MCQ Flashcards

Which type of galaxy is characterized by a central bulge, spiral arms, and a disk of stars and gas?

Answer: Spiral

Spiral galaxies feature a central bulge surrounded by a flat disk with curved spiral arms containing young stars, gas, and dust.

What is the Chandrasekhar limit in stellar astrophysics?

Answer: The maximum mass of a white dwarf (~1.4 solar masses)

The Chandrasekhar limit (~1.4 solar masses) is the maximum mass a white dwarf can have before electron degeneracy pressure can no longer support it.

Which force primarily drives the formation of stars from interstellar gas clouds?

Answer: Gravitational force

Gravity causes regions of a gas cloud to collapse inward; as density and temperature rise, nuclear fusion eventually ignites a new star.

What does the cosmic microwave background (CMB) radiation represent?

Answer: Afterglow light from the Big Bang about 380,000 years after it occurred

The CMB is the relic thermal radiation from when the universe cooled enough for atoms to form, releasing photons that now permeate all of space.

What unit is commonly used to measure distances within our solar system?

Answer: Astronomical unit (AU)

One astronomical unit (AU) equals the average Earth-Sun distance (~150 million km) and is the standard measure for intra-solar-system distances.

Which planet has the largest number of confirmed moons in our solar system?

Answer: Saturn

Saturn holds the record for the most confirmed moons, surpassing Jupiter after recent discoveries of many small irregular moons.

What is stellar parallax used to measure?

Answer: The distance to nearby stars

Stellar parallax measures the apparent shift of a nearby star against distant background stars as Earth orbits the Sun, yielding the star's distance.