The researchers’ new article argues that intelligent extraterrestrial civilizations would only be interested in contact with the most technologically advanced planets, and the Earth does not fall under these requirements.
Scientists believe that intelligent civilizations do not consider interesting planets where there is a ordinary life. If life has evolved on many planets in the galaxy, then aliens are likely to be more interested in those with signs of advanced technology, writes study author Amri Wandel, an astrophysicist from the Hebrew University of Jerusalem.
The study addresses the Fermi Paradox, which states that, given the age of the universe, it is likely that intelligent aliens would have developed long-distance space travel by now, and therefore it is likely that they would have visited Earth.
The fact that they haven’t done so may indicate that there is no other intelligent life in the Milky Way galaxy.
However, experts have offered other explanations for the disappearance of aliens: perhaps they visited Earth in the distant past, before humans evolved.
Or maybe long-distance space travel is more difficult to accomplish than thought. Perhaps the aliens have only recently evolved to the technological level to get to Earth. Or they just decided not to explore space.
In his paper, Wandel suggests another possible explanation: that life is actually very common in the Milky Way. If there is life on many rocky planets orbiting the habitable zone of stars, then aliens are probably not going to waste their resources by sending signals to everyone.
Intelligent extraterrestrial civilizations are probably more interested in signs of advanced technology. But technical signals can be hard to spot.
The earth has only emitted signals detectable from space since the 1930s. Theoretically, these signals have now reached about 15,000 stars and their planets, but this is a tiny fraction of the 400 billion stars in the Milky Way.
In addition, Wandel wrote, it takes time for any return message from aliens to return, so only stars within 50 light-years have had time to respond since humanity began to emit radio waves into space.
Wandell found that if intelligent civilizations are not very numerous, then it is likely that Earth’s signals did not reach them. However, over time, Earth’s technological signals will find intelligent listeners, Wandel wrote.
The findings suggest that perhaps there are no intelligent civilizations within 50 light-years of Earth, the scientist wrote. But intelligent life may exist, and it is waiting for a technically more attractive message from us.
On the other hand, perhaps it is good that no one has answered us yet. For example, the famous theoretical physicist Stephen Hawking warned: humanity must be careful. He assumed that sooner or later earthlings would receive a signal from a distant planet. However, they must be careful before giving an answer. He implied that this meeting could become similar to the meeting of Columbus with the native inhabitants of America. And we know how this meeting ended.