--- title: "Scientists Offer Ghoulish Theory for Why There Are No Planets of a Certain Size" description: "Size Medium Scientists have uncovered a macabre potential explanation for why a specific subset of exoplanets seem not to exist. Since the discovery of planets outside our Solar System, scientists have discovered a strange pattern: that there doesn't appear to be a happy medium between planets the size of rocky \"super-Earths,\" which are about 1.4 […]" date: "2023-01-18" modified: "2023-01-18" authors: - name: "Noor Al-Sibai" job_title: "Senior Staff Writer" link: "https://futurism.com/authors/nooralsibai" url: "https://futurism.com/the-byte/scientists-medium-exoplanets-gap-theory" categories: - "Off-World" - "Space" tags: - "astrophysics" - "Exoplanets" - "planetary science" - "the digest" --- # Scientists Offer Ghoulish Theory for Why There Are No Planets of a Certain Size ![Scientists have uncovered a macabre potential explanation for why a specific subset of exoplanets haven't been observed yet.]() *\Image: Getty / Futurism\* ## Size Medium Scientists are proffering a macabre potential explanation for why a specific subset of exoplanets seem not to exist. Since the discovery of planets outside our Solar System, scientists have discovered a strange pattern: that there doesn't appear to be a happy medium between planets the size of rocky "super-Earths," which are about 1.4 times wider than our pale blue dot, and icy or watery "mini-Neptunes," which are roughly 2.4 times wider than Earth. To date, as [*Scientific American* notes](), the prevailing hypothesis about this "radius gap" suggests that smaller planets tended to drift closer to their Sun-like stars over time — getting heated up so much that in essence, they burn to a crisp. Last year, however, a group of astrophysicists out of Rice University in Texas published a paper [in the *Astrophysics Journal Letters*]() explaining their own theory: that instead of burning up, smaller and less dense exoplanets may become involved in horrifying interplanetary collisions that destroy them as individuals and reassemble them into larger bodies. ## Rock Me Mama As lead study author André Izidoro told *Scientific American*, this new theory is based on the understanding that as the smaller rocky planets drift closer to their stars, their orbits become more unstable and put them on a potential collision course with one another. According to the Rice researchers' simulations, two rocky planets smashing together would increase their total mass, but because they would lose gas layers in doing so, it would also decrease their radii and cause them to form a single, more massive planet. Icy and watery planets could also collide, Izidoro explains to *SA*, but because "their size does not change that much because water is less dense," those types of collided planets would still "stay above the radius valley." The same goes for the collision of rocky planets with watery ones — it would result in a larger water-rich planet that would be on the mini-Neptune side of the gap. All said, it certainly seems plausible that out in the great beyond, planets are smashing into each other and creating single, bigger planets — or at least, as plausible as any of the [other weird stuff]() that happens out there. **More on exoplanets:** [*NASA Just Discovered an Earth-Like Habitable Planet Orbiting a Nearby Star*]() ## Author At Futurism, I've often been drawn to unpacking the narratives that underlie technological, scientific and medical progress, with a special interest in areas of conflict and ambiguity that end up setting agendas and steering the fates of both elites and the hoi polloi. I'm a committed generalist, but I often find myself returning to work involving NASA and the private space sector, the effects of AI on media and society, and the mechanics of the pharmaceutical industry, with a specific focus on the spread of GLP-1 drugs like Ozempic and Wegovy. Prior to Futurism, I worked for publications ranging from Media Matters and Truthdig to Raw Story and Bustle. I'm also the author of "Myspace Scene Queens," a 2024 title in Instar Books' acclaimed "Remember the Internet" series. My work at Futurism has been cited by outlets including the New Yorker, Slate, Nieman Lab, the Verge, the MIT Technology Review, the Sunday Times, and the Daily Beast. I grew up in North Carolina, attended the University of North Carolina at Asheville, and now live in Brooklyn, New York. In my free time, I'm an avid reader and music fan; you can probably find me at a local poetry reading, concert, underground rave, or DJ set. I'm the proud parent of an ineffable orange cat named Mee-Mow. ### Author social links [Bluesky]()