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The universe can be a giant loop, evidence suggests

New evidence suggests that, instead of being flat like a leaf, the universe can actually spin on itself.

What would happen if you could go drive with your spaceship faster than light and walked away in a perfectly straight line, never slowing down and never changing direction? Would you reach the edge of the universe or end up just where you started?

The idea that the universe is curved and curves over itself has existed for a while, however, it is a theory that is not really compatible with conventional ideas about how the universe works.

Now, however, a new document has ruined the idea of ​​a curved universe, since it suggests that there may be something in the idea of ​​a curved universe after all.

The study, which is based on the research of an international team of physicists, re-examines the data of the cosmic microwave background radiation (CMB), a remnant of the birth of our universe.

The key is in the discovery of an anomaly that suggests that there are significantly more “gravitational lenses” of the CMB than expected – more than can be explained by conventional physics.

According to the team’s findings, if the universe is really curved, then the curvature is very smooth, which means that on a planetary scale or even on a galactic scale it is unlikely that we will really notice.

universe-cosmic-microwave-background-cmb-big-bang

The cosmic microwave background is the faint echo of the Big Bang (Image: ESA/Max Planck Institute)

On a cosmic scale, however, this curvature becomes increasingly frequent until someone who moves through the entire universe in a straight line finally ends just where it began.

However, there is a long way to go to prove once and for all that this is really the case.

“I don’t want to say that I believe in a closed universe,” said study co-author Alessandro Melchiorri. “I am a little more neutral. I would say wait for the data and what the new data will say. ”

“What I think is that there is a discrepancy now, that we have to be careful and try to find what is producing this discrepancy.”

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Space

Is Planet X a miniature black hole? Astrophysicists have come up with a way to find out

This can be tracked by miniature flashes of light that will form after a black hole absorbs surrounding objects.

Could a hypothetical ninth planet of the solar system, the “X-planet,” be a miniature black hole? US astrophysicists have figured out how to find out with the LSST observational telescope under construction. An article describing the work was accepted for publication by the Astrophysical Journal Letters.

“If small celestial bodies fall in the vicinity of a black hole, they begin to melt under the influence of heat, which produces gas falling on the event horizon. After that, the attraction of the black hole begins to break them, resulting in characteristic flashes of light,” one of the authors work said, professor at Harvard University Abraham Loeb.

Almost five years ago, two American planetologists, Konstantin Batygin and Michael Brown, said they had found the first traces of the existence of the mysterious X-Planet. So scientists called the hypothetical ninth planet of the solar system, which is located at least 100 billion kilometers from the sun and is similar in size to Neptune or Uranus.

Until scientists found it, the researchers were only able to narrow down the area where it might be located, as well as find new hints of its existence. These failures made many astronomers doubt the hypothesis. Other planetologists have begun to look for alternatives for what the X-Planet might look like and where it might be.

For example, some astrophysicists now admit that the X-Planet may not actually be a gas giant, a large earth-like planet or a “guest” from another star system, but a much more exotic object – the so-called primary black hole.

It is a miniature analogue of ordinary and supermassive black holes, which in mass are comparable not with stars and galaxies, but with planets. As cosmologists suggest, such black holes could appear in the first moments of the existence of the Universe due to the fact that matter was unevenly distributed over its space. The largest of them could survive to the present day – however, they are gradually decreasing due to Hawking radiation.

Searches for “Planet X”

Finding such objects, as Professor Loeb notes, is even more difficult than the classic X-Planet. This is due to the fact that such black holes, unlike the coldest and most invisible planets, do not themselves generate any radiation.

Harvard astrophysicists have found that, nevertheless, the most sensitive telescopes on Earth can still notice the primary black hole. Astronomers came to this conclusion, drawing attention to the situation in that part of the solar system where the “X-planet” or primary black hole is supposedly located.

As scientists noted, they will be located at a point where the attraction of the Sun is weakening so much that a primary black hole the size of a planet will constantly attract clusters of matter from the surrounding space, including fragments of asteroids and comets that fill the outskirts of the solar system.

As a result, according to the calculations of scientists, due to the activity of a black hole, miniature flashes of light will almost constantly occur. They can appear after the attraction of a black hole will tear apart objects with a diameter from a few centimeters to several hundred meters. For existing ground-based telescopes, these flares will be barely visible, but they can be seen by the LSST observatory under construction, which is located at the edge of the Atacama Desert in Chile.

“The LSST observatory has an extremely wide field of view, so it will receive images of the entire night sky twice a week. This is very important, given that we do not know exactly where the X-planet is located. In addition, its high sensitivity will allow us to find traces flashes that produce even the smallest objects approaching a black hole,” Loeb continues.

If the theorists’ calculations are correct, then LSST can find traces of the existence of a black hole in the first three years of operation, provided that it is comparable in mass with Jupiter or significantly less than it. Otherwise, astronomers will prove that such objects in the solar system do not exist, and will also help theorists to impose more stringent restrictions on the permissible masses of primary black holes. This is important for studying how the expansion of the universe went.

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Space

An inconceivably ancient cosmic object was discovered

An international group of astronomers from the United States, Germany, China and Chile reported the discovery of a largest quasar called Poniua’ena, which in Hawaiian means “an invisible rotating source of creation surrounded by radiance.”

The object is located at a distance of about 30 billion light years, which corresponds to the age of the Universe at 710 million years. A preprint of the article, which will be published in the Astrophysical Journal Letters, is available on the arxiv website.

The light from the quasar J1007 + 2115 flew 13 billion years, however, due to the accelerated expansion of the Universe, its redshift is z = 7.515, which corresponds to the actual distance to it, equal to 29.3 billion light years. Astronomers see the object as it was in the era of reionization, when the first stars appeared, ionizing hydrogen atoms with their light.

Poniua’ena contains a supermassive black hole whose mass reaches 1.5 billion solar masses, making the quasar the largest object in the early Universe. According to Jinyi Yang, lead author of the work from the University of Arizona, this is the earliest object of such a monstrous size known to scientists.

Its existence poses a problem for theoretical models of the formation of supermassive black holes, according to which, J1007 + 2115 simply would not have time to grow in 710 million years if it had originally arisen as a result of the collapse of the star.

Instead, astronomers believe, a hundred million years after the Big Bang, there was already a black hole with a mass of 10 thousand Suns, which was formed as a result of direct gravitational collapse of clouds of cold hydrogen gas.

Poniua’ena is currently the second oldest quasar found to date. In 2018, the quasar J1342 + 0928 was discovered, which is two million years older than J1007 + 2115, but at the same time half as massive.

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Space

Wormholes. To anywhere in the universe in a minute

Wormholes or tunnels in the fabric of spacetime are terribly unstable. As soon as at least one photon hits them, the wormhole closes instantly. A new study suggests that the secret to a stable wormhole is in their form.

Wormholes, if they exist, will allow us to travel from point A to some extremely distant point B without worrying about travel time. The transition would be incredibly fast. Real cheat code of the universe. See a star for millions of light years? You could reach it in just a few minutes if you had a wormhole leading to it. No wonder this is a very popular science fiction theme.

But wormholes are not just a figment of our imagination, created to carve out all the boring scenes of interstellar travel (and this is centuries and millennia). We learned about them through Einstein’s general theory of relativity: matter and energy bend and deform the fabric of space-time, the curvature of which tells matter how to move.

Therefore, when it comes to wormholes, you just need to ask yourself: is it possible to deform space-time so that it overlaps itself, forming a tunnel between two distant points? The answer was given in the 1970s – yes.

Wormholes are entirely possible and not forbidden by the general theory of relativity. But the wormholes are very unstable, because, in essence, they consist of two black holes in contact with each other and forming a tunnel. That is, we are talking about points of infinite density, surrounded by areas known as the event horizon – one-sided space barriers. If you cross the event horizon of a black hole, you will never go back.

To solve this problem, the entrance to the wormhole must be outside the event horizon. Thus, you can cross the wormhole without touching the barrier. But as soon as you enter a wormhole located between huge masses, the gravity of your presence will distort the wormhole tunnel, collapsing it. Slammed shut, the tunnel will leave two lonely black holes, separated by a space in which the remains of your body will hang.

But it turns out there is a way to place the entrance to the wormhole away from the event horizon and make the tunnel stable enough for you to get through it. For this, material with a negative mass is needed. This is an ordinary mass, but with a minus sign. And if you put together enough negative mass in one place, you could use it to keep the wormhole open.

As far as we know, a substance with a negative mass does not exist. In any case, there is no evidence that it exists. Moreover, if it were, it would violate many laws of the Universe, such as inertia and conservation of momentum. For example, if you kicked a ball with a negative mass, it would fly backward. If you place an object with a negative mass next to an object with a positive mass, they will not be attracted. On the contrary, objects will repel each other, instantly accelerating.

Since negative mass seems like a myth, it can be assumed that wormholes are unlikely to exist in the universe. But the idea of ​​wormholes is based on the mathematics of the general theory of relativity – our current understanding of how gravity works. More precisely, our current, incomplete understanding of how gravity works.

We know that the general theory of relativity does not describe all the gravitational interactions in the universe. She gives in to strong gravity with a small body size. For example, before the bowels of black holes. To solve this problem, we need to turn to the quantum theory of gravity, which would combine our understanding of the world of subatomic particles with our broader understanding of gravity. But every time scientists try to put it together, everything just falls apart.

However, we have some clues on how quantum gravity can work, and we can understand wormholes. It is possible that a new and improved understanding of gravity will show that we do not need negative mass matter at all, and that stable, passable wormholes are real. A couple of theoreticians from Tehran University in Iran have published a new study of wormholes.

They applied some methods that allowed them to understand how quantum mechanics can change the standard general picture of relativity. Scientists have found that passable wormholes can exist without a substance with negative mass, but only if the entrance does not represent an ideal sphere, but is slightly elongated.

The results are interesting, but there is one snag. These hypothetical passable wormholes are tiny. Very tiny. Wormholes will be only 30% longer than Planck’s length – 1.6 x 10 ^ 35 meters. The traveler should be the same size. Yes, in addition, this microscopic traveler should fly at almost the speed of light. Despite emerging problems, the study opens a small crack, so to speak, for a look at the existence of wormholes, which can be expanded in the course of further research.

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