Astronomy and Cosmology Lecture Notes

These flashcards cover key concepts related to galaxies, cosmic evolution, and the universe's structure, providing a study aid based on lecture notes.

What is the local group?

The local group is a collection of nearby galaxies (including the Milky Way galaxy) loosely bound together by gravity.

Distinguish between the Local group, Virgo Supercluster, and Laniakea Supercluster.

The Milky Way is part of the local group, the local group is part of the Virgo supercluster, and the Virgo supercluster is part of the Laniakea Supercluster.

Rank the three largest galaxies in the local group from largest to smallest.

Andromeda galaxy, Milky Way Galaxy, Triangulum Galaxy.

What are the 5 types of galaxy shapes?

1. Spiral Galaxy 2. Spiral Barred Galaxy 3. Lenticular Galaxy 4. Elliptical Galaxy 5. Irregular Galaxy.

What does Hubble's tuning fork signify?

Hubble's tuning fork organizes galaxies based on their shape, indicating the evolution of galaxies from one shape to another.

How is Hubble's tuning fork read?

It is read backwards from right to left, from spirals toward elliptical galaxies.

Which type of galaxy is not on Hubble's tuning fork and why?

Irregular galaxies are not part of the tuning fork because they result from mergers and disturbances, hence not following normal evolution.

How does the movement of galaxies provide evidence for dark matter?

The fast rotation of stars in distant galaxies implies more mass is present than can be measured.

How can we use the color and size of stars to infer the relative ages of galaxies?

A galaxy with many young, blue-white stars signifies youth, while older stars tend to be less luminous and red.

How do the observed speeds of stars conflict with Kepler's laws of motion?

Stars throughout galaxies do not follow Kepler's laws; their speeds remain constant despite distance from the galactic center.

What are the three pieces of evidence supporting the Big Bang theory?

1. Expansion of the universe 2. Hydrogen to helium ratios 3. Cosmic Background radiation.

What is the age of the universe?

13.7 billion years old.

Describe the sequence of events that followed the Big Bang, from quarks to galaxies.

1. Inflation 2. Quark Soup 3. Big Freeze/Nucleosynthesis 4. End of the Dark Ages 5. First Stars and Galaxies.

How do redshift and blueshift observations help us understand galaxy movement?

Redshift indicates galaxies are moving away, while blueshift would indicate they are moving toward us.

What are the three potential futures for the universe?

1. Big Crunch 2. Big Rip 3. Big Freeze.

What role does dark matter play in explaining galactic motion?

Dark matter helps explain why stars farther from the galactic center orbit faster than expected.

How does dark energy affect the universe's future?

Dark energy causes the universe's expansion to accelerate.

What happens when galaxies collide?

Galaxies typically merge, causing the rearrangement of matter without direct star collisions.

What can galaxy collisions teach us about cosmic evolution?

They are thought to lead to larger galaxies and irregular shapes, providing evidence for cosmic evolution theories.

How does the distance of a galaxy from a supernova affect our observation?

The distance determines how long it takes for the light from a supernova to reach us.

Why do scientists believe supermassive black holes are at the centers of most galaxies?

Supermassive black holes are thought to be at the centers due to the accretion of matter over time.

How are we able to detect supermassive black holes at galaxy centers?

By observing the movement of stars orbiting near them and the energy emitted as they feed on gases.

How do collisions between galaxies alter their shapes?

Collisions cause dust and gas clouds to reform into new shapes, potentially leading to new star formation.