A team of astronomers found rare evidence that two planets collided in a distant solar system. Anastasios (Andy) Tzanidakis was checking old telescope data from 2020 and noticed the star Gaia20ehk behaving strangely. The star is about 11,000 light‑years away near the constellation Pupis and should normally shine steadily.
He saw three dips in brightness starting in 2016 and much stronger changes around 2021. Large amounts of rocks and dust passed in front of the star and blocked its visible light. The researchers then looked at infrared measurements and found that infrared light rose when visible light dimmed, a sign of very hot, glowing material. They conclude the debris likely came from a collision between two planets. The dust now orbits at roughly one astronomical unit, and the analysis appears in The Astrophysical Journal Letters.
Difficult words
- astronomer — person who studies stars and spaceastronomers
- telescope — tool used to look at distant objects
- brightness — how much light an object gives
- infrared — light we cannot see but feel as heat
- debris — small pieces left after a big object breaks
- collision — when two objects crash into each other
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Why do the researchers think two planets collided?
- Have you ever used a telescope to look at the sky? Why or why not?
- What would you expect to see after two planets collide near a star?
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