(ORDO NEWS) — In search of life outside the Earth, the main goal is the satellites of the giant planets of the solar system. Recently, data has emerged that strengthens the hopes of scientists. Where will they find the first “aliens” and what research is being carried out for this.
Titan: Journey into Earth’s Past
The largest satellite of Saturn is the only celestial body in the solar system, on the surface of which the liquid is in a stable state. But it’s not water. The rivers and lakes on Titan are methane. The volumes of hydrocarbons in them are many times greater than the total reserves of oil and gas on Earth.
The Americans are preparing to land on Titan. In 2027, a spacecraft with an unmanned helicopter on board should fly there. In 2034, he will reach the goal. The basic program is designed for two and a half years.
Conditions on a planetoid the size of one and a half moons are well suited for flights. The atmosphere of a celestial body is four times denser than on Earth.
At the same time, gravity is one-seventh of the earth’s. A tailwind will help the movement – on Titan it always blows in one direction. For one half-hour flight, the device called Dragonfly (“Dragonfly”) will be able to cover 16 kilometers.
A drone armed with various instruments will land in Shangri-La, an area characterized by structures reminiscent of the sand dunes of Namibia. Then, moving east, a drone that looks like an Osprey military transport tiltrotor will reach the Selk impact crater.
There is evidence of the existence of liquid water and organic substances in the past – complex molecules containing carbon combined with hydrogen, oxygen and nitrogen. That is, the components necessary for life.
A recent study by Cornell University determined the nature of the surface of the Dragonfly’s terminus. The calculations were made on the basis of data from the Cassini probe, which flew around Titan, and the Huygens descent vehicle, which landed on Saturn’s moon in 2005.
Selk Crater is located on Titan’s equator. Most of the time there is a fine methane drizzle. The geology of the crater is mainly sand from methane ice. According to NASA, it looks like coffee grounds.
Dragonfly will explore prebiological chemistry. The task is to unravel the mystery of the origin of life on Earth. Titan is the perfect laboratory for studying our planet’s past.
The conditions on it are very similar to those that we had about 2.5-3.8 billion years ago. Then the earth’s atmosphere, which, like on Titan, consisted mainly of nitrogen, also did not contain oxygen. That did not prevent the appearance of the first microorganisms.
Titan is obscured by an orange haze, making it difficult to see it from a distance. Perhaps, once the same veil shrouded the Earth and helped to grow life on it – it maintained a temperate climate, shielded the main part of the harmful ultraviolet radiation of the Sun, which can destroy DNA.
There is little chance of finding biological forms on Titan itself: there are no conditions for this on the surface of the moon. And the water in the global subsurface ocean is likely too salty to be anyone’s home. But there is no final refutation of the existence of life in this world either.
The creators of “Dragonfly” face difficult tasks. The air temperature at the surface of Titan is minus 180 degrees Celsius. But the drone needs heat to operate. A nuclear power source, powered by lithium batteries, heats the drone almost to room temperature.
And the cryogenic samples that Dragonfly will put into its DraMS mass spectrometer must not be melted. Therefore, engineers are developing Wonderwall technology – a “miracle wall” that separates the cold mini-laboratory of the apparatus from its heated parts.
Titan also inspires private developers. An international team of Conex Research enthusiasts recently presented the Astray mission project, during which they plan to send not only an aircraft, but also a bathyscaphe to Titan to study methane lakes.
Europe: underwater snow
The conditions of life are water, chemistry (certain chemical elements) and energy. Various data – from visual observation to measurements with a magnetometer – have proved that under the ice crust of Jupiter’s moon there is a global salty ocean. There is more water in it than in all the oceans of the Earth.
For the origin of life, chemical elements are needed: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Scientists believe that they were probably present on Europa at the time of formation.
Later, asteroids and comets that collided with this moon and fell through the icy crust into the ocean added organic or carbonaceous materials to it.
The energy of the bowels of Europe is set by Jupiter: under the influence of tidal forces, geological activity occurs on the satellite. Heat causes minerals to interact with water, which can lead to chemical reactions. In addition, on the surface of the planetoid, radiation from Jupiter splits water into hydrogen and oxygen.
H escapes, while O2 remains, making up the bulk of the moon’s thin atmosphere. Scientists hypothesize that oxygen can enter the ocean, providing the chemical energy for microbial life. All this makes Europe the most promising destination for the search for alien life.
According to experts, the temperature, pressure and salinity of the Europa ocean are similar to those under the ice shelf in Antarctica – and there, as you know, there is life.
Now the Jupiter system is being studied by the Juno probe (“Juno”). In early October, he photographed Europe at close range. In the image taken by the spacecraft’s star tracker, the moon’s surface is illuminated by light reflected from Jupiter. An area of 150 by 200 kilometers fell into the frame.
The resolution is 300 meters per pixel. In the photo you can see the double ice ridges. The musical note-like object, 67 kilometers north to south and 37 kilometers west to east, is what NASA calls a “surface feature.” Its origin is unclear.
Perhaps this is a trace from a cryovolcano. A recent study showed that the subglacial ocean is not the only reservoir of water on Europa.
Scientists suggest that there are lakes in the ice crust of the satellite at a depth of four to eight kilometers. They are credited with the ability to erupt: only instead of lava, ice porridge flows to the surface – the so-called cryolava.
Such bodies of water could be the target of the Europa Clipper mission. The device will land on the satellite of Jupiter in 2030 (the launch is scheduled for 2024).
In the meantime, you can watch in real time how it is collected in an ultra-hygienic compartment. NASA engineers are trying to prevent the entry of terrestrial organics to Europa.
The equipment aboard the Clipper is designed to search for signs of life. The lander will operate on Europa for three and a half years.
It will operate in conjunction with an orbiter circling above the satellite at an altitude of 25 to 2700 kilometers. For comparison: a fresh picture of “Juno” was taken from a height of more than 400 kilometers.
In preparation for the flight, remote studies of the planetoid are underway. Scientists find out the features of the “European” ice. In an August article, the authors made the assumption that in the satellite’s ocean, snow rises from the bottom to the surface, that is, it sort of falls from the bottom up.
Enceladus: candidate number one
Enceladus, another moon of Saturn, is the brightest object in the solar system. Like Europe, it is covered with ice, under which a layer of water is hidden.
In the region of the south pole, the shield is cut by giant scratches. These are traces from geysers: particles of ice and dust are ejected at a speed of 400 meters per second to a height of hundreds of kilometers. In 2008, Cassini flew through this plume.
The spacecraft’s ion and neutral mass spectrometer detected volatiles, gases, and organics in the plume, while a cosmic dust analyzer detected organics in some of the ice grains.
Among other things, the probe caught silica nanograins, which could only form where liquid water and rock interact at temperatures above 90 degrees Celsius.
This indicates that there are hydrothermal vents deep below the ice shell, not much different from those on Earth. According to NASA, the new data changed the direction of planetary science and Enceladus began to be seen as “the most suitable place for life outside the Earth.”
The collected material was enough for many years of research. In October 2022, an international team of scientists identified signs of the presence of phosphorus, the sixth important element for the origin of life, in the ocean of Enceladus.
Carbon, hydrogen, nitrogen, oxygen and sulfur have been found earlier. On Earth, phosphorus plays a key role in the formation of bones, teeth, cell membranes, DNA and RNA in living organisms.
The scientists performed thermodynamic and kinetic simulations that mimic the geochemistry of phosphorus based on Cassini data.
The result is a detailed geochemical model of how seafloor minerals dissolve into Enceladus’ ocean. She predicts that the phosphate minerals will be extraordinarily soluble there.
To get direct confirmation of the “building blocks” of life on Enceladus, it is necessary to send a special mission there. However, neither NASA nor other space agencies have plans to do so yet.
Perhaps recent research will change the situation and the growing interest of scientists in Saturn’s moon will help find funding.
The Enceladus research project may receive support in 2024, when a competition is held as part of NASA’s New Frontier program. Until now, preference has been given to competing directions.
It is not yet clear which of the three moons of the solar system’s giant planets is more likely to contain life.
“We only know that these satellites have the ingredients necessary, as we now think, for the appearance life. But this does not mean at all that something has already been cooked from them. Since we do not know what additional conditions are needed, we cannot calculate the probability. ”
And don’t expect a quick answer. Modern technologies do not yet allow drilling ice sheets on Titan and Europa, the scientist notes. Therefore, the study of phenomena such as cryovolcanism remains the main way to search for extraterrestrial life. So far, however, he has provided only circumstantial “evidence”.
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