A team of astronomers observing the recent movement of comets through our solar system are hypothesizing that the unusual movement of Comet A117uUD is due to an encounter with Saturn.

Comets are a common occurrence in our solar system; the only reason that this comet became notable to researchers was due to its unusual path through space.

Comet A117uUD is following what is known in astronomy as a hyperbolic trajectory. This means that rather than following a smooth curve, it is orbiting in more of a sharp oval shape.

Something has caused this comet to ping off in a more irregular direction.

According to researchers Carlos de la Fuente Marcos and Raúl de la Fuente Marcos in a paper recently published by the American Astronomical Society, the most likely reason for this is an encounter with Saturn:

“Small solar system bodies may reach hyperbolic orbits after a close interaction with a giant planet. [Comet A117uUD] reached its current hyperbolic trajectory after a close encounter with Saturn in 2022.”

So how does this happen?

Just like our Earth, comets usually orbit the sun. The gravitational pull of the sun means that usually they follow a regular path around space.

However, when they encounter a planet or star that has a strong gravitational pull of its own, they may be pulled off course.

The researchers explained that this is a normal thing to happen in space:

“As the solar system goes around the center of the Galaxy, interstellar objects may traverse our planetary neighborhood following hyperbolic paths. Passing stars or the Galactic tide may send Oort cloud comets toward the inner solar system along hyperbolic trajectories.”

Much less commonly, the hyperbolic paths of comets could be caused by encounters with planets in our solar system.

This is much rarer, with the last known instance happening almost 45 years ago:

“Small solar system bodies may also end up in a hyperbolic orbit after a close encounter with the Sun or a giant planet. Comet C/1980 E1 reached its present-day path after a close encounter with Jupiter on December 9 1980.”

In this case, the Comet known as ‘C/1980 E1’ is following a hyperbolic path around the solar system, and has been for over four decades, since it entered Jupiter’s gravitational pull in 1980.

As the comet entered Jupiter’s orbit, the planet’s gravity overpowered the force of the comet, pulling it into its own orbit before pinging it out the other side.

The direction in which the comet was launched by the gas giant has forever changed the trajectory of the comet.

In their investigations into the origins and path of Comet A117uUD, which was discovered by astronomers in South Africa on June 14 2024, the researchers found that it was not launched from outer space:

“Although the hyperbolic excess of its current path is statistically significant, it did not come from interstellar space. Our results show that the case of comet A117uUD is similar to that of C/1980 E1, disfavoring an extrasolar origin for A117uUD.”

This means that instead of its unusual orbit being a result of it entering our solar system at high and irregular speeds, the comet has actually taken its path because of factors local to us.

By comparing this comet to Comet C/1980 E1, they were able to conclude that the hyperbolic path was caused by Saturn, and that such events are not uncommon:

“The fact that two ejections after planetary encounter were observed in less than 45 yr suggests that such events are relatively frequent.”

Though 45 years may seem like a big timespan to the human mind, in terms of the lifespan of space, these two incidents happened mere moments apart.

So next time you are admiring a comet flying by in the night sky, take a moment to wonder: were you sent here by another planet?

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