Exam 2 - Survey of the Universe

How are clusters of galaxies organized?

Like soap bubbles filament.

Galaxies that we see as they were 11 billion years ago or more, as compared to galaxies today, are generally:

bluer and smaller

The reciprocal of the Hubble constant (1/H) is a rough measure of the: (theory)

universe's age

According to our textbook, roughly what percent of mass and energy contents of the universe is made up of dark matter plus dark energy?

95%

"Cosmic address"

Earth, Solar System, Milky Way, Local Group, Virgo Supercluster

Why is the use of Hubble's Law to measure distances to galaxies so important to astronomers?

Most galaxies are far away and this is the only way to obtain their distance

The standard bulbs (standard candles) that made it possible for astronomers to discover the acceleration in the expansion of the universe were

Type la supernovae

Which of the following types of objects (small or large) has NOT been ruled out as a potential source for dark matter in the Galaxy?

a new kind of subatomic particle

According to the general theory of relativity, the presence of mass

causes spacetime to bend

If quasars are at the distances most astronomers believe they are, then (for the most luminous ones) their luminosities must be:

combined luminosity of a hundred trillion (1014) Suns

Where would you look for the youngest stars in the Milky Way Galaxy?

disk

Where in space did the expansion of the universe begin?

everywhere at once

Edwin Hubble was able to show the farther a galaxy is from us the

faster it is moving away

Which of the following is "evidence" that the universe began with a "Big Bang"? (theory)

galaxies collide

What objects did Harlow Shapley use as "signposts" to figure out the extent of the Milky Way Galaxy and the location of its center?

globular clusters

According to the general theory of relativity, light and other radiation coming from a white dwarf or a neutron star should exhibit

gravitational redshift

What is not true about the Local Group galaxies?

has a thousand member galaxies

How do astronomers explain the energetic jets that come out of quasars and active galactic nuclei in opposite directions?

jets are "spit out" from the chaotic accretion disks of supermassive black holes in directions perpendicular to the disk

To predict whether a star will become a black hole, what is the key property of the star we should look at?

mass

What method do astronomers use with the Hubble Space Telescope to measure distances of far away galaxies?

measuring the period of Cepheid variables

According to Hubble's Law, if two galaxies are not part of our Local Group, and galaxy B is three times farther away from us as galaxy A, then galaxy B will

move away from us three times faster than A

What type of object shows the biggest redshift?

quasar

If a galaxy looks blue overall one can conclude that

the galaxy has young stars with active formation

Once a black hole forms, the size of its event horizon is determined only by

the mass inside

Which of the following is evidence that the formation process of our Galaxy may have included collisions with smaller neighbor galaxies?

the observation of long moving streams of stars that continue to orbit through our Galaxy's halo

When astronomers say that the groups of galaxies are distributed isotropically , they mean that

the way galaxies are arranged in space looks the same in all directions

Recently, astronomers have observed stars and other objects that orbit the center of the Milky Way Galaxy farther out than our Sun, but move around faster than we do. How do astronomers think such an observation can be explained?

there must be a lot of dark matter outside the orbit of the Sun

The first time that astronomers observed both gravitational waves and electromagnetic waves from the same event, what they were observing was:

two neutron stars spiraling towards each other

In our modern view of the expansion of the universe, we understand that it is space that is stretching; individual galaxies don't speed away from each other as if they were rockets. In that case, why do galaxies show a redshift?

waves of radiation in space stretch and their wavelength increases as space stretches

Where is the approximate location of the Sun in the Milky Way Galaxy?

we are in the disk of the Galaxy, about 3/5 of the way from the center

Astronomers today know a lot about the size and shape of the Milky Way Galaxy. Which of the following common objects most resembles the shape of our Galaxy?

CD or DVD

The very strong source of radio waves at the center of our Galaxy is called

Sagittarius A

In which of the following domains of the universe have astronomers NOT found evidence for the presence of dark matter?

Solar System

When quasars "shine" (in visible light and other kinds of radiation) with a lot of energy, where (what location) does this huge amount of energy come from?

accretion disk around a supermassive black hole

How did Edwin Hubble establish there are other galaxies than the Milky Way

observing a Cepheid variable in a nearby galaxy and using it to obtain the distance

How do astronomers now explain the fact that the energy emitting regions for quasars are so small?

quasars are the result of matter falling into a black hole and the event horizon of black holes are extremely small on the cosmic scale

Which of the following observations is a convincing argument for the idea that quasars are located inside galaxies?

quasars have "fuzz" with the same spectra and redshift as the galaxy

Today we know what all quasars have in common is that they appear to be small sources of energy with

redshifts that indicate they are far away

The Tully=Fisher method for measuring distance to galaxies relies on the observed relationship between luminosity of a spiral galaxy and its

rotational velocity

Far away from a black hole (at the distance of another star), which of the following is a possible way to detect it?

search for flickering x-rays being given off from an accretion disk

Edwin Hubble classified galaxies by

shape

The center of a black hole is called a

singularity

Which of the following did NOT happen during the first few minutes of the "Big Bang"? (Theory)

some very massive early stars formed

Milky Way Galaxy type

spiral

What is the strongest known force in the universe?

strong nuclear force

What observations in astronomy, made AFTER the discovery of quasars, was a big help to astronomers in figuring out what quasars really were?

the discovery that the Milky Way Galaxy has a black hole at the center with enough mass for 4 million Suns