Does Extraterrestrial life exists?

 

Are We Alone In The Whole Universe?

Anyone hoping to communicate with aliens on Earth will have to wait at least 400 years.

The senior scientist in astrophysics at the Hebrew University of Jerusalem, Amri Wandel, wrote the paper, which does not rely on new findings but rather a thoughtful analysis of the size and scope of the universe as we know it today, the likelihood that life exists on other worlds, and the likelihood that those life forms would be aware of our existence and show even the slightest interest in us.

The analysis begins with the following fundamental numbers: The Milky Way contains an estimated 400 billion stars, and the universe contains an estimated two trillion galaxies. The Kepler Space Telescope and other ground- and space-based observatories have found that nearly every star in the sky is surrounded by at least one planet, and that many, like our sun, are surrounded by a whole litter. That amounts to trillions upon trillions of worlds where life could, at least theoretically, have emerged. Why then is it referred to as the Great Silence by researchers from Mountain Valley, California's SETI (Search for Extraterrestrial Intelligence) Institute?

First and foremost, we have successfully concealed ourselves on Earth. According to Wandel, intelligent species studying biotic planets like ours would not pay much attention to just one more green and living world because biotic planets like ours may be extremely common in the universe. They would be seeking a living, green world with other intelligent beings.

The radio signals that we transmit to one another but that leak through the atmosphere and into space are the first and most obvious indication that we are just such a species. We have only been emitting those unintentional beacons for about a century. Our so-called radio bubble has a diameter of just 200 light years and extends in all directions—north, south, east, and west. That's a flyspeck in a universe that spans 94 billion light years and a galaxy that is 100,000 light years across.

In addition, given that it would take 50 years for our radio beacon, traveling at the speed of light, to reach it and another 50 years for the receiver to send back a message, any civilization that would have received our signal and responded by this point would have to be located just 50 light years away. For just a two-way greeting, that's a whopping century. Despite the fact that there aren't any candidates within that small area. Wandel claims that there are approximately 2,000 stars within 50 light years of Earth that are home to unknown numbers of planets.

How many of those planets might have life on them then? This requires you to use Frank Drake's Drake Equation, an astronomer and the founder of the SETI Institute. The number of civilizations in our galaxy that are capable of receiving and responding to radio signals is calculated as a function of a number of variables, such as the rate at which sun-like stars form, multiplied by the number of planets orbiting those stars, multiplied by the number of planets that could support life, multiplied by the number of planets on which life actually emerges, multiplied by the number of life forms that develop intelligence, multiplied by the number of civilizations that are intelligent enough

There are a lot of speculative x-factors to fill in, and the number that appears on the right side of the equals sign is only a guess or educated estimate. According to Wandel's own Drake estimates, between zero and a small number of the 2,000 planets within 50 light years of Earth contain intelligent life.

Does Aliens Have Sent A Secret Probe On Earth?

A highly advanced alien civilization could, of course, also send a probe toward Earth instead of a radio beacon, but that is even less probable—and harder to do in anywhere near the 100 years we’ve been sending our radio semaphores into space. Never mind all of the talk about Unexplained Aerial Phenomena of late, it would take a long, long time and a lot of technological prowess to send even a relatively small spacecraft our way. Accelerating a 1,000 kg (2,200 lb) probe to even one tenth of the speed of light would, Wandel calculates, take 10,000 times more power than the annual global energy production of Earth.

If Aliens Exixts, Then Are They More Advanced Then Us?

All of this assumes that we are looking for radio or spacecraft visits today. But the so-called “contact era”—the time when we could expect to have a two way exchange with E.T., might be much, much longer. Even assuming that there are one million intelligent civilizations scattered throughout the galaxy (a big number that seems much smaller when you take into consideration the number of planets circling the Milky Way’s 400 billion stars), Wandel puts the beginning of the contact era at 400 years from now at a minimum.

The possibility does always exist, of course, that other civilizations could be leaking radio signals just the way we are, and that we may detect them before they detect us. But here, technological progress gets in the way. Already, Wandel points out, earthlings are increasingly switching over to radio-silent communications like fiber optics. Ultimately, that could slam the window at least partly shut on the signals we send out—just as similar technological advances could silence other worlds.