A recent study claims that Intelligent aliens will only be interested in contacting the most technologically advanced planets. Earth, doesn't work in this regard because it might be considered unattractive or not smart enough for the aliens.

Preprint papers published in the arXiv database suggest that intelligent extraterrestrials may not find planets that house life particularly interesting.

If life has evolved on many planets in the galaxy, then aliens may be more interested in planets that have not only signs of biology but also technology," wrote study author Amri Wandel, an astrophysicist at The Hebrew University of Jerusalem.

The study explores the Fermi paradox, which argues that given the age of the universe, it is more likely that intelligent aliens will develop long-distance space travel now, and thus are more likely to visit Earth. The fact that they have not (as far as we know) contacted, may be evidence that there is no other intelligent life in the Milky Way galaxy.

But experts have given another explanation regarding the mystery of the existence of aliens. Perhaps they have visited Earth in the past, before humans evolved or were able to record those visits.

Or, perhaps long-distance space travel is more difficult than we believe. It could be that aliens developed advanced civilizations that were too new to get to Earth. Another possibility, they deliberately decided not to explore the cosmos. Maybe even they have disappeared.

In this new paper, as quoted from Live Science, Wandel offers another explanation: that life is actually very common in the Milky Way. If many rocky planets orbiting in the star's habitable zone host life, the alien probably won't waste its resources sending signals to each planet. They will probably try to communicate with alien algae or amoebas.

If life is something commonplace in our galaxy, intelligent aliens are most likely more interested in technological signs. But technological signals may be difficult to detect. Earth has only emitted detectable signals from space (in the form of radio waves) since the 1930s.

In theory, these signals have now swept away about 15 thousand stars and planets orbiting them, but even then only a fraction of the 400 billion stars in the Milky Way.

Further, Wandel writes, it takes time for each reply message from an alien to travel back, so only stars within 50 light-years have had time to respond since Earth began airborne outside the planet.

Unless intelligent civilization is very abundant, with more than 100 million technologically advanced planets in the Milky Way, it is very likely that the Earth's signal has not yet reached other forms of intelligent life. However, as time goes on, and as our planet emits more radio signals, it is more likely that Earth's technological signals will find listeners," Wandel wrote.

The findings suggest there may not be an intelligent civilization within about 50 light-years of our planet. But intelligent life may still be out there, they're just waiting for our callll.ll

"To make matters worse, the oldest radio signal on Earth was accidentally broadcast into space, so it's likely so chaotic after about a light-year that aliens can't tell the difference," the researchers said.

Earthlings sent the first deliberate high-power broadcast to alien creatures via the Arecibo Observatory in 1974. At that time, the message from Arecibo was directed to the globular star cluster M13. Some scientists think, it's time to send another message.

Unless intelligent civilization is very abundant, with more than 100 million technologically advanced planets in the Milky Way, it is very likely that the Earth's signal has not yet reached other forms of intelligent life. However, as time goes on, and as our planet emits more radio signals, it is more likely that Earth's technological signals will find listeners," Wandel wrote.

The findings suggest there may not be an intelligent civilization within about 50 light-years of our planet. But intelligent life may still be out there, they're just waiting for our call.