solar system

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What is known about the cometlike object spotted by scientists?

Quick notes:

  • The object will be visible to astronomers for close to a year

  • Its makeup doesn’t resemble that of its predecessor, Oumuamua

  • The discovery could break new ground on interstellar mysteries

On August 30, Gennady Borisov, an astronomer with the Crimean Astrophysical Observatory spotted an interstellar object coming into our solar system. Shortly after its discovery, NASA’s scout system noted that the object’s orbit was highly unusual compared to its predecessor, Oumuaamua.

When Oumuamua was discovered back in 2017, it opened the door to new information about how interstellar objects travel through the solar system on a regular basis. Unlike Oumuamua though, this second deep space object will be much more trackable, and for a longer period of time.

How do we know it’s extraterrestrial?

Objects in our solar system are bound to the sun’s orbit. Both Oumuamua and this second interstellar object, dubbed C/2019 Q4 in honor of the first astronomer to discover its presence, were not on that same orbit. This has led scientists to believe that the only explanation for where it came from would have to be deep outer space.

More than three different groups have studied C/2019 Q4 since its discovery, and they all came to that same conclusion, solidifying their theory that the object flew in from a galaxy far, far away. The possible comet will make it’s closest approach to earth on December 29 when it flies between Jupiter and Mars.

Data obtained from the Canada-France-Hawaii Telescope (CHFT) in Hawaii, is now being tested by the ESA to cast certainty on its interstellar status.

Unsplash / Guillermo Ferla

The difference in the two could mean big answers.

When Oumuamua was discovered, it was the first time scientists observed an interstellar object entering the solar system. At that time, the elongated one-of-a-kind object resembled more of an asteroid than a comet because of its lack of any trademark comet traits, such as a gas-like halo.

C/2019 Q4, however, has more of the typical markers of a comet. The data found shows that it is a few kilometers in diameter, is discarding gas and dust, and has a bright halo of material. Scientists expect it to “outgas” itself once it reaches the closest point to the sun, which will help them decide whether or not it is truly a comet or just another extraterrestrial object making its way around the universe.

Canada-France-Hawaii Telescope

The timing of the discovery spells a better chance for answers.

When the first interstellar object was discovered, it was on its way out of the solar system, so astronomers had very little time to capture data and explore what they were seeing. This led to a few unanswered questions as it continued its journey through outer space.

When it comes to C/2019 Q4, astronomers will have about a year to observe it, roughly 8 months longer than Ouamuamua, giving them a lot more to work with. Since Oumuamua was so unusual in its makeup and wasn’t available for further observance, it was hard to decipher the exact size and origin of the object without a shadow of a doubt.


However, with C/2019 Q4, the data is much more typical. It exhibits all the signs of being a planetesimal—an icy, leftover planetary building block—which only furthers the theory that it is from a planetary system far outside of our solar system. The fact that it is seemingly a planetesimal and astronomers have a lengthy amount of time to study it means the discovery could offer a whole new look into interstellar objects and the way they travel through space.

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