the solar system. this view of the rising earth was seen by the apollo 11 astronauts after they...
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THE SOLAR SYSTEM
This view of the rising Earth was seen by the Apollo 11 astronauts after they entered orbit around the Moon. Earth is just above the lunar horizon in this photograph.
Ideas about the Solar System• Geocentric• Heliocentric• Planetary Motion
The Geocentric Model
Saw the solar system as spheres with attached celestial bodies rotating around a fixed Earth.
Planets rotated around the Earth in perfect circles.
Model grew out of the ideas that:Humans were at the center of a perfect
universe created just for themTime period when religious beliefs dominated
science
The Heliocentric Model Nicolas Copernicus
1543 suggested that the Earth revolves around the Sun. In this model planets moved around the Sun in perfect circles at
different distances and at faster speeds the closer to the Sun a planet was
Tycho Brahe Made precise measurements of the Sun, Moon, planets, and
the stars. Johannes Kepler
Found that the planets did not move in perfect circles. Planets move in the path of a ellipse.
Kepler’s Laws of Planetary Motion
Kepler’s First Law. Each planet moves in an orbit that has the shape of a ellipse,
with the Sun located at one focus Kepler’s Second Law
Imaginary line between the Sun and a planet moves over equal areas of the ellipse during equal time intervals
The velocity of a planet varies as it is not always the same distance from the focus
Point where the planet comes closet to the Sun is the perihelion and the point at which it is farthest from the Sun is the aphelion
There is a third law that we will not talk about
Kepler's first law describes the shape of planetary orbit as an ellipse, which is exaggerated in this figure. The Sun is located at one focus of the ellipse.
Kepler's second law. A line from the Sun to a planet at point A sweeps over a certain area as the planet moves to point B in a given time interval. A line from the Sun to a planet at point C will sweep over the same area as the planet moves to point D during the same time interval. The time required to move from point A to point B is the same as the time required to move from point C to point D, so the planet moves faster in its orbit at perihelion.
Origin of the Solar System
Origins of Solar System Heliocentric model of the solar system
Commonly the most accepted model of the solar system Protoplanet nebular model
most accepted theory of the origin of the solar system “proto” = precursor, forming
Protoplanet Nebular ModelStage Overview:
A.Starts with a nebula of gas, dust, and chemical elements from previously existing stars
B.Nebula is pulled together by gravity, forming into the protosun and protoplanets.
C.As the planets form, they revolve around the Sun in orbits that are described by Kepler's laws of planetary motion
(A) The process starts with a nebula of gas, dust, and chemical elements from previously existing stars.
(B) The nebula is pulled together by gravity, collapsing into the protosun and protoplanets.
(C) As the planets form, they revolve around the Sun in orbits that are described by Kepler's laws of planetary motion.
Stage A All the elements that made up the current solar system were derived from stars that disappeared billions of year ago, even before our Sun was born.
Hydrogen fusion in the core of large stars results in the formation of elements through iron
Elements that are heavier that iron are formed in rare supernova explosions of dying massive stars
Stage BAll of the elements from Stage A began to form large, slowly rotating nebula
Because of gravity, size of this nebula begins to decrease, which increased its rate of spin
This spinning nebula formed an accretion disk (big, bulging disk of gases and elements formed as nebula condense)
Accretion disk becames compressed into protoplanets and a protosun
Stage CInitial flare-up of the Sun from the warming and condensing established the protosun as a star and it became our Sun.
Between the orbits of Mars and Jupiter there is an Asteroid belt that some think was formed by the breakup of a larger planet.
The Planets
DISTANCE
VERY LARGE!Measured in light-yearsThe distance which a ray of light would travel in one year
About 6,000,000,000,000 (6 trillion) miles186,000 miles per second 299 792 458 m / s
IntroThe solar system consists of: A middle aged main sequence G type star called the
Sun 8 planets 5 Recognized Dwarf planets Nearly fifty moons Thousands of asteroids, Many comets revolving around it This is all held together by the force of gravitational
attraction Terrestrial planets are those which have a
composition very similar to the Earth’s composition (composed mostly of rocky material with iron)
Mercury Innermost planet Period of revolution is 88 days. Rotation once every 59 days. High kinetic energy of gas molecules and a low gravitational pull Surface temperature 427OC (800OF)in the sunlight to –180OC (-
350OF)in the dark Surface covered with craters Presence of magnetic fields and high density so must have a
high iron content with at least a partial molten core
Mercury is close to the Sun and visible only briefly before or after sunrise or sunset, showing phases. Mercury actually appears much smaller in an orbit that is not tilted as much as shown in this figure.
A photomosaic of Mercury made from pictures taken by the Mariner 10 spacecraft. The surface of Mercury is heavily cratered, looking much like the surface of Earth's Moon. All the interior planets and the Moon were bombarded early in the life of the solar system.
Venus Very bright in morning and evening sky. revolves around the Sun once every 225 days. Rotates on its axis once every 243 days. Exhibits retrograde rotation where the rotation of the planet is
opposite its direct of revolution around the Sun and opposite most other planets.
Average surface temperature is 480 OC (900 OF) Atmospheric pressure approximately 100 times that experienced
on Earth. Clouds and rain consisting of sulfuric acid. No satellites and no magnetic field.
This is an image of an 8 km (5 mile) high volcano on the surface of Venus. The image was created by a computer using Magellan radar data, simulating a viewpoint elevation of 1.7 km (1 mile) above the surface. The lava flows extend for hundreds of km across the fractured plains shown in the foreground. The simulated colors are based on color images recorded by the Soviet Venera 13 and 14 spacecraft.
Mars Unique, bright reddish color which exhibits a swift retrograde
motion Revolves around the Sun in 687 days. Rotates on its axis once every 24 hours, 37 minutes Has an atmosphere A geologically active past and is divided into 4 provinces:
Volcanic regions Systems of canyons Terraced plateaus near the poles Flat regions pitted with impact craters.
average temperature is –53 OC (-63 OF) Atmosphere is 95% CO Atmospheric pressure 0.6 percent of Earth’s atmospheric pressure Two satellites
Deimos – 13 km acrossPhobos – 22 km acrossBoth are thought to be captured asteroids
Surface picture taken by the Viking 1 lander found reddish, fine-grained material, rocks coated with a reddish stain, and groups of blue-black volcanic rocks.
A view of the surface of Mars taken by the Viking Orbiter 1 cameras. The scene shows three volcanoes that rise an average of 17 km (about 11 mile) above the top of a 10 km (about 6 mile) high ridge. Clouds can be seen in the upper portion of the photograph, and haze is present in the valleys at the lower right.
Jupiter Largest of all planets Twice as massive as all other planets combined and
about 318 times as massive as the Earth. Radiates twice as much energy as it gets from the sun due
to slow gravitational compression Made mostly of hydrogen and helium with some rocky
substances A solid core with a radius of about 14,000 km (8,500 miles)
The interior structure of Jupiter.
Photos of Jupiter taken by Voyager 1. (A) From a distance of about 36 million km (about 22 million mi). (B) A closer view, from the Great Red Spot to the South Pole, showing organized cloud patterns. In general, dark features are warmer, and light features are colder. The Great Red spot soars about 25 km (about 15 mi) above the surrounding clouds and is the coldest place on the planet.
Jupiter Sixteen satellites – four are called Galilean moons as they were
discovered by Galileo in 1610
IoEuropaGanymedeCallisto
The four Galilean moons pictured by Voyager 1. Clockwise from upper left, Io, Europa, Ganymede, and Callisto. Io and Europa are about the size of Earth's Moon; Ganymede and Callisto are larger than Mercury.
Saturn Slightly smaller and less massive than Jupiter with a system
of rings The rings are made up of particles, some which are meters
across and some that are dust sized particles. 10 moons
Janus Mimas Enceladus Tethys Dione Rhea Titan Hyperion Iapetus Phoebe
Titan is the only moon in the solar system with an atmosphere and is larger than the planet Mercury
A part of Saturn's system of rings, pictured by Voyager 2 from a distance of about 3 million km (about 2 million mi). More than sixty bright and dark ringlets are seen here; different colors indicate different surface compositions.
Uranus and Neptune
Uranus revolves around the Sun once about every 84 years. Both Uranus and Neptune have a core of rocky material surrounded
by water and ice. Uranus and Neptune have an atmosphere of hydrogen and helium Average temperature on Uranus is-210 OC (-350 OF) Average temperature on Neptune is –235 OC (-391 OF) Uranus tilts 82O on its axis, which is different from the less that 30O
for other planets. 15 Known satellites around Uranus Uranus has 10 narrow rings and a number of dusty bands Neptune has 8 satellites Neptune also has a series of rings
PlutoNot a planet but we won’t leave it out!
Recently changed to a dwarf planet Pluto’s atmosphere is probably mostly nitrogen, with some
methane and CO2
Pluto orbits around the Sun once every 248 years
Dwarf Planet: Orbits the sun, but is not massive enough to have cleared its own orbit
(meaning that there are other masses at the same distance form the sun)
Are smaller than planets (can be smaller than the moon)
This is a photo image of Neptune taken by Voyager. Neptune has a turbulent atmosphere over a very cold surface of frozen hydrogen and helium.
The interior structure of Uranus and Neptune.
Smaller bodies of the Solar System
CometsSmall relative to other bodies in the solar system
Made of frozen CO2, NH3, CH4 and particles of dust and rock mixed in.
Originate approximately 30 A.U. from the Sun
As a comet nears the Sun it grows brighter, with the tail always pointing away from the Sun.
Asteroids The asteroid belt lies between Mars and Jupiter The asteroids in this belt are between 1 km up to the largest
(Ceres) which is 1,000 km (600 mi) The asteroids in the inside of the belt are made of a stony
material and the asteroids on the outside of the belt are made of a carbon material
Some other asteroids are metallic, made of iron and nickel
Most of the asteroids in the asteroid belt are about halfway between the Sun and Jupiter
Meteors and MeteoritesMeteroids
Remnants of asteroids and comets after the heat of the Sun and collisions.
Meteor The streak of light and smoke left in the sky by a meteoroid is called a
meteor. These are the shooting stars that we see in the sky
Meteor shower Occurs when the Earth passes through a stream of particles that are
left by a comet. There is an intense meteor shower the third week in October as the
Earth crosses the path of Halley’s Comet.
Meteorite on Mars
Meteorite
A meteorite is what is left of a meteoroid if it survives the flight through the Earth’s atmosphere.
Classified according to their makeup Iron meteorites
made up mostly of iron and nickel material Stony meteorites
composed mostly of rocky material much like that found on Earth
chondrites – have a structure of small spherical lumps of silicate materials.
Achondrites – do not contain this silicate clumps Stony-iron meteorites
Made up of a conglomerate of both types of materials.
(A)A stony meteorite. The smooth, black surface was melted by friction with the atmosphere.
(B) An iron meteorite that has been cut, polished, and etched with acid. The pattern indicates that the original material cooled from a molten material over millions of years.