Imagine being a young astronomer, looking up at the stars and wondering of your future in the industry you hold so dear. And when you glance at the sky in awe of the universe and all of creation, you see a small flicker of light far in the distance. With your intrigued conscience and your high-grade telescope, you take a good look at the interesting discovery and notice something very strange. Without hesitation you scream, “Holy moly, those two planets just hit each other!” Well, On October 11, 2023, two exoplanets of the ice category were seen colliding with each other while orbiting a distant star. This discovery is located roughly 1,800 lightyears away and was being watched closely for many months.
Co-Author of the Nature Article titled “A Planetary Collision Afterglow and Transit of the Resultant Debris Cloud” Dr. Matthew Kenworthy stated, “To be honest, this observation was a complete surprise to me. When we originally shared the visible light curve of this star with other astronomers, we started watching it with a network of other telescopes. An astronomer on social media pointed out that the star brightened up in the infrared over a thousand days before the optical fading. I knew then this was an unusual event.”
As stated, the discovery was all thanks to diversions in the registered brightness of the star ASASSN21qj, which had been monitored for years prior to the subsequent debris field and planetary collision. This discovery of light fluctuation was then chalked up to the planetary collision once the discovery was made. Though the collision was not visible to us yet, due to the light taking roughly 1,800 years to reach us, the light waves were still detectable through infrared.
One of the cooler elements to this discovery is taking into account how planets and planetary bodies form. So, planets form through gravitational pull from a star pulling space debris and matter into its orbit. Over millions of years, the debris will slowly form together and condense from the gravitational pull and form a rough planetary body. Depending on the size of the object in question, the shape can either be round and spherical or very rough and edged. Now, taking into account the fact that there is now an extremely large amount of space dust orbiting around this sun, the implications of a possible moon or even a new planet forming is looking extremely possible.
This collision could also cause light from the surrounding locations to spread out and become deflected off of the debris. Curved light will veer off course and emerge in locations that are not accurate to its original trajectory and could cause visuals in later studies to be skewed or inaccurate. Another implication is how the collision will affect the other planets that are orbiting the same sun or even the planets lightyears away. This collision not only sent millions of large chunks of planet barreling into the depths of space but it also sent gargantuan-sized shockwaves of gravity throughout their occupied space. I would not be surprised if the surrounding planets possibly suffered from gravitational earthquakes or some sort of distortion to their own gravitational fields.
Overall, the collision is changing the total form of the system and could cause major changes millions of years from now. With the new debris field, fluctuating infrared light, and disrupted gravitational waves within the system, its future is going to be under investigation for years to come.
Kenworthy, M., Lock, S., Kennedy, G., van Capelleveen, R., Mamajek, E., Carone, L., Hambsch, F.-J., Masiero, J., Mainzer, A., Kirkpatrick, J. D., Gomez, E., Leinhardt, Z., Dou, J., Tanna, P., Sainio, A., Barker, H., Charbonnel, S., Garde, O., Le Dû, P., … Rizzo Smith, M. (2023, October 11). A planetary collision afterglow and transit of the resultant debris cloud. Nature News. https://www.nature.com/articles/s41586-023-06573-9
University of Bristol. (2023, October 11). Researchers capture first-ever afterglow of huge planetary collision in Outer Space. October: Exoplanet collision | News and features | University of Bristol. https://www.bristol.ac.uk/news/2023/october/exoplanet-collision.html