(ORDO NEWS) — Have smart aliens ever visited the solar system? This is not a stupid question.
After all, the solar system has existed for more than 4 billion years, and if intelligent life arose in our galaxy, then it could reach the level of technological perfection necessary for the study of other systems, including ours.
And mankind can find evidence of such a visit, if it really took place.
A group of scientists and astronomers have detailed what artifacts we should look for if we hope to find traces of alien civilizations in the solar system. They also told what tools humanity can and does use for this.
What kind of life are we looking for in the universe
There are several basic methods for mind-hunting off-Earth. The first approach is to look for signs of any kind of life at all, intelligent or otherwise.
This is by far the most common method in astronomy, and is usually aimed at other star systems, such as looking for chemicals created by life in the atmospheres of other worlds.
But the search for extraterrestrial life can also take place within the solar system, at objects such as Mars and Saturn’s moon Titan, whose atmosphere is rich in hydrocarbons.
Another approach is to look for the most intelligent life, because it is likely that intelligent aliens are able to make their presence known much more easily than microbes.
For example, we can look for communicative aliens broadcasting their existence in radio or optical waves. The search for artificial radio signals is SETI’s bread and butter for finding extraterrestrial intelligence.
But intelligent aliens may leave other clues. If they become capable of building so-called megastructures, like Dyson swarms, for example, then we may be able to detect these megastructures when looking for other systems.
For example, large enough structures around a star change the light we see and could be a sign of intelligent activity.
So far, all searches for extraterrestrial life have yielded no results. But there is another path that is relatively unexplored: the search for extraterrestrial artifacts.
The idea behind this approach is that if aliens become advanced enough, they might want to explore the galaxy on their own or with the help of robotic spacecraft.
With about 4.5 billion years of solar system history, these extraterrestrials have enough time to look into our area and possibly leave their mark there.
What artifacts can we find
In fact, several civilizations may have visited and left our solar system and even left behind traces before disappearing.
Astronomers have proposed a strategy to use existing telescopes, surveys and planetary probes to hunt for signs of past alien visits. They discuss three categories of remnants that we can find.
– The first category is the usual surface artifacts – the remains of spaceships, probes, and even just garbage.
In the comparatively short time of human exploration of the solar system, we have littered the Moon and Mars with dozens of non-functioning spacecraft and random pieces of debris, so it is possible that an alien civilization would have done the same.
Also, since many surfaces in the solar system do not undergo weathering or volcanism, an artifact left there could be visible for billions of years.
– The second category is spacecraft that continue their aimless orbit around some body in interplanetary space. They can wait at a stable gravitational Lagrange point or in the orbit of some distant satellite.
They may be active, observing and recording interesting things happening in the solar system, or they may be long dead and not much different from an asteroid or a comet.
– The third category is interstellar artifacts, which should never remain in one star system, but wander aimlessly through the galaxy, moving from one system to another. We already have several means of detecting such artifacts, such as wide-field telescopes and planetary missions.
Traces of activity can be seen everywhere
Speaking of travel, we might be able to use existing research to find evidence of interstellar and interplanetary adventures.
For example, any interstellar spacecraft will require a certain method of propulsion. And since even aliens must obey Newton’s laws, there must be some kind of exhaust to propel the spacecraft.
The faster we want the ship to go, the more powerful its exhaust must be, potentially making it visible to the James Webb Space Telescope or the Chandra X-ray Observatory.
Interstellar travel could also be achieved by laser propulsion using a light sail that could be detected. Or we might find evidence of subtler clues, such as gravitational anomalies – the orbits of small objects that are not well understood because they may have been disturbed by a passing ship.
Finally, we can look for signs of past interference, and not just passive observation, in the solar system. If aliens opened a mine on Mercury, for example, we would be able to see it today.
Or if the heavy equipment is still running, then it will have some waste heat associated with it, which will be released against the background radiation emitted from the surface of the planet or the Moon.
Finally, we can find geochemical anomalies – the result of interference with the chemical processes on the planet (or simply outright pollution).
We can use existing and planned solar system observatories and probes to hunt these artifacts without having to change their mission parameters.
If we scan planetary surfaces and take pictures of large areas of the solar system, we can use these campaigns to find evidence of extraterrestrial life.
—
Online:
Contact us: [email protected]
Our Standards, Terms of Use: Standard Terms And Conditions.