Are we aliens? We may be (by "we," we mean organic life), according to a new study on the life-scattering possibilities of comets and meteors.
Researchers from Imperial College London, the University of Kent, and Lawrence Livermore National Laboratory have studied the effects of icy comets and meteorites smashing into planets with icy surfaces, and their findings suggest that such collisions can produce amino acids.
Amino acids are very important organic compounds that are essential to the building blocks of life - and are fundamental to making proteins and cells. The researchers found that the force of an impact of an icy comet or a meteorite on an icy surface can organize simpler organic compounds into amino acids, meaning, as the Guardian reported, that rather than being a purely destructive force, comets and meteors impacting planets might provide just the kind of punch needed to jostle inanimate molecules into precursors to life.
The team discovered this paradoxically constructive use of cosmic force by experimentally firing projectiles through a large high speed gun at targets made of different ice mixtures - meant to simulate the composition of comets. At a lab in the University of Kent, the researchers used compressed gas to fire the mock space rocks at up to 7.15 k/m per second. The resulting impact created a shock wave, followed by heat, which produced amino acids such as glycine and D-and L-alanine.
Comets and meteorites bombarded Earth between 4.5 and 3.8 billion years ago, and the research suggests that this process might have been instrumental in kick-starting life on Earth. "This process demonstrates a very simple mechanism whereby we can go from a mix of simple molecules, such as water and carbon-dioxide ice, to a more complicated molecule, such as an amino acid," said University of Kent professor Dr. Mark Price, who co-authored the study. "This is the first step towards life. The next step is to work out how to go from an amino acid to even more complex molecules such as proteins."
The study also suggests that past and current comet and meteorite impacts on other bodies throughout the solar system may be still creating amino acids. "We know that impacts are very common in the solar system, because we can see the craters left behind on different planetary bodies," said Zita Martins, an astrobiologist at Imperial College London, to the Guardian. "If impacts occur then more complex molecules can be made, so these building blocks of life could be widespread throughout our solar system."
Some of the first places to look may be on Jupiter's moon Europa, as well as Enceladus, a moon orbiting Saturn, where an abundance of ice on the surface may work with the impact shocks of incoming objects to create amino acids.
Still, don't expect the mystery of our origins in the primordial soup to be solved overnight by the findings (and don't worry about the Europans invading any time soon, as well). There is still much to know about how these building blocks can eventually result in life as we know it.
"What we have done is demonstrate a process that takes molecules that were present at the time of the birth of the solar system and made them into molecules that are required for life. It's like taking simple Lego bricks and sticking two together. You are a long way from building a house, but it is a start," said Price.