Interstellar Object 3I/ATLAS
Last year an interstellar object made headlines, a comet that had been spotted traveling towards our solar system and had the potential to impact our planet or our moon - causing conspiracy theories and predictions to spread like wild fire, from a comet containing unknown matter, to alien technology.
The object was named 3I/ATLAS, and was the third interstellar object that modern scientists have been able to observe, a rare opportunity to gain insight into other solar systems or even other galaxies.
Last month, on the 19th of December, 3I/ATLAS passed just inside Mars’ orbit, with Earth safely on the other side of the Sun!
This fly-by gave scientists the opportunity to observe what is probably the oldest interstellar object that we have discovered. Earlier in the year, a group from the University of Oxford used a model called the Ōtuatahi-Oxford Interstellar Object Population Model to predict the properties of 3I/ATLAS. The model showed that the properties of 3I/ATLAS were within the expected range, compared to the previous two interstellar objects we have observed (1I and 2I). The comet’s velocity indicated that its is over 7.6 billion years old and has a high water mass, allowing a visible pluming tail to be observed as it approached our Sun. The group also determined that it was highly unlikely that 3I/ATLAS had its origins in in the same star system or even the same star cluster as the previous two interstellar objects, but that it shares a galactic orbit with older, lower-metallicity stars which allowed them to predict the age of the comet.
Observing interstellar objects allow scientists the opportunity to gather evidence and gain insight into the processes that are at play when planets and stars are formed and potential explanations for how different elements are brought together for life to evolve.
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Matthew J. Hopkins, Rosemary C. Dorsey, John C. Forbes, Michele T. Bannister, Chris J. Lintott, Brayden Leicester