Ch 26 & 27 Astronomy Test

What is the meaning of isotropic?

• the same density everywhere

• the same in all directions

• the same at all times

• the same temperature everywhere

• the same in every way throughout space

________ is the concept that all large samples of the universe are alike in appearance anywhere in the universe.

• Confromity

• Isotropy

• Universality

• Homogeneity

• Cosmology

Because almost all of the galaxies are redshifted, we know that:

• there was no beginning to time.

• we are at or close to the center of the universe.

• the universe is expanding.

• the sky is dark at night.

• All of the above are correct.

The darkness of the night sky in a seemingly infinite universe is addressed in:

• the Doppler shift

• parallax shift

• Stefan's Law

• Olbers' Paradox

• the Cosmological Principle.

The redshift of galaxies in the universe is correctly interpreted as:

•  a Doppler shift due to the motions of the galaxies through space.

• an "aging" of the light.

• the effect of intergalactic dust.

• space itself is expanding with time; the wavelengths of photon are stretched while they travel through space.

• the difference in temperatures of distant and nearby galaxies.

While a variety of factors can produce red shifts in the spectrum, the one associated with the expansion of the universe is called:

• universal

• cosmological

• olberian

• relativistic

• the Zeeman Effect

If the density of the universe is less than critical, then:

• the universe will "survive" to expand forever.

•  the universe on average must be less than 2.73K in temperature.

• the universal expansion must stop within about twenty billion years.

•  the universe must be static, and the red shifts are not cosmological.

• the universe will begin contracting immediately into the "Big Crunch."

In which of the following models will the universe stop expanding?

• High Density Universe

• Low Density Universe

• Steady State Universe

• Critical Density Universe

• Euclidean Universe

What does the Hubble law imply about the history of the universe?

• The universe started expanding at some time in the past; the universe has an age.

• The universe has been expanding forever; it is infinitely old.

•  The Milky Way Galaxy is at the focus where the universe started to expand.

• That the farthest galaxies are the oldest and most evolved.

• Before the universe started this expansion, it had collapsed and expanded many times before.

In our best current theory, the first quasars formed about:

• 14.5 billion years ago

• 13 billion years ago

• 12 billion years ago

• 11 billion years ago

• 9 billion years ago