One of the most intriguing astronomy stories of the past year has been the discovery of ‘Oumuamua, the first-known interstellar object to visit our solar system. The object was first discovered around a year ago and has since been the source of endless speculation and study. While there are still those both within and without the astronomical community who believe ‘Oumuamua could be an alien probe, the prevailing theory states that ‘Oumuamua is likely an asteroid, comet, or possibly even a sliver of a planet blown apart by its dying host star.
‘Oumuamua is back in the headlines this week as Harvard researchers have published a study claiming that the strange object exhibited anomalous behavior as it approached our Sun which could bolster the theory that the object could be artificial in nature after all. According to Shmuel Bialy and Abraham Loeb of the Harvard Smithsonian Center for Astrophysics, the object increased in velocity as it passed our Sun without changing its spin, something abnormal for a comet.
Comets often experience a process known as outgassing when they warm and release gases trapped inside their icy bodies. When this occurs, the sudden release of gasses causes comets’ spins to change in either speed or direction. ‘Oumuamua, on the other hand, did neither. The researchers claim this could be due to the fact that the interstellar object might actually be a light sail, a spacecraft which uses solar radiation as its primary mode of propulsion:
We explain the excess acceleration of `Oumuamua away from the sun as the result of the force that the sunlight exerts on its surface. For this force to explain measured excess acceleration, the object needs to be extremely thin, of order a fraction of a millimeter in thickness but tens of meters in size. This makes the object lightweight for its surface area and allows it to act as a light-sail. Its origin could be either natural (in the interstellar medium or proto-planetary disks) or artificial (as a probe sent for a reconnaissance mission into the inner region of the solar system).
Of course, other astronomers and scientists have raised objections to this new study, arguing that these two astronomers have “taken advantage of [their] institution’s brand to over-amplify results that are unverified or highly speculative.” Still, given that scientists here on Earth are looking into the same technology as a means of exploring distant areas of the universe, it’s certainly not out of the realm of possibility.
Ultimately, while this new study is far from conclusive, it shows that ‘Oumuamua still presents one of the most fascinating astronomical mysteries of our time. Have we witnessed the first signs of extraterrestrial life? Could future generations look back on this discovery as first contact?
Let’s hope so.