Readers with a scientific inclination have probably read at least one headline about a research article that suggests that the mysterious little space stone with a very funny name that zoomed in between the Sun and Mercury last year has an extraterrestrial origin.
The research is from Harvard University, the Ivy & est or Ivy League schools. The Harvard Smithsonian Center for Astrophysics, to be precise.
So can it be that the object, called Oumuamua, Hawaiian for scout, is really a kind of extraterrestrial artifact, or a real space probe that is sent to spy on all of our earthlings?
Hate to be a buster, but no!
Let's throw away our scientific and journalistic objectivity for a moment and admit that most people want the answer to be answered. & # 39; yes & # 39; is.
That is why scientists spend so much time searching for extrasolar planets that resemble Earth, and why we want to look closer to Mars and send probes to Europe or Enceladus or any place with a sea of liquid water. Researchers and astronomers all want some evidence that people are not completely alone in the universe.
But in this case, based on discussions VOA has had with astronomers, and based on everything scientists know about spacestone, comets and asteroids, Oumuamua does not seem to act much more than any other space stone in the void.
But this is what scisntists do know about Oumuamua, and that might help explain why some scientists are so enthusiastic about it, whether it offers evidence of extraterrestrial intelligence or not.
Oumuamua was the first interstellar object that visited our solar system. That means that it came from another galaxy like ours. It almost flew in November 2017, almost exactly a year ago, between Mercury and the Sun.
It moved very quickly, with about 136 thousand kilometers per hour. Michele Bannister from the Queen's College in Belfast told VOA that scientists only had about three weeks to see it properly.
Oumuamua is reddish and about 400 meters long. However, it is ten times longer than it is wide, so it actually looks a bit like a gigantic, dirty interstellar icicle. In terms of space, 400 meters is very small, so finding the thing was a big win for astronomers.
"For decades we have theorized that such interstellar objects exist", says Thomas Zurbuchen of NASA "and now – for the first time – we have direct proof that they exist."
That is really interesting, but how is the whole alien & # 39; thing started? Well, it turns out that Oumuamua is absolutely & # 39; unusually & # 39; is because it does not just run through the galaxy. It changes the speed and direction itself. Bannister calls this "non-gravitational acceleration."
It turns out that it is not particularly strange or even unusual. Bannister says that this rock is probably filled with the kind of things that comets and asteroids generally have in abundance. Carbon monoxide, for example, or cyanide. If so, when they get close to the sun and warm up, they shoot like rays in a process called sublimation. This is probably what made Oumuamua look like it acted on its own, because it was in a certain way.
Here is how NASA explains this degassing acceleration:
We will never really know
But that perfectly reasonable explanation has not prevented Harvard scientists Shmuel Bialy and Abraham Loeb from presenting a few possible alternative possibilities for Oumuamua, including one that suggests that our interstellar space stone was a light sail, a gigantic sail using the sun's energy instead of wind to push a vehicle through space.
They suggest that this is possibly a possibility, because some other studies suggest that our interstellar wanderer is not a comet and is not an outburst. Hence the idea of solar sail. And the team does the math to show how Oumuamua fits the bill.
The other possibility brought forward by Bialy and Loeb is that "Oumuamua can be a fully operational probe that is deliberately sent to Earth by an extraterrestrial civilization." They also do mathematics to show how the route of Oumuamua could be useful if it was focused on our path.
It is important to note that the paper has not yet been assessed by colleagues, which is the process that all scientific research goes through before it is published by renowned journals such as Science of Nature. This means that other scientists in the same field read it out, give input and check its validity. So we will see what happens with this article.
But as far as Oumuamua is concerned, it's too small for even our best telescopes to take a look, so researchers have all the information they'll ever have.
But do not worry, there are probably many more Oumuamua's available. "The galaxy is filled with flying rocks," says Bannister. "Trillions on billions" of spaceships, varying in size from a "skyscraper" to a planet, are probably wandering through the galaxy. And if we are lucky, Bannister says we should be able to see about one per year.
So in one way or another the earth gets visitors from other stars, but they are just random stones that continue. So no extraterrestrials, but still pretty big science.