Where are the aliens?
Illustration: Aliens
One night 60 years ago, physicist EnricoFermi looked up at the sky and asked, "Where are the people?" "
He was talking about aliens.
Today, scientists know that there are millions, perhaps billions, of planets in the universe that can sustain life. So why, in the long history, why has none of these beings gone into space far enough to shake hands (or claws...) with humans. or tentacles)? This may be because the universe is too big to traverse.
It could also be that aliens deliberately ignore us. It may even be that every growing civilization is irreversibly doomed to destroy itself (Earthlings, something to look forward to).
Or maybe it could be something more and weirder. Like what, you ask? Here are nine strange answers that scientists have come up with for Fermi's paradox.
Aliens are hiding beneath a sea of landmarks
Image source: JPL- California Institute of Technology/SETI Institute/NASA
If humans want to communicate with aliens, they need to prepare something that can break the ice. Extraterrestrial life may be trapped in secret oceans buried deep in frozen planets.
Astronomers say the subsurface ocean of liquid water wobbles beneath multiple moons in our solar system and may be common throughout the Milky Way. NASA physicist Alan Stern believes that such a mysterious water world could provide a perfect platform for the evolution of life, even if inappropriate surface conditions plague these plants. Stern told Space.com, "Impacts and solar flares, nearby supernovae, the orbit you're in, whether you have a magnetosphere, and whether you have a toxic atmosphere, none of these things matter to life underground."
That's a good thing for aliens, but it also means we can never detect them just by scanning their planets with telescopes. Can we expect them to contact us? What's worse, Stern said — these little animals live so deeply that we can't even expect them to know there's a patch of sky above their heads.
Aliens are imprisoned on "Super-Earth".
Illustration: Super-Earth concept map, source JPL-Caltech/NASA
"Super-Earth" does not refer to the existence of "Captain Planet". In astronomy, a "super-Earth" refers to a planet with a mass 10 times larger than Earth. Star surveys have uncovered a large number of such worlds, which may have conditions suitable for liquid water. This means that it is conceivable that extraterrestrial life may be evolving on super-Earths in the universe.
Unfortunately, we may never encounter these aliens. According to a study published in April, a planet with a mass of 10 times earth will also be 2.4 times faster than Earth, and overcoming this pull could make rocket launches and space travel nearly impossible.
Michael Hipke, an author of the study and a researcher at the Sonneberg Observatory in Germany, previously told Living Sciences that "on planets of greater mass, the cost of spaceflight will multiply." "Instead, those aliens will be caught on their home planet in some way."
We're looking in the wrong direction — because aliens are actually robots
Illustration: Alien robots
Humans invented radio around 1900, built the first computer in 1945, and are now mass-producing handheld devices capable of performing billions of calculations per second. Full-blown ai could be at the inflection point, says futurist Seth Shostak, which is enough to replan our search for intelligent aliens. Simply put, we should be looking for machines, not little green people.
"Any [extraterrestrial] society that invented radio, so we can hear them, within centuries, they have invented successors," Shostak said at the Dent:Space conference in San Francisco in 2016. "I think it's important because their successors are machines."
Shostak said an advanced alien society could be made up entirely of superintelligent robots, which provides a reference for our search for aliens. Instead of focusing all our resources on finding other habitable planets, perhaps we should also look for places that are more attractive to machines. For example, places with a lot of energy, such as the center of a galaxy. "We're looking for analogues of our own," Shostak said, "but I don't know that most intelligence is in the universe." "
We were ready to spot aliens — but too scattered to realize a little
Illustrated pictures of other planets: Source: NASA
Influenced by popular culture, "aliens" may remind you of a ghostly humanoid figure with a large bald head. The styling is great for Hollywood, but these preconceived E.T. images could ruin our search for extraterrestrial life, a team of psychologists from Spain wrote earlier this year.
In a small study, the researchers asked 137 people to look at pictures of other planets and scan the pictures for signs of alien structures. In these pictures, several of them hide a little man dressed as a gorilla. When the participants looked for what extraterrestrial life looked like, only about 30 percent noticed the gorilla because they were looking for it according to imaginary alien creatures.
In reality, the researchers write, aliens may not look like orangutans; they may not even be detectable by light and sound waves. So, what does this study show us? Basically, our own imagination and attention limit our search for aliens. If we don't broaden our frame of reference, we may miss out on the gorilla staring at us.
Humans could kill all aliens
The closer we get to finding aliens, the closer we get to destroying them. Theoretical physicist Alexander Bryan says that either way, it's a possible outcome.
His idea was this: Any civilization capable of exploring beyond its solar system must embark on a path of unrestricted growth and expansion. And as we know on Earth, this expansion often comes at the expense of smaller, obstructive organisms. "When we finally encounter extraterrestrial life, assuming we notice it, this self-priority mentality may not end," Brian said.
"What if the first being to reach the ability to travel interstellar must destroy all competitors to drive its own expansion?" Bryan wrote in a paper published in the preprint journal arXiv.org in March. "I'm not saying that a highly developed civilization will consciously wipe out other life forms. Most likely, they won't notice at all, like a construction team demolishing an ant nest in order to build real estate, because they lack the motivation to protect the nest." In this case, it remains to be seen whether humans will be ants or bulldozers.)
Aliens have caused climate change (and death).
Illustration: Alien climate change
Disasters occur when a population consumes resources faster than its planet can provide. This can be fully understood from the ongoing climate change crisis on Earth. So is it possible for an advanced, energy-intensive extraterrestrial society to encounter the same problem?
According to astrophysicist Adam Frank, this is extremely possible. Earlier this year, Frank ran a series of mathematical models to simulate how a hypothetical alien civilization would rise and fall as it increasingly converted its planet's resources into energy. The bad news is that in three of the four programs, society collapsed and most of the population died. The civilization will survive only when the society detects problems early and immediately shifts to sustainable energy. This means that if aliens do exist, the probability of their self-destruction is quite high before we meet them.
"Throughout space and time, there will always be winners who manage to see what's going on and figure out a path through it. The losers just can't get their actions, and their civilization is eliminated," Frank said. "The question is, what kind of person do we want to be?"
Aliens can't evolve fast (and die)
Another reason for the "aliens are dead" is that the universe may be filled with hospitable planets, but there's no guarantee that they'll stay long enough for life to evolve. A 2016 study by the Australian National University showed that a wet rocky planet like Earth is very unstable at the start of its career; if any extraterrestrial life wants to evolve and prosper in such a world, it has a very limited window (hundreds of millions of years) to get the ball rolling.
"Between early heat pulses, freezing, volatile content changes, and runaway [greenhouse gases], sustaining life on an initially wet rocky planet in a habitable zone can be like trying to ride a bison, and most life will fall," the study authors wrote. "Life is very rare in the universe, but not because it's hard to start, but because a habitable environment is difficult to sustain for the first billion years."
Dark energy is splitting us apart
Illustration: Dark energy
The universe is expanding. Slowly but all the time, galaxies are moving farther away, distant stars appear dimming in front of us, all thanks to the pull of a mysterious, invisible substance that scientists call dark energy. Scientists speculate that in trillions of years, dark energy will stretch the universe so long that Earthlings will no longer be able to see the light of any galaxy outside of our nearest cosmic neighbor. It's a terrible thought. But if we don't explore the universe as much as we can before that, such an investigation could cost us forever.
Dan Hooper, an astrophysicist at the Fermi National Accelerator Laboratory in Illinois, wrote in a study earlier this year: "Stars have not only become unobservable, but also completely inaccessible. This means that we are in the deadline to find and greet any aliens out there. To stay one step ahead of the dark energy, we will have to expand our civilization to as many galaxies as possible before they all drift away.
Hooper said: "Of course, it is not easy to fuel this growth. It may involve rearranging the stars.
Twisted ending: We are aliens.
Illustrated: Human aliens
If you leave home today, you see an alien. The woman who delivered the letter? It's aliens. Your next door neighbor? Eventful aliens. Your parents and siblings? Aliens, aliens, aliens.
At the very least, this is one meaning of the fringe theory of astrobiology, known as "pansystemism." In short, the hypothesis holds that much of the life we see on Earth today did not originate here, but was "sown" here millions of years ago by meteors carrying bacteria from other worlds.
Proponents of this theory have argued that octopuses, lemmings, and humans were all sown here from elsewhere in the galaxy. Unfortunately, there is no real evidence to support this. And there's a huge rebuttal reason: If bacteria carrying human DNA evolve on another nearby planet, why haven't we found a trace of humans anywhere other than Earth? Even if this hypothesis proves to be justified, it still doesn't help us answer Fermi's nagging questions... Where are we?
BY: Brandon Specktor
FY: Autumn white
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