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Compression of the Universe, or how to fit all its stars in the Milky Way

Every day we are faced with compression in one form or another. When we squeeze water out of a sponge, pack a suitcase before vacation, trying to fill all the empty space with the necessary things, compress the files before sending them by e-mail. The idea of ​​removing “empty” space is very familiar.

Milky Way

Both on the cosmic and atomic scales, scientists have repeatedly confirmed that emptiness occupies the main space. And yet it is extremely surprising how true this statement is! When Dr. Caleb A. Sharf of Columbia University (USA) wrote his new book, “The Zoomable Universe,” he, by his own admission, planned to use it for some kind of dramatic effect.

What if we somehow manage to collect all the stars of the Milky Way and place them next to each other, like apples tightly packed in a large box? Of course, nature will never allow man to subjugate gravity, and stars will most likely merge into one colossal black hole. But, as a thought experiment, this is a great way to illustrate the amount of space in the Galaxy.

The result is shocking. If we assume that the Milky Way can have about 200 billion stars, and we generously believe that they are all the diameter of the Sun (which is overestimated, since the vast majority of stars are less massive and smaller in size), we could still assemble them into a cube, the length of the faces of which corresponds to two distances from Neptune to the Sun.

“There is a huge amount of empty space in space. And that brings me to the next level of craziness,” Dr. Scarf writes. According to the observable Universe, defined by the cosmic horizon of light movement since the Big Bang, current estimates suggest that there are between 200 billion and 2 trillion galaxies. Although this large number includes all the small “protogalaxies”, which will eventually merge into large galaxies.

Let’s be brave and take the largest number of them, after which we will pack all the stars in all these galaxies. Impressively generous, suppose they are all the size of the Milky Way (although most are actually much smaller than our Galaxy). We will get 2 trillion cubes, the faces of which will be 10 ^ 13 meters. We place these cubes in a larger cube, and we will remain with a megacube with a side length of approximately 10 ^ 17 meters.

Pretty big, right? But not on a cosmic scale. The diameter of the Milky Way is about 10 ^ 21 meters, so a cube of 10 ^ 17 meters in size still occupies only 1/10 000 of the size of the Galaxy. In fact, 10 ^ 17 meters is about 10 light years!

Naturally, this is just a little trick. But it effectively indicates how small the volume of the Universe actually occupied by dense matter, compared with the emptiness of space, perfectly characterized by Douglas Adams: “The cosmos is great. Really great. You simply won’t believe how vast, enormous, breathtakingly large the cosmos is. Here’s what we mean: you might think that the nearest diner is far away, but for space it means nothing.” (“The Hitchhiker’s Guide to the Galaxy ”).



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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