WITH the discovery of planets around distant stars in the Milky Way now almost routine, it takes evidence of planets beyond our own galaxy to turn heads 鈥� and that鈥檚 what Erin Mentuch at the University of Toronto in Canada has produced.
Mentuch analysed 88 remote galaxies whose light was emitted when the universe was between a quarter and half its current age 鈥� making them far too remote for their stars to be seen individually. The galaxies鈥� light output peaks at two distinct wavelengths. One represents the combined light of a galaxy鈥檚 stars; the other, at longer wavelengths, comes from the glow of its interstellar dust.
In each case, Mentuch noticed a faint third component between the two peaks. Whatever produces this light is too cold to be stars and too warm to be dust. The most likely source is circumstellar discs 鈥� embryonic solar systems around young stars. 鈥淚t鈥檚 the most surprising result I鈥檝e ever worked on,鈥� says Roberto Abraham, who collaborated with Mentuch.
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The opportunity to study discs that existed so long ago could help reveal how the rate of planet formation across the universe has changed over time, says Mentuch. The work .
