Why Are Exoplanets Shrinking? NASA Scientists May Have an Answer

Amaze Lab

Thus far astronomers have identified more than 5,000 exoplanets, but among all of those, most seem to be either super-Earths or sub-Neptune sized. Now, after observing several planets that have been shrinking, experts believe they might finally know why that might be the case.

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00:00Thus far, astronomers have identified more than 5,000 exoplanets, but among all of those,

00:08most seem to be either super-Earths or sub-Neptune-sized, meaning they are almost all at

00:13least 1.6 times the diameter of our planet, or upwards of 2 to 4 times the size, with

00:18little in between. Now, after observing several exoplanets that have been shrinking, experts

00:23believe they might finally know why that's the case. According to a recent release by

00:27the NASA Exoplanet Archive, quote, Exoplanet scientists have enough data now to say that

00:32this gap is not a fluke. There's something going on that impedes planets from reaching

00:36and or staying at this size. They say that sub-Neptunes are likely shrinking due to radiation

00:41from its planetary core, which pushes its atmosphere away until it's around the size of a super-Earth.

00:46They're calling the process core-powered mass loss, and they believe that the atmosphere of

00:49the planet is literally lost to space during the process. This is in contrast to previous

00:54theories, which suggested that the planet's host star dissipated the atmosphere of an exoplanet,

00:59though this process, called photoevaporation, is believed to only occur for around the first

01:03100 million years of a planet's life cycle, meaning older planets like the ones observed

01:08in this study would need another avenue for their planetary shrinkage.

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