Category: Mysteries of Space

The universe can be infinite. But it may not be. We don’t know the final answer yet. To date , the following is known:

— When it comes to the size of the universe, they mean the observable universe. It is not identical to the universe at all. We can observe the universe only from a certain point in its life, because before that the universe was opaque to radiation, therefore, no observable consequences of that era have reached us. In any case, direct consequences.

— The size of the observable universe in any direction is estimated at 46 billion. light years. The figure is theoretically obtained by substituting the Hubble constant into the equations of the Friedman model of the Universe and verified practically using several independent methods. In principle, the probability of error still remains, but it is small. Everything that lies beyond this distance is fundamentally inaccessible to our observations.

— Singularity is a mathematical concept, not a physical one. It is not quite correct to talk about the size of the singularity. This is about how to estimate the size of ln(-2) in meters. It is correct to estimate the size of the Universe at the first moment of its existence after the singularity.

— In addition to the expansion characterized by the Hubble constant (which is not exactly constant, but we will omit these details for now), the universe at the very beginning, immediately after the Big Bang, went through a period of inflationary expansion, the speed of which is significantly higher. In fact, inflation is a rapid exponential expansion. The inflation hypothesis is still a de facto hypothesis, but there is a lot of weighty evidence in its favor.

— Well, actually, what was the size of the universe before inflation, we do not know. Within the framework of the available mathematical models, it turns out to be finite (and close to zero) at time t= 0. But the trouble is that the available mathematical models cannot model this situation correctly. Actually, from where those mysterious singularities originate – read: singular points in solutions of equations of the theory of relativity.

There are no explicit experimental or observational confirmations of the infinity of the universe, but there are implicit ones. For example, the average measured density of the Universe is extremely close to the critical density. This, in turn, means that the spatial geometry of the Universe is close to flat, which means that the Universe cannot be closed to itself like a globe. It stretches endlessly. Well, or in any case much further than we are able to register with the available devices.

An international team of scientists has revealed the mysterious nature of the object PSR J2039−5617. It turned out that in the center of an unknown cosmic source of X-ray and gamma radiation is a pulsar that rotates around an evaporating star. In the system, the pulsar heats up one side of the satellite star, which appears brighter and bluish. The gravitational pull of the pulsar also stretches the star, allowing astronomers to track changes in its apparent size as it rotates. The orbital period of the binary system was 5.5 hours.

Pulsar J2039−5617 rotates around its axis at a speed of 377 times per second. Its radiation vaporizes the companion, which causes clouds of charged particles to form, absorbing radio waves. It is because of this that the pulsating radio emission characteristic of the pulsar was not detected earlier, which made it difficult to determine the nature of the source.

Astronomers have known about the existence of PSR J2039−5617 since 2014, and all the data indicated that it includes a neutron star, but so far this has not been proven.

Cameras can often capture colors in cases where the human eye does not distinguish them. The picture shows a meteor from the Quadrantid stream, photographed earlier this month in Missouri in the USA. It turned out to be not only very bright, but also multicolored.

A grain of sand, probably ejected from the asteroid 2003 EH1, left a trace in the earth’s atmosphere. The colors of meteors are usually caused by ionized elements evaporating during the destruction of meteors. Magnesium gives blue-green radiation, calcium – purple, and nickel – green.

The red glow is usually given by excited nitrogen and oxygen in the Earth’s atmosphere. The flash of this bright car lasted less than a second, but it left an ionization trail blown up by the wind, which was visible for several minutes.

According to a new study, supernova explosions occurring thousands of light-years from Earth could leave a mark on the biology and geology of our planet.

A supernova that erupts near Earth could wipe human civilization off the face of the planet. However, even stars born far out in space can cause catastrophic damage by plunging the Earth into dangerous radiation and damaging its protective ozone layer.

Scientists have drawn attention to the annual rings of trees, which are considered to be a kind of “prints” of such explosions. As a result, it turned out that relatively close supernovae could have disrupted the Earth’s climate at least four times in the last 40,000 years.

Scientists’ research is based on a curious atom – carbon-14. It is an isotope of carbon that is found on Earth only in tiny amounts. At the same time, it is formed as a result of the bombardment of the planet’s atmosphere by cosmic rays.

In the course of the work, experts found several cases when the concentration of this isotope inside the annual rings increases sharply – suddenly and for no apparent earthly reason. It is assumed that these “bursts” lasting several years could cause solar flares or supernova explosions.

To test it, the researchers compiled a list of supernovae that have appeared relatively close to Earth over the past 40,000 years. Then they compared their approximate age with the annual rings. As a result, eight candidates were selected, of which four suited the theory the most. One of the stars broke out at a distance of 815 light-years from Earth 13 thousand years ago. Shortly after that, the level of radiocarbon on the planet jumped by almost 3%.

All stars and planets retain their size and shape due to the balance between gravity, which tends to compress them, and pressure, which, on the contrary, tries to break them. If gravity disappears, then the balance between these two forces will be disrupted and the huge internal pressure will lead to the explosion of all stars and planets, only dwarf planets in which the pressure is not so great and does not exceed their own strength can survive in theory. Due to the disappearance of gravity, nothing will hold matter in star systems and galaxies, the debris will retain its momentum in space, as it was at the time of the disappearance of gravity and will scatter across the Universe. In a few tens of millions of years, galaxies will cease to exist as clusters of matter, and in a few billion years, superclusters will cease to exist.

When all the stars and planets explode at the same time, all life in star systems will stop, only those who will be away from the stars, on spaceships, will be able to survive, but this will not last long. With such an explosion, the universe will be illuminated by the brightest radiation in all ranges, sufficient to destroy all life in the galaxies, it’s only a matter of time before it reaches ships far from the stars.

Astronomers have long suspected that there is a mysterious planet on the outskirts of the Solar System that has yet to be discovered. The authors of the new hypothesis are sure that this is not a planet, but a primary black hole that has survived since the Big Bang.

“Official science has not yet confirmed the existence of primary black holes in reality, but such objects can be extremely common in the universe. Some theoretical models indicate that primary black holes account for up to 80 percent of the mass of the universe. If this is the case, then the primary black holes may be the very dark matter that cosmologists are searching for,” the researchers say.

Astronomers have revealed the strange behavior of the radio-loud magnetar Swift J1818.0-1607, which is a neutron star with an extremely strong magnetic field. Such objects are known as the strongest magnets in the universe.

The magnetar was detected in March 2020 by a powerful X-ray flash. After that, the object gave unusual radio pulses, which differed from those of other radio-loud magnetars. Usually radio pulses have constant brightness over a wide range of observed frequencies, however, the pulses from J18 are much brighter at low frequencies than at high frequencies, which makes it look like a pulsar.

In May, the magnetar was still emitting unusual pulsar-like pulses, but by June it began to flicker, fluctuating between pulsar-like and magnetic radio pulses. This behavior is unique and has not been observed before in any such object.

The magnificent spiral galaxy NGC 4565 is visible from the edge of the planet Earth. Because of its thin profile, it is often called the Needle Galaxy. The bright galaxy NGC 4565 is a good object for observations in the northern sky. She is in the faint but elegant constellation of Veronica’s Hair.

This image shows the central bulge of the galaxy intersected by bands of light-absorbing dust adorning the thin plane of the galaxy. The distance to NGC 4565 is about 40 million sv. years, and its size reaches 100 thousand sv. years.

NGC 4565 can be easily seen even with a small telescope, and lovers of contemplating the sky consider it a real heavenly treasure that Messier did not notice.

The fact is that the rotation of the Earth around its axis is accompanied by the rotation of the axis itself (as the axis of a slowing spinning top begins to rotate). This effect is called precession. The precession cycle is about 28,000 years and is also known as the Platonic Year.

That is, a fixed point in the starry sky also moves in a circle, but very slowly. A similar fixed point in the sky of the southern hemisphere is not so lucky and there are no bright stars nearby. For primitive navigation, the Southern Cross constellation is usually used.

Whenever you look at the night sky, the North Star will show you the way to the north

However, this was not always the case.

14 thousand years ago, its place was occupied by the star Vega from the constellation Lyra, and it will take it again in 13,727.

Until now, researchers have not found evidence of global tectonic activity on planets outside the Solar System. However, recently a group of researchers found evidence of flows inside the planet LHS 3844b. It is located 45 light-years from Earth.

“It is very difficult to observe signs of tectonic activity, because they are usually hidden under the atmosphere,” explains the scientist. However, recent results have shown that LHS 3844b probably has no atmosphere at all. This rocky world, which is slightly larger than Earth, orbits very closely around its star. Because of this, one side of the planet is in constant daylight, and the other in constant night. Similarly, the same side of the moon always faces the Earth. However, the “dark” half is illuminated by bright volcanic eruptions.
Due to the lack of an atmosphere protecting the planet from intense radiation, its surface reaches 800 °C. The night side freezes. The temperature here may fall below -250 °C.