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The best planets for aliens have been identified by astronomers

In their tireless search for signs of extraterrestrial life, astronomers have coined the intriguing term “Goldilocks Zone” when referring to the habitable zone of a star body: the distance from a star where liquid water can be present on the surface of a planet is not too hot, not too cold, but fair.

New research by astronomers based on decades of data has identified new criteria that can help assess the potential habitability of a planet.

The study, called the “Goldilocks Project”, presented by a team of astronomers from the University of Villanova at the 235th meeting of the American Astronomical Society in Hawaii, has identified what has been coined as “Goldilocks stars,” star systems where they hope to find the best planets for possible extraterrestrial life.

Many are already familiar with the concept of the habitable zone, the distance from a star in which liquid water can be present on the surface of a planet, not hot enough to vaporize it, not so cold that everything would be frozen.

That explains the reference to the story of Goldilocks and the Three Bears, where a blond girl enters an empty cabin in the forest, tries three bowls of porridge and discovers that one is “fair, neither too hot nor too cold! ”

The Goldilocks area around a star is like that. However, although we definitely consider liquid water as a vital ingredient for life, it is not the only criterion in our search for potentially habitable planets.

According to astronomers at the University of Villanova, the best stars for life are one step along the Hertzsprung-Russell star type table, that is, K-type stars. These are orange stars that are a bit colder than the sun, and a little warmer than a red dwarf.

“The K dwarf stars are in the” sweet spot “, with intermediate properties between the rarer, brighter but shorter-lived solar stars (G stars) and the more numerous red dwarf stars (M stars),” Villanova astronomer and astrophysicist Edward Guinan explained, who presented the new study with a colleague, astronomer Scott Engle.

“K stars, especially the warmest ones, have the best of all worlds. If you are looking for planets with habitability, the abundance of K stars increases your chances of finding life. ”

Guinan, Engle and their students have been monitoring a series of F and G stars in ultraviolet and X-rays for the past 30 years as part of their Sun in Time program, and red M-type dwarfs for 10 years as part of the program Live with a red dwarf.

Both programs have been helping to assess the impact of X-rays and ultraviolet radiation from the stars in question on the possible habitability of their planets.

The study has also been measuring age, rotation rate and X-rays and far ultraviolet radiation in a sample of mostly cold G and K stars.

In their investigation, they used the NASA Hubble Space Telescope, the Chandra X-ray Observatory and the XMM-Newton satellite of the European Space Agency for their observations. Hubble’s sensitive ultraviolet light observations of hydrogen radiation were used to evaluate the radiation of a sample of approximately 20 orange dwarfs.

“Hubble is the only telescope that can do this kind of observation,” Guinan said.

Guinan and Engle discovered that the radiation levels around the K stars were much more benign for the accompanying planets than those found around the red dwarfs.

K stars also have a longer lifespan and, therefore, the migration of the habitable zone occurs more slowly, pointing to the suggestion that K dwarfs could present the ideal place to look for signs of extraterrestrial life.

Guinan and Engle also observed some of the most interesting K stars that host planets, including Kepler-442, Tau Ceti and Epsilon Eridani.

“Kepler-442 is notable because this star houses what is considered one of the best Goldilocks planets, Kepler-442b, a rocky planet that is a little more than double the Earth’s mass. Therefore, the Kepler-442 system is a Goldilocks planet housed by a Goldilocks star! “Guinan said.

In another fact that inspires optimism, there are three times more K dwarfs in our galaxy than stars like our Sun.

Approximately 1,000 K stars are within 100 light years of our Sun, which makes them the best candidates for exploration.

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Space

Voyager 2 has discovered something amazing: Denser space outside the solar system

In November 2018, after a 41-year voyage, Voyager 2 crossed the boundary beyond which the Sun’s influence ends, and entered interstellar space. But the mission of the little probe is not yet complete – it continues to make amazing discoveries

Perhaps the probes have found some kind of traffic jam at the edge of the solar system. The Voyager flight continues and we will soon find out what it was.

Voyager 2 discovered something amazing: as the distance from the Sun increases, the density of space increases.

Voyager 1, which entered interstellar space in 2012, transmitted similar indicators to Earth. New data have shown that the increase in density may be a feature of the interstellar medium.

The solar system has several boundaries, one of which, called the heliopause, is determined by the solar wind, or rather by its significant weakening. The space inside the heliopause is the heliosphere, and the space outside is the interstellar medium. But the heliosphere is not round. It looks more like an oval, in which the solar system is at the leading edge, and a kind of tail stretches behind it.

Both Voyagers crossed the heliopause at the leading edge, but within 67 degrees heliographic latitude and 43 degrees longitude apart.

Interstellar space is usually considered a vacuum, but this is not entirely true. The density of matter is extremely small, but it still exists. In the solar system, the solar wind has an average density of protons and electrons from 3 to 10 particles per cubic centimeter, but it is lower the further from the Sun.

The average concentration of electrons in the interstellar space of the Milky Way is estimated to be about 0.037 particles per cubic centimeter. And the plasma density in the outer heliosphere reaches approximately 0.002 electrons per cubic centimeter. When the Voyager probes crossed the heliopause, their instruments recorded the electron density of the plasma through plasma oscillations.

Voyager 1 crossed the heliopause on August 25, 2012 at a distance of 121.6 astronomical units from the Earth (121.6 times the distance from Earth to the Sun – about 18.1 billion km). When he first measured plasma oscillations after crossing the heliopause on October 23, 2013 at a distance of 122.6 astronomical units (18.3 billion km), he found a plasma density of 0.055 electrons per cubic centimeter.

After flying another 20 astronomical units (2.9 billion kilometers), Voyager 1 reported an increase in the density of interstellar space to 0.13 electrons per cubic centimeter.

Voyager 2 crossed the heliopause on November 5, 2018 at a distance of 119 astronomical units (17.8 billion kilometers. On January 30, 2019, it measured plasma oscillations at a distance of 119.7 astronomical units (17.9 billion kilometers), finding that the density plasma is 0.039 electrons per cubic centimeter.

In June 2019, Voyager 2’s Instruments showed a sharp increase in density to about 0.12 electrons per cubic centimeter at a distance of 124.2 astronomical units (18.5 billion kilometers).

What caused the increase in the density of space? One theory is that the lines of force of the interstellar magnetic field become stronger with distance from the heliopause. This can cause electromagnetic ion cyclotron instability. Voyager 2 did detect an increase in the magnetic field after crossing the heliopause.

Another theory is that the material carried away by the interstellar wind should slow down in the heliopause, forming a kind of plug, as evidenced by the weak ultraviolet glow detected by the New Horizons probe in 2018, caused by the accumulation of neutral hydrogen in the heliopause.

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NASA has banned fighting and littering on the moon

New details of the agreement signed by representatives of a number of countries on the development of the moon and the extraction of minerals within the framework of the Artemis program have appeared. Reported by the National Aeronautics and Space Administration (NASA).

So, astronauts involved in the mission are prohibited from littering and fighting on the territory of a natural satellite of the Earth.

So, we present to you the new rules for being on the Moon:

Everyone comes in peace;

Confidentiality is prohibited, all launched objects must be identified and registered;

All travel participants agree to help each other in case of emergencies;

All received data is transferred to the rest of the participants, and space systems must be universal;

Historic sites must be preserved and all rubbish must be disposed of;

Rovers and spacecraft should not interfere with other participants.

“”It is important not only to go to the moon with our astronauts, but also that we bring our values ​​with us,” said Mike Gold, acting head of NASA’s international and inter-agency relations.

According to him, violators of the above rules will be asked to “just leave” the territory of the moon.

The effect of these principles so far applies to eight signatory countries of the agreement: the USA, Australia, Canada, Italy, Japan, Luxembourg, the United Arab Emirates and the United Kingdom. Countries other than China can join if they wish.

 It should be noted that at the moment NASA is prohibited from signing any bilateral agreements with the PRC leadership.

The first NASA mission to the moon, known as “Artemis 1”, is scheduled for 2021 without astronauts, and “Artemis 2” will fly with a crew in 2023.

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Methane snow found on the tops of Pluto’s equatorial mountains

Scientists believe that it arose as a result of the accumulation of large amounts of methane at an altitude of several kilometers above the surface of the planet.

In the images of the Cthulhu region – a dark region in the equatorial regions of Pluto – planetary scientists have found large reserves of methane snow that covers the peaks of local mountains and hills. It formed quite differently from how snow forms on Earth, astronomers write in the scientific journal Nature Communications.

“The white caps on the tops of Pluto’s mountains did not arise from the cooling of air currents that rise along the slopes into the upper atmosphere, as it happens on Earth, but from the accumulation of large amounts of methane at an altitude of several kilometers above Pluto’s surface. This gas condensed on the mountain tops, “the scientists write.

We owe almost everything we know about Pluto to the New Horizons interplanetary station. It was launched in January 2006, and in mid-July 2015 the station reached the Pluto system. New Horizons flew just 13 thousand km from the dwarf planet, taking many photographs of its surface. 

New Horizons data indicated an interesting feature of Pluto – in its depths, a giant subglacial ocean of liquid water can be hidden. It can be a kind of engine of those geological processes, traces of which can be seen on the surface of a dwarf planet. Because of this discovery of New Horizons, many discussions began among planetary scientists. Scientists are trying to understand how such a structure could have arisen, as well as to find out the appearance of Pluto in the distant past.

Members of the New Horizons science team and their colleagues from France, led by planetary scientist from NASA’s Ames Research Center (USA) Tanguy Bertrand, have discovered another unusual feature of Pluto. They studied the relief of one of the regions of the dwarf planet – the Cthulhu region. This is what astronomers call a large dark region at Pluto’s equator, which is whale-like in shape and is covered in many craters, mountains and hills.

Snow in Pluto’s mountains

By analyzing images of these structures taken by the LORRI camera installed on board New Horizons, astronomers have noticed many blank spots on the slopes of the highest mountain peaks. Having studied their composition, scientists have found that they consist mainly of methane.

Initially, planetary scientists assumed that these are deposits of methane ice. However, Bertrand and his colleagues found that the slopes and even the tops of Pluto’s equatorial mountains are actually covered not only with ice, but also with exotic methane snow that forms right on their surface.

Planetary scientists came to this conclusion by calculating how methane behaves in Pluto’s atmosphere. In doing so, they took into account how the molecules of its gases interact with the sun’s rays and other heat sources. It turned out that at the equator of Pluto, at an altitude of 2-3 km from its surface, due to the special nature of the movement of winds, unique conditions have formed, due to which snow is formed from methane vapor.

Unlike Earth, where such deposits are formed as a result of the rise of warm air into the upper atmosphere, on Pluto this process goes in the opposite direction – as a result of contact of the cold surface of the peaks and slopes of mountains with warm air masses from the relatively high layers of the dwarf planet’s atmosphere.

Previously, as noted by Bertrand and his colleagues, scientists did not suspect that this was possible. The fact is that they did not take into account that due to the deposition of even a small amount of methane snow and ice, the reflectivity of the peaks and slopes of mountains in the Cthulhu region increases. As a result, their surface temperature drops sharply, and snow forms even faster.

Scientists suggest that another mysterious feature of Pluto’s relief could have arisen in a similar way – the so-called Tartarus Ridges, located east of the Sputnik plain. A distinctive feature of this mountainous region is strange peaks that are shaped like skyscrapers or blades. Bertrand and his colleagues suggest that these peaks are also methane ice deposits that grow “from top to bottom.”

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