NEW EVIDENCE FOR THE BUILDING BLOCKS OF LIFE ON ENCELADUS

New Evidence for the Building Blocks of Life on Enceladus

Saturn's moon Enceladus is one of the celestial bodies in the solar system that is most likely to host life. There is strong evidence that the moon, which is about 500 kilometres in diameter, has an ocean beneath its surface. Water vapor is erupting from the moon's icy surface. Scientific studies have shown that the chemical composition of the vapours erupting from the surface of Saturn's moon Enceladus is richer than previously known.

The vapours erupting from the surface of Enceladus were first observed by the Cassini spacecraft in the mid-2000s. The spacecraft, which orbits Saturn, flew through the vapours erupting from Enceladus several times in 2011-2012 and analysed the composition of the vapours with its scientific instruments. Cassini's analyses concluded that there were five separate molecules in the vapor: water (HO), carbon dioxide (CO₂), methane (CH), ammonia (NH), and hydrogen gas (H). Jonah Peter and colleagues from Harvard University recently re-analysed the data collected by the Cassini spacecraft.

Peter and his colleagues' latest analysis is much more detailed than Cassini's own. Using statistical methods, the researchers looked at billions of possible combinations of compounds in the plumes from Enceladus and identified the ones that best matched the data collected by Cassini.

The results, published in Nature Astronomy , show that in addition to the five molecules identified by Cassini in the plumes from the surface of Enceladus, there are also other molecules, including hydrocarbons.

Some of the new molecules identified by the researchers are: hydrogen cyanide (HCN), ethane (C₂H), and methanol (CH,OH). Among the molecules detected, HCN is particularly important, because it can react with other substances to form amino acids or nucleotide bases, and later proteins and RNA. Experiments also show that these reactions are possible under conditions similar to those on Enceladus. Especially regions near the ocean floor, where there is hydrothermal activity, can provide a suitable environment for these chemical processes to take place.

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Exoplanets with Geysers on Their Surfaces

 Astronomers trying to discover habitable exoplanets typically focus on planets in the "habitable zones" of stars. The habitable zone refers to the region where liquid water can exist on the surface of planets orbiting a star. However, oceans can exist not only on the surface of a planet, but also under its surface. For example, it is known that Europa and Enceladus, moons in the solar system, have oceans under their icy surfaces.

NASA's Lynnae C. Quick and her colleagues announced in an article published in The Astrophysical Journal that they have identified 17 exoplanets that may have oceans under their icy surfaces. All of these planets may also have geysers.

One of the exoplanets that may have geysers on their surfaces is Proxima Centauri b, which is 4.2 light-years away from Earth, and the other is LHS 1140 b, which is 48.8 light-years away from Earth. According to the researchers' estimates, Proxima Centauri b's surface is covered with 58 meters of ice, while LHS 1140 b's surface is covered with 1.6 kilometres of ice. It is estimated that approximately 6 million kilograms of water are ejected from the surface of Proxima Centauri b every second, and approximately 290 thousand kilograms of water are ejected from the surface of LHS 1140 b every second.

It is stated that since both Proxima Centauri b and LHS 1140 b are relatively close to Earth, the geysers on these exoplanets can be observed with telescopes. If geysers do indeed exist on these exoplanets, the traces of water vapor in the light reaching the telescopes will change as the geysers erupt water from time to time. The observations can even provide information about whether the erupted water contains elements and compounds that can support life. In this way, it can also be understood to what extent the underground oceans on these planets are suitable for life.

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Map of Active Volcanoes on Io

Io is the closest of Jupiter's moons to the planet. One of the most prominent features of this moon is that it is the most volcanically active of all known celestial bodies. In fact, volcanic eruptions occur almost constantly on Io, and rivers of magma flow on its surface.

One of the questions still to be answered about Io is where the heat that causes volcanic activity comes from. Are Io's volcanoes powered by sources just below the surface, or is the heat coming from regions closer to the moon's centre? Finding the answer to this question is important not only for understanding Io's structure, but also for other moons that are thought to have oceans beneath their surface, such as Europa and Enceladus. Various maps of Io's volcanoes have been made in the past. However, these maps mostly included volcanoes in the mid-latitudes. Detailed mapping of volcanoes in the polar regions has not been possible due to the lack of a device that can directly focus on observing Io. Data on Io's volcanoes have largely come from spacecraft that have passed close to the moon. This changed in 2016 when the Juno satellite orbiting Jupiter entered an orbit that would allow it to observe Io's polar regions for long periods. Data collected by Juno's infrared cameras has produced the most detailed map of Io's volcanoes to date.

Dr. Gerard Ashley Davies and colleagues published a study in Nature Astronomy that examined the heat flow in 266 active volcanic regions on Io. The results show that the density of volcanoes in the polar regions is about the same as in the mid-latitudes, but that the volcanoes in the polar regions are not as energetic as those in the mid-latitudes. Based on their analysis, the researchers conclude that the main heat source of the volcanic activity is near the surface, not deep inside the moon. They also infer that there is a global magma ocean beneath the moon's surface.

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"Giant Quantum Vortex" That Mimics a Black Hole

The areas around black holes are very important for studying quantum gravity effects. However, the area around a black hole, which we know very little about, is still a mystery today.

A group of researchers developed quantum simulators to investigate the events that occur around black holes. Superfluid helium was used to create these simulators. This fluid, which moves without friction, is a type of quantum fluid where extraordinary quantum effects can be observed. Helium, which was placed in a tank with a rotating propeller at the bottom, created a vortex similar to a tornado as the propeller rotated.

Many small vortices appear in quantum fluids that are in a rotating motion. These small vortices tend not to come together. However, in this experiment, the researchers managed to create a giant quantum vortex by combining about 40,000 small vortices.

The strength and size of the vortex are crucial for observing the interactions between the vortex and the rest of the liquid in the tank. Although the researchers had previously tried to create similar vortices, the strength of these vortices was considerably weaker than the vortex created with helium.

The scientists observed how small waves in the helium superfluid interacted with the vortex. This process mimicked the interaction of cosmic fields in space with spinning black holes. They also obtained detailed clues about the merging of two black holes.

The researchers see the black hole-like behaviour of such vortices as a perfect starting point for investigating various black hole physics processes.