Last fall, when NASA's famed Cassini spacecraft escalated to its final, deadly descent into the clouds of Saturn, astrochemist Morgan Cable could not help but shed a tear for the school bus orbiter victim
At the start of his mission, Cassini spotted jets of ice and saltwater bubbling from rifts in the South Pole as he passed Saturn's ice-covered moon, Enceladus, a sign that the body contained an underground ocean could accommodate. When the orbiter began to consume little fuel, it shattered in Saturn rather than risking an unwanted fall that would contaminate the potentially habitable world.
Now the spaceship from beyond the grave has offered another prize for scientists. A new analysis of the Cassini data suggests that space ̵
The fact that an alternate orbiter was not suitable for life recognition was something that could be perceived by these molecules. Englisch: bio-pro.de/en/region/stern/magazine/…2/index.html and the most complex organs in the solar system – making the icy moon an even more tempting target in the search for extraterrestrial life, said Cable, a scientist at the Jet Propulsion Laboratory who was not involved in the new research
"This is a powerful study with a strong result, "she said.
The results published Wednesday in the journal Nature are based on data from two Cassini instruments – the Cosmic Dust Analyzer and the Ion and Neutral Mass Spectrometer – when the spacecraft passed through Saturn's outermost ring and the feathers of Enceladus (pronounced "en -SELL-a-dus ")
Earlier research using these instruments has revealed small molecules such as methane, which consists of four hydrogen atoms bound to a single carbon atom. The INMS has also detected molecular hydrogen – a chemical property of hydrothermal activity that provides important fuel for microbes living near seabed vents on Earth.
The molecules reported in the new Nature study are "orders of magnitude" larger than anything in the past. In the opinion of lead author Frank Postberg , a planetary scientist at the University of Heidelberg in Germany. There were stable carbon ring structures known as aromatics, as well as chains of carbon atoms bound to hydrogen, oxygen, perhaps even nitrogen.
Some of the molecules sampled by the CDA were so large that the instrument could not analyze them. This suggests that the organics Cassini found are only fragments of even larger compounds, Postberg said. It is quite possible that huge polymers – many segmented molecules such as DNA and proteins – are still waiting to be discovered.
"We astrobiologists are excited about larger molecules and something because it means building on themselves and making themselves more complex," said Kate Craft, a planetary scientist at the Applied Physics Laboratory at Johns Hopkins University who did not the research was involved.
The molecules discovered by Cassini can be produced abiotically – without the involvement of life. But they are also the types of compounds that microbes on Earth like to eat, and they could even be byproducts of microbial metabolism.
"Let's put it this way, if you did all these tests and did not see these larger molecules, [Enceladus] does not seem habitable," Craft said. "But these results … are a reason to say," Hey, we have to go back there and take a lot more data. "
Scientists believe that the gravitational influence of Saturn is the porous, rocky material in the core of Enceladus squeezes and bends and generates heat. This heat allows chemical interactions between the salty ocean and the seabed. On Earth, such water-rock interactions provide fuel for chemotrophic organisms that gain energy by breaking down chemicals in their environment – and support large ecosystems in the deepest and darkest depths of the ocean.
Postberg and his colleagues suggest that the organic molecules that emerge in the depths of Enceladus eventually float to the surface, where they form a thin film directly beneath the icy crust of the planet.
The oceans of Earth are covered with a similar film, they notice – a millimeter-thick blanket of tiny microbes and organic matter, which serves as an important interface between sea and sky. Research shows that this layer drives the weather. As bubbles break from breaking waves, particles from the film are lifted into the air, where they form a nucleus that allows the water to condense clouds and fog.
A similar process on the surface of Enceladus – Ocean may form ice crystals with Organics at its core, Postberg said. These grains are then sucked upwards by cracks in the lunar crust called "tiger stripes" and then thrown into the vacuum of space.
Enceladus & # 39; plumes are extremely thin – more like a thin veil than a beam from a fire hose – and scientists have questioned whether a spaceship flying through the spray could collect enough organic matter to draw conclusions about their origin to draw.
This result, Postberg says, shows that Enceladus "is kind to us and delivers his high-concentration organic inventory into space."
Cable is an associate project scientist for a concept called Enceladus Life Finder, which uses more advanced instruments which Cassini would use to inspect the cloud during a series of fly-bys. The mission was not funded by NASA, and the Space Agency has no development projects to return to Enceladus.
She, Postberg, and Craft expressed their hope that this latest finding would spark interest in a new mission to the Ice Moon. 19659002] "Enceladus yells at us that it has all the ingredients for life as we know it: water, chemistry, organic matter," said Cable. "We have to go back."