ISP 4

Which part of the galaxy contains the coldest gas?

The disk

1. Why do disk stars bob up and down as they orbit the galaxy?

The gravity of other disk stars always pulls them toward the disk

1. Which part of the galaxy has gas with the hottest average temperature?

The halo

What is the typical % (by mass) of elements other than hydrogen and helium in stars that are forming right now in the vicinity of the sun?

2%

Where would you be most likely to find an ionization nebula?

The disk

1. Where are most of the Milky Way’s globular clusters found?

The halo

1. How do we determine the Milky Way’s mass outside the Sun’s orbit?

From the orbits of stars and gas clouds orbiting the galactic center at greater distances than the Sun

The best measurements of the mass of the black hole at the galactic center come from?

The orbits of stars in the galactic center

1. Where would you least expect to find an ionization nebula?

The halo

Which kind of star is most likely to be part of the spheroidal population?

M star

Which of these galaxies would you most likely find at the center of a large cluster of galaxies?

A large elliptical galaxy

1. We determine the distance of a cepheid by?

Determining its luminosity from the period-luminosity relation and then applying the inverse square law for light

1. Which kind of object is the best standard candle for measuring distances to extremely distant galaxies?

A white dwarf supernova

Why do virtually all the galaxies in the universe appear to be moving away from our own?

Expansion causes all galaxies to move away from nearly all others

1. Which of these galaxies is most likely to be the oldest?

A galaxy in the local group

1. When we observe a distant galaxy whose photons have travelled for 10 billion years before reaching earth, we are seeing that galaxy as it was when the universe was?

4 billion years old (galaxy is 14 billion years old)

Which of these items is a key assumption in our most successful models for galaxy formation?

Some regions of the universe were slightly denser than others

Observations indicate that galaxies with more massive central black holes tend to also have?

A greater mass of stars in their central bulges 

1. The luminosity of a quasar is generated in a region the size of?

The solar system

1. The primary source of quasars energy is?

Gravitational potential energy

The charge of an antiproton is

Negative

1. When a proton and antiproton collide, they

Convert into 2 photons

1. The current temperature of the universe as a whole is

A few K

When the universe was 380,000 years old, its thermal radiation spectrum consisted mostly of

Visible and infrared photons

Which of the following does not provide strong evidence for the Big Bang Theory?

Observations of the amount of hydrogen in the universe

1. Which of the following does inflation help to explain?

The uniformity of the cosmic microwave background

the origin of galaxies

Which of these pieces of evidence supports the idea that inflation really happened?

Observations of the Cosmic Microwave Background that indicate a flat geometry for the universe

1. Which is the earliest time in the universe that we can directly observe?

A few hundred thousand years after the Big Bang

1.  Olbers' paradox is an apparently simple question, but its resolution suggests that the universe is finite in age. What is the simple question posed by Olbers' paradox?

Why is the sky dark at night?

1. Which of the following best explains why the night sky is dark?

The observable universe is not infinite

Dark Matter is inferred to exist because

We can observe its gravitational influence on visible matter

1. Dark energy has been hypothesized to exist in order to explain

Observations suggesting that the expansion of the universe is accelerating

1. Measurements of how orbital speeds depend on distance from the center of our galaxy tells us that stars in the outskirts of the galaxy?

Orbit the galactic center just as fast as stars closer to the center

Strong evidence for the existence of dark matter comes from the observation of

Clusters of galaxies

A photograph of a cluster of galaxies shows distorted images of galaxies that lie behind it at greater distances. This is an example of what astronomers call

gravitational lense

Based on the observational evidence, is it possible that dark matter doesn’t really exist?

Yes, but only if there is something wrong with our current understanding of how gravity should work on large scales

Based on current evidence, which of the following is considered a likely candidate for the majority of the dark matter in galaxies?

Subatomic particles that we have not yet detected

1. Which region of the early universe was most likely to become a galaxy?

A region whose matter density was higher than average

Based on current evidence, what is the overall inventory of the mass-energy content of the universe?

Current studies indicate that the actual density of the universe is about 32% of the critical density: 27% dark matter, 5% ordinary matter, including 0.5% from stars; that dark energy represents about 68% of the critical density.

 What implications does the evidence for dark energy have for the fate of the universe?

The expansion would accelerate with time, causing galaxies to recede from one another with ever-increasing speed

 Which of the following possible types of universe would not expand forever?

A recollapsing universe

 The major evidence for the idea that the expansion of the universe is accelerating comes from observations of

White dwarf supernova