Are we all “aliens”, after all?
The search for life in space might have just gotten a little bit sweeter. In the early stages of our solar system, ice grains that were hit by sunlight may have formed sugar molecules onto their surfaces. According to this new experiment, those sugars include Ribose (the backbone of RNA), which is implicated into the origin of life.
All known forms of life make at least some use of RNA as a genetic material. Also, the “R” (Ribose) in RNA, holds up the compounds that encode genetic messages. However, it has been difficult to fully comprehend how ribose could be made in the absence of living organisms, and be part of a precursor for life.
Other components of living cells, such as amino acids, which are the building blocks of proteins, have shown up in experiments and various samples from meteorites for years. Molecules that resemble cell membranes have also appeared alongside with these other components. Subsequently, if those components and ribose had all existed at the same time, then it could have set the stage for life to rapidly evolve.
But sugars, like Ribose, are hard to come by because often, the substance sticks together in a way that makes it almost impossible to extract. “Sugars like to react with each other,” says Cornelia Meinert at the University of Nice Sophia Antipolis in France. “In the end, everything is brown, like caramel.”
Now, Meinert’s team was able to produce Ribose by shining an ultraviolet light into a frozen blend of water, methanol, and ammonia. This mixture represents our solar system in its infancy; way before tiny grains of dust and ice collapsed into planets.
Lego castle of life
“It’s another example of how the universe seems to be hardwired to produce a lot of the kinds of compounds you would like to be around if you want to get life going.” says Scott Sandford of NASA Ames Research Center in California. Sandford’s own team is reporting similar results in a research paper that is now appearing in the press, he previously stated.
Whether or not sugars are made on real interstellar ice grains is still an open question. Because these grains are preserved, if they gently settle on small bodies far from the sun, subsequently checking the surfaces of comets or meteorites may help resolve the issue. ESA’s Rosetta mission and radio astronomers have both picked up simple sugars on comets before, but may have struggled to find something complex like Ribose, Meinert believes.
Finding these sugars on comets could potentially tell us that amino acids, molecules in cell membranes, and Ribose could all have been made in space, and dropped on Earth just in time for the genesis of life.
We certainly are far from assimilating what could be happening next, though. “Just because now you have all the molecules doesn’t mean you have life.” Meinert says.
Still, it doesn’t hurt. “If you think of all these little molecules we’re making as Lego blocks, and life as a kind of very complex, organized Lego castle, the fact that Lego blocks are falling out of the sky can’t be a bad thing.” Sandford says.
Reference: Science Journal
Wikipedia
NMJ Library
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