When the first sign of intelligent life first visits us from space, it will not be a giant saucer floating over New York. More likely it will be trash from an alien civilization.
Avi Loeb, the chairman of Harvard’s Astronomy Department, thinks he’s already found some of that trash.
In his forthcoming book, “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” (Houghton Mifflin Harcourt), out Jan. 26, the professor explains convincing evidence why one object that recently entered our solar system was not just another. rock but actually a piece of alien technology.
The object in question traveled to our Solar System from the direction of Vega, a nearby star 25 light-years away, and intercepted our solar system’s orbit on September 6, 2017.
On September 9, his trajectory brought him closest to the sun. In late September, it shot past Venus’ orbital distance at about 58,900 miles per hour, and then, on October 7, it shot past Earth’s before “ moving rapidly towards the constellation Pegasus and the darkness beyond, ” Loeb writes in the book. .
The object was first spotted by an observatory in Hawaii with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) – the highest resolution telescope on Earth.
The space object was named ‘Oumuamua’ (pronounced ‘oh moo ah moo ah’), which is Hawaiian for – roughly – ‘scout’.
While space travelers travel, it was relatively small at only about 100 meters in length, but it was a major problem in the scientific community.
For starters, it was the first interstellar object ever detected in our solar system. Judging by the object’s trajectory, astronomers concluded that it was not bound by the sun’s gravity – suggesting it was simply traveling through it.
No sharp pictures could be taken, but astronomers could train their telescopes on the object for 11 days and collect so much other data.
At first, scientists thought it was an ordinary comet. But Loeb said that assumption carries the risk that “the familiar may determine what we might discover.”
“What would happen if a caveman saw a cell phone?” he asked. “He’s seen stones all his life, and he would have thought it was just a shiny stone.”
Loeb soon opened his mind to another possibility: it was not a comet but discarded technology from an alien civilization.
A number of unusual properties of the object helped Loeb reach this conclusion.
The first were ‘Oumuamua’s dimensions.
Astronomers looked at the way the object reflected sunlight. Brightness varied by a factor of ten every eight hours, suggesting that this was the amount of time it took to complete a full rotation.
Scientists concluded that the object was at least five to 10 times longer than it was wide – something like the shape of a cigar.
No naturally occurring space body we’ve ever seen has looked like this – or even close.
“This would make ‘Oumuamua’s geometry in aspect ratio at least a few times more extreme – or width to height – than the most extreme asteroids or comets we’ve ever seen,” Loeb writes in his book.
What’s more, ‘Oumuamua was unusually smart. It was at least “ten times more reflective than a typical solar system [stony] asteroids or comets, ”the author writes.
He compares the surface to that of shiny metal.
But the anomaly that really pushed Loeb towards his ET hypothesis was the way ‘Oumuamua moved.
“The excess push away from the sun – that was the thing that broke the camel,” he said.
Using physics, scientists can calculate the exact path an object must travel and the speed it must travel because of the gravitational pull exerted by the sun. The pull of the sun will greatly accelerate an object as it gets closer and then kick it out on the other side, only to slow the object down significantly as it gets further away.
But ‘Oumuamua did not follow this calculated trajectory. In fact, the object accelerated “somewhat, but to a very statistically significant degree,” Loeb writes as it moved away from the sun.
In other words, it was clearly propelled by a force not just caused by the sun’s gravity.
At first the explanation seemed simple. Comets show a similar acceleration, because as they approach the sun their surface heats up, releasing once frozen gases that act like a rocket engine.
Those released materials, however, form a comet’s signature tail. Scientists looked carefully at that tail or any sign of gases or dust that might propel ‘Oumuamua and came up empty.
Loeb calculated that with these and other anomalies, the probability that ‘Oumuamua was a random comet was about one in a trillion, leading him to his blockbuster hypothesis.
But what exactly was it?
One possibility, strangely enough, is to be found in the technology that we already have here on Earth.
“Some people don’t want to talk about the possibility that there are other civilizations.”
Avi Loeb, Harvard astronomer and author of “Extraterrestrial”
Some 400 years ago, astronomer Johannes Kepler saw comet tails blowing in what looked like a sun breeze and wondered if that same force could propel rocket ships through space like the wind pushes boats through water.
It was a smart idea that scientists are now using to develop light sails for probes. Thin, reflective foil is rolled out into space to catch the particles streaming from the sun and propelling a ship through the empty void at great speed. Alternatively, powerful lasers from Earth can be aimed at the sail to make it go even faster.
Loeb, who is involved in a lightsail project to send a small, unmanned vessel to a nearby star, said that if we Earthlings have thought of this idea, why should aliens not be able to?
He and a colleague crunched the numbers and hypothesized that ‘Oumuamua was not quite cigar-shaped, but possibly a disk less than a millimeter thick, with sail-like proportions that would explain the unusual acceleration as it moved away from the sun.
Loeb is not entirely sure about the goal. He speculated it could be ‘space junk’ that once served as some sort of spaceflight buoy used by a long-ago civilization.
The only way to search [alien civilizations] is to look for their trash, like investigative journalists looking through celebrity trash, ”said Loeb.
Of course, not everyone in the scientific community agrees with his theory.
In July 2019, the International Space Science Institute’s ‘Oumuamua team published an article in Nature Astronomy concluding, “We find no compelling evidence for an alien explanation for’ Oumuamua.”
Loeb admits his theories have raised the eyebrows of astronomers, but he is firm about his findings. “Some people don’t want to talk about the possibility that there are other civilizations,” he told The Post. “They believe we are special and unique. I think it is a prejudice that must be abandoned. ”
Loeb said that the skeptics bend over to attribute a natural origin to the object and that the explanations they have given to explain its strange properties cannot withstand criticism.
For example, some scientists have suggested that “ Oumuamua’s acceleration was caused by frozen hydrogen on the surface turning to gas and propelling it like a comet, and that hydrogen would have been invisible to Earth’s infrared cameras, so we didn’t detect it.
But Loeb and a colleague published a paper showing that “a hydrogen iceberg traveling through interstellar space would evaporate long before it reached our solar system.”
Whatever the truth, the stakes are high.
The acceptance that an alien race has made contact – even through its debris – would trigger a serious search for more debris, making us search the moon and Mars for debris that could have crashed thousands or millions of years ago, for example. .
And if more evidence is found, we Earthlings should start building tools to help us grapple with aliens, such as space treaties and academic fields such as astro-linguistics and astroeconomics.
Perhaps more importantly, further discoveries could redefine our place in the universe.
“It would put us in perspective,” Loeb said. If we’re not alone, are we the smartest kids around? If there was a species that eliminated itself through war or through climate change, we can get our affairs in order and behave better. Instead, we waste a lot of resources on Earth fighting each other and other negative things that are a big waste. ”
Since ‘Oumuamua’s appearance in 2019, a second interstellar object, known as 2I / Borisov, has entered the solar system through a Crimean telescope. But that turned out to be a simple old comet.
Until recently, our instruments were not sensitive enough to pick up these types of visitors. But Loeb said technology will soon make it possible to locate more space travelers, and the only way the mystery of ‘Oumuamua will be solved is if a similar object is spotted and explored more thoroughly with a probe.
He said his book should “motivate people to gather more data about the next object that looks weird.”
“If we find another one and take a picture and it looks like a light sail, I don’t think anyone will argue with that.”