Science I read recently about the possibility of two white dwarfs colliding to create a type la supernova. Why do astronomers think it has to be two white dwarfs instead of a white dwarf colliding with a regular star?
Science The Hubble Space Telescope found a galaxy that was completely formed within 480 million years of the Big Bang. How could gas and dust clouds condense into stars and organize themselves via gravity into an entire galaxy in less time than it takes the Milky Way to make two rotations?