The universe is beginning to look a lot less lonely than it used to.
The probability of all of the components coming together in an environment that can support life is an indicator of how many places in the universe might have life. The search for the origins of life is a numbers game, and it’s starting to look a lot more probable it might exist elsewhere.

A recent study from McMaster University has shown that amino acids (the building blocks of protein, and life as we know it) may be more common in the cosmos than previously thought. The study used a compilation of data taken from meteorites and some brain-busting math to show that the 10 simplest amino acids are thermodynamically favoured in atmospheres that contain water, ammonia, carbon dioxide and hydrogen cyanide — four molecules that may have been abundant on a young Earth. This study provides evidence that protein based life may be destined to form wherever the materials and conditions are present. Glycine, being the simplest amino acid and therefore the easiest to form is also the most likely to be present in other places besides here on Earth.

A second study, this one based on samples obtained from NASA’s Stardust probe, which performed a daredevil flyby of the comet Wild2 in January 2004, captured some of the gas on a special collection grid and returned it to Earth. The findings confirmed a presence in the gas surrounding the comet of — you guessed it — glycine. After carefully eliminating the possibility of earthly contamination through a process akin to carbon dating, NASA scientists have determined that the building blocks of proteins can be found in extraterrestrial sources.

So is the universe teaming with protein-based life that we just haven’t discovered yet? Well, maybe not. Protein still needs an environment to form in; too hot and it will fall apart as soon as it forms, too cold and the energy needed to form it will be absent. And in order to be considered “alive” by biological standards, protein needs a way of reproducing, something possible here on Earth only with very small and simple proteins or with the help of DNA and cellular machinery, such as the ones found in cells. These methods for life may be a lot harder to find outside of Earth.

But even DNA and its partner-in-crime, RNA, are looking to be a lot easier to make than we previously thought.

RNA, DNA’s harder-working brother, has its own little world. According to the RNA world theory, before there was deoxyribonucleic acid (DNA) there was ribonucleic acid (RNA), and it did everything, from manufacturing protein and more RNA to storing genetic information. Support for this theory is found in your cells right now, where RNA acts as a messenger between your DNA, and the rest of the cell makes up an assembly plant for new proteins. With an abundant supply of RNA, life as we know it would be just a few billion oxygen atoms away. The only problem is that the formation of RNA under early Earth conditions was completely improbable.

Enter a recent paper in Nature that took a new, more convoluted, route to try and spontaneously form RNA in an early-Earth like environment than had previously been tried. The result was an RNA analog, which was structurally very close to the RNA that we have inside of us right now.
These papers could be interpreted to mean that life on Earth is far more probable than was previously thought, and this has major implications on the search for life elsewhere in the universe. A higher probability for life here is presumably a higher probability for life anywhere the same materials and conditions exist. Finding an amino acid in a comet is a big indication there may be the right materials all over the place.

With a rough estimate of how probable it is for the components of life to come together, we now only need a tally of the places that can support the chemical reactions necessary for life to exist to figure out the probability of life existing beyond our solar system. Toward that end the Massachusetts Institute of Technology and NASA have just calibrated the Kepler orbiting observatory to search for planets like our own. With over two billion stars in the Milky Way galaxy alone, they could be in for a long search, but it also means that the odds of finding something are pretty high.

Should we start keeping an eye out for the arrival of flying saucers? Probably not. As with amino acids, simpler things tend to be much more abundant than complex ones. If there are other places with life out there, it is likely in the form of a few simple proteins replicating themselves inside an oily blob not too different from the oil floating in your salad dressing. Intelligent life, like that on Earth, is still probably a very rare thing. Although humans have done very well with our big brains, intelligence is by no means necessary for life, and the bacteria surrounding us are proof of that.