The possibility of an extraterrestrial life in the outer space

The host star is a companion to two other low-mass stars, which are seen here in the distance.

The possibility of an extraterrestrial life in the outer space

April 26, Might it support life? New evidence raises the possibility, but scientists say it's more likely the findings involve non-biological processes. Given that our star and Earth are part of a young planetary system compared to the rest of the universe — and that interstellar travel might be fairly easy to achieve — the theory says that Earth should have been visited by aliens already.

As the story goes, Italian physicist Enrico Fermi, most famous for creating the first nuclear reactor, came up with the theory with a casual lunchtime remark in The implications, however, have had extraterrestrial researchers scratching their heads in the decades since.

Ten million years may sound long, but in fact it's quite short compared with the age of the galaxy, which is roughly ten thousand million years. Colonization of the Milky Way should be a quick exercise.

Signs of Alien Life Will Be Found by , NASA's Chief Scientist Predicts

Some say this is the first such paper to explore the Fermi paradox, although this claim is a bit hard to prove. While Hart was more of the opinion that we were the only advanced civilization in the galaxy he argued that in Earth's history, somebody could have visited us already unless they started their journey less than two million years agohe outlined four arguments exploring the paradox: The argument has been challenged on many grounds.

Gray in a Scientific American blog post. Frank Tipler, a professor of physics at Tulane University, followed up on the argument in with a paper titled " Extraterrestrial intelligent beings do not exist ," also published in the RAS Quarterly Journal. The bulk of his paper dealt with how to get resources for interstellar travel, which he suggested could be achieved by having some kind of self-replicating artificial intelligence moving from star system to star system and create copies using materials there.

Since these beings aren't on Earth, Tipler argued we are likely the only intelligence out there. He also said that those who believe in extraterrestrial intelligence are similar those who think about UFOs, because both camps believe "we are going to be saved from ourselves by some miraculous interstellar intervention.

It's also been fueled by the discovery of exoplanets. Plentiful planets The universe is incredibly vast and old. One estimate says the universe spans 92 billion light-years in diameter while growing faster and faster.

Separate measurements indicate it is about At first blush, this would give alien civilizations plenty of time to propagate, but then they would have a cosmic distance barrier to cross before getting too far into space. Fermi first formed his theory long before scientists found planets outside of our solar system.

There are now more than 3, confirmed planets, with more being found frequently. The sheer number of planets that we have found outside of our solar system indicates that life could be plentiful.

Over time, with more advanced telescopes, scientists will be able to probe the chemical compositions of their atmospheres. The eventual goal is to understand how often rocky planets form in the habitable regions of their stars, which is traditionally defined as the zone in which water can exist on the surface.

Searching for extraterrestrial intelligence

Habitability, however, isn't just about water. Other factors must be considered, such as how active the star is, and what is the composition of the planet's atmosphere. A November study using data from the Kepler Space Telescope suggested that one in five sun-like stars has an Earth-size planet orbiting in the habitable region of its star.

That zone is not necessarily an indication of life, as other factors, such as the planet's atmosphere, come into play. Further, "life" could encompass anything from bacteria to starship-sailing extraterrestrials. A few months later, Kepler scientists released a "planet bonanza" of newly discovered worlds, pioneering a new technique called " verification by multiplicity.

A multiple star system at such close proximity would destabilize over time, the technique postulates. Using this will accelerate the pace of exoplanet discovery, NASA said in Researchers previously focused on red dwarf stars as a possible host for habitable planets, but as the years of study continued, limitations arose.

It was exciting to find nearby planets such as Proxima Centauri b and the seven rocky planets of TRAPPIST-1 in the regions of their stars where liquid water could exist on the planets' surface. The trouble is, red dwarfs are volatile and could send several forms of life-killing radiation towards the surface.

More study is required to better understand these stars. More exoplanet-hunting spacecraft are coming online in the next few years. And larger ground-based observatories are also being envisioned, such as the European Extremely Large Telescope that should see first light around Our understanding of astrobiology life in the universe is just at a beginning, however.Humanity is on the verge of discovering alien life, high-ranking NASA scientists say.

Argument for extraterrestrial intelligence

"I think we're going to have strong indications of life beyond Earth within a decade, and I think we're going to have definitive evidence within 20 to 30 years," NASA chief scientist Ellen Stofan said Tuesday (April 7) during a panel discussion that focused on the . Strange messages coming from the stars are ‘probably’ from aliens, scientists say 'It is too early to unequivocally attribute these purported signals to the activities of extraterrestrial.

The Physics of Extraterrestrial Civilizations How advanced could they possibly be? The late Carl Sagan once asked this question, “What does it mean for a civilization to be a million years old?

Ellie Arroway, played by Jodie Foster in the movie "Contact," was consumed by the thought of life on other planets. Getty Images Trying to calculate the probability that extraterrestrial life exists in the universe is actually quite complicated. An octopus sits on rocks at the the Oceanopolis sea center in Brest, France.

Did octopuses come from outer space? A group of scientists have suggested these bizarre creatures descend from organic. Extraterrestrial life, life that may exist or may have existed in the universe outside of search for extraterrestrial life encompasses many fundamental scientific questions.

The possibility of an extraterrestrial life in the outer space

What are the basic requirements for life? Could life have arisen elsewhere in the .

What are the odds there is life in outer space? | HowStuffWorks