As a graduate student, Earth came up with a hide.

Original author: Maddie Stone
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A still from the film “ Independence Day: Revival ”. Unfriendly aliens again take up the old.

We have been dreaming about contact with aliens for a long time. In someone's fantasies, it looks like a meeting or exchange of messages of two highly developed civilizations, guided by the principles of scientific objectivity and peaceful coexistence. But let's face it: if aliens can fly to Earth, it will mean that they have gone much further than us in technological and scientific development. Translating into a language understandable to humanity, we will be completely defenseless before them. So, maybe it is better to think about how to remain unnoticed for the time being, instead of persistently looking for brothers in mind?



The history of mankind says that the contacts of civilizations always lead to wars. As the Captain suggests, aliens are not humans (sounded ambiguous), and therefore they cannot be approached with human standards. But precisely because we are completely unaware of the principles of the morality of a different rational biological species, and even much more technically developed, it is better to exercise caution. Otherwise, when hordes of some insectoids begin to land on the beaches of Normandy, Borjomi will be late in drinking.

Suppose a certain “wisest advice” of the planet Earth will decide tomorrow that a little caution will not hurt, and it is better for us not to shine on the sky of the Milky Way. What should this be expressed in?



Here we need to recall what the Kepler space telescope is doing today .- he is looking for exoplanets. The search method can be described very simply as follows:

  • telescope for some time watching the selected star;
  • observational results are analyzed in terms of changes in the brightness of the glow and the presence of the Doppler shift . We are talking about very weak periodic changes;
  • if changes are detected, astronomers can conclude that one or more planets rotate around a star. A change in the glow of a star occurs when the planet passes against its disk (relative to the observer) - the transit method, and the Doppler shift is caused by the influence of the gravity of the planet - the Doppler method.

Further, we proceed from the fact that alien civilizations similarly search for planets in the vicinity of stars. Despite their hypothetical high development, the laws of physics are still considered to be the same for everyone, and it is difficult to assume the possibility of creating a telescope that can visually detect the Earth from a distance of, say, 20 light-years (at this distance is Glyze 581 exoplanet very similar to our planet probable conditions). If someone nevertheless built such a device, then we can only hope for his good manners.


Laser beam emitted by Very Large Telescope ( VLT) Southern European Observatory (Chile). The beam acts on the sodium atoms in the upper layers of the earth’s atmosphere and creates a bright point there that serves as a guide for the telescope’s optical systems.

So, aliens scan the sky in search of other planets and civilizations. Our task is to go unnoticed. Ideally, you need to create the impression that there is no Earth at all. But how to do that? A half solution was proposed.a graduate student at Columbia University Alex Tichy (Alex Teachey). To protect against detection by the transit method, he proposed to place laser systems in orbits around the Earth, which will emit pulses in the direction of another star when our planet passes between it and the Sun. Thanks to the selection of the spectrum, power and pulse duration, it is possible to compensate for the change in the brightness of the solar glow from the point of view of a remote observer.

According to Alex’s calculations, to successfully conceal the Earth from observers from another star system, it is enough to emit a monochromatic pulse with a peak power of ~ 30 MW with a duration of ~ 10 hours once a year using a set of laser systems - this is enough to ensure invisibility in the optical range. To hide the Earth in the whole spectrum, lasers must have a tunable radiation spectrum, and the peak pulse power will reach 250 MW.



Is it a lot or a little? As a comparison, the International Space Station is given.For a year, solar panels produce an amount of energy comparable to the required 30 MW. From the point of view of the survival of humanity in the face of the Martian alien threat - a penny. By the way, Alex calculated that if you do not chase the invisibility of the entire planet, and be satisfied only with concealing signatures in the spectrum of the atmosphere associated with life (for example, oxygen), then at each transit you can emit a pulse with a peak power of only ~ 160 kW. Let the aliens believe that the Earth is just another lifeless stone ball.

The idea is beautiful and even realizable. For the construction of orbital lasers, we do not need additional scientific discoveries or technologies - mankind already has everything that is necessary. Of course, you will have to break your head over the calculations when and in the direction of which stars you need to "shoot" with lasers. However, there is an opinion that if we want to hide from a much more developed civilization, then it is possible that its representatives will only grin at the sight of our pathetic attempts.

Although, all other things being equal, it is better to have an invisible cover for the Earth on hand than not to have it.

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