The diagram numbers the Sun's layers outward from the center. Which numbered layer is the visible surface that emits most of the Sun's light?

The graph plots monthly sunspot number across one 11-year solar cycle. Which year on the graph shows the fewest sunspots?

Which process inside the Sun's core converts hydrogen into helium and releases the energy that powers the Sun?

The diagram shows the sequence of energy production in the Sun's core. Which stage directly produces the energy that eventually reaches the surface?

A sudden brightening in the Sun's chromosphere that releases a burst of radiation across the electromagnetic spectrum is called what?

A sunspot appears darker in a photograph than the surrounding photosphere. What does this darker appearance indicate about the sunspot?

Using the same numbered diagram of the Sun's layers, which numbered layer appears only during a total solar eclipse as a thin reddish rim above the surface?

Between a red star and a blue star, which one has the cooler surface temperature?

Use the spectra. Star A and Star B show the same set of hydrogen lines. What does the position of Star B's lines most likely indicate about Star B?

What quantity, measured from the apparent shift in a nearby star's position against distant background stars, gives that star's distance from Earth?

The bar graph shows the apparent magnitudes of Star P and Star Q as seen from Earth on the same night. Which star appears brighter in the sky?

Two stars share the same surface temperature, but one shows much stronger absorption lines from heavy elements in its spectrum. What does this difference reveal about the two stars?

The bar graph compares the luminosity of Star R and Star S in units of the Sun's luminosity. What can you conclude about Star S compared to Star R?

A star's parallax angle is measured as 0.1 arcseconds. Using $d=\frac{1}{p}$, where $p$ is in arcseconds and $d$ is in parsecs, what is the star's distance?

Use the H-R diagram. What kind of star is Star W?

Use the H-R diagram. What kind of star is Star X?

Use the H-R diagram. Where does Star Y fall on the diagram?

Use the H-R diagram. Which kind of star is Star Z?

Use the H-R diagram. Which star, A or B, has the larger radius?

On a standard H-R diagram, which axis plots surface temperature, running hotter on the left to cooler on the right?

The diagram plots the same star at two points in its life: on the main sequence, and later as a red giant. How did its plotted position change between the two points?

What is the term for a hot, dense ball of gas that has not yet begun nuclear fusion, formed from a collapsing cloud of gas and dust?

The diagram shows the life cycle stages of a low-mass star like the Sun. Which stage belongs at the blank, immediately after the red giant stage?

The diagram shows the life cycle of a high-mass star. Which event belongs at the blank, immediately before a neutron star or black hole forms?

What determines whether the collapsed core left behind after a supernova becomes a neutron star or a black hole?

A colorful shell of gas is observed expanding steadily outward from a small, extremely hot and dense star at its center, glowing from that star's ultraviolet light. What is this object?

Which stellar remnant is composed almost entirely of tightly packed neutrons and can be smaller than a city while containing more mass than the Sun?

A rapidly expanding, filamentary shell of hot debris is seen surrounding the site of a massive star's explosion centuries earlier. What is this structure called?

The bar graph compares the approximate main-sequence lifetimes of a 1-solar-mass star and a 10-solar-mass star. What does the comparison reveal about mass and lifetime?

What is the name of the galaxy that contains our solar system?

A galaxy is observed as a smooth, football-shaped glow of old yellow and red stars, with no spiral arms, no disk and almost no gas or dust anywhere in it. How is this galaxy classified?

The diagram shows the Milky Way's structure viewed from above. Which numbered feature marks the location of our solar system?

Spiral galaxies show far more active star formation and young blue stars than elliptical galaxies do. What does this difference suggest about their gas and dust content?

A galaxy shows no organized spiral arms and no smooth oval shape, only a patchy clump of gas, dust and young star clusters. How is this galaxy classified?

What is the name of the faint radiation detected uniformly from every direction in space, considered strong evidence for the Big Bang?

Use the spectra. The two galaxies show the same set of absorption lines. What does the position of the distant galaxy's lines indicate about it?

Which law states that a galaxy's recession speed is directly proportional to its distance from Earth, providing key evidence for an expanding universe?

A galaxy 200 million light years away is receding at 4,000 km/s. By Hubble's Law, about how far away is a second galaxy receding at 8,000 km/s?

The scatter plot shows recession speed against distance for several galaxies, with a trend line fitted through the points. What pattern does the plot show?

The timeline shows major events since the Big Bang. According to the timeline, which event occurred first after the Big Bang itself?