AST201H1 Study Guide - Final Guide: Universe Today, Mass Number, Spiral Galaxy

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skylocust785

13 Oct 2012

School

UTSG

Department

Astronomy & Astrophysics

Course

AST201H1

Professor

Marija Stankovic

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AST201H1 Full Course Notes

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1. 1 - our modern view of the universe. If we looked at a galaxy that is 7 billion light years away, we"d see the universe at half its current age. If we looked at a galaxy that is 12 billion light years away we"d see the universe as it was when it was 2 billion years old. If we tried to look beyond 14 billion light years we"d be looking to a time more than 14 billion years ago - before the universe existed: our observable universe is 13. 7 billion light years. 150 million kilometers: earth"s orbital path defines a flat plane that we call the eliptic plane, when we look outside the local group we discover, 1. Virtually every galaxy outside the local group is moving away from us: 2. The more distant the galaxy the faster it appears to be racing away: this happens because the universe is expanding, planets orbit a star.

Related Questions

The great astronomer Edwin Hubble discovered that all distant galaxies are receding from our Milky Way Galaxy with velocities proportional to their distances. It appears to an observer on the Earth that we are at the center of an expanding universe. Figure 3.64 illustrates this for five galaxies lying along a straight line, with the Milky Way Galaxy at the center. Using the data from the figure, calculate the velocities: (a) relative to galaxy 2 and (b) relative to galaxy 5. The results mean that observers on all galaxies will see themselves at the center of the expanding universe, and they would likely be aware of relative velocities, concluding that it is not possible to locate the center of expansion with the given information.

Figure 3.64 Five galaxies on a straight line, showing their distances and velocities relative to the Milky Way (MW) Galaxy. The distances are in millions of light-years (Mly), where a light-year is the distance light travels in one year. The velocities are nearly proportional to the distances. The sizes of the galaxies are greatly exaggerated; an average galaxy is about 0.1 MlY across.

ceruleangiraffe295

(a) relative to galaxy 2 and

(b) relative to galaxy 5.

The results mean that observers on all galaxies will see themselves at the center of the expanding universe, and they would likely be aware of relative velocities, concluding that it is not possible to locate the center of expansion with the given information.

pinkswan477

Which, if any, of the following statements is/are true?

1)Our galaxy, The Milky Way, is a member of The Local Group, whichis one of several groups of galaxies located in the VirgoSupercluster.
2)Most astrophysicists believe that our Solar System formed from animmense cloud of gas and dust about 4-1/2 million years ago.
3)Planets are believed to have formed by a process known asaccretion.
4)Two key elements in the Condensation Theory of PlanetaryFormation are 5)Conservation of Angular Momentum and CondensationNuclei.
6)The name of the second largest object in the Universe is TheSouthern Wall.
7)In our Solar System, the four jovian planets, Jupiter, Saturn,Uranus, and Neptune, are separated from the four terrestrialplanets, Mercury, Venus, Earth, and Mars, by the Kuiper Belt.
8)Our star, The Sun, is located on the Orion Arm, about 26,000light-years from the center of the Andromeda Galaxy.
9)It takes a photon of light about 4-1/5 years to travel from ourSolar System to the second closest star to Earth, ProximaCentauri.
10)The full range of human knowledge about our Universe spans about40 or 41 orders of magnitude on a spatial scale and about 13.7billion years on a temporal scale.
11)It takes a photon of light about 5-1/2 hours to travel from theSun to the orbit of the former planet Pluto.

AST201H1 Study Guide - Final Guide: Universe Today, Mass Number, Spiral Galaxy

AST201H1 Full Course Notes

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