct answer is: on the surfaces of clays or other minerals

Question 967. All multicellular organisms areSelect one:a. Eukarya b. Archaeac. Prokaryotes

d. BacteriaFeedbackThe correct answer is: Eukarya

Question 1087. Impacts of large asteroids on the Earth's surface generally result inSelect one:a. localized destruction close to the impact areab. the destruction of most but not all life on Earthc. total destruction of all life on Earth d. the formation of MoonsFeedbackThe correct answer is: the destruction of most but not all life on Earth

Question 1131. The first self replicating molecule was probablySelect one:a. DNAb. a simple proteinc. a simple carbohydrated. RNA FeedbackThe correct answer is: RNA

Question 1280. The study of 2 3 billion year old banded iron formations shows thatSelect one:a. Earth's atmosphere contained much more oxygen in the past compared to todayb. Earth's atmosphere contained much less oxygen in the past compared to today c. the amount of oxygen in the Earth's atmosphere has remained constant throughout its historyd. there was no oxygen in the Earth's atmosphere at that timeFeedbackThe correct answer is: Earth's atmosphere contained much less oxygen in the past compared to today

Question 1335. Why do we think that RNA was probably the first self replicating molecule?Select one:a. it is able to replicate at high temperatures found near deep sea ocean ventsb. it is able to replicate using carbohydrates rather than proteinsc. it is much simpler than DNAd. in laboratory studies researchers have shown that it is able to catalyze its own replication FeedbackThe correct answer is: in laboratory studies researchers have shown that it is able to catalyze its own replication

Question 1414. A sample of an ancient sedimentary rock contains slightly less of the isotope carbon 13 than normal. One possible explanation for this is thatSelect one:a. it used to be at the bottom of an ancient ocean

b. it was a meteorite that fell from the skyc. some kind of biological activity occurred in it in the past d. some kind of radioactive decay occurred in it in the pastFeedbackThe correct answer is: some kind of biological activity occurred in it in the past

Question 1527. One factor that hampers the use of Miller Urey experiments in studying the chemical processes that may have occurred on the early Earth is that theSelect one:a. amount of water that was present is not knownb. contribution from impacts is not well understoodc. amount of UV radiation present from the Sun cannot be estimatedd. composition of the Earth's early atmosphere is not well known FeedbackThe correct answer is: composition of the Earth's early atmosphere is not well known

Question 1622. As life on Earth evolved, its DNASelect one:a. became gradually more complexb. changed gradually into RNAc. became gradually less complexd. stayed the same FeedbackThe correct answer is: became gradually more complex

Question 1774. During the Carboniferous Period,Select one:a. the carbon dioxide cycle started to operate for the first timeb. carbon rich meteorites impacted the Earthc. land was covered with dense forests with the appearance of the first insects and amphibians d. the first carbon based life appearedFeedbackThe correct answer is: land was covered with dense forests with the appearance of the first insects and amphibians

Question 1876. The fossil fuel deposits we use today are the remains of organisms from which period in Earth's history?Select one:a. The Carboniferous Periodb. The Cretaceous Periodc. The Cambrian Period d. The Archaean EonFeedbackThe correct answer is: The Carboniferous Period

Question 19

56. If we eventually find life on Mars, we could tell if panspermia may have occurred between Mars and Earth ifSelect one:a. Martian life shows evidence for natural selectionb. the biochemistry of Martian life is very similar to life on Earth c. the biochemistry of Martian life is very different than life on Earthd. Martian life is cellularFeedbackThe correct answer is: the biochemistry of Martian life is very similar to life on Earth

Question 2011. Why can studies of carbon isotopes be used to detect the presence of past biological activity in rocks?Select one:a. living organisms absorb certain carbon isotopes more easily than others b. living organisms remove all carbon from rocksc. living organisms absorb only the most common carbon isotoped. carbon isotopes are found only in living organismsFeedbackThe correct answer is: living organisms absorb certain carbon isotopes more easily than others

Question 2190. Dust and smoke blown up into the Earth's atmosphere from the massive impact of an asteroid 65 million years agoSelect one:a. blocked sunlight, causing global temperatures to fall on the Earth and subsequently shutting down photosynthesis for up to a year b. removed most of the oxygen in the Earth's atmosphere by oxidationc. trapped heat in the Earth's atmosphere, causing global temperatures to rised. rapidly escaped into space, having very little effect on the Earth's climateFeedbackThe correct answer is: blocked sunlight, causing global temperatures to fall on the Earth and subsequently shutting down photosynthesis for up to a year

Question 2263. The first eukarya appearedSelect one:a. 4.0 billion years agob. around 3.5 billion years agoc. 4.6 billion years agod. at least 2.1 billion years ago or perhaps even earlier FeedbackThe correct answer is: at least 2.1 billion years ago or perhaps even earlier

Question 2355. The possibility of life being transferred from another planet like Mars largely depends on whether that life can surviveSelect one:a. the impact onto the Earth's surfaceb. long enough in space to make the journey to Earthc. inside the meteorite with very little water present

d. being lasted from the parent planetFeedbackThe correct answer is: long enough in space to make the journey to Earth

Question 2454. To date, meteorites have been identified originating from which planets and moons?Select one:a. The Moon and Marsb. Mars onlyc. All terrestrial planets d. The Moon onlyFeedbackThe correct answer is: The Moon and Mars

Question 257. Microbes in the top layers of living stromatolites in western Australia obtain their energy fromSelect one:a. poop deposited on them by birdsb. photosynthesis c. oxygen in the aird. corals that live on their surfacesFeedbackThe correct answer is: photosynthesis

Question 2683. What is the K T boundary?Select one:a. a layer of dark sediment in the geological record separating the Cretaceous and Tertiary periods of Earth's history b. a boundary between the Earth's crust and the molten rock beneath itc. a boundary between rocks containing the oldest life and older rocks that contained no lifed. a layer of dark sediment in the geological record formed at the same time humans learned to use fireFeedbackThe correct answer is: a layer of dark sediment in the geological record separating the Cretaceous and Tertiary periods of Earth's history

Question 2747. One theory for the origin of life suggests that life was transported to Earth in meteorites. This is referred to asSelect one:a. intelligent designb. naturismc. panspermia d. chemical evolutionFeedbackThe correct answer is: panspermia

Question 2820. Organisms close to each other on the Tree of LifeSelect one:

a. are genetically very different b. are genetically identicalc. are genetically very similard. look very similar to the eyeFeedbackThe correct answer is: are genetically very similar

Question 2918. Current geological evidence suggests that lifeSelect one:a. must have appeared exactly 3.5 billion years agob. must have appeared exactly 3.85 billion years agoc. could have appeared more than 3.85 billion years agod. could have appeared as soon as the Earth formed, 4.6 billion years ago FeedbackThe correct answer is: could have appeared more than 3.85 billion years ago

Question 3026. In the original Miller Urey experiment it was assumed that carbon and nitrogen in the early atmosphere were present asSelect one:a. carbon dioxide (CO2) and nitrogen (N2) b. carbon and nitrogen atomsc. methane (CH4) and ammonia (NH3)d. carbonates (CO3-) and nitrates (NO3-)FeedbackThe correct answer is: methane (CH4) and ammonia (NH3)

Question 3189. What is the one piece of evidence that suggests strongly that the dinosaurs were made extinct by the impact of an asteroid 65 million years ago?Select one:a. a layer of sediment laid down at that time contains grains of shocked quartz, solidified rock droplets, and soot from global wildfires b. dinosaur fossils are found in rock layers older than 65 million years and diminish in frequency with ensuing yearsc. the crater from this impact can still be seen in the deserts of Arizonad. a layer of sediment laid down at that time is littered with dinosaur fossilsFeedbackThe correct answer is: a layer of sediment laid down at that time contains grains of shocked quartz, solidified rock droplets, and soot from global wildfires

Question 3272. The colonization of life onto land was closely tied to theSelect one:a. oceans being overcrowdedb. development of the ozone layerc. appearance of multicellular organisms d. development of photosynthesisFeedback

The correct answer is: development of the ozone layer

Question 3340. One type of early pre cell (vesicle) probably consisted of small droplets ofSelect one:a. clay b. waterc. nucleic acidsd. concentrated amino acidsFeedbackThe correct answer is: concentrated amino acids

Question 3470. What happened at the start of the Cambrian Period?Select one:a. early humans first appearedb. an explosion of genetic diversity appeared, leading to the appearance of the first animals c. the first oxygen producing bacteria appearedd. the first dinosaurs appearedFeedbackThe correct answer is: an explosion of genetic diversity appeared, leading to the appearance of the first animals

OCA 7Started on Tuesday, 28 January 2014, 12:46 AM

State Finished

Completed on Tuesday, 28 January 2014, 1:28 AM

Time taken 42 mins 13 secs

Marks 30.00/30.00

Grade 100.00 out of a maximum of 100.00

Question 119. Mercury and the Moon are probably the least habitable bodies in the solar system because theySelect one:a. are unlikely to have liquids anywhere b. have never had carbon compounds on their surfacesc. do not receive any sunlightd. do not have atmospheres containing oxygenFeedback

The correct answer is: are unlikely to have liquids anywhere

Question 216. Which of the following is NOT a basic requirement for chemically based life?Select one:a. a source of energy to fuel metabolismb. a liquid medium to transport biological moleculesc. a source of molecules from which to build living cellsd. oxygen from photosynthesis FeedbackThe correct answer is: oxygen from photosynthesis

Question 341. Most of the detailed information about the planets in our solar system comes fromSelect one:a. robotic spacecraft b. meteoritesc. human visitsd. telescopic observations from EarthFeedbackThe correct answer is: telescopic observations from Earth

Question 45. The planet Saturn is approximately 10 times farther away from the Sun than the Earth is. Given this, how much sunlight does it receive compared to the Earth?Select one:a. 1/1,000thb. 1/10,000thc. 1/10thd. 1/100th FeedbackThe correct answer is: 1/100th

Question 554. The Cassini mission is currently in orbit around which planet?Select one:a. Erosb. Marsc. Saturn d. JupiterFeedbackThe correct answer is: Saturn

Question 626. The surface of Venus is much hotter than the Earth because itSelect one:a. has a very thick atmosphere of carbon dioxide b. has no magnetic fieldc. has a much higher rate of volcanic activityd. is closer to the SunFeedback

The correct answer is: has a very thick atmosphere of carbon dioxide

Question 734. The biggest obstacle to life being present in the atmospheres of Jupiter and Saturn is theSelect one:a. high levels of solar radiation that would destroy any biological moleculesb. strong vertical wind speeds that would rapidly carry organisms into the hot interior where they would be destroyed c. absence of liquid water in their atmospheresd. very low temperatures at the tops of the clouds where water would not be liquidFeedbackThe correct answer is: strong vertical wind speeds that would rapidly carry organisms into the hot interior where they would be destroyed

Question 89. Which of the following makes water an ideal solvent for life?Select one:a. all of the aboveb. ice is less dense than water so when a body of water is cooled, only the surface freezesc. water is a polar molecule, making it an excellent solvent d. water remains liquid over a wide and high range of temperaturesFeedbackThe correct answer is: all of the above

Question 92. Habitability generally refers to an environment capable of sustainingSelect one:a. human lifeb. plant lifec. microbial life onlyd. any kind of life FeedbackThe correct answer is: any kind of life

Question 1011. What happens to the rate of most chemical reactions as the temperature decreases?Select one:a. the rate of reaction stays the sameb. the rate of reaction drops only slightlyc. the rate of reaction increases rapidly d. the rate of reaction drops rapidlyFeedbackThe correct answer is: the rate of reaction drops rapidly

Question 1110. Which one of the following properties is unique to water?Select one:a. it expands on freezingb. it is a good solvent c. it has a high heat capacity

d. it is a liquid over a wide temperature rangeFeedbackThe correct answer is: it expands on freezing

Question 1250. Which spacecraft is currently on its way to Pluto?Select one:a. Cassinib. New Horizonsc. Messengerd. Voyager 2 FeedbackThe correct answer is: New Horizons

Question 131. If life does indeed exist elsewhere in our solar system it will most likely take the form ofSelect one:a. birdsb. human beingsc. plantsd. microbes or other simple life FeedbackThe correct answer is: microbes or other simple life

Question 147. Photosynthetic life existing on a planet much farther from the Sun than the Earth would most likelySelect one:a. be smaller than photosynthetic life on Earth or less efficient at collecting solar radiation b. be larger than photosynthetic life on Earth but less efficient at collecting solar radiationc. be larger than photosynthetic life on Earth or more efficient at collecting solar radiationd. be identical to photosynthetic life on EarthFeedbackThe correct answer is: be larger than photosynthetic life on Earth or more efficient at collecting solar radiation

Question 1547. A technique that uses a planetary atmosphere to slow down an orbiting spacecraft and place it in a circular orbit is calledSelect one:a. orbital insertionb. a gravitational assistc. hydrodynamic decelerationd. aerobraking FeedbackThe correct answer is: aerobraking

Question 1621. Water is present on the Moon in the form ofSelect one:a. vapor in the atmosphere

b. ice in polar craters c. oceans of liquid water on the surfaced. liquid water present just beneath the surfaceFeedbackThe correct answer is: ice in polar craters

Question 1717. In searching for life in the solar system, which basic requirement of life is the most fundamental and the one we always look for?Select one:a. the presence of liquid waterb. the presence of oxygenc. the presence of organic matterd. the presence of an energy source FeedbackThe correct answer is: the presence of liquid water

Question 1824. The planet Venus is often referred to as the Earth's 'sister planet' becauseSelect one:a. its surface is very similarb. it is almost the same size and density c. it looks like the Earth through a telescoped. its atmosphere has the same compositionFeedbackThe correct answer is: it is almost the same size and density

Question 1933. Mars may have been more Earth like in the past becauseSelect one:a. the Sun was dimmer, putting out less solar radiation b. it was not as close to the Sunc. it was rotating more rapidlyd. its atmosphere was thickerFeedbackThe correct answer is: its atmosphere was thicker

Question 203. The necessary elements of life shouldSelect one:a. only be found on the Earth and Marsb. be widespread throughout the universec. be widespread in our Milky Way galaxy but not in other galaxiesd. be widespread in the solar system but not elsewhere in our Milky Way galaxy FeedbackThe correct answer is: be widespread throughout the universe

Question 2127. How does the surface temperature and atmospheric pressure on Venus compare with the Earth?

Select one:a. higher temperatures and pressures b. higher temperatures but lower pressuresc. lower temperatures and pressuresd. lower temperatures but higher pressuresFeedbackThe correct answer is: higher temperatures and pressures

Question 2235. In order for life to survive in the atmospheres of Jupiter and Saturn it would have toSelect one:a. be large and buoyant, allowing it to maintain a stable altitude in the atmosphere b. be at the center, close to the rocky core where a rocky surface existsc. be high in the atmosphere where it could collect solar radiationd. float on the surface of the layer of liquid metallic hydrogenFeedbackThe correct answer is: be large and buoyant, allowing it to maintain a stable altitude in the atmosphere

Question 2331. Although extremely unlikely, if life exists on Venus today, it will most likely be foundSelect one:a. just beneath the surface, where it would be cooler b. on the surface where plenty of heat is present to drive metabolismc. floating high in the atmosphere where droplets of liquid water existd. at the center of the planet where liquid iron existsFeedbackThe correct answer is: floating high in the atmosphere where droplets of liquid water exist

Question 248. Since chemically based life requires biological molecules to come into contact with each other, this will require a planet withSelect one:a. either an atmosphere to mix gases or a liquid medium on or below the surface b. a large moonc. a strong magnetic fieldd. a liquid on its surfaceFeedbackThe correct answer is: either an atmosphere to mix gases or a liquid medium on or below the surface

Question 2537. Some Jovian moons may have liquid waterSelect one:a. at their centersb. on their surfacesc. beneath their surfaces d. in their atmospheresFeedbackThe correct answer is: beneath their surfaces

Question 2629. Most of the carbon dioxide on VenusSelect one:a. has frozen out in the polar regionsb. is still present in the atmospherec. has escaped into spaced. is dissolved in oceans of liquid water, forming carbonate rocks FeedbackThe correct answer is: is still present in the atmosphere

Question 2740. Small bodies like asteroids and comets are unlikely to harbor life because theySelect one:a. have not had liquid water inside them for extended periods now or in the pastb. are constantly colliding with each other, sterilizing any life that may be present c. are so far from the Sun that any water would be permanently frozend. do not contain any organic moleculesFeedbackThe correct answer is: have not had liquid water inside them for extended periods now or in the past

Question 2838. Europa may have a subsurface ocean of liquid water due toSelect one:a. the insulating properties of its icy surface b. tidal heating from Jupiter and the other Galilean moonsc. tidal heating from the Sund. internal heat left over from its formationFeedbackThe correct answer is: tidal heating from Jupiter and the other Galilean moons

Question 2943. Which kind of robotic space mission enables us to study a planet for an extended period of time?Select one:a. flybyb. lander/probe c. sample returnd. orbiterFeedbackThe correct answer is: orbiter

Question 3045. Which kind of robotic space mission enables us to determine the chemical composition of a solar system body in a laboratory?Select one:a. sample return b. lander/probec. flybyd. orbiterFeedback

The correct answer is: sample return

OCA 8Started on Saturday, 8 February 2014, 8:57 PM

State Finished

Completed on Saturday, 8 February 2014, 9:19 PM

Time taken 22 mins 7 secs

Marks 30.00/30.00

Grade 100.00 out of a maximum of 100.00

Question 180. Why must lander probes on Mars be sterilized before launch?Select one:a. to prevent Martian dust from building up on the probe on the surfaceb. to prevent terrestrial microbes hitching a ride on the probe and contaminating the Martian surface c. to prevent Martian microbes from contaminating the lander probed. to prevent terrestrial microbes destroying the electronics in the probe during its passage to MarsFeedbackThe correct answer is: to prevent terrestrial microbes hitching a ride on the probe and contaminating the Martian surface

Question 212. Seasons on MarsSelect one:a. are similar to those on the Earth but twice as long b. are similar to those on the Earth but half as longc. are exactly the same at the Earthd. are more intense than on the Earth but the same lengthFeedbackThe correct answer is: are similar to those on the Earth but twice as longQuestion 331. The most important geological process that has removed craters from the Martian surface in the past isSelect one:a. wind erosionb. volcanism c. plate tectonicsd. water erosion

FeedbackThe correct answer is: volcanism

Question 443. Significant quantities of water last flowed on the surface of Mars during which geological era?Select one:a. Amazonianb. Hadeanc. Hesperian d. NoachianFeedbackThe correct answer is: Hesperian

Question 542. The ancient water erosion features on the surface of Mars suggest that the planet must have had a muchSelect one:a. cooler, thinner atmosphere in the pastb. warmer, thinner atmosphere in the pastc. cooler, thicker atmosphere in the pastd. warmer, thicker atmosphere in the past FeedbackThe correct answer is: warmer, thicker atmosphere in the past

Question 634. In the Tharsis region of Mars we findSelect one:a. heavily cratered highlandsb. smooth rolling plainsc. huge shield volcanoes like Olympus Mons d. a huge impact basinFeedbackThe correct answer is: huge shield volcanoes like Olympus Mons

Question 785. What is the most convincing piece of evidence to suggest that Martian meteorites actually come from Mars?Select one:a. they are red in colorb. they contain trapped gases with a similar composition to the Martian atmospherec. they are igneous rocksd. they show evidence for having been in contact with water FeedbackThe correct answer is: they contain trapped gases with a similar composition to the Martian atmosphere

Question 83. The first astronomer to claim to see linear features on the surface of Mars wasSelect one:a. Giovanni Schiaparelli

b. William Herschelc. Percival Lowelld. Angelo SecchiFeedbackThe correct answer is: Giovanni Schiaparelli

Question 954. The most recent time that water appears to have flowed on Mars, if only briefly, is during theSelect one:a. Noachian Erab. Hesperian Erac. Amazonian Era d. Hadean EraFeedbackThe correct answer is: Amazonian Era

Question 1022. During summer, the northern polar cap of Mars is made ofSelect one:a. water ice overlaying carbon dioxide iceb. a layer of carbon dioxide icec. carbon dioxide ice overlaying water iced. a layer of water ice FeedbackThe correct answer is: a layer of water ice

Question 1168. Compared to the Earth, Mars has experienced wild swings in its axis tilt over relatively short time periods. This is because of itsSelect one:a. greater distance from the Sunb. proximity to Jupiter and its lack of a large moon c. small sized. slower rotation rateFeedbackThe correct answer is: proximity to Jupiter and its lack of a large moon

Question 1232. The most important geological process occurring on Mars today isSelect one:a. wind erosionb. water erosionc. plate tectonicsd. volcanism FeedbackThe correct answer is: wind erosion

Question 1355. The presence of channels carved out on the slopes of large Martian volcanoes is consistent withSelect one:

a. the action of plate tectonicsb. the existence of past underground pockets of water c. recent impactsd. recent wind erosionFeedbackThe correct answer is: the existence of past underground pockets of water

Question 1458. If melted, the ice now known to be on Mars would represent water to cover the entire planet to a depth ofSelect one:a. a few centimetersb. around 11 meters c. less than a millimeterd. several kilometersFeedbackThe correct answer is: around 11 meters

Question 1589. Why is the claim of fossilized life in the Martian meteorite ALH84001 controversial?Select one:a. the rock is too young to have fossilized life within itb. the proposed fossilized organisms in no way resemble any kind of life found on Earth c. there are many possible non-biological explanations for the observed evidenced. it is doubtful that the rock actually came from MarsFeedbackThe correct answer is: there are many possible non-biological explanations for the observed evidence

Question 1628. The Southern hemisphere of Mars is atSelect one:a. a higher than average elevation and is covered with impact craters b. a higher than average elevation and is relatively smoothc. a lower than average elevation and is relatively smoothd. an average elevation and is covered with impact cratersFeedbackThe correct answer is: a higher than average elevation and is covered with impact craters

Question 1737. The lightly cratered terrain surrounding the Tharsis volcanoes represents which geological era?Select one:a. Amazonian b. Hesperianc. Noachiand. CenozoicFeedbackThe correct answer is: Amazonian

Question 1810. Liquid water cannot exist for very long on the surface of Mars today becauseSelect one:a. its surface temperature is too highb. it gets rapidly destroyed by intense solar radiationc. its atmosphere is too thin d. it rapidly reacts with the Martian surface to form peroxidesFeedbackThe correct answer is: its atmosphere is too thin

Question 1986. The Martian meteorite ALH84001 was found in theSelect one:a. Yucatanb. Arizona desertc. Arcticd. Antarctic FeedbackThe correct answer is: Antarctic

Question 2063. Which of the following did NOT contribute to the thinning of the Martian atmosphere during its early history?Select one:a. atmospheric gases being blasted into space by large impactsb. the photodissociation of water molecules by ultraviolet light in the atmospherec. the stripping of the atmosphere by solar wind particles from the Sund. the consumption of carbon dioxide by photosynthetic bacteria FeedbackThe correct answer is: the consumption of carbon dioxide by photosynthetic bacteria

Question 2115. Due to its elliptical orbit, Mars is closer to the Sun on average during summer in the Southern Hemisphere. This means Southern Summer on Mars will beSelect one:a. short and hot b. long and hotc. short and mildd. long and mildFeedbackThe correct answer is: short and hot

Question 2250. The tiny spheres called 'blueberries' discovered by the rover Opportunity are made ofSelect one:a. carbonateb. fruitc. silicated. hematite FeedbackThe correct answer is: hematite

Question 2384. What is the origin of Martian meteorites?Select one:a. they are rocks brought back to Earth by sample return missionsb. they are rocks blasted from the surface of Mars by volcanoes; these rocks then floated around in interplanetary space before falling to Earthc. they are rocks blasted from the surface of Mars by impacts; these rocks then floated around in interplanetary space before falling to Earth d. they are rocks brought to Earth by MartiansFeedbackThe correct answer is: they are rocks blasted from the surface of Mars by impacts; these rocks then floated around in interplanetary space before falling to Earth

Question 2459. The water that formed many of the erosion features seen on Mars appears to have originatedSelect one:a. from volcanic outgassingb. comet impactsc. from beneath the surface of the planet d. from clouds in the atmosphereFeedbackThe correct answer is: from beneath the surface of the planet

Question 2520. The seasonal polar caps on Mars are made ofSelect one:a. methane iceb. water ice c. carbon dioxide iced. a uniform mixture of water and carbon dioxide icesFeedbackThe correct answer is: carbon dioxide ice

Question 2681. Why is the possible contamination of the Earth by Martian microbes in a future sample return mission not considered to be a significant problem?Select one:a. any Martian microbes will be destroyed by high-energy particles and radiation on their trip back to Earth b. Martian microbes are likely to be quite different than terrestrial microbes and, hence, will probably not be able to affect life on Earthc. Martian microbes will be rapidly destroyed by oxygen in the Earth's atmosphered. Martian microbes will certainly be destroyed by terrestrial microbesFeedbackThe correct answer is: Martian microbes are likely to be quite different than terrestrial microbes and, hence, will probably not be able to affect life on Earth

Question 2740. Where is probably the best place to find life on Mars today?

Select one:a. inside craters that used to be filled with waterb. in the residual polar capsc. in geologically active areas like Tharsis where subsurface water may exist d. in the Mariner ValleyFeedbackThe correct answer is: in geologically active areas like Tharsis where subsurface water may exist

Question 2857. The Phoenix spacecraft which landed in the Martian arctic in 2008 foundSelect one:a. water ice just beneath the surface b. water ice several feet beneath the surfacec. water ice on the surfaced. no water ice either on or below the surfaceFeedbackThe correct answer is: water ice just beneath the surface

Question 2919. The residual polar caps on Mars are made ofSelect one:a. a uniform mixture of water and carbon dioxide ices b. water icec. methane iced. carbon dioxide iceFeedbackThe correct answer is: water ice

Question 3078. What are the most likely sources of the methane gas detected in the Martian atmosphere by the Mars Express orbiter?Select one:a. volcanic activity onlyb. biological and/or volcanic activity c. comet impacts onlyd. biological activity onlyFeedbackThe correct answer is: biological and/or volcanic activity

OCA 9Started on Tuesday, 25 February 2014, 11:56 PM

State Finished

Completed on Tuesday, 25 February 2014, 11:58 PM

Time taken 2 mins 12 secs

Grade 30.00 out of a maximum of 30.00 (100%)

Question 145. On Saturn's moon Enceladus, fountains of ice particles and water vapor are seen to be spraying out ofSelect one:a. young impact craters near the north poleb. cryovolcanoes close to the equator c. tiger stripe regions close to the south poled. tectonic plate boundariesFeedbackThe correct answer is: tiger stripe regions close to the south pole

Question 232. Which of the four Galilean moons is least likely to harbor life beneath its surface?Select one:a. Europab. Ioc. Callisto d. GanymedeFeedbackThe correct answer is: Io

Question 320. Perhaps the MOST convincing piece of evidence suggesting that Europa has a subsurface ocean is theSelect one:a. fact that the magnetic field of Jupiter is able to induce a magnetic field in Europa consistent with a salty ocean beneath its crust b. lack of impact craters on its surfacec. fact that calculations suggest that there is enough internal heat to keep the ice melted beneath the crustd. observation of iceberg like features on its surfaceFeedbackThe correct answer is: fact that the magnetic field of Jupiter is able to induce a magnetic field in Europa consistent with a salty ocean beneath its crust

Question 418. The lack of large impact craters on the surface of Europa is consistent withSelect one:a. the crust being so thick and hard that impacts leave no marks on the surfaceb. a subsurface ocean of water because large impacts will break the thin crust causing water and slushy ice below to flood out and resurface the crustc. active volcanism that is constantly resurfacing the crust d. the surface being covered with an ocean of liquid water

FeedbackThe correct answer is: a subsurface ocean of water because large impacts will break the thin crust causing water and slushy ice below to flood out and resurface the crust

Question 535. How is Titan, the moon of Saturn, similar to the Earth?Select one:a. like the Earth, Titan has oceans of liquid water on its surfaceb. like the Earth, Titan has an atmosphere made mostly of molecular nitrogen c. Titan is almost the same size as the Earthd. Titan, like the Earth, has an internal magnetic fieldFeedbackThe correct answer is: like the Earth, Titan has an atmosphere made mostly of molecular nitrogen

Question 649. If Triton has a subsurface ocean, it will most likely consist ofSelect one:a. water mixed with ammonia, methane, or other melted ices b. liquid nitrogenc. liquid waterd. liquid ammonia and methaneFeedbackThe correct answer is: water mixed with ammonia, methane, or other melted ices

Question 76. Jovian moons are typically made ofSelect one:a. rock and ironb. solid rockc. ice and rockd. solid ice FeedbackThe correct answer is: ice and rock

Question 813. Io has an elliptical orbit becauseSelect one:a. of its synchronous rotationb. of orbital resonances with Europa and Ganymede c. of the strong gravitational influence of Jupiterd. of its rapid rotationFeedbackThe correct answer is: of orbital resonances with Europa and Ganymede

Question 925. In the subsurface ocean beneath Europa's icy crust, if life exists, it most likely originatedSelect one:a. via panspermia from impactsb. just below the surface of its thin icy crust where sunlight is still able to penetratec. on the surface and then migrated down into the ocean

d. close to volcanic vents on its ocean floorFeedbackThe correct answer is: close to volcanic vents on its ocean floor

Question 1046. Neptune's moon TritonSelect one:a. orbits about Neptune's rotational axes b. orbits in the opposite direction to Neptune's rotationc. orbits in the same direction to Neptune's rotationd. rotates in the opposite direction to Neptune's rotationFeedbackThe correct answer is: orbits in the opposite direction to Neptune's rotation

Question 1128. Which of the following is the most convincing observation that suggests that like Europa, Ganymede may also have a subsurface ocean?Select one:a. the fact that it is the largest moon in the solar system and, hence, should have plenty of internal heat to maintain liquid water beneath its surface b. the presence of young grooved terrain that may be the result of cryovolcanismc. the detection of salts on the surface that may have been brought up from below the crustd. in addition to its internal magnetic field, Ganymede has a magnetic field induced by Jupiter which is consistent with a salty ocean beneath its crustFeedbackThe correct answer is: in addition to its internal magnetic field, Ganymede has a magnetic field induced by Jupiter which is consistent with a salty ocean beneath its crust

Question 1216. Which feature seen on Saturn's moon Iapetus suggests that its interior must have been warm at some time in the past?Select one:a. the observation of extinct volcanoes on its surfaceb. the presence of a steep ridge running along its equatorc. the presence of several large impact features d. the fact that one half is very bright while the other half is very darkFeedbackThe correct answer is: the presence of a steep ridge running along its equator

Question 1344. Saturn's icy moon EnceladusSelect one:a. has an ancient, heavily cratered surface reminiscent of the Moonb. has a smooth, icy surface criss crossed with dark cracks c. is small and irregular in shape like an asteroidd. has fountains of ice particles and water vapor spraying out from its surfaceFeedbackThe correct answer is: has fountains of ice particles and water vapor spraying out from its surface

Question 14

33. In addition to being the second largest moon in the solar system, Saturn's moon Titan, isSelect one:a. more geologically active than the Earth b. the only moon to show evidence for a subsurface ocean of waterc. the only moon to have its own internal magnetic fieldd. the only moon to have its own atmosphereFeedbackThe correct answer is: the only moon to have its own atmosphere

Question 1541. When the Huygens probe touched down on Titan, it landedSelect one:a. in a shallow pool of liquid methaneb. in a vast ocean of liquid methanec. on the slopes of an icy volcano covered with water and methane iced. on a solid surface of frozen water and methane ices that resembled a streambed FeedbackThe correct answer is: on a solid surface of frozen water and methane ices that resembled a streambed

Question 1639. Titan is roughly the same size as Mercury, yet Titan has an atmosphere while Mercury does not. How can this be?Select one:a. Even though Titan's gravity is weak, it is much colder, allowing molecules to be trapped in its atmosphereb. Although Titan is roughly the same size as Mercury, it is much denser, making its gravitational field stronger c. Unlike Mercury, Titan is constantly being bombarded by icy comets that evaporate and maintain its atmosphered. On its surface, Titan has volcanism that is constantly replenishing its atmosphere while Mercury does notFeedbackThe correct answer is: Even though Titan's gravity is weak, it is much colder, allowing molecules to be trapped in its atmosphere

Question 173. The fact that many of the larger Jovian moons orbit nearly in the equatorial plane of their host world, moving in the same direction as their planet's spin, suggest that theySelect one:a. formed elsewhere in the solar system and were later capturedb. formed from a rotating disk of gas and dust like a miniature solar system c. were spun out from the rapidly spinning host world as it formedd. were formed from a giant impact between the host world and another bodyFeedbackThe correct answer is: formed from a rotating disk of gas and dust like a miniature solar system

Question 18

31. Which Galilean moons of Jupiter show evidence for subsurface oceans of water beneath their icy crusts?Select one:a. Europa, Ganymede, and Callistob. Europac. all four show evidence for subsurface oceansd. Europa and Ganymede FeedbackThe correct answer is: Europa, Ganymede, and Callisto

Question 1927. The complexity of any life present in Europa's subsurface ocean is mainly limited by theSelect one:a. amount of available energy to sustain it b. amount of water in the oceanc. average temperature of the waterd. amount of organic material presentFeedbackThe correct answer is: amount of available energy to sustain it

Question 2047. Triton's retrograde orbit is consistent with it havingSelect one:a. formed from a rotating disk of gas and dust around Neptuneb. undergone a massive impactc. been captured by Neptune's gravity d. been spun out from a rapidly rotating NeptuneFeedbackThe correct answer is: been captured by Neptune's gravity

Question 2143. Even though Titan has liquid methane on its surface, some internal heat, and plenty of carbon containing compounds, it is not a suitable place for life becauseSelect one:a. it is far too cold, and methane is not a very good biological solventb. it has no ozone layer to protect the surface from harmful UV rays from the Sun c. Titan orbits within Saturn's radiation belt so its surface is completely sterilized by high energy particlesd. there is too much volcanic activity on the surfaceFeedbackThe correct answer is: it is far too cold, and methane is not a very good biological solvent

Question 2230. In addition to being the largest moon in the solar system, Ganymede, the Galilean moon of Jupiter, isSelect one:a. the only moon to show evidence for a subsurface ocean of water b. the only moon to have its own atmospherec. more geologically active than the Earthd. the only moon to have its own internal magnetic fieldFeedback

The correct answer is: the only moon to have its own internal magnetic field

Question 2342. Which of the following has the Cassini orbiter observed on the surface of Saturn's moon Titan?Select one:a. small pools of hydrocarbons close to the equatorb. lakes of hydrocarbons in the north polar regionsc. no evidence for any liquid hydrocarbons at all d. oceans of methane and ethane covering much of the surfaceFeedbackThe correct answer is: lakes of hydrocarbons in the north polar regions

Question 2415. Even though Jupiter's moon Io is similar in size to our geologically dead Moon, it is more geologically active than the Earth. How can this be?Select one:a. Io is tidally heated due to its elliptical orbit, which causes the large tidal forces exerted by Jupiter to constantly change, flexing and distorting its interiorb. because Io orbits very close to Jupiter, it still has a lot of heat trapped inside from its formationc. Io has much more radioactive decay occurring inside it than does the Earth d. Io is tidally heated by tidal forces exerted by the outer Galilean moons, which flex and distort its interiorFeedbackThe correct answer is: Io is tidally heated due to its elliptical orbit, which causes the large tidal forces exerted by Jupiter to constantly change, flexing and distorting its interiorQuestion 251. The first Jovian moons were discovered bySelect one:a. Galileob. Cassini c. Tychod. HuygensFeedbackThe correct answer is: Galileo

Question 268. Compared to the moons of Jupiter, the moons of Saturn, Uranus, and NeptuneSelect one:a. are made of pure rockb. contain less methane ice and more water icec. are made of pure methane ice d. contain not only water ice but also methane and other icesFeedbackThe correct answer is: contain not only water ice but also methane and other ices

Question 272. The largest Jovian moon Ganymede and Titan areSelect one:a. larger than Mercury but smaller than the Earth

b. larger than the Earth c. about the same size as Marsd. larger than the Moon but smaller than MercuryFeedbackThe correct answer is: larger than Mercury but smaller than the Earth

Question 2819. Much of Europa's surface appears chaotic and clogged with huge iceberg like blocks. This is consistent withSelect one:a. a thin icy crust that has been broken into pieces by tidal forces below which is a subsurface ocean of waterb. the breaking up of the surface due to plate tectonicsc. a giant impact that has recently shattered the crust into piecesd. the surface thawing due to heat emitted by Jupiter FeedbackThe correct answer is: a thin icy crust that has been broken into pieces by tidal forces below which is a subsurface ocean of water

Question 2937. What is the origin of the nitrogen in Titan's atmosphere?Select one:a. gas captured from the solar nebulab. impacts from comets c. breakdown of ammonia (NH3) by ultraviolet light from the Sund. outgassing from Titan's interiorFeedbackThe correct answer is: breakdown of ammonia (NH3) by ultraviolet light from the Sun

Question 3017. Which of the following best describes the internal structure of Europa?Select one:a. thin icy crust, subsurface ocean of water, thick iron mantle, central rocky coreb. thin icy crust, subsurface ocean of water, thick rocky mantle, central iron corec. surface ocean of water, thick rocky mantle, central iron core d. thin icy crust, thick rocky mantle, central iron coreFeedbackThe correct answer is: thin icy crust, subsurface ocean of water, thick rocky mantle, central iron core

OCA 10Started on Saturday, 8 March 2014, 7:30 PM

State Finished

Completed on Saturday, 8 March 2014, 8:10 PM

Time taken 39 mins 53 secs

Grade 20.00 out of a maximum of 30.00 (67%)

Question 133. Overall, the likelihood of finding planets in a star's habitable zone depends on theSelect one:a. width of the zone b. distance from the outer edge of the zone to the nearest other starc. distance from the star to the outer edge of the zoned. distance from the star to the inner edge of the zoneFeedbackThe correct answer is: width of the zone

Question 247. Over the last century, global temperatures have risen by aboutSelect one:a. 0.1 oCb. 0.8 oC c. 2.0 oCd. 3.2 oCFeedbackThe correct answer is: 0.8 oC

Question 314. Unlike the Earth, Venus does not have a protective magnetic field becauseSelect one:a. of its proximity to the Sunb. it lacks a partially molten iron core c. of its slow rotationd. there is less magnetized iron on its surfaceFeedbackThe correct answer is: of its slow rotation

Question 441. When the Sun runs out of nuclear fuel and expands to become a red giant,Select one:a. the Earth will be ejected from the solar systemb. the Earth will experience a runaway greenhouse effect followed by the total loss of its atmospherec. the Earth will be destroyedd. the Earth's oceans will freeze solid FeedbackThe correct answer is: the Earth will experience a runaway greenhouse effect followed by the total loss of its atmosphere

Question 51. What is the definition of a star's habitable zone?Select one:a. the range of distances from the star where rocky planets can formb. the range of distances from the star where planets with life have been detectedc. the range of distances from the star where organic molecules can be stable on the surface of a suitable planetd. the range of distances from the star where liquid water can be stable on the surface of a suitable planet FeedbackThe correct answer is: the range of distances from the star where liquid water can be stable on the surface of a suitable planet

Question 621. A star more luminous than our Sun will have a habitable zone that isSelect one:a. narrower and closer to the star than the habitable zone of the Sunb. narrower and farther from the star than the habitable zone of the Sunc. wider and farther from the star than the habitable zone of the Sun d. wider and closer to the star than the habitable zone of the SunFeedbackThe correct answer is: wider and farther from the star than the habitable zone of the Sun

Question 735. When the Sun was younger, how did its habitable zone compare with its habitable zone today?Select one:a. wider and farther from the Sunb. narrower and closer to the Sun c. narrower and farther from the Sund. wider and closer to the SunFeedbackThe correct answer is: narrower and closer to the Sun

Question 810. Most of the carbon dioxide on the EarthSelect one:a. is locked up in carbonate rocks in its crust or is dissolved in the oceans b. has escaped into spacec. is trapped beneath the surface of the planet in gaseous formd. is located in its atmosphereFeedbackThe correct answer is: is locked up in carbonate rocks in its crust or is dissolved in the oceans

Question 923. Stars much more luminous than the Sun haveSelect one:a. narrower habitable zones, decreasing the odds of finding habitable planets but much longer lifetimes allowing life to appear and evolve b. narrower habitable zones, decreasing the odds of finding habitable planets and lifetimes too short for life to appear

c. wider habitable zones, increasing the odds of finding habitable planets and much longer lifetimes allowing life to appear and evolved. wider habitable zones, increasing the odds of finding habitable planets but lifetimes too short for life to appearFeedbackThe correct answer is: wider habitable zones, increasing the odds of finding habitable planets but lifetimes too short for life to appear

Question 1019. Around 4 billion years ago Venus could have been more Earth like with liquid water on its surface becauseSelect one:a. Venus was farther from the Sunb. the Sun was dimmer so Venus would have received less radiation c. its atmosphere was thinnerd. Venus has a protective magnetic fieldFeedbackThe correct answer is: the Sun was dimmer so Venus would have received less radiation

Question 1158. During the last century, sea levels have risen bySelect one:a. less than 1 millimeterb. about 1 meterc. about 2 millimetersd. about 20 centimeters FeedbackThe correct answer is: about 20 centimeters

Question 126. Apart from its distance from its parent star, what is the next most important factor that determines a planet's habitability?Select one:a. the chemical composition of its atmosphereb. whether it has a large moonc. the size of the planetd. the chemical composition of its surface FeedbackThe correct answer is: the size of the planet

Question 1327. Which of the following factors influence the surface habitability of a planet?Select one:a. planetary sizeb. all of these c. distance from parent stard. presence of an atmopshereFeedbackThe correct answer is: all of these

Question 14

20. If life is present on Venus today, it will most likely beSelect one:a. inside large rocks that are protected from the heatb. found in the atmosphere where droplets of water can be found c. endoliths living beneath the crust where liquid water may still be presentd. hyperthermaphiles found on the surfaceFeedbackThe correct answer is: found in the atmosphere where droplets of water can be found

Question 1555. As global warming continues, weather patterns will change causingSelect one:a. only the landmasses to become warmer while the oceans will become colderb. all parts of the Earth's surface will become warmerc. only the oceans to become warmer while the landmasses will become colderd. some parts of the Earth's landmass to become warmer while other parts will actually get colder. The ocean temperatures will continue to rise FeedbackThe correct answer is: some parts of the Earth's landmass to become warmer while other parts will actually get colder. The ocean temperatures will continue to rise

Question 162. Over time the Sun's habitable zone hasSelect one:a. widened and moved away from the Sun b. narrowed and moved closer to the Sunc. narrowed and moved away from the Sund. widened and moved closer to the SunFeedbackThe correct answer is: widened and moved away from the Sun

Question 173. Europa is located outside the Sun's habitable zone and yet may be habitable. How can this be?Select one:a. Europa's subsurface ocean contains lots of minerals that allow water to remain liquid at much lower temperaturesb. Europa is continually being hit by comets and asteroids which keeps water beneath its surface liquidc. Europa is tidally heated, allowing liquid water to exist beneath its icy surface d. Europa is large enough to have appreciable heat trapped inside it to keep water beneath the surface liquidFeedbackThe correct answer is: Europa is tidally heated, allowing liquid water to exist beneath its icy surface

Question 187. The possible habitability of Mars today is mostly determined bySelect one:a. the thickness of its atmosphere b. the composition of its atmosphere

c. geological conditions existing beneath its surfaced. the amount of heat it receives from the SunFeedbackThe correct answer is: geological conditions existing beneath its surface

Question 1937. Why does the Sun brighten with time?Select one:a. as time progresses, more and more heat is trapped inside the core, leading to an increase in brightnessb. as hydrogen is converted into helium in the core, the number of hydrogen nuclei decreases, decreasing the fusion rate. To maintain the balance with gravity pressing inward, the core compensates by shrinking and heating up c. as hydrogen is converted into helium in the core, the number of hydrogen nuclei decreases, decreasing the fusion rate. To maintain the balance with gravity pressing inward, the core compensates by expanding and coolingd. as time progresses, helium starts to fuse in the core, in addition to hydrogen, leading to an increase in brightnessFeedbackThe correct answer is: as hydrogen is converted into helium in the core, the number of hydrogen nuclei decreases, decreasing the fusion rate. To maintain the balance with gravity pressing inward, the core compensates by shrinking and heating up

Question 2017. If the Earth were to be moved to where Venus is today,Select one:a. carbon dioxide would be released from the oceans leading to higher temperatures but liquid water could still exist on the surfaceb. the oceans would evaporate slightly producing a slightly warmer, more humid planetc. the oceans would evaporate, blocking light from the Sun and causing global temperatures to falld. the oceans would evaporate and carbonate rocks would decompose producing a runaway greenhouse effect much more severe than the one that exists on Venus today FeedbackThe correct answer is: the oceans would evaporate and carbonate rocks would decompose producing a runaway greenhouse effect much more severe than the one that exists on Venus today

Question 2128. The moist greenhouse effect refers toSelect one:a. the point at which water is evaporating from the surface at a faster rate than it is condensing b. the natural greenhouse effect due to clouds of water vapor in the lower atmospherec. an enhanced greenhouse effect above tropical regions of the Earth's surfaced. the warming process by which water vapor rises into the upper atmosphere above the ozone layer where it is then broken apart by ultraviolet radiationFeedbackThe correct answer is: the warming process by which water vapor rises into the upper atmosphere above the ozone layer where it is then broken apart by ultraviolet radiation

Question 22

38. The range of distances that has remained habitable for the entire duration of the Sun's lifetime is referred to as theSelect one:a. habitable zone of consistencyb. continuously habitable zone c. zone of water stabilityd. permanently habitable zoneFeedbackThe correct answer is: continuously habitable zone

Question 234. The Moon is in the habitable zone of the Sun at the same distance as the Earth but is not habitable. How can this be?Select one:a. the Moon has never had water on its surface at any timeb. the Moon did have water on its surface in the past, but it was destroyed by high energy particles from the Sunc. the Moon did have water on its surface in the past, but it was blasted off the surface by impactsd. the Moon is too small to retain an atmosphere necessary for liquid water to be stable FeedbackThe correct answer is: the Moon is too small to retain an atmosphere necessary for liquid water to be stable

Question 2418. Venus is locatedSelect one:a. within the Sun's habitable zone b. just inside the outer border of the Sun's habitable zonec. outside the Sun's habitable zoned. outside the outer border of the Sun's habitable zoneFeedbackThe correct answer is: outside the Sun's habitable zone

Question 2552. The atmospheric carbon dioxide concentrationSelect one:a. is lower than it has been at any time during the last million yearsb. is higher than it has been at any time during the Earth's historyc. is higher than it has been at any time during the last million years d. has remained roughly constant during the last million yearsFeedbackThe correct answer is: is higher than it has been at any time during the last million years

Question 2646. The term 'global warming' refers to an increase in the average temperatureSelect one:a. at the equatorb. at the polesc. of the planet as a wholed. of the ozone layer

FeedbackThe correct answer is: of the planet as a whole

Question 2731. If we allow for a planet with a thick atmosphere and a strong greenhouse effect, the outer boundary of the Sun's habitable zone would beSelect one:a. at exactly the current orbital distance of Marsb. roughly halfway between the orbits of the Earth and Mars c. just inside the orbit of Marsd. well beyond the orbital distance of MarsFeedbackThe correct answer is: well beyond the orbital distance of Mars

Question 2853. If we do nothing to slow our emissions of carbon dioxide and other greenhouse gases, by the end of the century the global average temperatures are predicted to increase bySelect one:a. 5 to 10 oC b. less than 1 oCc. 3 to 5 oCd. 1 to 2 oCFeedbackThe correct answer is: 3 to 5 oC

Question 2915. Most of the water that used to be present in the Venusian atmosphereSelect one:a. escaped into spaceb. was destroyed in the atmosphere by ultraviolet light from the Sun c. became chemically incorporated into rocks in the crustd. was blasted into space by impactsFeedbackThe correct answer is: was destroyed in the atmosphere by ultraviolet light from the Sun

Question 3040. According to optimistic estimates, the end of habitability of Earth will come aboutSelect one:a. 3 to 4 billion years from now b. a billion years from nowc. 100 million years from nowd. a few hundred thousand years from nowFeedbackThe correct answer is: 3 to 4 billion years from now

OCA 11

Started on Monday, 17 March 2014, 4:52 PM

State Finished

Completed on Monday, 17 March 2014, 5:35 PM

Time taken 43 mins 15 secs

Grade 30.00 out of a maximum of 30.00 (100%)

Question 128. Even though K- and M-type stars are suitable for life, why might they not have many habitable planets around them?Select one:a. because their habitable zones are very wideb. because their habitable zones are very narrow c. because their lifetimes are too shortd. because they contain too few heavy elements to form planetsFeedbackThe correct answer is: because their habitable zones are very narrow

Question 251. The wavelengths of radiation from a star that is moving perpendicular to usSelect one:a. are longer than if the star were not moving b. are shorter than if the star were not movingc. are the same as if the star were not movingd. can be longer or shorter depending on the distance to the starFeedbackThe correct answer is: are the same as if the star were not moving

Question 383. How can we explain the presence of extrasolar planetary systems with Jovian-sized planets at distances at which we normally find terrestrial planets?Select one:a. they are brown dwarfs that were captured by their parent starsb. they are Jovian planets that were spun out from their rapidly spinning parent starsc. the Jovian planets formed farther out and then migrated inward d. these are massive terrestrial planets that formed close to their parent starsFeedbackThe correct answer is: the Jovian planets formed farther out and then migrated inward

Question 473. Why is it better to search for extrasolar planets directly using infrared (IR) rather than visible radiation?Select one:a. the visible light from planets will be blocked by interstellar dust along our line of sight while the IR radiation will not b. the planet doesn't reflect any visible radiation, only IR radiationc. the planet emits more IR radiation than it reflects in the visibled. the star doesn't emit any IR radiation because it is too hotFeedbackThe correct answer is: the planet emits more IR radiation than it reflects in the visible

Question 585. How might the inward migration of a Jovian-like planet in an extrasolar planetary system alter the probability of life appearing on inner terrestrial planets?Select one:a. it would make no difference at allb. it might improve chances slightly because some of the terrestrial planets may become moons of the Jovian planetc. it might improve chances because it would protect inner, terrestrial-like planets from impactsd. it might greatly decrease the chance because the orbits of the inner, terrestrial-like planets would be disrupted FeedbackThe correct answer is: it might greatly decrease the chance because the orbits of the inner, terrestrial-like planets would be disrupted

Question 667. The decrease in brightness observed when a transiting exoplanet passes in front of its parent star is a measure of the exoplanet'sSelect one:a. chemical compositionb. size c. temperatured. massFeedbackThe correct answer is: size

Question 715. The most fundamental property of star is itsSelect one:a. mass b. surface temperaturec. sized. chemical compositionFeedbackThe correct answer is: mass

Question 88. The luminosity of a star isSelect one:a. only determined by its distanceb. determined by its apparent brightness and surface temperature c. only determined by its surface temperatured. determined by its apparent brightness and distanceFeedbackThe correct answer is: determined by its apparent brightness and distance

Question 997. At the top of the Hertzprung-Russell diagram we findSelect one:a. red giant stars b. main sequence stars

c. white dwarfsd. supergiant starsFeedbackThe correct answer is: supergiant stars

Question 1046. In an extrasolar planetary system containing a single planet, the parent star is measured to move about its center of mass every 24 years. Given this, what is the orbital period of the planet?Select one:a. 24 years b. 12 yearsc. 48 yearsd. this cannot be determined from this observationFeedbackThe correct answer is: 24 years

Question 1199. Red giantsSelect one:a. have exhausted their nuclear fuel and are in the process of dyingb. are mature stars that are fusing hydrogen into helium in their cores c. are in the process of formingd. are dead starsFeedbackThe correct answer is: have exhausted their nuclear fuel and are in the process of dying

Question 1252. The radial velocity curve of a star with an extrasolar planet is a plot of radial velocity againstSelect one:a. distanceb. brightnessc. luminosityd. time FeedbackThe correct answer is: time

Question 1365. When an exoplanet passes behind its parent star, we call thisSelect one:a. a shadow eventb. a transit c. an occultationd. an eclipseFeedbackThe correct answer is: an eclipse

Question 1460. Which of the following extrasolar planets would be the most difficult to detect using the Doppler shift method?

Select one:a. a low mass planet close to its parent starb. a massive planet far from its parent star c. a low mass planet far from its parent stard. a massive planet close to its parent starFeedbackThe correct answer is: a low mass planet far from its parent star

Question 1545. Which of the following methods has been the LEAST successful in detecting extrasolar planets around other star systems?Select one:a. detection of Doppler shifts in the spectra of the parent stars b. detection of reflected starlightc. regular changes in the positions of the parent stars with respect to more distant stars as they move across the skyd. detection of brightness changes in a star as a planet passes in front of itFeedbackThe correct answer is: detection of reflected starlight

Question 1687. What is the simplest way we might detect life on an extrasolar planet?Select one:a. analyze the spectrum of reflected light from the planet b. send an interstellar probe to the planetary systemc. wait for aliens from the planet to visit usd. listen for radio signals coming from an advanced civilization on the planetFeedbackThe correct answer is: analyze the spectrum of reflected light from the planet

Question 1734. Brown dwarfs occupy the range of masses betweenSelect one:a. white dwarfs and neutron starsb. giants and supergiantsc. terrestrial and Jovian planetsd. large planets and small stars FeedbackThe correct answer is: large planets and small stars

Question 185. When a star much more massive than our Sun dies it willSelect one:a. explode as a supernova forming a supernova remnant, leaving behind a dead star called a neutron starb. eject its outer layers into space forming a planetary nebula, leaving behind a dead star called a white dwarfc. eject its outer layers into space forming a planetary nebula, leaving behind a dead star called a neutron stard. explode as a supernova forming a supernova remnant, leaving behind a dead star called a white dwarf

FeedbackThe correct answer is: explode as a supernova forming a supernova remnant, leaving behind a dead star called a neutron star

Question 1919. What is the most common class of star in our galaxy?Select one:a. G-typeb. A-typec. M-type d. O-typeFeedbackThe correct answer is: M-type

Question 2054. If a star has an extrasolar planet, the wavelength of its radial velocity curve is related to the planet'sSelect one:a. massb. orbital period c. orbital shaped. radiusFeedbackThe correct answer is: orbital period

Question 2193. The Hertzprung-Russell diagram is a plot ofSelect one:a. apparent brightness against timeb. luminosity against distancec. radial velocity against distanced. luminosity against surface temperature FeedbackThe correct answer is: luminosity against surface temperature

Question 2257. Why does the Doppler shift method of detecting extrasolar planets only give us the minimum mass of a planet?Select one:a. because we don't necessarily know the diameter (size) of the planetb. because we don't necessarily know the mass of the parent star veryc. because we don't necessarily know the density of the planetd. because we don't necessarily know the angle the planet's orbit makes with our line of sight FeedbackThe correct answer is: because we don't necessarily know the angle the planet's orbit makes with our line of sight

Question 2348. Stars only exhibit a Doppler shift if they are movingSelect one:a. toward or away from us along the line of sight

b. away from us along the line of sightc. in a circular motion about usd. perpendicular to our line of sightFeedbackThe correct answer is: toward or away from us along the line of sight

Question 2437. Overall, multiple star systems in our galaxySelect one:a. are very common, making up about 60% of the total b. are fairly common, making up around 30% of the totalc. do not existd. are extremely rare, making up less than 1% of the totalFeedbackThe correct answer is: are fairly common, making up around 30% of the total

Question 2569. For the transit of an extrasolar planet to be observed, theSelect one:a. planet has to be very largeb. parent star has to be very small c. orbital plane has to be perpendicular to our line of sightd. orbital plane of the planet has to be aligned along our line of sightFeedbackThe correct answer is: orbital plane of the planet has to be aligned along our line of sight

Question 2663. Which of the following methods describes the transit method for detecting extrasolar planets?Select one:a. detection of brightness changes in a star as a planet passes in front of itb. regular changes in the positions of the parent stars with respect to more distant stars as they move across the skyc. detection of Doppler shifts in the spectra of the parent stars d. detection of reflected starlightFeedbackThe correct answer is: detection of brightness changes in a star as a planet passes in front of it

Question 2729. Even though M-stars have very narrow habitable zones, they may still host a large number of inhabited worlds because they are soSelect one:a. coolb. common c. smalld. long livedFeedbackThe correct answer is: common

Question 2830. Which of the following types of stars are NOT suitable for advanced life?Select one:a. M-typeb. G-typec. F-type d. K-typeFeedbackThe correct answer is: F-type

Question 2989. What parameters determine the position of a galaxy's Galactic Habitable Zone?Select one:a. both the amount of heavy elements AND the amount of radiation from the centerb. only the amount of heavy elements in the disk c. only the temperature in the galactic diskd. only the amount of harmful radiation from the centerFeedbackThe correct answer is: both the amount of heavy elements AND the amount of radiation from the center

Question 3042. The center of mass of the solar system isSelect one:a. close to center but not exactly at the center of the Sun b. just outside the orbit of Mercuryc. midway between the Sun and Jupiterd. exactly at the center of the SunFeedbackThe correct answer is: close to center but not exactly at the center of the Sun

OCA 12Started on Thursday, 27 March 2014, 5:06 PM

State Finished

Completed on Thursday, 27 March 2014, 5:45 PM

Time taken 38 mins 36 secs

Grade 30.00 out of a maximum of 30.00 (100%)

Question 139. The 1420 MHz (21 cm) radio line generated by neutral hydrogen atoms is a good choice for interstellar communications because

Select one:a. it is the only radio frequency that is not blocked by interstellar matterb. it is the easiest radio frequency to generatec. all intelligent civilizations should be aware of its universal significance and would probably also think of sending and receiving signals at this frequency d. it is the only frequency to which radio telescopes can be tunedFeedbackThe correct answer is: all intelligent civilizations should be aware of its universal significance and would probably also think of sending and receiving signals at this frequency

Question 252. The search for radio signals from intelligent civilizations on planets around nearby solar-type stars is an example of aSelect one:a. targeted searchb. sky surveyc. random sweepd. intentional search FeedbackThe correct answer is: targeted search

Question 31. How is intelligence defined in the Drake Equation?Select one:a. a civilization that has developed languageb. a civilization capable of spaceflightc. a civilization willing and able to communicate over interstellar distances d. a civilization that communicates using telepathyFeedbackThe correct answer is: a civilization willing and able to communicate over interstellar distances

Question 4

75. The object recovered from a pasture close to Roswell, New Mexico, in 1947 is now believed to have been aSelect one:a. secret military balloon designed to detect Soviet nuclear testsb. small passenger aircraftc. flying saucer with alien occupantsd. weather balloon FeedbackThe correct answer is: secret military balloon designed to detect Soviet nuclear tests

Question 558. Sending signals at optical wavelengths might be a viable alternative to radio wavelengthsSelect one:a. only between civilizations around solar-type stars whose eyes have evolved to see such radiationb. over relatively short distances where absorption by interstellar matter would not be a problem c. over all distances as long as the intensity of the signal is strong enoughd. as long as the light transmitted is a different color than the light given off by the parent star

FeedbackThe correct answer is: over relatively short distances where absorption by interstellar matter would not be a problem

Question 667. The Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence states that the first thing to do after the detection of a possible signal is toSelect one:a. classify it top secretb. announce the discovery to the publicc. confirm that it is genuined. send a reply FeedbackThe correct answer is: confirm that it is genuine

Question 728. Encephalization Quotient (EQ) values can be estimated for extinct species becauseSelect one:a. we can always find similar species in existence today to make measurements ofb. by studying their fossilized remains we can estimate their body masses from the size of the remains and their brain masses from the sizes of their cranial cavities c. there is a linear relationship between the EQ and time, thus allowing extrapolationd. extinct species always have the same EQ valueFeedbackThe correct answer is: by studying their fossilized remains we can estimate their body masses from the size of the remains and their brain masses from the sizes of their cranial cavities

Question 825. The organisms with the highest Encephalization Quotient (EQ) ratios areSelect one:a. humansb. whalesc. chimpsd. dolphins FeedbackThe correct answer is: humans

Question 99. What do we know for certain about the various factors in the Drake equations?Select one:a. that none of them can be equal to 1b. that at least one of them must be equal to 0c. that at least one of them must be equal to 1 d. that none of them can be equal to 0FeedbackThe correct answer is: that none of them can be equal to 0

Question 1038. Which of the following signals from an advanced civilization would be easiest to detect?

Select one:a. small amplitude, narrow bandwidthb. small amplitude, wide bandwidthc. large amplitude, narrow bandwidth d. large amplitude, wide bandwidthFeedbackThe correct answer is: large amplitude, narrow bandwidth

Question 1133. Why are radio waves probably the most efficient way to communicate between civilizations?Select one:a. radio waves are the only kind of electromagnetic radiation that can carry informationb. radio waves are easy to produce and are not affected much by interstellar matter in the galaxy c. all advanced civilizations are certain to use radio waves for communicationd. radio waves are the most penetrating of all electromagnetic radiationsFeedbackThe correct answer is: radio waves are easy to produce and are not affected much by interstellar matter in the galaxy

Question 1263. One of the most likely places an advanced civilization might leave an artifact for us to find would beSelect one:a. in the Cydonia region of Mars b. the L4 and L5 points in thec. on the far side of the Moond. in the desert of Roswell, New MexicoFeedbackThe correct answer is: the L4 and L5 points in the

Question 1320. Intelligence may be subject to convergent evolution because itSelect one:a. is required for survivalb. is inevitablec. is a fundamental characteristic of lifed. has survival value FeedbackThe correct answer is: has survival value

Question 1465. What type of civilization would be able to construct a 'Dyson Sphere' around its parent star to capture its radiation?Select one:a. Type IVb. Type Ic. Type II d. Type IIIFeedbackThe correct answer is: Type II

Question 1544. Which of the following kinds of signal do we currently have the best chance of detecting with currently technology?Select one:a. an intentional signal beaconb. a signal used for communication between a civilization's home world and another planet in its own planetary systemc. a signal used for local communication in the world where the intelligent beings existd. a signal used for communication between a civilization's home world and another star system FeedbackThe correct answer is: an intentional signal beaconQuestion 1670. A UFO isSelect one:a. an unidentified object seen in the sky b. a natural phenomenonc. a hoaxd. an alien spaceshipFeedbackThe correct answer is: an unidentified object seen in the skyQuestion 17

Correct3. In principle, the Drake equation should enable us to calculate the exact number of intelligent civilizations capable of interstellar communication in our galaxy right now. However, currently this is not feasible becauseSelect one:a. we have a precise values for the first factor, but not for any of the other factorsb. we do not have precise values for any of the factors in the equation c. it is impossible for us to ever know the precise values of any of the factorsd. we have precise values for the first three factors, but not the last factorFeedbackThe correct answer is: we do not have precise values for any of the factors in the equation

Question 188. What is the minimum value of N in the Drake Equation?Select one:a. 0b. 1000c. 100d. 1 FeedbackThe correct answer is: 1

Question 1976. Scientists are generally are not involved in research dealing with the possibility of alien visits to Earth becauseSelect one:a. there is a lack of evidence to suggest there is anything to study

b. they are simply not interested in the subjectc. it is already well known that aliens are visiting the Earthd. they have been told not to study this subject by military intelligenceFeedbackThe correct answer is: there is a lack of evidence to suggest there is anything to study

Question 2010. Given that life on Earth appears to have arisen quite easily and rapidly suggests that the factor flife, in the Drake equation could be close toSelect one:a. 0.25 b. 1c. 0d. 0.5FeedbackThe correct answer is: 1

Question 2160. An optical SETI signal would most likely consist ofSelect one:a. rapid, short bursts of intense laser light b. using mirrors to reflect light from the surface of a planetc. using a giant disk to block out the light from the parent stard. a continuous beam of laser lightFeedbackThe correct answer is: rapid, short bursts of intense laser light

Question 2242. If we were to intercept a signal from a civilization that was sent to another of its colonies on the other side of the galaxy, this would be an example ofSelect one:a. an intentional signal beaconb. a signal used for local communication the world where the intelligent beings existc. a signal used for communication between a civilization's home world and another planet in its own planetary systemd. a signal used for communication between a civilization's home world and another star system FeedbackThe correct answer is: a signal used for communication between a civilization's home world and another star system

Question 2337. Which type of signal could carry the largest amount of information?Select one:a. low intensity b. high intensityc. small bandwidthd. large bandwidthFeedbackThe correct answer is: large bandwidth

Question 2461. A Lagrange point in the Earth-Moon system is a positionSelect one:a. in space where the effects of the Earth's and Moon's gravity cancel each other outb. directly between the Earth and Moonc. on the surface of the Moon that points directly away from the Earthd. on the Earth's surface that the Moon's gravity is concentrated FeedbackThe correct answer is: in space where the effects of the Earth's and Moon's gravity cancel each other out

Question 2556. The major advantage the Allen Telescope Array (which will eventually consist of 350 small radio dishes) has over a conventional single-dish radio telescope is that itSelect one:a. is simpler to operate than a single-dishb. can collect more radiation than a single-dish of comparable size c. is less expensive to build than a single-dishd. can monitor several targets simultaneouslyFeedbackThe correct answer is: can monitor several targets simultaneously

Question 2612. The rare-Earth hypothesis would predict that the factor flife, in the Drake equation should beSelect one:a. exactly 1b. close to 0c. exactly 0d. close to 1 FeedbackThe correct answer is: close to 0

Question 2732. Which type of electromagnetic radiation is able to carry the most information?Select one:a. all types have equal abilityb. radio wavesc. gamma rays d. microwavesFeedbackThe correct answer is: all types have equal ability

Question 2822. An organism with an Encephalization Quotient (EQ) of 1 is expected to be ofSelect one:a. below-average intelligenceb. the lowest possible intelligencec. average intelligence d. above-average intelligenceFeedbackThe correct answer is: average intelligence

Question 2918. The adoption of very similar streamlined body shapes by both sharks and dolphins provides evidence forSelect one:a. life originating in the oceansb. genetic mutationsc. cross-breedingd. convergent evolution FeedbackThe correct answer is: convergent evolution

Question 3027. A dinosaur like a Brontosaurus with a small head and a large body would be expected to have an Encephalization Quotient (EQ) ofSelect one:a. less than 1 but greater than zero b. greater than 1c. exactly 1d. zeroFeedbackThe correct answer is: less than 1 but greater than zero

OCA 13Started on Thursday, 10 April 2014, 5:28 PM

State Finished

Completed on Thursday, 10 April 2014, 6:09 PM

Time taken 40 mins 22 secs

Grade 20.00 out of a maximum of 30.00 (67%)

Question 132. The observed slowing down of time predicted by Einstein's Special Theory of Relativity for an object traveling close to the speed of light is referred to asSelect one:a. time contractionb. a time warpc. time dilation d. time expansionFeedbackThe correct answer is: time dilation

Question 239. An antihydrogen atom would consist ofSelect one:a. a proton and a positronb. a proton and an antielectronc. an antiproton and an antielectrond. an antiproton and a positron FeedbackThe correct answer is: an antiproton and a positron

Question 315. In order to get large payloads into space using chemical rockets,Select one:a. rockets must be launched from the tops of tall mountainsb. very lightweight rocketsc. extremely large single-staged rockets must be used d. multiple rocket stages are necessaryFeedbackThe correct answer is: multiple rocket stages are necessary

Question 428. In order for a solar sail spacecraft to be accelerated to speeds high enough to accomplish interstellar travel in a reasonable amount of time, it would need to be startedSelect one:a. from a lunar orbit where the gravity is weakerb. close to Earth using mirrors on the surface to reflect sunlight onto the sailsc. close to the Sun where the radiation pressure is higher d. far from the Sun so Jupiter could be used to help it on its way using a gravitational assistFeedbackThe correct answer is: close to the Sun where the radiation pressure is higher

Question 562. The theory of relativity predicts that everything in the universeSelect one:a. is relative except the laws of physics, which are absolutesb. is relative except the laws of physics and the speed of light, which are absolutesc. is relative except the speed of light, which is an absolute d. is relative, there are no absolutesFeedbackThe correct answer is: is relative except the laws of physics and the speed of light, which are absolutes

Question 634. The Luyten 726-8 binary system is approximately 9 light-years away. If we send a spacecraft to visit this system traveling at 90% of the speed of light, about how long will a one-way trip take as measured from the Earth?Select one:a. less than 10 yearsb. it's impossible to tell unless we know the spacecraft's method of propulsionc. more than 10 years

d. 10 years FeedbackThe correct answer is: 10 years

Question 759. Which of the following is not a solution to the Fermi Paradox?Select one:a. no one is interested or able to communicate b. no one is out therec. we are not interested in communicatingd. we are unable to detect their communicationsFeedbackThe correct answer is: we are not interested in communicating

Question 85. According to Einstein's Special Theory of Relativity, it is not possible to travelSelect one:a. faster than 90 % of the speed of lightb. at or faster than the speed of light c. faster than 75 % of the speed of lightd. slower than 1 % of the speed of lightFeedbackThe correct answer is: at or faster than the speed of light

Question 925. The maximum terminal velocity we could accelerate a nuclear rocket to is approximatelySelect one:a. 0.1 % of the speed of light b. 10 % of the speed of lightc. 50 % of the speed of lightd. 0.001 % of the speed of lightFeedbackThe correct answer is: 10 % of the speed of light

Question 1045. Which kind of spacecraft collects its fuel during its passage?Select one:a. interstellar arkb. solar sailc. matter-antimatter rocketd. interstellar ramjet FeedbackThe correct answer is: interstellar ramjet

Question 1112. The Earth's escape velocity is defined to be theSelect one:a. minimum orbital speed for the Moon to escape from the Earth's gravityb. velocity that objects are pulled toward the Earth's surface by gravityc. minimum velocity required for an object to escape the Earth's gravity d. minimum orbital speed for the Earth to escape from the Sun's gravity

FeedbackThe correct answer is: minimum velocity required for an object to escape the Earth's gravity

Question 128. Chemical rockets work on which basic physical principle?Select one:a. the law of conservation of energyb. Einstein's special theory of relativityc. Kepler's first law of planetary motiond. Newton's third law of motion FeedbackThe correct answer is: Newton's third law of motion

Question 1364. You are traveling in a space ship at half the speed of light (0.5c) directly toward an oncoming photon traveling at the speed of light (c). At what speed would you see the photon coming toward you?Select one:a. 0.5cb. 0.25cc. 1.5cd. c FeedbackThe correct answer is: c

Question 1436. Particles of matter and antimatter have theSelect one:a. same charge and massb. same mass but opposite charge c. different charge and massd. same charge but different massFeedbackThe correct answer is: same mass but opposite charge

Question 1557. Based on human history, the likelihood that we will eventually colonize other habitable planets in our galaxy isSelect one:a. highb. zeroc. impossible to predictd. low FeedbackThe correct answer is: high

Question 1652. How is the 'Fermi Paradox' normally stated?Select one:a. Where are we?b. Where is everybody?

c. Why are we here?d. Who are we?FeedbackThe correct answer is: Where is everybody?

Question 1727. Which type of spacecraft does not need to carry any fuel?Select one:a. chemical rocketsb. ion enginesc. nuclear rocketsd. solar sails FeedbackThe correct answer is: solar sails

Question 1831. Which kind of interstellar spacecraft would require the crew to be placed in suspended animation, perhaps for thousands of years?Select one:a. interstellar arkb. matter-antimatter rocketc. solar sail d. nuclear rocketFeedbackThe correct answer is: interstellar ark

Question 1955. Von Neumann machines are hypotheticalSelect one:a. devices capable of creating wormholesb. self-replicating probes sent out to explore the galaxy by an advanced civilization c. devices capable of time traveld. spacecraft capable of traveling faster than the speed of lightFeedbackThe correct answer is: self-replicating probes sent out to explore the galaxy by an advanced civilization

Question 2060. The idea that other civilizations are aware of our existence but have deliberately chosen to hide from us is referred to as theSelect one:a. conspiracy hypothesisb. UFO hypothesisc. sentinel hypothesisd. zoo hypothesis FeedbackThe correct answer is: zoo hypothesis

Question 21

61. The idea that other civilizations are waiting for us to reach a certain technological level before revealing themselves to us is referred to as theSelect one:a. UFO hypothesisb. zoo hypothesisc. sentinel hypothesis d. conspiracy hypothesisFeedbackThe correct answer is: sentinel hypothesis

Question 2237. The antimatter equivalent of an electron is calledSelect one:a. a positron b. an auntielectronc. a posielectrond. a cation electronFeedbackThe correct answer is: a positron

Question 2342. During the annihilation of matter and antimatter, what percentage of the mass of the colliding particles is converted into energy?Select one:a. 0.07%b. 0.7%c. 70% d. 100%FeedbackThe correct answer is: 100%

Question 2458. What might we expect to be a possible motivation for human beings to eventually colonize other star systems?Select one:a. natural curiosityb. depletion of natural resourcesc. the rapid rise of the human populationd. all of the above might be motivators FeedbackThe correct answer is: all of the above might be motivators

Question 2519. During the nuclear fission of uranium, what percentage of the original mass of the uranium is converted into energy?Select one:a. 0.07%b. 70%c. 100%d. 0.7% Feedback

The correct answer is: 0.07%

Question 2610. The rocket equation relates the final velocity of a chemical rocket toSelect one:a. the velocity of its exhaust gases and the ratio of the mass of the rocket with all its fuel to the mass of the rocket after all its fuel has been consumed b. the escape velocity of the Earthc. the mass of its payloadd. the velocity of its exhaust gases and mass of the rocket before launchFeedbackThe correct answer is: the velocity of its exhaust gases and the ratio of the mass of the rocket with all its fuel to the mass of the rocket after all its fuel has been consumed

Question 2721. During the nuclear fusion of hydrogen to helium in the core of our Sun, what percentage of the original mass of the hydrogen is converted into energy?Select one:a. 100%b. 0.07%c. 0.7% d. 70%FeedbackThe correct answer is: 0.7%Question 2854. Given how many times intelligent civilizations could have appeared over the universe's history, it is most likely that if other civilizations exist, they willSelect one:a. be much more advanced than us b. be much less advanced than usc. be slightly less advanced than usd. have about the same level of technology as usFeedbackThe correct answer is: be much more advanced than us

Question 2941. When an electron collides with a positron producing a pair of high gamma rays, we call this processSelect one:a. photodisintegrationb. annihilationc. matter obliterationd. pair production FeedbackThe correct answer is: annihilation

Question 3011. The mass ratio of a rocket is defined to be theSelect one:a. mass of the empty rocket without fuel divided by the mass of the payload b. mass of the fuel in the rocket divided by the mass of the rocket payload

c. mass of the rocket after the fuel is burned divided by the mass of the fully fueled rocketd. mass of the fully fueled rocket divided by the mass of the rocket after the fuel is burnedFeedbackThe correct answer is: mass of the fully fueled rocket divided by the mass of the rocket after the fuel is burned

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