A typical Hollywood alien is "soft, squishy and big on mucus," in the words of Seth Shostak, senior astronomer at the SETI Institute in Mountain View, Calif. These sci-fi lumps of goo are inclined to abduct us, probe us, hover above us and even walk among us (in disguise, of course). But far beyond Hollywood's limited scope, aliens may really exist. What are they like, and how would they actually manage a human encounter?
Astrobiologists have deduced a few answers by combining their knowledge of life on Earth with their understanding of the cosmos as a whole. Their profile of ET could not be what you expected.
1. They won't come in peace
The renowned physicist Stephen Hawking once famously warned that humanity's efforts to radio communicate with extraterrestrials could be endangering us. If the aliens that detect our signals are technologically capable of coming right here — proof that they are far more advanced than we — "I think the outcome would be considerably as when Christopher Columbus first landed in America, which did not turn out really well for the Native Americans," Hawking said.
But how can we know the first thing about ET's behavior, be it malevolent or otherwise? Shostak stated we want look no farther than Earth. Aggression evolved as a trait amongst Earthlings since it assists us obtain and shield resources. Though aliens would have arisen and evolved beneath completely diverse situations, pressure to secure finite resources would most likely have molded their behavior, also. "I suspect resources would be finite anyplace in the universe," Shostak told Life's Little Mysteries.
2. They didn't put us here
A common fringe theory holds that humans are alien's gift to Earth. Some men and women say we were delivered right here for the duration of a close to pass of a life-bearing planet referred to as Nibiru. This alleged planet, which has not in fact been observed by astronomers, is stated to skirt the edges of the solar system and swing inward from time to time. [A Field Guide to Alien Planets]
"I get emails each week saying that Homo sapiens are the outcome of alien intervention," Shostak stated. "I am not sure why aliens would be interested in producing us. I assume people like to assume we're special. But isn't that what got Galileo and Copernicus into difficulty — questioning how special we had been? But if we're just another duck in the road, it's not very thrilling."
3. They are immune to Earth's bacteria
Alien visitors to Earth are sometimes depicted in science fiction as becoming brought down by their personal alien nature. Lacking immunity to Earth-based bacteria, they all die of infections. This would not really happen. "Alien life forms would not come here only to be completed in by our bacteria, unless they were connected biochemically to humans," Shostak told IEEE Spectrum. "Bacteria would have to be in a position to interact with their biochemistry to be unsafe, and their potential to do that is far from a sure point."
4. They won't eat us
Just as they would not be recognized by the local pathogens as possible hosts, aliens would also not recognize Earth's organic matter as a prospective food source. They could not digest us. And they almost certainly would not need to have to, anyway. As Jacob Haqq-Misra, an astronomer at Pennsylvania State University, pointed out, "A society capable of interstellar travel should have solved their development issues such that they do not need to have humans for food."
5. They will not mate with us
Human DNA cannot combine with XYZ, or whatever it is that encodes alien life. "The concept that they've come for breeding purposes is much more akin to wishful thinking by members of the audience who don't have great social lives," Shostak told IEEE Spectrum. "Feel about how well we breed with other species on Earth, and they have DNA. It would be like trying to breed with an oak tree ( via huffingtonpost.com ).