Ch. 26.5 - The Expanding Universe

Ch. 26.5

The Expanding Universe

Multiple Choice

True or false? The apparent change in frequency and wavelength of a wave as it moves towards or away from an observer is known as the Doppler effect.

• True

• False

Open Ended

How can astronomers use the Doppler effect?

Multiple Select

Select each sentence that is true about spectrums of stars or galaxies.

• As a star moves toward Earth, the lines in its spectrum are shifted toward shorter wavelengths.

• As a star or galaxy circles the Earth, the lines in its spectrum shift toward the middle of the spectrum.

• As a star or galaxy moves away from Earth, the lines in its spectrum are shifted toward longer wavelengths.

• The greater the observed shift in spectrum, the greater the speed the star or galaxy is moving.

Fill in the Blank

The shift in the light of a galaxy toward the red wavelengths is called a(n) ______________.

Open Ended

Describe Hubble’s Law.

Fill in the Blank

Astronomers theorize that the universe came into being in an event called the _______________.

Multiple Select

Select each sentence that is true according to the big bang theory.

• the matter and energy in the universe was once concentrated in a very hot region smaller than a sentence period.

• the universe began billions of years ago with an enormous explosion.

• the universe came into existence in an instant.

• the matter and energy in the universe has taken billions of years to form.

Fill in the Blank

After the big bang, it is theorized that the universe expanded quickly and _______ down.

Multiple Select

Select each sentence that gives evidence that supports the big bang theory.

• the existence of cosmic microwave background radiation.

• the red shift in the spectra of distant galaxies.

• the fact that the sun is about 20 billion years old.

• the pulling of atoms together into gas clouds by gravity.

Fill in the Blank

Matter that does not give off radiation is known as ________________.

Multiple Select

Select each sentence that is true about dark matter.

• astronomers currently don’t know what it is or how it is distributed.

• it cannot be seen directly.

• it can be measured using the Doppler effect.

• it can be detected by observing how its gravity affects visible matter.