Is there life on Mars?

How do galaxies form?

How big is the Universe?

What would happen if you fell into a black hole?

What would it take for people to travel beyond our Solar System?

Is the expansion of the Universe accelerating?

How old is the Universe?

Do neutrinos have mass?

What is dark energy?

How big do galaxies get?

What were the first stars like and when did they form?

What is the cause of Gamma Ray Bursts?

Are luminous matter and dark matter distributed the same way in space?

Should Pluto be called a planet?

Do massive black holes lie in the centers of most galaxies?

How is energy released from the Sun?

Is the Sun part of a binary star system?

Are there other Universes?

Is there evidence for another ocean elsewhere in the Solar System?

How do we know the Earth revolves around the Sun?

Should our exploration of the Solar System be robotic or manned?