Scientists have seen evidence of a mysterious series of “free-floating” planets that travel through space without being attached to a star.
The research was carried out using NASA’s Kepler Sapce Telescope, which picked up an interesting signal indicating an Earth-sized planet lurking in space.
However, these signals are not affected by the long signals expected if a parent star like our Sun were to join them.
The researchers therefore suspect that stars may have formed around their own stars before they were flung out of their solar system by the gravitational effects of other, heavier neighbours.
The signal is recorded according to the “micro-lens” principle predicted by Albert Einstein. It happens when the star in the foreground can act like a magnifying glass for the star behind, which can be thought of as bursts of brightness.
Most of these rare occurrences are caused by stars. But a small number of those minuscule incidents are caused by planets.
Those are signals that appear to be caused by another world that scientists are picking up on in the new study — despite concerns that they may never actually be discovered.
“These signals are very hard to find,” said Iain McDonald of the University of Manchester, who led the research.
“Our observations show an older, diseased telescope with blurred vision of one of the densest parts of the sky, where there are already thousands of bright stars of varying brightness and thousands of asteroids hurtling in our field.
“From this cacophony we tried to extract the tiny illuminations typical of the planets, and we only had one chance to see the signal before it disappeared. It’s as easy as looking for a blink of a firefly with a cell phone in the middle of the freeway.”
The Kepler Space Telescope was never intended for this type of work. Its main role is to search for other planets by looking for the shadows they cast when they pass in front of their star.
“Kepler is doing what it was never intended to do by providing further preliminary evidence for the existence of a population of free-floating planets of Earth mass,” said Eamonn Kerins, also of the University of Manchester, who co-authored the study.
“Now he’s leaving the baton to another mission designed to find signals like these, signals so elusive that Einstein himself thought they might never be observed. I am very pleased that ESA’s upcoming Euclid mission can complement this effort as an additional scientific activity to their primary mission.”
These missions – and other research by NASA and various space agencies – will try to confirm the existence of these free-floating planets and what they look like.
A paper detailing the results is available at Monthly notification from the Royal Astronomical Society.
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