Astronomy Cosmology and Deep Space 3 — Questions and Answers
Question 1: What is a light-year a measure of?
- Distance (Correct answer)
- Time
- Brightness
- Temperature
Correct answer: Distance
A light-year is the distance light travels in one year, about 9.46 trillion kilometers.
Question 2: Which type of galaxy is the Milky Way classified as?
- Spiral galaxy (Correct answer)
- Elliptical galaxy
- Irregular galaxy
- Lenticular galaxy
Correct answer: Spiral galaxy
The Milky Way is a barred spiral galaxy with a central bar and winding arms.
Question 3: Dark matter is inferred to exist primarily because of its effect on:
- The rotation and motion of galaxies (Correct answer)
- The color of stars
- The taste of interstellar gas
- Radio broadcasts from Earth
Correct answer: The rotation and motion of galaxies
Galaxies rotate faster than their visible mass allows, implying unseen dark matter provides extra gravity.
Question 4: The nearest major galaxy to the Milky Way is:
- Andromeda (Correct answer)
- The Large Magellanic Cloud's core
- Whirlpool Galaxy
- Sombrero Galaxy
Correct answer: Andromeda
The Andromeda Galaxy is the nearest large spiral galaxy and is approaching the Milky Way.
Question 5: What cosmic structure is a vast, mostly empty region between galaxy filaments?
- A void (Correct answer)
- A quasar
- A supernova remnant
- An accretion disk
Correct answer: A void
Cosmic voids are enormous low-density regions in the large-scale structure of the universe.
Question 6: The observable universe is finite mainly because:
- Light has only had a finite time to reach us (Correct answer)
- Space physically ends at a wall
- Telescopes are too weak
- The universe is very small
Correct answer: Light has only had a finite time to reach us
We can only see regions from which light has had time to reach us since the universe began.
Question 7: A quasar is powered by what?
- A supermassive black hole accreting matter (Correct answer)
- Nuclear fusion in a single giant star
- Colliding comets
- Reflected galactic light
Correct answer: A supermassive black hole accreting matter
Quasars shine brightly as gas heats up while falling into a supermassive black hole.
Astronomy Cosmology and Deep Space 3
What is a light-year a measure of?