Dark matter could be destroyed in the ventral cavities of exoplanets.

Large gas planets could be filled with self-destructive dark matter. And now, a team of researchers has proposed using the soon-to-be-launched James Webb Space Telescope to scan distant behemoths in the galaxy for potential heating effects that could arise from the mysterious substance, which outweighs regular matter by almost 6 to 1 in the universe.

Physicists are aware that dark matter exists because it gravitationally attracts stars and galaxies. But, thus far, the invisible material has thwarted all attempts to better understand its properties.

Many theories of dark matter propose that it is made of individual particles and that these particles can sometimes hit one another as well as regular matter particles, Juri Smirnov, an astroparticle physicist at The Ohio State University, told Live Science. Under these models, two dark matter particles could also shatter and annihilate, generating heat, he said.

If these assumptions are true, dark matter particles are sometimes expected to crash into large objects like exoplanets, causing them to lose energy and accumulate inside these worlds. There they might annihilate one another and produce a measurable heat signal that is visible from afar, Smirnov said.

Along with his colleague Rebecca Leane, a postdoctoral researcher at SLAC National Accelerator Laboratory in Menlo Park, California, Smirnov has suggested using the space-based Webb telescope, which will scan the skies in the infrared part of the electromagnetic spectrum, to look for this characteristic heat signature.

Larger exoplanets would accumulate more dark matter, so the best candidates for such searches would be gas giants bigger than Jupiter, or brown dwarfs — enormous worlds that nearly became stars but failed to gather enough gas to ignite nuclear fusion in their cores, the researchers wrote in a paper published April 22 in the journal Physical Review Letters.

Determining that the heat is coming from dark matter annihilation and not some other process would be tricky, so Smirnov and Leane propose looking for exoplanets that have been flung away from their parent star and are quite old, meaning they will have cooled to very low temperatures. If such an object was anomalously shining in the infrared, it could indicate the presence of dark matter.

But an even more reliable method would be to look for many exoplanets throughout the Milky Way and make a map of their temperatures, Smirnov said. It is expected that dark matter will accumulate in the galactic center, so this map should show that exoplanet temperatures rise slightly as you approach the core of the Milky Way.

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This signature cannot be explained by any known astrophysical activity. “If we look at this, it must be dark matter,” Smirnov said.

Capturing such a signal could help physicists determine the mass of dark matter particles and how rapidly they interact with regular matter. Since Webb, which is expected to be launched in October, will already be looking at exoplanets throughout the galaxy, Smirnov thinks the map of dark matter's potential heat signature could be made within four to five years.

'This is a good idea,' Bruce Macintosh, an astronomer who studies exoplanets at Stanford University in California and was not involved in the work, says Live Science. Researchers have built enormous underground detectors on Earth to try capturing dark matter particles, but "there's a limit to how big a detector you can build as a human being," he added."We should take advantage of the big things nature provides," Macintosh said.

His only problem with the study was that Webb—who will do focused and thorough studies on relatively few objects—might not be the best telescope for the work. The Nancy Grace Roman Space Telescope, scheduled to launch in the mid-2020s, will map the sky in great detail and may be more suitable for this task, he added.

Original publication on Live Science.