Universe reached peak heat 11 billion years ago

Astronomers have identified the point where the Universe moved from heating to cooling - 11 billion years ago, when the temperature was an astonishing 13,000 degrees Celsius, hotter than the surface of the Sun.

Revealed: How our galaxies are connected

Know how galaxies across the universe are connected? Opening a new chapter in unlocking this mystery, for the first time, astronomers have taken unprecedented images of the intergalactic medium (IGM) - the diffuse gas that connects galaxies.