The Big Bang

Oxygen in a galaxy that is moving away from us emits light with a wavelength of 501 nm.

When detected on Earth, the light will have a wavelength that is:

• greater than 501 nm due to redshift

• less than 501 nm due to redshift

• exactly 501 nm – there is no redshift under these conditions

The discoveries of Slipher and Hubble revealed that:

• most galaxies are getting further away from us, all at about the same speed

• most galaxies are moving towards a common point

• galaxies stay in fixed positions

• most galaxies are getting further away from us, moving faster the further away they are

Einstein's general theory of relativity explained the observed redshift of galaxies by proposing that:

• gravitational waves cause galaxies to move around

• light is always redshifted when it travels through space

• an anti-gravitational force pushes galaxies apart

• the empty space between galaxies is expanding

According to Big Bang theory, the entire observable universe was at one stage of its history about 10 cm across.

• True

• False

According to Big Bang theory, the universe:

• is 13.7 million years old

• is 13.7 billion years old

• is 13.7 trillion years old

• has always existed

Which of these statements are true?

• Atoms existed at the time of the Big Bang

• The moment after the Big Bang, the universe expanded rapidly

• Our Sun was one of the first stars in the universe to form

• Since the Big Bang, the universe has not expanded at a constant rate

If an object's spectrum is blue-shifted, what can you conclude about its motion?

• It's not moving

• It's moving away

• It's moving towards you

What did Hubble discover in the 1920s?

• The universe is expanding

• The universe is getting smaller

• CMB

• We are one of many Earths

Hubble's Law says that...

• Galaxies farther away are moving slower away

• Galaxies do not move

• Galaxies further away from us are moving faster away

• Galaxies closer to Earth are moving faster away

How does redshift of distant galaxies support The Big Bang Theory?

• Expansion means that we probably started from one point

• It doesn't support this theory

• Contraction means that we will condense again someday

• Expansion means that steady state is correct