Astro 6: Stars, Galaxies and the Universe Exam 1 Review

This set of flashcards is designed to help students review key concepts and questions relating to stars, galaxies, and the universe as covered in their exam lecture notes.

What is the proper way to write the mass of the Sun in scientific notation?

1.9884 x 10^30 kg

Why do we see the ink on a page as black?

It reflects all colors of visible light.

Which correctly orders the parts of the electromagnetic spectrum from shortest to longest wavelength?

Gamma ray, X-ray, Ultraviolet, Visible, Infrared, Radio.

Which photon has the highest energy?

An X-ray photon.

Which photon has the highest frequency?

A blue photon.

Which of the following will never be visible from State College, PA?

The Tarantula Nebula.

Who observes a greater flux of photons from the Sun, an observer on Earth's Moon or one on Mars?

The observer on Earth's Moon.

Where is an X-ray telescope most effective?

In space.

Why are nearly all modern telescopes reflectors?

All of the above are correct.

What process generates energy in the Sun?

Hydrogen fusing into helium via the proton-proton chain.

What happens if a white dwarf exceeds the Chandrasekhar limit?

It will explode as a type 1a supernova.

What can JWST do better than Hubble?

It will have better angular resolution and can see fainter objects.

Which is not a basic nucleosynthesis process?

Add an electron.

What causes Earth's seasons to change?

The tilt of Earth's rotational axis relative to its orbit.

Why is Sirius brighter than Rigel despite its apparent magnitude?

Sirius is closer to Earth.

What does the mirror principle of hydrostatic equilibrium state?

As the core contracts, the outer layers will respond by expanding.

Where does the Sun currently live on the H-R diagram?

It is located in position C.

Which star is likely the most massive on the H-R diagram?

The star at position A.

Which star will live the longest on the main sequence?

The star at position E.

What is the zenith?

The sky directly above you.

What is mass?

The amount of matter that makes up an object.

Why do astronauts experience weightlessness?

Due to the lack of a surface pushing against them.

What is an emission spectrum?

Light from electrons cascading from higher energy states to lower energy states.

What is a black hole?

A dense enough mass that not even light can escape.

What is a pulsar?

A rapidly rotating neutron star that emits signals like a lighthouse.

What is a brown dwarf?

A 'failed star' that never fused hydrogen into helium.

What is a helium flash?

A burst of runaway nuclear fusion in a low-mass star.

What is a planetary nebula?

The outer layers shed by a low-mass star at the end of its red giant phase.

What is the Algol paradox?

Stars in a binary system can exchange mass and alter their masses.

What do continuous spectra exist from?

Because photons of any energy can be absorbed and emitted by hydrogen.

What does a star 10 pc from Earth signify?

It will have a parallax angle of 10 arcseconds.