In October 2020, NASA announced with great fanfare that water had been discovered on the Moon. Neither one nor two, the press then seized on this information, distorting it at the same time.
Because NASA’s discoveries were still only preliminary. On the ground, space missions had to confirm the theories and other analyzes of the American space agency. Finally, after more than a year of waiting for the scientific community, it is finally, ironically, the Chinese competitor (CNSA) which with its Chang’e 5 probe has provided NASA with the precious answer.
How the water came to our nocturnal star ?
Now that the presence of water on the surface of the Moon is no longer lacking (or almost), the big question is to know how this water could end up there. According to CNSA scientists who deliver their conclusions in an article published in the journal Science Advances, water would have arrived on the Moon because of the solar wind.
In fact, hydrogen particles traveled to the heart of this stellar wind before coming to rest on the Moon. Once deposited on the surface of our satellite, the hydrogen met the oxygen there, thus forming molecules of water (H2O) and hydroxyl (OH). This idea had already been developed by NASA researchers in 2018 and 2020 when the American space agency found traces of water on the Moon.
On the site of the University of Copenhagen, a research team announced at the end of August 2021 the discovery of a new island. But the latter is not classic: at present, it is the most northerly island on the planet.
The discovery was made by chance. It is the result of an expedition carried out in July 2021 by a team of scientists affiliated with this university. Originally, their objective was to collect samples from the farthest point – the most northerly precisely – from Greenland. It’s successful, but not quite as expected.
Scientists headed for Oodaaq, the most distant territory recorded so far in the North. Except that it was not Oodaaq, but an island located 780 meters even further north. The identification could have taken place in part thanks to participatory science. Expedition leader Morten Rasch posted pictures of the place on his social media, until island hunters noticed that it seemed highly unlikely that it was Oodaaq.The northernmost island ever discovered is 30 meters by 60 meters. // Source: Morten Rasch
Morten Rasch and his team then decided to contact an expert in the matter. They were able to see, thanks to the latter, that the field GPS was wrong in reporting this location as Oodaaq. They then checked with the helicopter’s GPS. This is how they were finally able to identify the territory they were standing on as a new island to add to the repertoire, and the most northerly ever discovered.null
For how long ?
This island, which does not yet have a name, is very small: it stretches 30 by 60 meters, with a thickness of 3 to 4 meters compared to the level of the pack ice. It has just extended Greenland and Danish territory by one iota.
The island was formed by the aggregation of mounds of gravel and silt (a rocky material forming certain soils, consisting of grains intermediate between sand and clay and sometimes mixed with these two other materials). » It may be the result of a great storm which, with the help of the sea, gradually gathered material from the seabed, » suggest its discoverers.
It remains to be seen whether scientists will have the time to name this remote island. What a mighty storm has done, it can undo just as quickly before long.
About 4.5 billion years ago, the Solar System gradually adopted this arrangement that we know today. At this time, an interstellar molecular cloud collapsed, composing the Sun at its center. Around, a disk of gas and dust appeared. » The Earth formed when gravity attracted swirling gases and dust to become the third planet from the Sun, » observes NASA on its website. Each planet in the Solar System has formed with a mixture of its own. But where does this dust come from which finally condensed to give our planet?
According to a study published at the end of 2019 in the journal Nature Astronomy and relayed on the Sciences et Avenir website, it would come in part from red giants, old stars which have already burned their hydrogen, as will be the case for our star within 4 to 5 billion years. To achieve this result, the researchers performed measurements of the abundance of palladium. This element, which is formed during the process of « slow neutron capture » taking place in the hearts of red giants, was remarkably present in our planet. The latter therefore inherited, in « its mixture », dust from one of these old stars. In general, stars disperse throughout their life or at the end, thanks to stellar winds, by exploding, or even by merging, chemical elements which are the building blocks of matter.
And the Moon in all of this?
According to the theory most accepted by the scientific community, that of the « giant impact », the Moon was created around 4.5 billion years ago when the primitive Earth was violently struck by a celestial body named Théia (mother of the Moon, Selene, in Greek mythology). The proto-planet was as massive as the planet Mars and the shock was tremendously violent. It vaporized Théia and a large part of the earth’s crust and mantle, poor in metals. Part of the cloud of vaporized rocks would have aggregated to Earth again, while the other part would have solidified not far away, giving rise to our satellite.
Problem: the lunar subsoil is richer in metals than the portions of Earth excavated by Théia. This fact has long been known to scientists who are looking for an explanation. But a new study relayed by Sciences et Avenir in 2020indicates that there are still more metals than imagined which makes it even more difficult to interpret this shift while preserving the hypothesis of the giant impact. The study’s authors suggest that the collision between Theia and Terra was more violent and devastating than expected, and propelled deeper sections of the planet into orbit, including chunks of cores much richer in metals. Unless the collision happened much earlier when the Earth was still a ball covered in molten magma. Other theories exist to explain the formation of the Moon, some call for a series of impacts and others even believe that our satellite is older than the Earth. ! Further investigations will still be necessary to settle this thorny debate.
Many people still think of the Earth as flat. They might change their mind if they realized the ways that would make life on a flat planet strange.
We live on a spherical planet, slightly flattened at the poles. The shape of the Earth should no longer be debated, as science has confirmed it time and time again. Despite this, there are still people who believe that we are living on a huge record . Researchers have already carried out work to show how ridiculous a flat planet would be. Here are a few.
No gravity on a flat earth
Gravity as we know it would change dramatically. On a spherical planet, it is the same for all objects, no matter where they are on the surface. A flat Earth would have no gravity , and a disk-shaped planet would not be possible under actual gravity conditions, according to the calculations of mathematician and physicist James Clerk Maxwell in the
An absence of atmosphere
Without gravity , a flat Earth could not have an atmosphere. It is the force of gravity that keeps this veil around our planet. And without this protective blanket, all life forms would be exposed to the void of space. This would lead to asphyxiation within seconds, zoologist Luis Villazon wrote in BBC Science Focus magazine. In addition, the water would evaporate in the void of space. The surface temperature would also drop, causing the remaining water to freeze quickly.
Water at the center of the planetary disk
If the Earth were a huge disk, the geographic North Pole would be in the middle of the disk. The existence of gravity would cause him to concentrate at this point. Precipitation would also gravitate towards this point. The further away from the center, the more horizontal the precipitation would be. Water from rivers and oceans also collects in the center of the huge structure, according to the Lamont-Doherty Earth Observatory at Columbia University in the United States.
GPS would not exist. It would indeed be difficult to put satellites into orbit around a flat planet . “ There are a number of satellite missions that society depends on that just wouldn’t work, ” said James David , a geophysicist at the Lamont-Doherty Earth Observatory.
Much more trying trips
The trips would be much longer and more trying. Traveling on a spherical planet is much more convenient than on a large disk.
The starry nights would be the same regardless of the observation point on a disc planet. Humanity would then miss many astronomical discoveries.
The devastating rotating nature of tropical storms stems from the Coriolis effect of the spherical Earth. Storms in the northern hemisphere rotate clockwise and those in the southern hemisphere counterclockwise. However, on a flat, stationary planet, no Coriolis effect would be generated. The absence of this effect means the absence of hurricanes, typhoons and cyclones.
Current astrophysical models describe the formation of planets from rotating circumstellar discs. This rotational motion is then transmitted to the forming protoplanet by virtue of the conservation of angular momentum. All planets are therefore supposed to rotate, and Earth is no exception. But what if, suddenly, our planet stops spinning?
If the rotation stopped, the angular momentum of every object on Earth would tear its surface, which would be a disaster. However, as James Zimbelman, a geologist at the Smithsonian’s National Air and Space Museum , recalls , there is no natural force that would prevent the Earth from rotating. This is partly why our planet has been spinning since its formation.
The Earth rotates fully on its axis every 23 hours, 56 minutes and 4.09053 seconds. This results in the equator moving at around 1,770 km / h, with the rotational speed decreasing to zero at the poles, according to Zimbelman. If the planet were to come to a sudden stop, the angular momentum transmitted to air, water and even rocks along the equator would continue to move at this speed of 1,770 km / h. The movement would scour the surface while tearing it apart and sending shards to the upper regions of the atmosphere and space.
Linear momentum is the product of an object’s mass and its speed (direction and speed). A passenger in a moving car that comes to an abrupt stop will continue to move forward due to linear momentum. Angular momentum is a rotational analogue of linear momentum. It is the product of the moment of inertia (the rotational force required to rotate the mass) and the angular velocity. One of the fundamental principles of physics is the conservation of angular momentum. Once something turns, you have to exert the same force in the opposite direction to keep it from turning.
A chaotic situation for Earth
According to Zimbelman, the pieces that broke off the surface would regain some rotation as the Earth and its remnants continued on their way around the Sun. Eventually, the planet’s gravitational pull would bring back the halo of fragments with an unexpected effect. “ What Isaac Newton helped us understand with classical mechanics is that parts that accumulate and come together release some of their own energy in the form of heat, ” Zimbelman says.
The remains that ended up in the far reaches of the atmosphere and outer space would be attracted to the surface by the planet’s gravitational pull, and they would release energy on impact. The constant bombardment of these lumps would liquefy the crust into an ocean of molten rock, Zimbelman explains. Eventually, the colliding fragments would be reabsorbed back into the molten sea through a process called accretion.
The rapid and destructive transition would also vaporize most of the water on the planet’s surface. While most of this vaporized water would be wasted, some could be incorporated into newly solidified minerals, like olivine. Finally, all the fragments would not be reabsorbed by accretion. Some of the planetary pieces would be swept away by the Moon’s gravitational pull, bombarding the nearby satellite and creating countless more craters on its surface.
It was a huge cataclysm that gave birth to it! At least, scientists are sure. Even if they struggle to understand in detail how our satellite was born.
At the origin of everything, there was therefore a spectacular clash between the primitive Earth and a planetary embryo the size of Mars. Debris from the impactor and a fraction of the Earth’s mantle were thrown into orbit before coming together to form the Moon. This scenario, known as the giant impact, was established in 2004 thanks to numerical simulations carried out by Robin Canup, of the University of Boulder (United States).
Contrary to the hypothesis of gravitational capture or that of a fission of a piece of young Earth, it is the only one capable of accounting for the current dynamics of the Earth-Moon system.
But this scenario implies that the Moon should be composed of a mixture of 80% of the impactor and 20% of the Earth’s mantle, while we observe a strict geochemical similarity between the two stars!
Three hypotheses are now proposed to resolve this inconsistency. For Matija Cuk, of the Seti Institute (United States), and Sarah Stewart, of Harvard, it is enough to modify the speed of rotation of the Earth on itself at the moment of the impact with a planet of half of the mass of Mars to generate a Moon composed of 92% of terrestrial materials.
For Robin Canup, we must imagine an impactor of the mass of the Earth, producing a phenomenal cataclysm capable of mixing the materials of the young Earth and the impactor in a homogeneous way.
THE MYSTERY REMAINS
As for Willy Benz, from the University of Bern (Switzerland), he suggests a conventional impactor (the size of Mars), but much faster than previously imagined, and colliding with a rapidly rotating Earth on its axis. With this abundance of scenarios, specialists still do not know how the moon was formed.
Let us add that they also ignore when it started to shine in our night sky. At least, their response varies according to the dating methods used and the simulations carried out. Decidedly, the star of the night is not about to reveal all its mysteries …
The study, led by Dimitri Veras and published in Monthly Notices of the Royal Astronomical Society, sought to understand how the death of a star like our sun affects the planets around it, and any life that might be there.
White dwarfs are the final stage of many stars. When stars have no more hydrogen to merge in their nucleus, they transform into red giants burning helium. Red Giants are incredibly volatile, and emit raging solar winds that crush all nearby planets . Recently, it was the red giant Betelgeuse which had mysteriously lost its shine .
The study concludes that it is almost impossible for life to survive cataclysmic stellar evolution unless the planet has an intensely strong magnetic field, or magnetosphere, that can protect it from adverse effects.
Life could reappear on Earth after the Sun dies
In about five billion years, our sun’s core will contract and get hotter. And in response, its outer layers will swell and cool considerably. This will transform our star into a « red giant » with a diameter of tens of millions of kilometers which will engulf a few planets in our solar system .
Indeed, the orbits of planets and habitable zones are shifted during such a stellar phase. Some planets are swallowed up by the star’s expansion, while others are pushed back . Unfortunately, the habitable zone is pushed back faster than the planets, which means that a habitable planet could find itself deprived of protection and favorable conditions for life .
As a result, we now know that when the Sun dies, the Earth’s magnetic field may not be enough to protect it against a stronger solar wind and against changes in our star. In other words , it is therefore extremely unlikely that life on a planet could survive the death of its sun , but new life could be born from the ashes of the old one.
THE MOOD OF THE DAY – Canada and West Virginia go up in smoke, Germany and China drown. And during this time, the big bosses play cosmonauts and dream of colonies on Mars …
All over the planet, trapped humans, engulfed by sudden floods, fleeing from mega-fire, annihilated by « heat domes ». We barely have time to take an interest in the fate of the Germans drowned in their homes that we have to run in a flooded subway in China, and return to Canada, which we had left below 50 degrees to witness the destruction by the West Virginia forest fire. The media are doing their job. Nothing is spared us, and we « know ». Absolutely nothing that happens to us was unpredictable, the best scientists on the planet, climatologists and oceanographers, brought together in the IPCC thirty years ago by Ronald Reagan and Margaret Thatcher, two not particularly visionary leaders, have perfectly planned the steps past the disaster, and tell us the following.
Getting laid between the rich
No future on Earth? We do not care ! They are smart, have created « disruptive » companies thanks to which they amass billions, and scramble to send the ultra-rich of the planet into the air, with rocket planes that we had the first. seen for a fortnight. Behind these flights with an exciting carbon footprint, two visions as crazy as the other, that we struggle to prioritize: Jeff Bezos, boss of Amazon, wants to build space colonies where millions of people could live and especially work Aboveground ; Tesla boss Elon Musk believes the last humans will live on Mars. They’ve already sorted it out. What is it called?
Jeff Bezos seems to be very inspired by his little trip to space. Is it for the best? Here’s what he came up with on CBS This Morning : Getting rid of the industries that pollute the Earth by sending them into space.
“What I’m about to tell you is going to sound fantastic to you, but it will happen. We can move all heavy industries and all polluting industries off Earth by managing them in space, ”said the former Amazon boss .
Jeff Bezos has been criticized for going for a walk in space for fun , causing an astronomical carbon footprint (between 200 and 300 tons of carbon dioxide to launch a four-passenger rocket, the Guardian says ). However, the businessman seems to have heard of global warming. Only, he worries about it in his own way.
Where others are proposing to reduce overconsumption or even switch to renewable energies , anyone who has made a fortune with an e-commerce site does not particularly intend to reduce the production rate. “We must move heavy and polluting industries into space to preserve this sublime treasure that is the Earth. It’s going to take decades and decades, but you have to start somewhere and big things start with small steps. This is what this suborbital tourism mission allows us to do, it allows us to train, ”he added.
To go and pollute space instead of the Earth to preserve the environment, it was perhaps necessary to hover at 15,000 to think about it …
WEATHER Glaciers around the world lost 267 billion tonnes of ice on average per year between 2000 and 2019, study finds
Now contributing to more than 20% of the rise in sea level, the melting of the planet’s glaciers , caused by global warming , has accelerated further over the past twenty years, according to a study published on Wednesday.
While the Earth has already gained more than 1 ° C since the start of the pre-industrial era, glaciers, from the Himalayas to the Andes via the Alps, have already been on a slimming diet since the middle of the 20th century.
A first complete mapping of glaciers
But only a few hundred of the planet’s 220,000 glaciers – excluding the Greenland and Antarctic ice caps – are monitored in situ. “There are many regions where we did not know how the glaciers evolved,” explains Romain Hugonnet, lead author of the study, published in Nature . Thanks to half a million satellite images, « the first comprehensive mapping of glacier thinning in the world » concludes that « all glaciers are melting », with a few exceptions, continues the researcher from ETH University in Zurich and the University of Toulouse. The planet’s glaciers lost an average of 267 billion tonnes of ice per year between 2000 and 2019, according to the study.
Enough to completely submerge Switzerland under six meters of water each year, comments ETH Zurich in a press release. And the melting has greatly accelerated: from 227 billion tonnes per year on average between 2000 and 2004 to 298 billion tonnes per year between 2015 and 2019. “Excluding the areas on the outskirts of Greenland and Antarctica, therefore by keeping 70% of the planet’s glaciers, we go in twenty years from an average thinning of about a third of a meter per year to two thirds of a meter per year ”, underlines Romain Hugonnet. “In twenty years, we have doubled this speed of thinning. It is very worrying ”.
Those of Alaska, the Alps and Iceland in peril
The glaciers of Alaska, the Alps and Iceland are among those that have shrunk the fastest. The general conclusions of the study are in line with those of the UN climate experts (IPCC), which however included very large margins of uncertainty. « Ours has an uncertainty reduced by a factor of 10 », assures Romain Hugonnet. In particular concerning the impact on the rise in sea level. This melting has contributed to 21% of this rise since the beginning of the century, or 0.74 mm per year, according to the study.
The new data, much finer geographically, could also help with planning in densely populated areas where glaciers play a major role in water supply and agriculture. “In the short term, glaciers which are melting faster and faster will provide more and more water to rivers, serving as a buffer in certain regions such as India or in the Andes in arid periods. But then we will reach a peak, and the quantity of water will rapidly decrease, until there is no more, ”warns the researcher, estimating that“ in a few decades, most of the regions will begin this downward slope ”.