Astro 150 S 2024 Final Review 1/2 - Apr 25, 2024 (1-14)

What was the Copernican Revolution?

• The shift from using a geocentric model to a heliocentric one

• The shift from philosophy and intuition to empirical evidence to find truth

• Copernicus's failed attempt to overthrow the Polish government

• The shift to using the simplest explanation as the most likely one

Answer explanation

The shift from a geocentric to a heliocentric model was part of the Copernican revolution, but the Copernican revolution was more about how we found truth.

In ancient times, what was the major flaw of the Heliocentric model?

• It could not explain retrograde loops

• The Sun moved in the sky too much

• It wasn't the simplest explanation

• Parallax was not observed

Answer explanation

It wasn't until we developed advanced telescopes that we had instruments sensitive enough to detect stellar parallax.

What would the semimajor axis of a star with a 3 year period be?

• 9.14 AU

• 5.20 AU

• 3.02 AU

• 2.08 AU

Answer explanation

P is the period, so if we square the period of 3, we get 9. And then we take the cube root of 9 and that gets us 2.08 AU.

Which force is responsible for light?

• Strong nuclear force

• Electromagnetic force

• Gravitational force
• Weak nuclear force

• Star 1

• Star 2

• They are the same

An blackbody with a blue peak wavelength should be ________ than one with a red peak wavelength?

• Hotter

• Cooler

• Faster

• Slower

Answer explanation

According to Wien's law, the peak wavelength of a blackbody is inversely proportional to its temperature. So, objects with a shorter (bluer) peak wavelength must be hotter.

What kind of spectrum do we see from the sun (and other stars)?

• Emission spectrum

• Absorption spectrum

• Continuous spectrum

• Blackbody spectrum

Answer explanation

This picture is the spectrum we see from the sun. It looks largely continuous, but there are some dark lines in there. Those are absorption lines, making this an absorption spectrum.

If space telescopes get better data, why don't we put all of our telescopes in space?

• It costs a lot to put telescopes in space

• Some wavelengths can't be observed in space

• Space telescopes get hit with too many cosmic rays

• There's too much space junk that might hit space telescopes

Which type of telescope would have better resolving power?

• A 2-meter radio telescope

• A 2-meter infrared telescope

• A 2-meter optical telescope

• A 2-meter UV telescope

What size is the largest radio interferometer we feasibly make today?

• 10 km diameter

• 100 km diameter

• The diameter of Earth

• The Earth-moon distance