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Some potentially inhabited worlds may not have “zones of life”

An artistic representation of a tidal trapped potentially inhabited exoplanet, with the open ocean of liquid water surrounded by a global ice shell covering the rest of the extra-solar world on the day side.

They may be completely covered in ice and their oceans do not receive starlight.

Some of the potentially inhabited exoplanets orbiting red dwarfs may be completely covered in ice and not have open surface oceans of liquid water even on the side facing the star, which, under certain conditions, makes them unsuitable for life, scientists say in a study presented in Nature Astronomy.


“Perhaps some of the tidal traps of extrasolar worlds that were previously considered potentially inhabitable are frozen snowballs and have no open areas with liquid water. As a result, the starlight necessary for photosynthetic organisms does not reach the ocean, sealed under a global ice shell, which greatly limits the chances of the development and prosperity of life, ”says Jun Yan, lead author of the study from Peking University (China).

Potentially inhabited tidal rocky extra-solar worlds in red dwarf systems, especially the Proxima b, TRAPPIST-1e, and LHS 1140b, which are especially close to us, are the main goals for future studies of exoplanetary atmospheres, which can provide clues about their ability to support life.


Current models predict that if such a planet contains a vast surface ocean, then on its warmer day side there should be an ice-free area, locked on all sides by a global ice shell. However, as noted by Jun Yan, previous simulations did not fully take into account the important component of the climate system – ice dynamics – which did not allow revealing the issue of ocean resilience to global glaciation.

“In our work, we show that ice drifting from the night side of the exoplanet flows into an open area, gradually cooling, reducing, and ultimately completely sealing it.

It should be noted that such a scenario is applicable only to worlds living in the outer and, possibly, in the middle regions of the inhabited zone, but not to those located at its inner edge, since for them the flux of stellar radiation is high enough to melt ice and snow on the surface and maintain liquid water on the day and even night sides. In addition, the presence of greenhouse gases in the atmosphere plays a small role, since a large number of them will save the exoplanet from turning into a snowball, ”Jun Yan explained.

But, in spite of the fact that planets completely covered with ice are extremely inhospitable for life, one should not put an end to their potential for habitability, because the Earth itself in the past twice experienced periods of global glaciation: 2.2 billion years ago and 630 million years ago.

“For example, photosynthetic organisms can develop in areas with thin ice, where stellar radiation nevertheless reaches liquid water, or in local unsealed areas where active geothermal processes occur, or, finally, in some“ bays, ”where access to drifting ice is limited.” – concluded Jun Yan.



Unusual signals come from the GJ 1151 system

Most likely, radio emission is created by the interaction of a planet the size of the Earth with the strong magnetic fields of its star.

Using the LOFAR low-frequency radio telescope, astronomers recorded unusual radio emission coming from the red dwarf GJ 1151, which is located at a distance of about 28 light-years from Earth, these signals, according to scientists, contain evidence of the auroras created by the interaction of the planet with the strongest magnetic fields of the star. The results of the study are presented in the journal Nature Astronomy.

“Radio emission from the interaction of a star and a planet was predicted more than thirty years ago, but only now we were able to identify its signature in the data. Success achieved paves the way for a new way to detect exoplanets in the habitable zone and study their surroundings, ”the authors of the study say.

Red dwarfs are the most common type of star in the Milky Way. They are much smaller and colder than the Sun and have extremely strong magnetic fields. This means that any potentially inhabited planet in the system of such a star, due to its proximity to it, is subjected to intense magnetic activity, which can heat it and even destroy the atmosphere. The radio emission associated with this process is one of the few tools available to evaluate this effect.

“The movement of the planet through the strong magnetic field of the red dwarf acts like an electric motor. This process generates a huge current that provokes radiance and creates radio emission, ”explained Harish Vedantam, lead author of the study from the Netherlands Institute of Radio Astronomy.

In the solar system, similar currents are not generated due to the weak magnetic field of the sun and the large distance to the planets. However, the interaction of the Io satellite with the magnetic field of Jupiter also creates a fairly bright radio emission, at low frequencies superior to the sun.

“We adapted our knowledge from decades of radio observations of Jupiter to the data on the star GJ 1151. For many years it was predicted that the Jupiter-Io system should exist in a larger version of the star-planet, and the radiation recorded by us from GJ 1151 is very well consistent with theory. Today we know that almost every red dwarf contains terrestrial planets, so there must be other stars showing such radiation,” Joe Cullingham added, the co-author of a study from the Netherlands Institute of Radio Astronomy.

Astronomers note that the sensitivity of modern instruments should allow them to find about a hundred more of such systems in the solar vicinity, and, more importantly, assess the conditions in which exoplanets reside in them.

“The main goal is to determine what effect the magnetic activity of a star has on the habitability of an exoplanet, and radio emission is the most important link in this puzzle,” Harish Vedantam concluded.

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Mankind may face deadly viruses in search of new life in space

Professor Dov Greenbaum hypothesized that humanity’s search for signs of life outside the Earth could lead to an even greater threat of infection than a new kind of coronavirus.

In his material, the scientist notes that in the era of human mobility, new viruses spread very quickly, while bacteria grown in outer space can become even more deadly.

For a more detailed study of this issue, samples of genetically engineered bacteria samples are sent aboard the ISS. Despite the fact that the spread of extraterrestrial viruses in real life is considered a very unlikely scenario, the scientist warns against excessive optimism. The astrobiologist claims that dangerous viruses and infections can live in space on rocks that seem dead to the surface. In connection with these, Greenbaum believes that in the case of the reality of the existence of extraterrestrial life forms, their search without appropriate precautions “can lead to infections that will be even more dangerous and deadly than the acclaimed coronavirus.”

The professor also recalled that life was found in those places that were previously considered impossible for the existence of living organisms. So, NASA is going to deliver stones from the surface of Mars, and the Japanese space mission is already returning from the asteroid Ryugu with samples of its rock. At the end of this year, the Japanese Hayabusa2 will reach Earth. According to Greenbaum, it is likely that one of these missions will deliver a fundamentally new type of space infections to Earth.

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Unknown carbon form found in Chelyabinsk meteorite

Scientists have discovered an unknown form of carbon on Earth in fragments of a meteorite that fell in the Chelyabinsk region in 2013, said Sergei Zamozdra, assistant professor of theoretical physics at the Chelyabinsk State University.

He said that the dean of the Faculty of Physics Sergey Taskaev (now the rector of the university. – Ed.), while studying samples of meteorite dust, noticed something amazing.

“At first he thought it was a diamond, because there were six faces. Later in Germany, this crystal was pulled out using micro-tweezers and when X-rayed – it turned out to be not a diamond, but a carbon crystal. We measured the position of atoms, the planes of interatomic, then Korean specialists on a computer calculated that, indeed, such an arrangement of atoms is possible, “he explained.

According to the scientist, carbon can have many modifications. However, such carbon has not yet been found on Earth, and experts will have to figure out how it came about, calculating different options.

“One option is that it arose in space conditions, because we are talking about a process of billions of years. Another is directly during a flight in the Earth’s atmosphere,” the scientist believes.

According to the press service of Chelyabinsk State University, the study of meteorite fragments was carried out by Sergey Taskaev together with colleagues from the Technical University of Darmstadt (Germany) and the National University of Kengpuk (Republic of Korea).

In the Chelyabinsk region on February 15, 2013, thousands of people watched a very bright object in the sky. In the first minutes, the expansion and twisting of its smoky plume was visible, followed by an air wave strike, similar to the sound of a strong explosion.

Fragments of the meteorite were found in the vicinity of Chebarkul, but the largest – more than 600 kilograms – was raised from the lake of the same name. Now it is stored in Chelyabinsk in the South Ural State Historical Museum under a special dome in the exhibition hall, where everyone can see it.

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