William F. Strong
We have reported previously on these pages about “Oumuamua,” a mysterious, interstellar object that crashed through our solar system two years ago. Because of its unusual shape and trajectory – many speculated that it could be some sort of alien craft or probe.
For years since its original sighting, the conventional scientific community has dismissed such claims, arguing that Oumuamua is indeed a natural, albeit, unusual phenomena. However, more recent studies of the object say that it might in fact be alien technology. That’s because the most common alternative, “non-alien” scientific explanation might be “fatally flawed,” as a new study argues.
In 2018, our solar system was “visited” by an object lost in interstellar space. The object, dubbed “Oumuamua,” seemed to be long and thin — cigar-shaped — and tumbling end over end. Close observations of the object showed it was accelerating, as if something were pushing on it. Scientists still aren't sure why.
At the time, an explanation offered by SETI researchers and reported on in these pages was that the unexplained object was being propelled by some kind of alien tech, such as a Solar Sail — a wide, millimeter-thin machine that accelerates as it's pushed by solar radiation. A main proponent of this argument was actually a respected scientist Avi Loeb, a Harvard University astrophysicist.
However most of Loeb’s colleagues think Oumuamua's weird acceleration was likely due to a natural phenomenon. In June, a research team proposed that solid hydrogen was blasting invisibly off the interstellar object's surface and causing it to speed up.
However, in a new paper published Aug. 17 in The Astrophysical Journal Letters, Loeb and Thiem Hoang, an astrophysicist at the Korea Astronomy and Space Science Institute, argue that the hydrogen hypothesis couldn't work in the real world — which would mean that there is still hope that our neck of space was once visited by advanced aliens — and that we actually spotted their presence at the time!
When a Comet Isn’t a Comet
Oumuamua is an anomaly because it moved like a comet, but didn't have the classic coma, or tail, of a comet, said astrophysicist Darryl Seligman, an author of the solid hydrogen hypothesis.
“Oumuamua was the first object ever seen flying into our solar system and back out again. That's opposed to most solar system objects that turn circles around the sun, never leaving the celestial neighborhood.” Its journey and the fact that it was accelerating suggested Oumuamua, which is estimated to be about 1,300 to 2,600 feet (400 to 800 meters) long, was a comet. And yet, "there was no 'coma' or outgassing detected coming from the object," Seligman said. Normally, comets come from regions more distant from the sun than asteroids, and “ice on their surface turns straight into gas as they approach the sun, leaving behind a trail of gas, or what we see as a beautiful comet tail,” Seligman said.
That outgassing changes how the comet moves through space, he said. It's a bit like a very slow rocket engine, “The sun strikes the comet, the warmest part of the comet bursts with gas, and that gas flowing away from the comet sends it tumbling faster and faster away from the sun,” explained Seligman.
Seligman hypothesized that the same manner of propulsion could be driving Oumuamua via the thawing of “light hydrogen” or H2 molecules. The venting of such gas would propel the object like a comet but would not leave the typical visible tail.
But that assumes that Oumuamua is basically a “hydrogen iceberg,” something that Hoang and Loeb say is nearly impossible. Their paper argued that even starlight in the coldest parts of space would warm up small chunks of solid hydrogen before they could clump together and form a comet of Oumuamua's large scale. And more importantly, the trek from the nearest "giant molecular cloud" — a dusty, gassy region of space where hydrogen icebergs are thought to form — is far too long. A hydrogen iceberg traveling hundreds of millions of years through interstellar space would have fallen apart, cooked by starlight, long before it could loop through our Solar System.
What Oumuamua actually is, or is made of remains mysterious. But most scientists still think the idea that we spotted alien technology in our solar system is a long shot.
What do you think -- is Oumuamua a natural phenomenon, or Alien Artifact? Please reply in the comments below.