Are we alone or do we share our solar system and galaxy with other forms of life? And how widespread are advanced civilizations with whom we could communicate? Right now we don’t have answers to these profound questions. But scientists are in hot pursuit...
If the Big Bang theory is correct, how fast is the universe expanding? Astronomers are facing a troubling disconnect between different methods used to measure the expansion rate, known as the Hubble constant. The two methods are giving similar but slightly different rates. Either one method is providing inaccurate results, or there is some kind of unknown physics operating in the universe.
