The discovery of biologically relevant molecules such as nucleobases in completely untouched extraterrestrial samples without contamination from Earth ensures that such ones do indeed exist in extraterrestrial environments, study lead researcher Yasuhiro Ohba of Hokkaido University in Japan tells Space.com. com.
Hundreds of building blocks
Translated into Swedish, this means that the world’s astrobiologists, those who study the question of life in the universe, as researchers discover, have a couple more things to conjure up as evidence that the processes necessary for life here on Earth can actually be happening on other planets, too.
Uracil, for example, is found in RNA, a large molecule related to DNA that you find in all living things and that, among other things, regulates gene activity. While Niacin or Vitamin B3 plays an important role in the metabolism of living cells.
To these molecules, simple, complex and carbon-based, nearly 300 molecules can be added that researchers have already established that could occur outside of Earth.
– It itself depends a bit on what you mean by “connected to life”. Water, for example, is found in large quantities everywhere in the universe, while the organic molecules associated with life are more difficult to find. But yes, the Japanese study reminds us that such things have also been found, such as amino acids, says Karina Pearson, an astrophysicist at Chalmers who works every day to search for exoplanets, that is, planets around other stars.
Do the Japanese find it any help in understanding the origin of life?
The issue is complicated by the presence of many unknown factors. We still don’t know exactly what the environment looked like on early Earth. The atmosphere, for example, has changed drastically since then. Oxygen has evolved from life – it didn’t exist to begin with. If we knew exactly what conditions were like on early Earth, that would be much easier. But it sure helps a lot if we know that the building blocks of life may have been delivered from space to the early Earth.
Distance causes it
Speaking of deliveries to Earth, proponents of the panspermia hypothesis are perhaps most pleased that the list of extraterrestrial-created molecules has expanded.
In its original form, this 2,500-year-old hypothesis posits that life is common in the universe and that it spread to all corners of the universe by hitchhiking with orbiting comets, asteroids, meteorites, and other space material. To one day collide with a planet in the right conditions and practically fertilize it with the embryo of life.
In theory, this is quite possible. Asteroids originating from Mars, for example, have been shown to impact Earth. But few believe that multicellular organisms will actually survive such a flight, given the dangerous inhospitable conditions that prevail in space.
In addition to the need for living organisms to survive at temperatures close to absolute zero, cosmic rays – high-energy particles that mercilessly and mercilessly penetrate every square centimeter of the fabric of space – also present a fatal obstacle because they increase the risk of dangerous DNA mutations appearing in every cell without protection against it.
There are certainly organisms that can be demonstrated to survive in space – bears are perhaps the best-known example – but from there it’s a long way from surviving the enormous lengths of time required by interplanetary travel.
– Over a few decades, experiments have shown that organisms from Earth can survive, and for example, microbes in the form of spores inside asteroids can live significantly longer. They probably won’t live for millions or billions of years, Karina Persson says, which goes against life’s ability to spread between solar systems.
“controversial topic”
On the other hand, panspermia comes in many forms. One of them is pseudopanspermia, soft panspermia, or molecular panspermia. Accordingly, it is not life itself that arose in space, on comets, asteroids and other aimlessly wandering celestial bodies – but rather the organic molecules necessary for the complex system that underlies all life.
– Yes, complex molecules that are part of the building blocks of life, such as those discovered now, are a completely different matter. They can form directly in space, on dust grains and in asteroids or comets, and survive journeys through space to spread to planets. How these processes relate to the origin of life on our planet remains a controversial research topic. It’s undoubtedly a very exciting discovery, says Karina Persson.
What does it mean if it turns out that all the ingredients necessary for life could form anywhere?
– If this is the case, then this means that the building blocks of life are found everywhere in the gas clouds that form the stars and planets in our galaxy, which undoubtedly looks promising for the development of life in the universe, she says.
But the fact that the building blocks of life can be found everywhere does not necessarily mean that all environments have conditions for autogenesis, and that dead matter takes a step into living matter in a way hitherto unknown.
– The problem is that we only have one statistical point to start from – our planet. It is insanely difficult to draw conclusions about the possibility of life elsewhere. In addition, if we look at the phylogenetic tree of organisms (genetic mapping of species kinship and relationships, editor’s note), there is a huge gap in terms of knowledge about how amino acids and simple molecules were able to create life. that can reproduce itself.
So says Rickard Johnson, instructor of the Conditions of Life in the Universe course at Chalmers. Who does not want to give any odds as to whether man will ever find the answer to the origin of life and whether it can arise elsewhere in the universe.
But if we look around us, there is nothing truly unique about nature. Everything repeats itself. Why wouldn’t the same apply to life?
– Of course, everything repeats itself, that’s how it is. One can find the same kind of molecules, water or methane here and on the other side of the Milky Way, but cannot solidify them in any way. There may still be an insanely small chance of life emerging.
– At the same time – it is possible that we live in a universe and then it is clear that even if the probability of the emergence of life is small, it will appear anyway.
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