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The universe is close to celebrating its 14 billionth birthday. Here’s what it looked like when it turned 5 billion:
We know, because that’s a photo of a what a star looked like nine billion years taken by the Hubble Space Telescope.
The star pointed to in the bottom right frame is an enormous blue one called Icarus, and it’s the farthest individual star ever seen.
Its official name is MACS J1149+2223 Lensed Star 1, and a team from the universities of Minnesota, South Carolina and the Instituto de Física de Cantabria have been studying it since it was spotted in 2016.
Icarus was named after the Greek mythological character who flew too near the Sun because it was a similar quirk that allowed it to be seen hiding in a far-distant spiral galaxy.
The “Lensed Star 1” refers to the fact that the team spotted it due to a phenomenon know as “gravitational lensing”. When a galaxy cluster hosting a star about as big as our Sun moved in front of Icarus, that gravitational lensing amplified the light from Icarus by 2000 times, allowing the team to see a normally faint pin-prick stand out from a cluster as flickering light in the background.
It appears to us as it did when the universe was about 30 per cent of its current age.
Having analysed the colours of the light coming from Icarus, the team are now confident they were not seeing a surge of light from a supernova.
“The source isn’t getting hotter; it’s not exploding,” study leader Patrick Kelly at the University of Minnesota, Twin Cities said.
“The light is just being magnified. And that’s what you expect from gravitational lensing.”
Icarus, they say, is much larger, more massive, hotter, and possibly hundreds of thousands of times brighter than our Sun.
And by the time they spotted it, was at least nine billion years old.
