WORLD
Distant Quasar Confirms Universe Was Warmer 7 Billion Years Ago
Baku, January 24 (AZERTAC). The astronomers using CSIRO’s Australia Telescope Compact Array - an array of six 22-m radio telescopes in eastern Australia - measured the temperature of the cosmic microwave background, the very weak remnant of the heat of the Big Bang that pervades the entire Universe.
They studied gas in an unnamed galaxy 7.2 billion light-years away.
“When we look at this galaxy with our telescopes, we see it as it was when the Universe was younger - and warmer - than it is now,” Dr Muller said. “The only thing keeping this gas warm is the cosmic background radiation - the glow left over from the Big Bang.”
By chance, there is another powerful galaxy, a quasar called PKS 1830-211, lying behind the unnamed galaxy.
Radio waves from PKS 1830-211 come through the gas of the foreground galaxy. As they do so, the gas molecules absorb some of the energy of the radio waves. This leaves a distinctive ‘fingerprint’ on the radio waves.
From this ‘fingerprint’ the astronomers calculated the gas’s temperature. They found it to be 5.08 Kelvin (minus 450.5 F): extremely cold, but still warmer than today’s Universe, which is at 2.73 Kelvin (minus 454.8 F).