- Scientists observed a dramatic collision between two planets in a distant galaxy near Pupis constellation
- The star Gaia20ehk showed unusual flickering due to dust from a recent planetary collision
- The debris cloud formed by the collision caused significant dimming events in the star's light output
Scientists have witnessed a dramatic collision between two planets in a distant galaxy that might mirror the way a Mars-like planet crashed into Earth, leading to the formation of the Moon. The violent cosmic incident took place near the constellation Pupis, approximately 11,000 light-years from Earth. Astronomer Andy Tzanidakis was combing through old telescope data from 2020 when he found an old star named Gaia20ehk, akin to our Sun, behaving strangely. Gaia20ehk was flickering wildly instead of emitting steady, predictable light, prompting Tzanidakis to dig deeper.
"The star's 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," he said. "I can't emphasise enough that stars like our sun don't do that. So when we saw this one, we were like 'Hello, what's going on here?'"
Tzanidakis and other researchers eventually found that the star itself was not flickering, albeit it had huge quantities of rocks and dust floating in front, which dimmed the light reaching Earth. The researchers hypothesised that the heavy debris was formed by a brutal collision between two heavenly bodies.
"We hypothesise that Gaia20ehk represents debris recently formed in a planetary collision, which produced a clumpy dust cloud on a bound orbit, producing the observed dimming events. The ongoing collisional activity in this system presents a unique opportunity for understanding terrestrial planet formation," the study published in The Astrophysical Journal Letters highlighted.
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Similarities To Moon's Formation
Tzanidakis said the chaos around Gaia20ehk also offers insights into how our world was born. Several theories about our Moon's formation have floated in the last few decades, but nearly all of them share a similar point. At the time of the solar system's formation, about 4.5 billion years ago, a single object the size of Mars or a series of objects crashed into the young Earth and flung enough molten and vaporised debris into space to create the Moon.
Tzanidakis pointed out that the debris cloud around Gaia20ehk was located around 1 astronomical unit, roughly the distance between Earth and the Sun. At this location, the debris could cool and combine to form new planetary bodies, similar to the Earth-Moon system.
The process, however, could either take a few years or a few million. Despite the lack of clarity about the eventual outcome, the researchers stated that finding and studying these collisions can provide insights into how planetary systems form and evolve.
