Exotic Objects, Stars How many solar masses must a star be to end up a black hole (before normal mass loss during its life)?
Galaxies Do all spiral galaxies rotate in the same direction, and how can I tell the rotation from a photo?
Exotic Objects Has a meteorite ever been found that is suspected to have come from a solar system other than our own? How would we recognize such a meteorite?
Science Gamma radiation from space has very high energy levels. What is the theoretical limit on the energies of gamma-ray photons? Is there a current technology to detect and measure the highest energy level?
