Discovery of a tiny black hole very close to Earth

A tiny black hole, named Unicorn, has been discovered by scientists at Ohio University. Located 1,500 light years from Earth, it is the smallest ever observed and the closest to our planet.

Scientists at Ohio University have detected a unicorn. Not a white horse with a goat’s head and split feet, nor the cute and trendy animal with a multicolored mane that one finds in children’s books. No seriously, they discovered a tiny black hole, dubbed the Unicorn, 1,500 light years from Earth.

It is the smallest ever observed and the closest to our planet, according to researchers whose results were published in  Monthly Notices of the Royal Astronomical Society .

The fact that it weighs « only » three suns also makes it one of the smallest black holes ever to be found. Indeed, very few black holes so « light » have been observed in the universe, notes the University of Ohio. It could also be the « smallest black hole in the Milky Way so far discovered, » said Tharindu Jayasinghe, a doctoral student at Ohio University and one of the study’s authors.

This cosmic object was baptized « Unicorn », from the name of the constellation in which it is located.

This unicorn is distorting its star

This small black hole was not seen directly by the instruments of astrophysicists: its presence was deduced from the attraction it exerts on a nearby red giant star, inflicting a slight deformation on it.

Indeed, the scientists focused on a star to which it was close, called V 7232 Mon and which seemed to change regularly in luminosity but also… to deform! This meant for the researchers that an object not far from her had an influence on the star. By analyzing the images transmitted by NASA’s TESS telescope, astronomers were able to observe that this deformation could only be due to a black hole.

Unlike many black holes that swallow the surrounding stars, this unicorn is much less greedy, content – for now – to distort its neighbor.

Thanks to observations made near V 7232 Mon, scientists now expect to detect other mini black holes. Each discovery like this gives them a better understanding of the formation and death of stars in our universe.

Global warming is changing the axis of rotation of our planet

The axis of rotation of the Earth is not fixed. This is manifested by a shift in the position of the poles. A movement followed for some time now by scientists. Today, they emphasize that anthropogenic global warming and more broadly, human activities, have significantly accelerated this natural movement.

The inclination of the axis of  rotation of the Earth  with respect to the  plane of the ecliptic  is not constant. Scientists are still trying to understand what exactly are the phenomena behind this variation. But the way water is distributed on the surface of our planet seems to be an important factor. And today,  researchers at the Chinese Academy of Sciences tell  us that the  melting  of  glaciers  due to the ongoing anthropogenic global warming has redistributed the water sufficiently to accelerate the displacement of the North Pole, causing it to swing from south to east. in the mid-1990s.

To reach this conclusion, the researchers calculated the total loss of water stored on land in the 1990s. They relied on data from  melting glaciers  and estimates of groundwater pumping. And the loss of water from the polar regions is the main driver of the polar drift. A drift whose   average speed between 1995 and 2020 is approximately 17 times greater than that of the period 1981-1995.

The amazing impact of human activities on Earth

The increasingly rapid melting of the ice with  global warming,  however, cannot explain all of the drift. Although the researchers did not take their analysis that far, they believe that the remaining gap could result from disturbances in non-polar regions. Due, in particular, to the unsustainable pumping of groundwater for agriculture.

Results which show, according to the researchers, to what extent  human activities  can have an impact on our Earth. Going so far as to move its axis of rotation. Despite everything, without any real effect on our daily life. Since the operation could not, at most, change the  length  of our days by only a few milliseconds.

Our planet is not quite spherical. And its axis of rotation – which connects the North Pole to the South Pole through the center of the Earth – tends to oscillate and drift little by little. The 10 centimeters per year drift, that is to say some 10 meters in the single XX th  century. Of  researchers from NASA  (USA) wanted to study the phenomenon. Using observational data and powerful models, they identified three processes that could explain it.

The glacial rebound, already incriminated by previous studies, is the best known of them. Glaciers tend to sink the surface of the Earth (much like when a person settles on a  mattress ). When the  ice melts , it gradually rises. But, according to NASA researchers, this phenomenon could not explain more than a third   of the rotational drifts observed.

Natural causes and an anthropogenic cause

The  convection of the Earth’s mantle is  also involved for a third. Thus, under the effect of the  heat  emitted by the  core of the Earth , rocks undergo a vertical circulation pattern. What to redistribute the masses and disrupt the rotation of our planet.

The last process involved is attributable to Man. It is indeed the melting ice of  Greenland  resulting from  global warming . No less than 7,500 gigatons would in fact have been transferred to the oceans, responsible for a  rise in sea level … and a drift in the axis of rotation of our planet.

Pink Super Moon: what you need to know about this phenomenon expected in the night today and tomorrow

On the night of Monday April 26 to Tuesday April 27, the Moon will be closer to Earth than every other night of the year, making it appear larger than usual.

This phenomenon only occurs once or twice a year. But why do we speak of « super moon »? Will it be really pink? What do you need to know to make the most of it?

Why do we speak of a “super moon”? 

This alignment of the Earth, the Moon and the Sun is an astrological phenomenon which owes its name of « Supermoon » in English (super-moon) to the American astrologer Richard Nolle who named it thus in 1979. Since the term remained, it is notably taken over by NASA.

In fact, the moon will appear larger to us than usual because it will  be closer to the Earth . “The average distance between the Earth and the Moon is 384,000 km,” explains Gilles Dawidowicz, secretary general of the Société astronomique de France. The minimum distance of 356,000 km was reached in 2016, a record since 1948 and which will not happen again until 2034 ”.

The 2016 super moon was 30% brighter than usual. « There, it will be less exceptional but it is still a nice spectacle », warns the specialist. 

With the naked eye, it’s quite difficult to see a difference in size between a full moon and a super moon. If we put two photos side by side, it would be like having a lime on one side and a lemon on the other. Gilles Dawidowicz

Will it be really pink? 

No the moon will not be pink

No need to look for the Moon in the hope of seeing it take on a pinkish hue today: it will not have changed color. The expression « pink moon » has no scientific value.

It is an imprint of a North American cultural tradition, probably stemming from the Amerindians. Moon names were applied each lunar month (not just the full moon day), starting with either a new moon or a full moon. Since the 1930s, these names attributed to the Moon have been used in  The Old Farmer’s Almanac  , an American periodical published since the 18th century, popular for its weather forecasts and cooking recipes. For the month of April, the almanac uses the nickname  « Full Pink Moon »  (which was inspired by the spring flowering of the plant  Phlox subulata ).

NASA regularly uses these nicknames in its official communications, which may contribute to maintaining a certain confusion between this cultural tradition and scientific reality. On April 20, for example, the space agency headlined  “  The Next Full Moon Is A Pink ‘Supermoon’ ,  ” referring to the April 27 Full Moon.

How to observe it well? 

To be full of eyesight, it is better to  watch for the sunset or the sunrise . The Earth’s atmosphere creates a magnifying effect on our vision of the Moon, ideal for taking pretty pictures. 

And for a more precise observation, it is advisable to equip yourself with a telescope or a telescope, « a spectacle without danger », certifies Gilles Dawidowicz.

But for the latter, nothing beats an eclipse for total amazement. Note the date: the next lunar eclipse will take place on November 19, 2021.

What does rain look like on other stars in the solar system?

It doesn’t just rain on Earth. Venus, Jupiter, Saturn or even Titan, Saturn’s largest satellite, also experience showers. What do they look like? Researchers at Harvard University in the United States modeled the drops of these extraterrestrial rains, and compared them to ours …

Illustration of what could be a Martian rain.Nasa

On Earth, it rains water. But on Venus, it tumbles sulfuric acid. The thick atmosphere of Jupiter is traversed by showers of helium or hailstones of ammonia and water mixed together. And on Titan, the largest satellite of Saturn, we can wipe a grain of liquid methane … With their atmospheres varied in composition, pressure, temperature, the planets of the solar system and their satellites offer sometimes very exotic rains. But what do the drops that carry them look like? According to a study conducted by researchers at Harvard University, and published in the Journal of Geophysical Research , they would ultimately be quite similar to ours

20 mm drops on Titan

To reach this conclusion, the American planetologists Kaitlyn Loftus and Robin Wordsworth modeled the formation of these drops according to the characteristics of the atmosphere and the gravitational pull of the planet. First observation: the more massive the star, the smaller the drops. This is understandable: for a drop to detach from the cloud where it forms, it must be sufficiently attracted by the gravitational field of the planet. However, the more massive a star, the more intense this field. Thus, a drop of methane on Titan (0.22 times the Earth’s mass) is twice as large (20 mm maximum) than on Earth, according to the researchers’ simulations. Severity is not the only criterion that matters. This work emphasizes that the size of the drops is also constrained by their fall. Too small, they evaporate before hitting the ground. Too big, they break into several smaller droplets. Applied to the Earth, this means that a drop measures between a tenth of a millimeter and 11 millimeters. This is why the Breton drizzle is so different from the stormy downpour …

The researchers also studied how drops composed only of water would fall on different planets in the solar system. By comparing with the Earth, Mars (when the climatic conditions were compatible with the presence of water), and the gas giants (Jupiter and Saturn), they found that the raindrops behaved in their fall (speed, shape of gout) in a similar way in these atmospheres which have nothing to do with it. As for their size, it would vary from 7 mm on Jupiter to 30 mm on Titan. This remains a modest difference given the difference between these stars. This relative homogeneity could be explained by the fact that the characteristics of the drops are more dependent on molecular interactions within the fluid than on external conditions.

Sizes of water drops on different planets. Credits: AGU. Click on it to see in big

Rains of iron or diamonds

 » This work is useful because it will make it possible to include rain and hail in the modeling of the atmospheric circulation of planets , comments for Sciences et Avenir Tristan Guillot, planetologist at the Observatory of the Côte d’Azur, at the origin of the theory of hailstones mixing water and ammonia on Jupiter. However, we saw with the space probe Juno that it is essential to understand the deep atmosphere of Jupiter, and by extension those of all the gas giant planets which do not have They are also valuable a few months before the launch of the James Webb Space Telescope (JWST), scheduled for the end of 2021, and which should observe many exoplanets, many of which are gas giants« By finely analyzing the light coming from these planets orbiting other stars, astrophysicists should be able to deduce the composition, but also the dynamics of their sometimes very exotic atmospheres. » For that, we will need the tools like these models developed by Harvard researchers « ,  concludes Tristan Guillot. When we consider that on certain exoplanets, it could rain iron, or diamonds, we are in fact eager for the JWST to turn to them.

Here’s what will kill all life on Earth in a billion years

The evolution of the Earth does not bode well: the oxygen, so precious to life, will be eliminated from the atmosphere in a billion years due to the lack of photosynthesis. Oxygen was thus only a small parenthesis in the evolution of the Planet.

In 5 to 7 billion years, the Sun will have used up its helium and will turn into a red giant , multiplying its radius by 1,000, and gradually snapping up the Earth in its burning halo. The temperature on the Earth’s surface will then be so high that the oceans will evaporate. But most of the life forms will have been wiped from the surface of the planet long before and this, due to the lack of oxygen , estimates a new study published in Nature Geoscience .

In reality, it is first of all the lack of carbon dioxide that will lead to this cataclysmic scenario. Indeed, as the Earth warms, more and more water vapor will form, which will result in a regular absorption of carbon dioxide, necessary for the photosynthesis of plants. These will then be unable to survive and produce oxygen .  »  The collapse of the oxygen level will be dizzying,  » warns Christopher Reinhard, one of the two authors of the article. In a billion years, the atmosphere will contain only 1% oxygen compared to 20 to 21% today.

Evolution of the concentration of oxygen, methane and CO2 over time.  © Kazumi Ozaki and Christopher Reinhard, Nature Geoscience, 2021
Evolution of the concentration of oxygen, methane and CO 2 over time. © Kazumi Ozaki and Christopher Reinhard,  Nature Geoscience , 2021

A super-rapid oxygen collapse

And the fall will be particularly brutal: according to the researchers’ models , all the oxygen could disappear in less than 10,000 years. At the same time, the methane content in the atmosphere will be multiplied by 10,000.  »  The composition of the atmosphere will then resemble that experienced by the Earth before the Great Oxidation , which occurred around 2.4 billion years ago,  » warns Christopher Reinhard.

The consequences on the biosphere will be catastrophic. Deprived of oxygen, terrestrial and aquatic plants will die, along with all animals that depend on them for their food. The disappearance of oxygen will also cause ozone to disappear , exposing the Earth to ultraviolet radiation from the Sun which will burn marine organisms on the water surface and plants.  »  Then only anaerobic and primitive bacteria will remain , » says Christopher Reinhard.

The disappearance of the ozone layer will result in the death of most living organisms.  © sarayut_sy, Adobe Stock
The disappearance of the ozone layer will result in the death of most living organisms. © sarayut_sy, Adobe Stock

Oxygen, a small parenthesis in the history of the Earth

These predictions roughly match that of a previous study conducted in 2013 (see below) which calculated that the Earth would cease to be habitable between 1.75 and 3.25 billion years ago. The authors estimated that the least resistant plant species (C3 plants) will disappear in 500 million years and that only a few microbes will still survive in 2.8 billion years. Man, for his part, will have disappeared long before all this . Perhaps decimated by a giant asteroid like dinosaurs or a devastating virus.

In the history of the Earth, atmospheric oxygenation will therefore have been only a small parenthesis. If we place the appearance of the Earth at 4.5 billion years and its death at about 5 billion years, we will have had only 3.5 billion years with a sufficient level of oxygen to aerobic life , or one third of earthly existence. In other words, finding a planet in the universe with an atmosphere comparable to ours would be an extraordinary coincidence .

What is the mission of the Perseverance robot

published by Jules Bercy

NASA’s perseverance rover, which left Cape Canaveral on July 30, 2020, landed safely on the Red Planet, Thursday, February 18, after having traveled 480 million kilometers. A crucial scientific step to try to find out if life existed on Mars

The main objective pursued with this rover is to search for signs of a possible past microbial life on  Mars . If these predecessors – Spirit, Opportunity and Curiosity – have demonstrated that liquid water flowed over the Red Planet and that it once fulfilled the conditions necessary for the development of life, Perseverance will attempt to determine whether it is. actually sheltered.

The rover will collect rock and soil samples, enclose them in tubes, and leave them on the planet’s surface for a return to Earth by 2031. In addition to studying geology, Perseverance’s instruments will allow the testing of various technologies, with a view to a future mission inhabited by humans on Mars. One of the planned experiments is to produce oxygen from carbon dioxide in the atmosphere of the red planet. This oxygen could be used for respiration and fuel.

Quelle est la mission du robot Persévérance

Le rover persévérance de la Nasa, parti de Cap Canaveral le 30 juillet 2020 s’est posé sans encombre sur la planète rouge, jeudi 18 février, après avoir parcouru 480 millions de kilomètres. Une étape scientifique cruciale pour tenter de savoir si la vie a existé sur Mars

Le rover persévérance de la NASA qui s’est posé sur Mars jeudi

Le principal objectif poursuivi avec ce rover est la recherche de signes d’une possible vie passée microbienne sur Mars. Si ces prédécesseurs – Spirit, Opportunity et Curiosity – ont permis de démontrer que de l’eau liquide a coulé sur la Planète rouge et qu’elle a autrefois rempli les conditions nécessaires au développement de la vie, Perseverance tentera de déterminer si elle l’a réellement abritée.

Le rover collectera des échantillons de roche et de sol, les enfermera dans des tubes et les laissera à la surface de la planète pour un retour sur Terre d’ici 2031. En plus de l’étude de la géologie, les instruments de Perseverance vont permettre de tester diverses technologies, dans la perspective d’une future mission habitée par des humains sur Mars. Produire de l’oxygène à partir du dioxyde de carbone présent dans l’atmosphère de la planète rouge fait notamment partie des expériences prévues. Cet oxygène pourrait être utilisé pour la respiration et le carburant.

Perseverance’s landing on Mars in « seven minutes of terror »

Source : NASA

published by Jules Bercy

About seven months after taking off, NASA’s last vehicle, Perseverance, will still have to survive « seven minutes of terror, » as the ultra-perilous maneuver preceding its landing on Mars is dubbed. 

The chosen location, Jezero Crater, is the most dangerous landing site ever attempted. In seven minutes, the rover must go from a speed of 20,000 km / h to zero. 

The landing will take place at 8:55 p.m. GMT Thursday (3:55 p.m. Washington).

-130km: entry into the atmosphere-

Ten minutes before entering the Martian atmosphere, the vessel separated from the cruise stage which supplied it with fuel during the trip. 

It is then only composed of a rear shield, a heat shield at the front, and, caught between the two, the descent stage, connected to the rover itself. 

At about 130km altitude, it enters the atmosphere at a speed of 20,000km / h, causing friction raising the temperature to 1,300 ° C. The heat shield protects the rover from this infernal heat. 

-11km: opening of the parachute-

But the atmosphere is not enough to slow the ship enough, which is still going at 1,500 km / h. 

At about 11km altitude, at an opportune moment calculated according to the distance remaining to the landing place, a huge supersonic parachute 21 meters in diameter, located in the rear shield, is deployed. 

This slows down the ship to about 300 km / h. 

-9km: heat shield released-

20 seconds after opening the parachute, the heat shield is released: the rover it was protecting is exposed for the first time to the Martian atmosphere. 

A whole new technology, called “Terrain Relative Navigation” (TRN), comes into play: the images recorded live by the cameras of the vessel are compared to maps recorded in its system, where the dangerous zones to be avoided are pre-defined. Taking these data into account, the ship decides on the final landing place.

-2km: retro-propelled phase-

At an altitude of around 2km, the rear shield – and its parachute – are dropped. 

The rover is no longer attached to the descent stage, equipped with eight motors pointed downwards, which light up to finish slowing it down. After performing a maneuver to get away from the parachute, the rover ended up descending vertically, right above its landing site.

-20m: separation of the rover-

At about 20m from the ground, it reached a speed of 2.7km / h, slower than that at which a man walks. The rover then descends along the cables thanks to a system of pulleys, during a final fifteen seconds (stage called « skycrane »). 

The vehicle deploys its wheels at this time. When the latter feel the ground, the lines are cut and the descent stage makes a final push to crash as far as possible. 

Because of the transmission delay between Earth and Mars, when the landing will be confirmed by NASA, it will actually have taken place several minutes earlier. 

Source: Orange with NASA

The life of a small second on Earth for man

published by Jules bercy

99.9% of species that lived on earth have now disappeared

The earth is the cradle of humanity. Man reigns supreme there, without anything seeming to be able to stop him. Yet planet earth did not wait for man to begin its history.

Since life appeared, the earth has hosted countless species, which have followed one another for more or less long time. But 99.9% of the species that lived on earth have now disappeared. Some have gradually evolved into other species. Others died suddenly. On average, their passage on earth lasts only a few million years.

If the history of the earth were written in a thousand-page book, life would appear there around page 185. This life would only be represented by single cells for more than 700 pages. Until the explosion of the multicellular species, from pages 870 to 880. The outflow of the waters was only found on page 916.

During this constant transformation, the planet has also undergone 5 major crises including one, 250 million years ago, during which life on earth almost disappeared. This mass extinction has led to the disappearance of 70% of terrestrial species and 96% of marine species. The planet took nearly 10 million years to recover and resume dance of evolution, with its disappearances, and its newcomers like this time the dinosaurs on page 960 of the history of the Earth.

 At the end of the book, the entire history of Homo sapiens from its appearance until today, would be the subject of only a handful of lines, at the very bottom of the very last page. Its presence on earth therefore represents only 0.004% of its very long history. Man has not been around for a long time, but it does not mean to evolve any more.

 All species are at the peak of evolution, and all are perfectly adapted to their natural environment, from the barnacle, firmly anchored on its whale … to the tiny Dik-Dik apparently so fragile but which survives the repeated attacks of eagles , pythons and lions since time immemorial.

There is no indication that the human species should be eternal. Nor even that it will take longer than the others to disappear. The most probable is that its passage on earth represents only a blink of an eye on the scale of the history of its planet.

A derisory duration. Almost… insignificant?

A unique life on one planet

The only planet that shelters living beings, the earth is an oasis of life in the middle of the great cosmic desert

Humans inhabit a planet in their image: special, unique, perfect. The only planet that shelters living beings, the earth is an oasis of life in the middle of the great cosmic desert. But is she really that exceptional?

Man has in fact only a very vague vision of the universe in which he evolves. His scale is so vast and empty, that he called for lack of anything better, « Space ». Far from being deserted, this space is full of a multitude of planets, as diverse as they are varied.
Since there is on average one planet per star in the universe, there are probably over 100 billion planets in the Milky Way alone, and as many in each of the hundreds of billions of other galaxies.

With such a profusion of planets, how could life have evolved only once? Even with ridiculously low odds of occurrence, the universe is probably teeming with life. Especially since this universe is continuously changing.

Every day, 275 million stars and therefore planets are born. As many arrive at the end of their life, and all are in constant motion. Man cannot even identify his own position, which is not fixed. Starting with the orbit of the earth, rushing around its sun at a speed of 100,000 km / h, and of which humans are not even aware. Nor does he perceive that his entire solar system is propelling his galaxy even faster. And finally, his galaxy, like all the others, is itself in motion. And rushes towards the nearest galaxy, Andromeda has the speed of 720,000 km / h.

The man, so superior seems indeed lost in a cosmic ocean in perpetual motion. In this disproportionate universe, doesn’t asserting that it has no life amounts to prolonging a drink in the ocean and concluding that it does not shelter fish?

In the end, humans have no idea of ​​their place in the universe. Are they alone or just insignificant?