Regardless of what we imagine when we think of aliens, aggressors with ray throwers or green men, we do not know if they exist in principle. And if they exist, what if they are trying to contact us? It turns out that scientists are seriously concerned about this issue. Here are ten theoretical and extremely strange ways in which aliens, according to scientists, can try to contact us.
Megastructure
The mysterious monolith in A Space Odyssey 2001 turned out to be an alien machine designed to monitor species and control evolutionary behavior. Some scientists argue that alien megastructures could act as giant beacons for other civilizations.
In fact, scientists are closely watching the star KIC 8462852, whose glow has mysteriously changed over the past few years. Some argue that this star is surrounded by a giant structure that sometimes blocks light from the star. Other, less exciting explanations include a swarm of exoplanets or a planetary disk. Scientists have looked for short laser pulses from this star, but have not found it yet. And they are unlikely to find it.
"The alien megastructure hypothesis near KIC 8462852 is falling apart rapidly," said Douglas Vacoch, president and author of SETI International. And he adds: "We have not found any evidence of an advanced civilization intentionally sending laser signals in the direction of the Earth."
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Laser pulses
Astrophysicist Ragbir Bhatal works with SETI, scanning the sky for possible signals from extraterrestrial intelligence. Unlike most SETI sites that search for radio signals, Bhatal's site searches for laser pulses. The pulses are searched for over huge volumes of space - 100 light-years away - to detect laser flashes that occur at regular intervals. Scientists today can capture signals even in one photon of light that flies through every few fractions of a second.
Basically, lasers can transmit messages over incredible distances. But although scientists have studied a huge number of stars in search of laser signals from aliens - objects at Harvard and Princeton scanned more than 10,000 stars like our Sun - they found no evidence of alien communications.
Alien Probes
It may well be that the signals from the aliens are not traveling in the form of electromagnetic waves. Instead, very small objects exploring the universe could be signs of intelligent life. After all, we ourselves send probes to the planets: Mars, Saturn, Venus and others. Mathematicians from Scotland have suggested that "self-replicating" alien probes could already explore our solar system and remain here, but remain elusive for our detection technologies.
Robot probes could explore our galaxy and self-replicate from interstellar dust and gas. Then the parents and children of the probes would each go to their own star, where they would repeat the process again: search for life and reproduce again. Doctors Nicholson and Forgan concluded that a fleet of such probes could explore the entire galaxy in a relatively short span of time over 10 million years.
Dr. Forgan believes that the fact that we have not found or seen any evidence of alien probes in the solar system suggests that either there are no probe builders in our neighborhood, or the probes are so advanced that we cannot observe them. Another possibility is that we have failed an alien intelligence test without detecting these probes.
Radio waves from afar
For many years, mysterious bursts of radio waves, reaching us through billions of light years, have puzzled our scientists. Just a few thousandths of a second long, these flashes - fast radio bursts - appear in the sky by accident. Scientists have not been able to figure out the cause of the appearance of these bursts, but suggested that they could be marks of evaporating black holes, colliding dense objects or burning dead stars.
By studying how the incoming radio waves curl and scatter from the recently discovered burst, scientists have found important clues to the origin of the explosion: it appeared far away, in an area of dense and highly magnetized plasma, and passed through two gas clouds before being captured by the Green Bank Telescope in West Virginia.
Now astronomers suspect that magnetic stars (magnetars) can also emit radio waves and be the culprit behind the appearance of fast radio bursts. Be that as it may, scientists are gradually moving towards unraveling the reasons for this cosmic event.
Excess radiation
Not all aliens can look for other creatures in the universe. Theoretical physicist Freeman Dyson has suggested that even humble aliens could develop technology to suck energy from a nearby star using an object in orbit, the Dyson Sphere. If humans were to collect all the energy from the Sun, we would most likely use something like a Dyson sphere.
Freeman Dyson first came up with such an idea as a thought experiment in the 1960s. He suggested that the search for such structures could lead to the discovery of advanced civilizations elsewhere in the galaxy. These Dyson spheres would throw off excess heat in the form of infrared radiation. Scientists at the Allen Telescope and the WISE Space Telescope are studying the skies looking for this excess radiation.
Space tractors
Geron Lanier suggested that it was time to think about repositioning the Sun and other stars in order to send signals to the aliens. It's also worth starting to look for signs that aliens might be doing the same to us.
When neutron stars were first discovered, scientists first thought they were messages from "little green men."
Lanier proposed sending a large number of space "tractors" over the years to the outer solar system. Such a spacecraft would have to be programmed to operate for hundreds of thousands of years, during which its gravitational attraction would move the objects of our system. The point is to make them rotate in a form that does not occur in nature. Such a method of cosmic writing.
A needle in a haystack
If aliens have ever tried to contact us, there is no guarantee that we received their messages. The universe is huge and messages can come from anywhere. To narrow down the search, some have suggested that the aliens would most likely send a message in our direction if they knew we were here. That is, if we had found our planet using the methods that we ourselves use to find other planets. A study published in February 2016 showed that we currently only know 82 stars that are in a direct line of sight with the Earth, that is, from which the transit of the Earth in front of the Sun can be observed.
Rene Geller and his colleague Ralph Pudritz of McMaster University in Hamilton, Canada, predicted that this small region (0.520 to 0.537 degrees wide) could contain 100,000 stars - some of which have planets teeming with life. One of the advantages of this approach is that this tiny piece of sky is relatively easy to find.
“You can just scan the entire transit zone of the Earth in a few dozen nights or so, depending on how large your radio telescope's field of view is,” Geller says. If these hidden exoplanets have life, they could end up in our galactic neighborhood, just a few hundred light years away.
Destruction of an alien planet
One way to discover another civilization is to catch it destroying its own planet, according to Dr. Natalie Cabrol, who leads the hunt for alien life at the SETI Institute in California. “There is a time window in which civilization can be expected to reach the same imbalance that we are in now. At this time, you can find typical signs of destruction in the planet's atmosphere."
Cabrol's point of view coincides with that of former astronaut John Grunsfeld, who said earlier this year: "If life exists, alien life, then it will know that we are here." He believes that an advanced alien civilization can detect people from afar by the changes that we cause in the environment on Earth. Our atmosphere ensures that anyone with a large telescope 20 light years away can see exactly what we're doing here.
Wait a few billion years
Scientists from STScl (NASA Space Telescope Science Institute) armed themselves with observations of telescopes like Hubble and Kepler, to find out that the Earth is included in 8% of all terrestrial planets that will ever form. The other 92% of terrestrial planets have not yet formed. The author of the work, Peter Behruzi, says that compared to all the planets that are just forming in the Universe, the Earth appeared too early.
And since it appeared so early, scientists believe that it is unlikely that our planet will be the only one on which intelligent life appeared. The chance that we are the only intelligent civilization that this universe will see is about 8%. It remains only to wait a couple of billion years and see.
A copy of our Sun
What if we find a star with the same temperature, size, and chemical composition as our sun? Our Earth relies on the energy of the Sun - it is necessary for life for successful photosynthesis. If we could find a star similar to ours, perhaps it could be in the same solar system as us.
In 2012, astronomers discovered HP 56948, a "clone" of the Sun, just 200 light years away. The chemical composition of HP 56548 has increased amounts of aluminum, calcium, magnesium and silicon - just like our sun. But in this system there may be no terrestrial planets in the habitable zone. Even if it did, it might not have the right chemistry for life, like water and carbon. And even if it was filled with blooming life forms, they might not become intelligent.
ILYA KHEL