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Astronomers say they\u2019ve spotted evidence of a cataclysmic collision between two distant planets.\u00a0<\/p>\n
In addition to sending a shiver up our spines, the resulting study published in the journal The Astrophysical Journal Letters<\/a> could also provide new insight into the evolution of our own solar system \u2014 and perhaps even how the Earth got its Moon.<\/p>\n The clues to this cosmic tragedy come from a main sequence star known as Gaia20ehk. It by all accounts seemed thoroughly ordinary, burning at a steady brightness like our Sun. That is, until it began flickering out of control.\u00a0<\/p>\n \u201cThe star\u2019s light output was nice and flat, but starting in 2016 it had these three dips in brightness. And then, right around 2021, it went completely bonkers,\u201d said lead author Anastasios Tzanidakis, an astronomer at the University of Washington, in a statement about the work<\/a>.<\/p>\n \u201cI can\u2019t emphasize enough that stars like our Sun don\u2019t do that,\u201d he added. \u201cSo when we saw this one, we were like \u2018Hello, what\u2019s going on here?’\u201d<\/p>\n The star, it turned out, wasn\u2019t flickering like a giant dying lightbulb. Instead, the dark patches were caused by huge streams of rock and dust passing in front of it. The quantities would have to be enormous to even partially blot out starlight, so the astronomers say the most likely explanation was that they\u2019re the debris from a planetary collision.<\/p>\n Observations taken with another telescope corroborated this theory. In the infrared data, the light curve spiked while the visible light dimmed. This \u201ccould mean that the material blocking the star is hot \u2014 so hot that it\u2019s glowing in the infrared.\u201d\u00a0<\/p>\n A collision between two massive bodies would produce these levels of heat. Before a brutal bodyslam, the planets would\u2019ve been locked in a morbid dance.<\/p>\n \u201cThat could be caused by the two planets spiraling closer and closer to each other,\u201d Tzanidakis said. \u201cAt first, they had a series of grazing impacts, which wouldn\u2019t produce a lot of infrared energy. Then, they had their big catastrophic collision, and the infrared really ramped up.\u201d<\/p>\n \u201cIt\u2019s incredible that various telescopes caught this impact in real time,\u201d Tzanidakis said. \u201cThere are only a few other planetary collisions of any kind on record, and none that bear so many similarities to the impact that created the Earth and Moon. If we can observe more moments like this elsewhere in the galaxy, it will teach us lots about the formation of our world.\u201d<\/p>\n