Aliens exist, but will be prudent to contact them?
Aliens exist or at least it is unlikely they don’t exist. Reason with us: the universe is large, it contains between 300 and 500 billion galaxies (each containing an average of 100 billion stars) and old, almost 14 billion Earth years. We can observe only a small fraction compared to a grand total space 10 to the 23rd power times bigger. That the Earth is the only planet where life has ever been developed is a hypothesis with a probability very close to zero, that human civilization is the only one that has begun to fathom the universe and travel in space is equally unlikely.
For now except that are right those who speak of contacts with ancient astronauts or of a conspiracy by the major world governments to keep secret the presence of aliens on the planet, we had no way to verify if any alien visitors were likely to be benevolent or malicious. The second case can’t however be excluded as was stated scientists even of the caliber of Stephen Hawking.
To prevent possible close encounters of the third kind by unpleasant consequences astronomers David Kipping and Alex Teachey of Columbia University in New York propose to use laser technology to get some sort of invisibility cloak. It would mean ignite a powerful laser for 10 hours a year to compensate for the drop in brightness that an alien observer would record each time the Earth passes in front of the Sun, succeeding so to go unnoticed. A second more modest power lasers would serve to mask the presence of oxygen in the atmosphere, hiding to the aliens the presence of life on Earth.
The hypothesis is appealing, but there are at least two aspects which at the moment seems not to have taken into account: first, similar or more effective camouflage techniques may already be used by any alien civilization inhabitants of extrasolar planets (whose systematic observation began relatively few years ago); second, the Earth is a very “noisy” planet for over a century, as a part of the radio waves is dispersed in the universe, not to mention the various messages that for years we are trying to send to aliens.
Trying to hide from prying eyes a “radio” broadcasting blaring does not seem in fact the best, but especially the debate remains open: have we to try or not a contact with alien civilizations that supposedly are somewhere out there in the universe? The answer to this question might one day depend, in a positive or negative sense, the fate of humanity, with or without invisibility cloak.