Select the statement that provides evidence of the Big Bang Theory.

• Presence of light elements like hydrogen and helium in abundance
• Discovery of meteorites
• Discovery of millions of galaxies by Hubble Telescope
• Acceptance of idea that the Sun is the center of the solar system

What does the 1755 Island Universe Hypothesis suggest about the Milky Way?

• It is the only galaxy in the universe
• It is one of many galaxies in a vast universe
• It is a nebula
• It is the center of the universe

For what reason did the heliocentric model of the universe replace the geocentric model of the universe?

• The heliocentric model proved that the Earth rotates.
• The geocentric model did not predict the phases of the Moon.
• The geocentric model no longer predicted the positions of the constellations.
• The heliocentric model provided a simpler explanation of the motions of the planets.

Which statement BEST explains how the Doppler shift provides evidence for the Big Bang Theory?

• The Doppler shift of light from distant galaxies implies that planets are moving away from Earth, suggesting the universe is expanding.
• The Doppler shift of cosmic microwave background radiation indicates that it originated from a hot, dense state and has shown a redshift over time.
• The Doppler shift of sound waves from distant galaxies suggests that the planets are moving closer to Earth, supporting the expansion of the universe.
• The Doppler shift of light from galaxies in different directions reveals a pattern of redshifts, supporting that the universe continues to expand from a central point.

Throughout the years, scientists have had many different theories on how the Sun produces energy. At first they believed it was a giant ball of burning gas, then they believed it was shrinking due to gravity and releasing energy. Currently, they believe the reason the Sun has been able to release so much energy for such a long time is because of —

• nuclear fusion on the surface of the Sun converting hydrogen into helium
• nuclear fission in the core converting helium into hydrogen
• nuclear fusion in the core converting hydrogen into helium
• nuclear fission on the surface of the Sun converting helium into hydrogen

R136a1 is a star in the R136 cluster, located in the Large Magellanic Cloud galaxy that revolves around the Milky Way. R136a1 is about 300 times more massive than the Sun and about 9 million times brighter. What would be the likely last stage of R136a1 in its life cycle?

• Black hole
• Blue giant
• Red giant
• Supernova

The image shows the various stages in the life cycle of Sun-like stars. Which describes the correct sequence of the stages in the life cycle of Sun-like stars?

• Average star → White dwarf → Black dwarf → Nebula → Red giant
• Planetary nebula → Nebula → Red giant → Average star → White dwarf
• Nebula → Average star → Red giant → Planetary nebula → White dwarf
• Red giant → Planetary nebula → Nebula → White dwarf → Black dwarf

The diagram shows the spectrogram of some elements and an unknown star. Identify which element is present in the unknown star.

• Calcium
• Hydrogen
• Magnesium
• Sodium

The image shows a Hertzsprung-Russell Diagram. If Rigel has a surface temperature of 6,000 K and an absolute magnitude of -7.4 M, which statement accurately describes the star?

• Rigel is in its longest life stage.
• Rigel is a hot, supergiant star.
• Rigel is a cool, giant star.
• Rigel is a dim star.

Astronomers have observed that absorption bands in the spectra of distant stars are shifted towards the red end of the light spectrum. This observation provides evidence that:

• those stars are moving away from earth
• the universe is becoming warmer
• the universe is contracting
• the elemental composition of those stars is changing