Galaxies quiz

More questions about Galaxies

These visible examples show the question style. LearnClash turns the full topic into ranked duels and spaced repetition.

1. 1 Easy

   Where in the Milky Way does the Sun lie?

   Answer: About halfway out

   Why: Harlow Shapley showed in 1918, by mapping where globular clusters sit, that the Sun lies far from the galaxy's center.

2. 2 Medium

   What mainly keeps the Sun on its path around the Milky Way's center?

   Answer: Mass inside its orbit

   Why: Matter farther out than the Sun pulls from all sides and largely cancels out, so only the mass inside its orbit steers it.

3. 3 Hard

   What holds the most mass in a galaxy cluster besides dark matter?

   Answer: Hot gas

   Why: This gas is heated to tens of millions of degrees, so it glows in X-rays and stays invisible to ordinary telescopes.

4. 4 Easy

   About how many stars does the Milky Way hold?

   Answer: Hundreds of billions

   Why: Nobody counts them one by one: astronomers estimate the total from the galaxy's mass and the mass of a typical star.

5. 5 Medium

   Which element's 21-centimeter radio signal maps the Milky Way's arms?

   Answer: Hydrogen

   Why: Unlike starlight, this radio signal is not absorbed by dust, so it traces arms far too distant to see in visible light.

6. 6 Hard

   What are the giant gamma-ray lobes above and below the Milky Way called?

   Answer: Fermi bubbles

   Why: Each bubble towers about 25,000 light-years above or below the galaxy's center.