Are we alone? (Photo – maxpixel.net).
As an astronomer working at JPL, one of the most frequent questions I’m asked at talks and events is if I think there is life beyond Earth.
By Joe Masiero
This touches on some of our most deeply held questions as a species: What is our place in the universe? Are there others like us? Is the Earth unique, or are we one of an innumerable family of living worlds?
To begin to answer that, we need to realize that the universe is BIG, bigger than anything we can possibly imagine. There are 100 billion stars in our galaxy, 100 billion galaxies in the part of the universe we can see, and potentially an infinite number of galaxies that are so far away that their light may never reach us. If every star has a planet (and recent research is pointing to more than one planet per star on average), then there are a lot of possible places for life to get a foothold.
Life on Earth began very quickly after the surface solidified and the oceans appeared, and has permeated our planet from the depths of the oceans to the summits of mountains. It has survived countless cataclysms, from ice ages to super volcanoes to asteroid impacts. When conditions are right, it appears that life forms almost immediately. With so many planets around so many stars, it seems naive to assume that ours is the only one lucky enough to host life forms. It is inconceivable to me that life doesn’t permeate the universe.
But much of this teeming life may just be microbes. The heart of the question, of course, is: “What about intelligent life; is there someone, someday, who will wave back?” That’s a much harder question, for we only have the way life evolved on Earth to compare it to. Is life on land common? Intelligence? Technology? These are much harder questions to probe. However, given the incredible distances between stars, which are dwarfed by the impossibly huge gulfs between galaxies, I think that it is highly unlikely that we have been visited by aliens. Our best bet at finding an interstellar pen-pal is by using radio listening and transmission stations, as is done by the Search for Extraterrestrial Intelligence Institute, or (SETI).
Settled (Photo – Randall Munroe, XKCD)
Although a few people continue to claim seeing UFOs, we have not seen an explosion of evidence of these encounters. One of the best comments on this was made by Randall Munroe in his webcomic XKCD.
And besides, if aliens truly had crossed vast gulfs of space to answer the question “Are we alone?,” don’t you think they would come to us to trade knowledge, stories, or at least say hi?
Joe Masiero is a Scientist at NASA’s Jet Propulsion Laboratory and holds a Ph.D. in Astronomy from the University of Hawaii’s Institute for Astronomy. His research primarily focuses on the asteroids and comets of our Solar system, and he is a member of the science team for the NEOWISE space telescope.
We have no evidence that life of any kind exists anywhere else. Of course our access to anywhere else is severely limited, both physically and cognitively. Why is there life on earth? How did the cosmos begin? Is there life elsewhere in the cosmos? We’ll never know. We’re still trying to figure out how to sustain life here, and doing a pretty rotten job of it.
Joe can I use the photo above in a talk I’m giving on searches for new physics? (particle physics)
Hi Robin,
We have updated the images on this article for copyright reasons. You may use the above image if you like as long you use the credit as stated above.
A very down to earth answer. Thank you for being concise. Humans are just another bacteria struggling for its survival and space in our ever changing conditions on Earth. And if there is alien life out there, it’s just that. The chances are it’s so alien that we’ll wet our pants upon seeing it.