FRED ANSWERS YOUR QUESTIONS
We are told the Universe began as an incandescent gas ball that cooled during millions of years to form galaxies, and so on. Where was this heat dissipated? Not in space, because we know it is empty.
Jeff Lewry, Bowna, NSW
The Big Bang’s heat must still be around, physicist George Gamow first noted decades ago. Observations of the Cosmic Microwave Background Radiation, which permeates the Universe, bear that out today. We interpret this as the Big Bang’s flash, seen at a look-back time of 13.8 billion years and stretched into microwaves by the Universe’s expansion. Far from being empty, space is full of photons of radiation, 99 per cent of which originated in the Big Bang. The rest is mostly starlight.
If you have a space question for Fred, email it to firstname.lastname@example.org