The cigar-shaped asteroid ‘Oumuamua got a lot of attention when it first appeared in our solar system in October of last year. Several teams of researchers even suspected that it was emitting alien signals and were conducting studies regarding that. Now, new research published in Nature Astronomy suggests that the unusual movement of ‘Oumuamua could be the result of a collision with another object.
The asteroid is likely going to continue its tumbling movement for at least a billion more years, unless it doesn’t crash somewhere or collide with another object, astronomers suggest. ‘Oumuamua is the first object that entered our Solar System from interstellar space. Given its distant and unknown origin, astronomers quickly got interested in the unusual movement of the cigar-shaped asteroid when it was discovered.
Researchers and astronomers have never seen an asteroid in a shape such as ‘’Oumuamua. It is quite peculiar and is roughly eight times longer compared to its width. Researchers also debate on what this object truly is. While some suggest it is an organic-rich rocky asteroid, others believe that it’s actually a comet with an icy core.
The unusual movement of ‘Oumuamua also puzzles the scientists. It has likely been travelling through space for hundreds of millions of years, tumbling end over end. The team of scientists from Queen’s University Belfast, led by Wes Fraser wanted to figure out what caused this movement.
They conducted a study on the object’s brightness from all the optical photometry available, in order to decide why it was tumbling so chaotically. Researchers knew that this type of unusual movement has been recorded on objects in other Solar Systems, but that are much smaller and have traditional asteroid shapes compared to ‘Oumuamua. In their case, several factors could have affected their movements.
Some of the potential causes could be tidal torques which are made from planetary close encounters, cometary activity, and something known as the Yarkovsky-O’Keefe-Radzievskii-Paddack effect, which includes solar radiation and internal thermal activity.
In Oumuamua’s case, there’s one case which stands out compared to the others and it’s a collision that possibly caused the unusual movement of ‘Oumuamua
“At some point or another, it’s been a collision,” Fraser told the BBC.
‘Oumuamua is already leaving the Solar System. It will reach Jupiter’s orbit in May of this year and Saturn’s in January 2019. However, it’ll continue it’s odd movement even upon leaving our solar system, according to the researchers. Eventually, its tumbling will stop due to internal strains and stresses that come with motion.
The researchers decided to make calculations on when the cigar-shaped asteroid would eventually stop its unusual movements. The results suggest that it’ll be at least a billion years before it stops tumbling.
“Certainly, more collisions happen while planets are growing than afterwards, so that’s a very good guess. But unfortunately we can’t get a high-resolution image of this thing to see what kind of crater is on it that might be attributed to the collision that caused it to start tumbling.”