solar system summary

7/31/2019 Solar System Summary

1/5

The Universe

The universe is everything that exists.

All the planets, stars, and galaxies are part of the universe, and so, is all of space.

The universe is so large that contains billions of stars.

Cosmology- is the study of the universe.

Traditional Views about the Universe

The Geocentric Universe

- Sphere that stayed motionless at the center of the universe.

- The Earth is the center

- Aristotle and Claudius Ptolemy

The Heliocentric System

- Nicolaus Copernicus proposed the heliocentric model and Galileo

- The center of the universe is the Sun, not the Earth. The Earth is just another planet orbiting around the Sun and

the Earth no longer has a special place ( the center ) in the heaven.

- it might rather be called Pythagorean.

Theories on the Origin of the Universe

Big Bang Theory

Collapsing cloud of interstellar dust

Cloud dense and cold so collapses under its own self-gravity (cold gas has less internal pressure to counteract

gravity)

Once collapsed, it immediately warms up because of release of gravitational energy during collapse

All mass and energy concentrated at a geometric point

Open universe

- Not enough matter to overcome the initial velocities and cause gravitational collapse

- The galaxies will continue to expand "forever"

- All stars will eventually use up their fuel and burn out

- Universe will then be cold and dead, forever


2/5

Steady State

- Suggest that there is neither beginning nor end to the Universe and it has a constant density.

Creation theory

Many people believe that the Earth and all the creatures in it were created by God.

These Creationists believe the version of creation found in the Bible in the book ofGenesis.

In this account, God created the Universe, including the Earth and all the creatures in it, in seven days.

Galaxy - a massive collection of stars, gas, and dust kept together by gravity.

Type of Galaxy

Spirals

- Spiral galaxies like the one to the left have flat disks of stars with bright bulges called nuclei in their centers.

Spiral arms wrap around these bulges

Barred Spirals - In some spirals, the density wave organizes the stars in the center into a bar. Thearms of barred spiral galaxies spiral outward from the ends of the bar. The Milky Way may fall into

this class of spirals, called barred spirals.

Irregular

The final class of galaxies, "irregulars," contains a hodge-podge of shapes - anything that looks neither spiral nor

elliptical.

Any galaxy with no identifiable form - whose stars, gas, and dust are spread randomly - is classified as irregular.

Irregulars are the smallest galaxies, and they may contain as few as one million stars.

Components of the Galaxy

A spiral galaxy like the Milky Way has 3 basic components to its visible matter:

The Disk of the Galaxy

- Most of the gas and dust of the Milky Way is contained in the disk. This material between the stars is often

termed theinterstellar medium.

- The gas is primarily hydrogen and helium, and the dust makes many regions of the disk opaque.

- which contain many hot young stars and therefore is luminous

The Halo of the Galaxy

- The halo of the galaxy is rather spherical in shape and contains little gas, dust, or star formation. It is difficult to

measure precisely, but the halo appears to extend beyond the disk.

-The clusters found in the halo areglobular clusters (approximately 100 of them), so the halo is population II, and

contains very old stars.
http://library.thinkquest.org/29178/HowthewbC.htmhttp://library.thinkquest.org/29178/HowthewbC.htmhttp://csep10.phys.utk.edu/astr162/lect/milkyway/ism.htmlhttp://csep10.phys.utk.edu/astr162/lect/milkyway/ism.htmlhttp://csep10.phys.utk.edu/astr162/lect/milkyway/ism.htmlhttp://csep10.phys.utk.edu/astr162/lect/clusters/globular.htmlhttp://csep10.phys.utk.edu/astr162/lect/clusters/globular.htmlhttp://library.thinkquest.org/29178/HowthewbC.htmhttp://csep10.phys.utk.edu/astr162/lect/milkyway/ism.htmlhttp://csep10.phys.utk.edu/astr162/lect/clusters/globular.html


3/5


4/5

1. Average distance between Earth and the Sun is 150 million km

2. Water exists on surface as solid, liquid, and gas.

3. More than 70 percent of surface covered with water

4. Atmosphere protects surface from most meteors and Suns radiation

D. Marsfourth planet from the Sun

1. Called red planet because iron oxide in rocks makes them reddish-yellow

2. Polar ice caps made mostly of frozen carbon dioxide and frozen water

3. Has largest volcano in the solar system

4. Soil shows no evidence of life.

5. Has gullies and deposits of soil and rocks, which may indicate the presence of liquid groundwater

6. Thin atmosphere of mostly carbon dioxide

7. Strong winds caused by differences in temperature between day and night

8. Is tilted on its axis, which causes seasons

9. Two small moons: Phobos and Deimos

Section 3-The Outer Planets

A. Jupiterfifth planet from the Sun, largest planet in the solar system

1. Atmosphere primarily hydrogen and helium

a. Below atmosphere, liquid hydrogen and helium are suspected.

b. Solid rocky core may exist below liquid level.

c. The Great Red Spot is the most spectacular of Jupiters many constant high-pressure gas storms.

2. Has at least 61 moonsfour are relatively large and have atmospheres

a. Iois very volcanically active; the closest large moon to Jupiter

b. Europacomposed mostly of rock; may have an ocean of water under a thick layer of ice

c. Ganymedelargest moon in solar system, even larger than planet Mercury

d. Callistocratered rock and ice crust may surround a salty ocean and rock core

B. Saturnsixth planet from the Sun, second largest in the solar system, lowest density

1. Thick outer atmosphere of hydrogen, helium, ammonia, methane, and water vapor

2. Might have a small, rocky core

3. Each large ring composed of thousands of ringlets of ice and rock particles

4. Has at least 31 moons

a. Largest moon, Titan, is larger than the planet Mercury.

b. Thick clouds on Titan prevent scientists from seeing surface.

C. Uranusseventh planet from the Sun, large and gaseous

1. Has thin, dark rings

2. Atmosphere of hydrogen, helium, and methane

3. Methane makes the planet bluish-green in color.

4. Axis of rotation nearly parallel to plane of orbit

D. Neptunethe eighth planet from the Sun, large and gaseous

1. Bluish-green-colored atmosphere similar to that of Uranus

2. Storms on Neptune reveal an active and rapidly changing atmosphere

3. Has at least 61 moons, of which pinkish Triton is largest

E. Dwarf PlanetsPlutooccasionally closer to the Sun than Neptune, was once the smallest planet in the solar system

but as of 2006, Pluto is now considered to be a dwarf planet

1. Has a thin atmosphere and a solid, rocky surface

2. Discovered in 1978, moon Charon is half the planets size.

3.Hubble Space Telescope reveals group of icy bodies that lie in the Kuiper Belt beyond Neptunes orbit.

Section 4-Other Objects in the Solar System

A. Cometdust and rock particles combined with frozen water, methane, and ammonia

1. Halleys comet orbits the Sun every 76 years.

2. Oort Cloudlarge group of comets surrounding solar system beyond Pluto

3. Amateur astronomers discovered Comet Hale-Bopp in 1995

4. Comet structurelarge dirty snowball of frozen rock and ice

a. Ice and dust vaporize as comet nears Sun.

b. Vaporized material forms bright cloud called coma around comet nucleus.


5/5

c. Solar wind pushes on gas and dust in the coma, causing the particles to form a tail that always points

away from the Sun.

d. Eventually, most of the ice in the comets nucleus vaporizes, leaving only small particles.

B. Small pieces of the old comets nucleus

1. Meteoroidname given to small pieces of comet when they move through space

2. Meteorsmall meteoroid that burns up in Earths atmosphere

3. Meteor showersoccur when Earths orbit passes through a group of meteoroids that enter the atmosphere

4. Meteoritemeteoroid that strikes Earth

C. Asteroidrock similar to that which formed planets

1. Most asteroids lie in an asteroid belt located between Mars and Jupiter.2. Jupiters gravity may have kept these asteroids from forming a planet.

3. Some planets moons may be asteroids pulled from the asteroid belt.

4. Asteroid sizes range from very tiny to 940 km in diameter.

5. TheNear Earth Asteroid Rendezvousprobe indicates asteroid 433 Eros has been in many collisions over time.

solar system summary

Documents