Astronomy Homework

Early in the last century, astronomers discovered that most galaxies are moving away from our own, by observing that their light is redshifted. What is the important implications of this discovery?

What is the origin of the cosmic background radiation (CBR)?

Order the following historical ideas of "everything" (the universe) from the earliest to most recently developed -The Milky Way Galaxy, -All of Spacetime created by the Big Bang, "Island Universes", or galaxies, including our own Earth, with the stars and planets on concentrated shells The Solar system, with stars on a shell ouside

What does the cosmological redshift of a distant galaxy tell astronomers about that galaxy?

Order the following methods for distance measurement from shortest distance to long distance. parallax cepheid variables galactic redshifts radar type 1a supernovae main-sequence fitting

True or False: The relative abundance of protons and neutrons right after the Big Bang is consistent with the subsequent created of more hydrogen than helium.

What element was synthesized in the Big Bang?

What can we infer from the fact that nearly all galaxies are moving away from us?

Some galaxies have regions that are relatively blue in color, while other regions appear redder. aside from color, what can you say about the differences between these regions?

What is the evidence that most galaxies are composed largely of dark matter?

True or False: galaxy interactions are likely to result in the formation of hot new stars.

True or False: Galaxy collisions cause the disk of a spiral galaxy to become warped and the spiral arms to widen.

true or false: Elliptical galaxies that we see today may one have been spirals that lost their original shapes after many interactions with other galaxies.

Spiral arms are delineated by luminous, massive stars because:

Where is dark mater typically found in a spiral galaxy?

What do astronomers mean when they speak of a "standard candle?"

Why are globular clusters so useful as standard candles in determining the size of the galaxy?

Where are the oldest stars in the milky way located?

What does the abundance of a star's massive elements tell us about the age of the star?

To observers in Earth's Southern Hemisphere, the Large and Small Magellanic Clouds look like detached pieces of the Milky Way. What are these clouds and why is it not surprising that they look so much like pieces of the Milky Way?

Place these objects in order based on their mass. hint: assume the Large Magellanic Cloud has a mass of approximately 10^10 solar masses. Globular cluster large magellanic cloud open cluster sagittarious A

true or false: Dark matter is a solved mystery.

true or false: according to Newton's laws, if mass if concentrated in the center of a galaxy, stars closer to the center should move faster in their orbits than those farther away.

Each of the following items existed at one time, and some exist today in our Milky Way Galaxy. Rank them on their expected abundance of massive elements.(lowest - highest) Interstellar cloud with primordial matter star in inner part of the disk star in a globular cluster star in the outer edge of the disk

What piece of observational evidence suggest that Einstein's cosmological constant (a repulsive force) may be needed to explain the historical expansion of the universe?

If a circle is drawn on a spherical surface, will the circumference be greater than, less than, or equal to 2 Pi?

If a triangle is draw on a spherical curface, will the sum of the interior angles be greater than, less than, or equal to 180 degrees?

Do astronomers believe we live in a closed, flat, or open universe?

The critical mass density of a non-accelerating universe determines:

Order these events in the history of the universe (early-Late) -First stars form -Protons and neutrons combine to form light elements -Quantum theory of gravity is necessary -Quarks combine to form protons and neutrons -universe becomes transparent to photons -universe undergoes exponential inflation

What explanation do cosmologists currently invoke to explain the horizon and flatness problems?

In the first 100 seconds, the universe contained:

As clumps containing dark matter and normal collapse, they heat up. when a clump collapses to about half its maximum size, the increased thermal motion of particles tends to inhibit further collapse. Whereas normal matter can overcome this effect and continue to collapse, dark matter cannot. What is the cause for this difference?

Imagine some galaxies in the universe are composed mostly of dark matter with relatively few stars or other luminous normal matter. If this were true, how might we learn of the existence of such galaxies?

how are the processes of star formation (as studied earlier) and galaxy formation similar?

What is the origin of large-scale structure?

Astronomers believe that cold dark matter is composed of:

what are the largest structures in the universe?

Approximately, when do scientists believe life first appeared on Earth?

If we should eventually find life on Europea, what would this tell you about the probability of finding life on worlds around other stars?

Order the following variables from the Drake Equation according to the certainty with which astronomers know their value. (most certain - least certain) -Fraction of worlds where life actually arises -fraction of worlds with life that develop into a technological advanced civilization - Fraction of stars with planetary systems -Likelihood that each civilization still exists today - Number of moons and planets capable of supporting life - Stars in our galaxy