Physics Milestone 4 review

Galaxies that are redshifted are:

• actually blue.

• really far away.

• invisible.

• moving away from us.

Answer explanation

Galaxies that are redshifted are moving away from us, which causes their light to stretch and shift towards the red end of the spectrum. This phenomenon is a key observation in understanding the expansion of the universe.

Tags

NGSS.HS-ESS1-2

The CMB is:

• the remaining energy from the big bang.

• incredibly hot.

• visible to the human eye.

• only located in certain places in the universe.

Answer explanation

The CMB, or Cosmic Microwave Background, is the remnant radiation from the Big Bang, providing evidence of the universe's early hot state. It is not visible to the human eye and is uniformly distributed throughout the universe.

Tags

NGSS.HS-ESS1-2

Our theory of the universe was confirmed by the discovery of:

• fusion.

• cosmic microwave background radiation.

• the Andromeda galaxy.

• the Doppler effect.

Answer explanation

The discovery of cosmic microwave background radiation provided strong evidence for the Big Bang theory, confirming our understanding of the universe's origin and evolution, making it the correct choice.

Tags

NGSS.HS-ESS1-2

Light waves that are stretched out by objects moving apart:

• have a shorter wavelength.

• travel faster than the speed of light.

• are invisible.

• appear more red.

Answer explanation

When objects move apart, the light waves they emit are stretched, leading to a phenomenon called redshift. This causes the waves to appear more red, as their wavelength increases.

The universe is ____________ years old.

• 8.13 billion

• 13.8 billion

• 1.83 billion

• 381 million

Answer explanation

The universe is estimated to be 13.8 billion years old based on measurements of cosmic microwave background radiation and the expansion of the universe, making this the correct choice.

Tags

NGSS.HS-ESS1-2

The greater the redshift:

• the faster the galaxy is moving.

• the shorter the light waves.

• the bigger the galaxy.

• the closer the galaxy.

Answer explanation

The greater the redshift indicates that a galaxy is moving away from us at a faster speed due to the Doppler effect. This is why the correct answer is 'the faster the galaxy is moving.'

Tags

NGSS.HS-ESS1-2

What is true about these two galaxies?

• The Sombrero Galaxy is closer to us.

• The Pinwheel Galaxy is moving away from us more slowly.

• The Pinwheel Galaxy is moving towards us.

• The Sombrero Galaxy is not moving.

Answer explanation

The Pinwheel Galaxy is moving away from us more slowly compared to the Sombrero Galaxy, which is moving faster. This makes the correct statement about their relative motion the one regarding the Pinwheel Galaxy.

Tags

NGSS.HS-ESS1-2

The universe is expanding.  This means that:

• Galaxies are getting bigger.

• Atoms are getting bigger.

• The universe is creating more matter.

• The amount of space between galaxies is increasing.

Answer explanation

The universe's expansion refers to the increasing distance between galaxies, not their size or the creation of more matter. Thus, the correct statement is that the amount of space between galaxies is increasing.

Tags

NGSS.HS-ESS1-2

In red shift, the wavelengths of light become

• Longer

• Shorter

• Bluer

• Slower

Answer explanation

In red shift, light waves are stretched as objects move away, resulting in longer wavelengths. This is why the correct answer is 'Longer', indicating a shift towards the red end of the spectrum.

Tags

NGSS.HS-ESS1-2

What happens to spectral lines as a star is moving towards an observer?

• They are shifted towards the red light.

• They are shifted towards the blue light.

• They appear more red.

• They appear more blue.

Answer explanation

As a star moves towards an observer, its spectral lines are shifted towards the blue end of the spectrum due to the Doppler effect. This phenomenon is known as blue shift, indicating that the star is approaching.

Tags

NGSS.HS-ESS1-2