The Solar SystemThe Solar System

The SunThe Sun

MythologyMythology

People have worshiped the sun and gods People have worshiped the sun and gods related to the sun for all of recorded related to the sun for all of recorded history. history.

Egypt—sun god = Ra. He was considered Egypt—sun god = Ra. He was considered the creator of all things.the creator of all things.

Greek—Helios. He drove the sun across Greek—Helios. He drove the sun across the sky from east to west in his chariot.the sky from east to west in his chariot.

Size of the SunSize of the Sun

The Sun's diameter is 864,938 miles The Sun's diameter is 864,938 miles (1,391,980 km). This is almost 10 times (1,391,980 km). This is almost 10 times larger than the planet Jupiter and about larger than the planet Jupiter and about 109 times as big as the Earth. 109 times as big as the Earth.

The volume of the Sun is 1,299,400 times The volume of the Sun is 1,299,400 times bigger than the volume of the Earth. bigger than the volume of the Earth.

About 1,300,000 Earths could fit inside the About 1,300,000 Earths could fit inside the Sun Sun

Mass of the SunMass of the Sun

mass of the sun = 1.98892 × 10mass of the sun = 1.98892 × 103030 kilogramskilograms

ThisThis number was derived by using number was derived by using Newton’s laws of motion relating mass, Newton’s laws of motion relating mass, velocity, gravity, and distance.velocity, gravity, and distance.

Rotation of the SunRotation of the Sun

The Sun has a north and south pole, just The Sun has a north and south pole, just as the Earth does, and rotates on its axis.as the Earth does, and rotates on its axis.

Unlike Earth which rotates at all latitudes Unlike Earth which rotates at all latitudes every 24 hours, the Sun rotates every 25 every 24 hours, the Sun rotates every 25 days at the equator and takes days at the equator and takes progressively longer to rotate at higher progressively longer to rotate at higher latitudes, up to 35 days at the poles.latitudes, up to 35 days at the poles.

This is known as differential rotation This is known as differential rotation

Composition of the SunComposition of the Sun

71% Hydrogen71% Hydrogen27.1% Helium27.1% Helium .97% Oxygen.97% Oxygen .4% Carbon.4% Carbon .09% Nitrogen.09% Nitrogen

Parts of the SunParts of the Sun

The CoronaThe Corona The outer most part of The outer most part of

the sun’s atmosphere.the sun’s atmosphere. Lowest levels of the Lowest levels of the

corona’s temperature corona’s temperature is 2,000,000 Kis 2,000,000 K

Has less than 1 Has less than 1 billionth the density of billionth the density of the Earth’s the Earth’s atmosphere.atmosphere.

Very irregular in form.Very irregular in form.

Solar ActivitySolar Activity

Sunspots—Occur near areas of very Sunspots—Occur near areas of very strong magnetic fields. strong magnetic fields.

Magnetic fields are able to retain matter Magnetic fields are able to retain matter that holds an electric chargethat holds an electric charge

The strong magnetic fields in sunspots The strong magnetic fields in sunspots keep energy from reaching the surface of keep energy from reaching the surface of the sun.the sun.

Sunspots are, therefore, cooler than the Sunspots are, therefore, cooler than the rest of the sun.rest of the sun.

Sun SpotsSun Spots

Occur in an 11 year Occur in an 11 year cycle. cycle.

Each 11 years the Each 11 years the north magnetic pole north magnetic pole and the south and the south magnetic pole switch.magnetic pole switch.

FlaresFlares

High energy solar High energy solar storms on the Sun.storms on the Sun.

No theory is widely No theory is widely accepted, but accepted, but scientists believe that scientists believe that they are related to the they are related to the large amounts of large amounts of energy “stored” by energy “stored” by sunspots.sunspots.

The Sun SongThe Sun Song

The PlanetsThe Planets

The nine PlanetsThe nine Planets

MercuryMercury

MythologyMythology

In Roman mythology Mercury is the god of commerce, travel and thievery, the Roman counterpart of the Greek god Hermes, the messenger of the Gods.

The planet probably received this name because it moves so quickly across the sky.

Size of MercurySize of Mercury

Mercury’s diameter is 4,880 km

Mercury’s mass is 3.30x1023 kg

Distance to the SunDistance to the Sun

Mercury's orbit is highly eccentric; at Mercury's orbit is highly eccentric; at perihelion it is only 46 million km from the perihelion it is only 46 million km from the Sun but at aphelion it is 70 million.Sun but at aphelion it is 70 million.

Composition of PlanetComposition of Planet

Mercury is a very dense planet.Mercury is a very dense planet.Scientists believe Mercury has a crust of Scientists believe Mercury has a crust of

light silicate rocks (rocks that contain light silicate rocks (rocks that contain Silicon and Oxygen)Silicon and Oxygen)

Mercury contains a large iron core.Mercury contains a large iron core.

Temperature of MercuryTemperature of Mercury

Daytime temperature may reach 750 Daytime temperature may reach 750 degrees Fahrenheitdegrees Fahrenheit

Nighttime temperature may reach -240 Nighttime temperature may reach -240 degrees Fahrenheitdegrees Fahrenheit

Mercury’s GeologyMercury’s Geology

Mercury is a geologically dead planet. Mercury is a geologically dead planet. It has no plate tectonics like Earth.It has no plate tectonics like Earth.Much of the activity that takes place or has Much of the activity that takes place or has

taken place on mercury is form cooling taken place on mercury is form cooling and impacting comets or meteors. and impacting comets or meteors.

Moons Of MercuryMoons Of Mercury

Mercury has Mercury has no known no known moons.moons.

Transient of Transient of mercury—mercury—Picture of Picture of mercury as it mercury as it crosses the crosses the sun.sun.

VenusVenus

MythologyMythology

Venus (Greek: Aphrodite; Babylonian: Ishtar) is the goddess of love and beauty. The planet is so named probably because it is the brightest of the planets known to the ancients.

Size of VenusSize of Venus

Venus is the second planet from the Sun and the sixth largest.

orbit: 108,200,000 km (0.72 AU) diameter of Venus: 12,103.6 km mass: 4.869e24 kg

Distance to the SunDistance to the Sun

Venus is on average 108 million km, or Venus is on average 108 million km, or 0.7233 AU, to the sun.0.7233 AU, to the sun.

Venus' orbit is the most nearly circular of any planet, with an eccentricity of less than 1%.

Phases of VenusPhases of VenusSince Venus is an interior planet, it Since Venus is an interior planet, it

shows phases when viewed with a shows phases when viewed with a telescope from the perspective of Earth. telescope from the perspective of Earth.

Galileo's observation of this Galileo's observation of this phenomenon was important evidence in phenomenon was important evidence in favor of Copernicus's heliocentric theory favor of Copernicus's heliocentric theory of the solar system.of the solar system.

Phases of VenusPhases of Venus

Rotation of VenusRotation of Venus

243 Earth days = 1 Venus day

Retrograde (it rotates in an east to west direction).

The periods of Venus' rotation and of its orbit are synchronized such that it always presents the same face toward Earth.

Similar to EarthSimilar to Earth

Venus is sometimes regarded as Earth's sister planet. In some ways they are very similar:

Venus is only slightly smaller than Earth (95% of Earth's diameter, 80% of Earth's mass).

Both have few craters indicating relatively young surfaces.

Their densities and chemical compositions are similar.

AtmosphereAtmosphere

The pressure of Venus' atmosphere at the The pressure of Venus' atmosphere at the surface is 90 atmospheres (about the surface is 90 atmospheres (about the same as the pressuresame as the pressureat a depth of 1 km in Earth's oceans). at a depth of 1 km in Earth's oceans).

It is composed mostly of carbon dioxide. It is composed mostly of carbon dioxide. There are several layersThere are several layersof clouds many kilometers thick composed of clouds many kilometers thick composed of sulfuric acid.of sulfuric acid.

AtmosphereAtmosphere

Temperature on VenusTemperature on Venus

This dense atmosphere produces a run-away greenhouse effect that raises Venus' surface temperature by about 400 degrees to over 740 K (hot enough to melt lead). Venus' surface is actually hotter than Mercury's despite being nearly twice as far from the Sun.

Geology of VenusGeology of Venus

Data from Data from Magellan's imaging Magellan's imaging radar shows that radar shows that much of the surface much of the surface of Venus is covered of Venus is covered by lava flows. There by lava flows. There are several large are several large shield volcanoes shield volcanoes such as Sif Mons.such as Sif Mons.

Geology of VenusGeology of Venus

The interior of Venus is probably very similar to that of Earth:

an iron core about 3000 km in radius a molten rocky mantle comprising the

majority of the planet. Recent results from the Magellan gravity

data indicate that Venus' crust is stronger and thicker than had previously been assumed.

Geology of VenusGeology of Venus

Like Earth, convection in the mantle produces stress on the surface which is relieved in many relatively small regions instead of being concentrated at plate boundaries as is the case on Earth.

MoonsMoons

There are no known There are no known moons around Venusmoons around Venus

MarsMars

Size of MarsSize of Mars

Mars is the fourth planet from the Sun and Mars is the fourth planet from the Sun and the seventh largest:the seventh largest:Diameter: 6,794 kmDiameter: 6,794 kmMass: 6.4219e23 kgMass: 6.4219e23 kg

Distance to the SunDistance to the Sun

Orbit: 227,940,000 Orbit: 227,940,000 km (1.52 AU) from km (1.52 AU) from SunSun

Orbit and Temperature of MarsOrbit and Temperature of Mars

Very elliptical orbit that causes drastic Very elliptical orbit that causes drastic temperature changes from aphelion to temperature changes from aphelion to perihelionperihelion

Martian surface temperatures range widely from as little as 140 K (-133 C, -207 F) at the winter pole to almost 300 K (27 C, 80 F) on the day side during summer.

Atmosphere of MarsAtmosphere of Mars

Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide (95.3%) plus nitrogen (2.7%), argon (1.6%) and traces of oxygen (0.15%) and water (0.03%).

Mars is unable to recycle any of this carbon dioxide back into its atmosphere and so cannot sustain a significant greenhouse effect. The surface of Mars is therefore much colder than the Earth would be at that distance from the Sun.

Geology of MarsGeology of Mars

Valles Marineris: Valles Marineris: a system of a system of canyons 4000 canyons 4000 km long and km long and from 2 to 7 km from 2 to 7 km deepdeep

Olympus Mons: the Olympus Mons: the largest mountain in largest mountain in the Solar System the Solar System rising 24 km (78,000 rising 24 km (78,000 ft.) above the ft.) above the surrounding plain. Its surrounding plain. Its base is more than base is more than 500 km in diameter 500 km in diameter and is rimmed by a and is rimmed by a cliff 6 km (20,000 ft) cliff 6 km (20,000 ft) highhigh

There is very clear evidence of erosion in many There is very clear evidence of erosion in many places on Mars including large floods and small river places on Mars including large floods and small river systems At some time in the past there was clearly systems At some time in the past there was clearly some sort of fluid on the surface.some sort of fluid on the surface.

Surface DunesSurface Dunes

Moons of MarsMoons of Mars

Mars has two tiny satellites which orbit very Mars has two tiny satellites which orbit very close to the surface: close to the surface:

Distance Radius MassDistance Radius MassSatellite (000 km) (km) (kg) Discoverer DateSatellite (000 km) (km) (kg) Discoverer Date--------- -------- ------ ------- ---------- ------------- -------- ------ ------- ---------- ----Phobos 9 11 1.08e16 Hall 1877Phobos 9 11 1.08e16 Hall 1877Deimos 23 6 1.80e15 Hall 1877Deimos 23 6 1.80e15 Hall 1877