Planets 'spotted' outside our own galaxy for first time

Discoveries of exoplanets within the Milky Way have been happening regularly for some years now, with 403 found since the first one was spotted in 1995.

However, scientists studying remote galaxies, some up to 10 billion light years away, believe they have seen signs of planetary formation within them – the first such evidence found.

Erin Mentuch and a team at the University of Toronto looked at 88 remote galaxies, each so far away that the light reaching us is from when the galaxy was between a half and a quarter of its present age of 13.7 billion years. That is far too far away for individual stars to be made out.

When the research team studied the wavelengths of light emitted from the galaxies, they found, as expected, that it peaked at two main wavelengths – one short, the bright light coming from glowing stars, and one long, the faint heat coming from interstellar dust.

What they did not expect was a third, smaller peak in between them, too hot to be dust and too cold to be stars.

The team say that the most likely source of this unexpected radiation was “circumstellar discs” – the swirling circles of dust, gas and rocks that will coalesce under their own gravity into solar systems.

Roberto Abraham, another of the Toronto researchers, said: "It's the most surprising result I've ever worked on." He says that the discovery could show whether the rate of planet formation has changed as the universe has aged.