The story you will read next, like any good science story, surprises more by the hypotheses that it opens not because of the certainties it provides. So get ready because this scientific discovery comes with curves. A team of Japanese astrobiologists announced on Tuesday the find traces of uracil on the asteroid Ryugu, a celestial body that travels through space about 300 million kilometers from our planet. On Earth, uracil is one of the key elements to form RNA so, in a way, it is considered a key ingredient for life. But what happens when this substance is in space? Does this mean that a precursor to life has been found in space? This is where the story starts to get interesting.
The discovery supports the theory that the basic ingredients of life are pervading the cosmos and just have to fall in the right place for ‘magic to happen’
For millennia, humanity has wondered if we are alone in the universe. This is why, in recent decades, more and more missions have focused on searching for traces of life beyond our planet. For this purpose, in 2018, the Japanese Space Agency (JAXA) sent a spacecraft to the asteroid Ryugu. His goal was collect samples of this space body and Tbring them back to earth for analysis. In December 2020, space rock fragments reached our planet. Their analysis, as explained by the scientists at the University of Japan who conducted this latest study, shook the foundations of astrobiology. That is to say, the guide to understanding how life could have appeared in the universe.
In 2018, a Japanese spacecraft traveled to the asteroid, collected samples and brought them back to Earth.
Analysis of various rock fragments from the asteroid Ryugu, published this Tuesday in the journal ‘Nature Communications’, revealed the presence of uracil, niacin (vitamin B3) and other organic molecules which are considered key elements in the formation of more complex organic molecules. To give you an idea of what this means, it’s as if each of these compounds were a small LEGO brick which, if placed in the right order and in the right shape, could form a much larger and more complex construction. In the case of organic molecules, the hope is that one day their presence may help to understand how life formed on our planet. Or to find past, present or future life forms beyond our world.
ingredients for life
But what does the discovery of uracil in Ryagu mean? Well, here begins the fun part of the story. The team led by Yasuhiro Oba suggests that the building blocks for the formation of life on Earth could have formed in space and reached our planet aboard carbon-rich meteorites. This hypothesis, known as panspermia, has also been supported by other studies conducted by Oba’s Japanese laboratory as well as other international research groups. According to this theory, the basic ingredients for life to germinate already they swarm through the cosmos and they just need to land in the right place at the right time for the “magic to happen”.
He discovery of uracil in Ryagu could indicate that the basic ingredients for life to form on our planet could have an extraterrestrial origin. “This is an exciting discovery, as it reveals that uracil (one of the RNA nucleobases) can be synthesized in space“, explains Izaskun Jiménez-Serra, senior scientist at the CSIC of the Madrid Astrobiology Center (CAB). As this researcher from the Science Media Center (SMC) explains, this discovery suggests that this compound could have reached the Earth from from the impact of meteorites between 4,100 and 3,800 million years ago and, from there, they would have “trigger the first biochemical processes What leads to the origin of life” In the ground.
“It’s an exciting discovery”
Izaskun Jiménez-Serra, CSIC scientist
The panspermia hypothesis, although interesting, does not convince all scientists. In fact, some argue that the discovery of traces of uracil on the asteroid Ryugu is, at bottom, a expected discovery. “Ryugu’s analysis is not surprising and agree with analyzes of type meteorites carbonaceous chondrite and with what we know about the chemistry of these materials”, emphasizes César Ángel Menor Salvan, astrobiologist and professor of biochemistry at the University of Alcalá. “What would have been a big surprise is if there was no uracil and other related molecules”, emphasizes the scientist in statements to the Science Media Center Spain (SMC).
“This study is historic and represents an important step in space research”
César Ángel Menor Salvan, astrobiologist
The astrobiologist argues that the importance of this work is, in fact, proof that we are able to collect samples from another solar system body, bring them back to Earth and analyze them in detail. All this, by creating a reliable protocol in the storage and handling of samples to avoid its contamination by terrestrial compounds. “This study is historic and represents an important step in space research”, underlines the scientist who, all the same, nuances that “as usually happens in this type of case, work leaves us with more questions than answers“.