Astronomers are surprised anyway. ‘This is a very strange object,’ says Simon Portuguese Swart of the Leiden Observatory. “I slept badly because of that.”

UN271 was recently found in photos recently taken as part of the Dark Energy Survey. The celestial bodies move in a very long and steep orbit, with an orbital period of a few million years – ten times longer than their current lifespan. Homo sapiens.

In 2031 it will reach the nearest distance from the Sun, which is much larger than Saturn. But the farthest distance from orbit is 7.5 trillion kilometers – in the interior of what is known as the Ort cloud.

John Hendrick Ort

The Ort Cloud is named after the Dutch astronomer John Hendrik Ort. In the middle of the last century, unpredictable comets were predicted to orbit the sun at great distances – a few kilometers thick ice cubes.

Occasionally such a comet is blown into the sun, and we can see it in the starry sky. For example, Comet Nouveau was visible last year, with beautiful tails and dust clouds.

If UN271 were a comet, it would be a horrible size. The diameter ranges from 130 to 370 km. Never before has such a large object been observed from the Ort cloud.

Michelle Hogerhaijde of the Leiden Observatory hopes to find more such whips in the near future. “Then we can find out if they are rare large comets or if there are very different populations in the sky,” he says.

Uranus

But the Portuguese Swart (not included in the discovery like Hoger Heidge) has a completely different question: UN271 actually orbited the outer layers of the Solar System and was ejected from the planet Uranus by a gravitational pull a few hundred million years ago. To the ort cloud? Or has he been in the orbit cloud for the last few billion years and ‘kept’ from there?

In the latter case, the ‘mega-comet’ must have had a big move. ‘It only works if there are larger celestial objects in the orbit cloud compared to Earth,’ says Portuguese Swart.

It also explains the existence of ice dwarfs, perhaps the so-called centaurs, in unstable orbits between Saturn and Uranus. ‘I will definitely make some extensive calculations about the stability of the orbit of this new object.’

There are already temporary voices to send a space probe to UN 271 for further investigation. By itself, there is plenty of time for this: only in 2031 will the luminous object slowly but again begin to move away from the Sun. ‘Always fun, of course,’ and very expensive. Fortunately, with Earth telescopes, we can learn a lot in the years to come. ‘