• How far away is the Sun?
  The distance varies between 91 and 94 million miles from Earth. This ...

• How far is it to the nearest star?
  The nearest star is Proxima Centauri, which is 4.3 light-years ...

• How strong is a planet’s gravity?
  The more massive the planet-that is, the more matter it contains the ...

• What happens inside a black hole?
  Nothing that goes into a black hole comes out, and there is a point ...

• How big is a black hole?
  The singularity at the heart of a black hole is infinitely small. The ...

• How do astronomers measure distance?
  For nearby stars, they use parallax. With middle distance stars, they ...

• What are orbits?
  In space, many objects like planets and moons continually circle ...

• What did Newton discover?
  The discoveries of Isaac Newton (1642-1727) include the three ...

• How many black holes are there?
  No one really knows. Because they trap light they are hard to see. ...

• What are constellations?
  Constellations are small patterns of stars in the sky, each with its ...