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 …
When billionaire Jeff Bezos straps onto his company’s rocket capsule on July 20, he and his fellow travelers will be taking a calculated risk to their lives and physical integrity during their suborbital flight. Only 382 space flights have been launched from the United States, and four of them have ended catastrophically.
So the failure rate is around one in a hundred, which is much higher than that of commercial air transport, which is one in a million, or that of most other land-based activities, according to the. analysis by the Center for Space Policy and Strategy .
« Until we get a lot of experience, as we have done with millions of airplane flights over the years, there will be some learning, » said George Nield, co-author of the report, to Insider’s Morgan McFall-Johnsen. « With cars, boats, planes and trains, people die every year. And spaceflight will be no different in that regard. »
Work accidents are more numerous
But if you look at it another way, space flight accidents in the United States have claimed the lives of far fewer people than the number of people who die from work-related accidents. According to US labor statistics , approximately 5,000 workers die each year, while 15 astronauts have died in the history of US spaceflight. What’s more, of the 5,333 American workers who died in 2019 alone, more than 913 worked in the transportation and warehouse industry. In other words, if a person dies on the job, there is a high probability that they were driving a truck or working in a warehouse.
Across all sectors, more than half of worker fatalities are due to transportation incidents or slips, trips and falls. The rates of injury and non-fatal illness are naturally much higher. In 2019, there were about three incidents per 100 workers, in which one person suffered an illness or injury on the job that required at least one day of sick leave.
It’s difficult to make direct statistical comparisons between spaceflight and other activities, in part because the industry is still so new, which amplifies the risk. In addition, the Federal Civil Aviation Administration is not empowered to issue rules relating to the health and safety of participants in space flights.
Blue Origin’s New Shepard rocket has made 15 flights since 2015, including three successful tests of its emergency escape system that drops the passenger capsule in the event of a rocket failure. Jeff Bezos’ flight will be the spacecraft’s first flight with humans on board. Blue Origin’s approach to product development is « much less risky » than NASA’s space shuttle program, which had a full crew on its very first flight, said John Logsdon, founder of the Space Policy Institute from George Washington University and former NASA Advisory Board member to Morgan McFall-Johnsen.
Amazon wants to reduce workplace accidents
Meanwhile, on Earth, drivers for Amazon’s delivery partners have described how the delivery scheduling app sometimes asks them to cross multiple lanes of traffic, or they have to choose between filling quotas or driving safely. security.
One of Jeff Bezos’ latest actions as CEO was to highlight the problem the company is currently having with workplace injuries and to pledge to make Amazon « the safest place in the world to. to work ». In his letter to shareholders, Jeff Bezos said he would make workplace safety one of his main areas of focus in his continued role as executive chairman. The company will invest $ 300 million (around € 253 million in 2021 to halve workplace accidents by 2025, including a $ 66 million (around € 56 million) project to prevent accidents at work. collisions between forklifts and industrial vehicles.
“Jeff Bezos is a risk taker,” John Logsdon said. « He certainly understands that there are risks [in spaceflight], and probably has a good idea of the degree of risk. »
Once again, the Simpsons had accurately predicted a historic event.
On July 11, 2021, Richard Branson flew into space aboard the VSS Unity spacecraft, a dream for the one who founded Virgin Galactic almost 17 years ago for the purpose of space tourism. He thus became the first billionaire founder of such a company to travel himself beyond the limits of the Earth, before Jeff Bezos who is to fly next week with Blue Origin, and Elon Musk who would have booked a flight. at… Virgin Galactic.
This first excursion into space, the Simpsons had already imagined it… seven years ago, in 2014. That year, in an episode of season 25 called “The Art of War” , we could see a certain Richard Branson contemplating a painting from his spaceship. Seven years later, reality replicates this fictional image almost verbatim.
Well its been known Virgin Galactic has been trying to get Richard Branson into space for 17 of the 34 years The Simpsons have been on the air, so the show wasn’t exactly being Nostradamus here.
Even so, as this surfer points out above, the Simpsons’ prediction is not so surprising. “It’s well known that Virgin Galactic has been trying to send Richard Branson for 17 years. The Simpsons are not Nostradamus here, ”he explains.
Indeed, when the episode in question aired, Branson had already founded Virgin Galactic for a decade to serve this purpose. In the end, the Simpsons did nothing but anticipate a more than probable future… correctly, once again.
The element also called C / 2014 UN271 is about ten times larger and has a mass 1,000 times greater than that of the average comet. Scientists thus estimated that its diameter was between 100 and 200 kilometers. Specialists have struggled to make precise assessments because it is still extremely far from Earth.
Visible with very powerful instruments
To calculate its size, astronomers had to rely on the amount of sunlight it reflects. The object should however approach our planet and be closest to it in 2031. It will nevertheless remain at a distance of 11 astronomical units from the Blue Planet, or approximately 1.65 billion kilometers. Even as close as possible to the Earth, the comet will therefore only be visible with particularly powerful instruments.
In addition to its size and trajectory, C / 2014 UN271 stands out from other celestial elements by the rarity of its appearances in our internal solar system. Its last passage dates back to three million years ago, that is to say at the time when our planet was, among other things, populated by Australopithecines. The comet was born in the Oort cloud, to 40,000 astronomical units from the sun.
Never had a body come from so far away been spotted heading towards Earth. Scientists hope to learn a lot from the study of this celestial object, especially when it comes to the formation of massive celestial bodies and the movements of the planets.
Mars is known for its thin atmosphere, where CO₂ dominates and provides most of the atmospheric mass and pressure, the latter comparable to that found in the Earth’s stratosphere more than 30 kilometers above. from the surface.
But what about water? Water on Mars is currently seen on the surface as a layer of ice at the North Pole several kilometers thick, as seasonal frost at colder times of the year, and in the atmosphere, in the form of vapor and ice in the clouds. Nevertheless, the Martian atmosphere is extremely dry compared to the Earth: in proportion, 100 times less water is present in the atmosphere of Mars than in that of the Earth. While precipitation on Earth results in water films of several centimeters, the water that would be precipitated on Mars would only form a thin film less than a millimeter.
From new data to better understand why there is (almost) of water on Mars when it had to be abundant in the past.
Water escapes from the Martian atmosphere
Because everything indicates that Mars was not always the cold and arid planet we know today. Mars exhibits many testimonies on its surface of a distant past – about four billion years ago, where liquid water circulated in great streams and stagnated in the form of basins or lakes, such as in the Jezero crater as the rover Perseverance is exploring for traces of past life.
In order for liquid water to circulate as much and to reside on the surface long enough to make all these imprints, it is necessary to invoke a climate radically different from the one we observe today. Mars, Earth and Venus were arguably accreted from the same basic materials, which means they must have known great similarities very early in their history. But while the Earth and Venus have retained most of their thick atmosphere, Mars, due to its small size and low gravity, has not been able to retain its atmosphere over time.
It is indeed this “ escape theory ” that explains the current thinness of Mars’ atmosphere. This escape occurs very high in the atmosphere, above 200 kilometers, where the molecules have already dissociated into atoms and where the lighter ones, like hydrogen, can tear themselves away from the weak gravity of Mars. Exposed to the energetic particles of the solar wind, this “ exosphere ” of Mars is also its “Achilles heel”, because over time it has allowed the equivalent of hundreds of current atmospheres to be lost in space.
This escape was known to all, especially because Martian water has a composition that is unique to it. Indeed, the isotopes of water, in particular “semi-heavy” water HDO where a hydrogen atom (H) is replaced by a deuterium atom (D) twice as heavy, which one has. measured on Mars since the 80s, reveal a relative concentration 6 times greater in deuterium on Mars than on Earth. This relative enrichment is interpreted precisely as the result of the escape of hydrogen, which gradually left behind the heaviest isotopes, in this case D and HDO, explaining this enrichment ratio of 6.
By extrapolation, the initial quantity of water on Mars must have been at least 6 times greater than now, or the equivalent of a liquid layer of a hundred meters covering the planet. This shows to what extent the HDO / H20 ratio is crucial for projecting oneself into the youth of Mars and for shedding light on the hypothesis of a past hot and humid climate, prior to its habitability.
These results from the Trace Gas Orbiter allow us to better understand the conditions under which water and semi-heavy water present in the lower atmosphere are transported to the very upper atmosphere and then transform into atoms capable of escaping. Indeed, we have long wondered to what extent intermediate processes can modify the way in which hydrogen and deuterium from water access the exosphere. For twenty years, two theories have suggested that hydrogen and deuterium cannot reach the exosphere in the proportions that are theirs in the water molecules of the lower atmosphere. These intermediate processes are on the one hand condensation, which forms the clouds of Martian water ice, and on the other hand photolysis., which breaks the water molecule and releases a hydrogen or deuterium atom under the action of UV rays.
Studied in the laboratory for decades, condensation and photolysis are known to affect water and its isotopes in a specific way: this is called “isotopic fractionation”. It is also thanks to our understanding of isotopic fractionation that it is possible to trace the past climatic course of the Earth by drilling ice cores at the poles, where the concentration of HDO reveals the more or less cold climate that reigned. when the water has condensed into ice. It is a discipline where the French community excels , and which has made it possible to initiate exploratory work in the Martian context within French laboratories.
On Mars, fractionation by photolysis operates in an opposite way to fractionation by condensation. Above all, the two do not operate at the same time in the course of water – this last point has a major impact on the fate of the hydrogen and deuterium atoms. In fact, the condensation of water vapor tends to concentrate the HDO in the ice formed, and thus de facto de facto depletes the vapor in HDO. Photolysis, for its part, tends to promote the release of deuterium present in the HDO molecule. For a long time, it was assumed that isotopic fractionation by condensation, which makes the vapor poorer in deuterium, dominated photolysis and forced the proportion of deuterium in the exosphere to be lower than in water in the lower atmosphere.
What the recent study reveals is that condensation actually plays a minor role in the proportion of deuterium in the exosphere. Thanks to the Atmospheric Chemistry Suite instrument of the Trace Gas Orbiter and its simultaneous measurements of H20 and HDO, we were able to show where the hydrogen and deuterium atoms come from, at an altitude and a period of the Martian year. where condensation does not have the possibility of interfering with photolysis.
It is indeed photolysis which produces most of the atoms and which dictates the isotopic fractionation of the hydrogen atoms which escape from the upper Martian atmosphere.
Next destination: understanding the path of water, from the surface to the upper atmosphere
This questioning of our understanding of the processes that lead to the escape of water poses a critical milestone in attempts to trace the history of water on Mars. Only the Trace Gas Orbiter satellite is capable of revealing the joint concentrations of H20 and HDO. But another satellite, this time from NASA, MAVEN , is able to observe and characterize the hydrogen and deuterium populations in the exosphere.
Disappointment! While Psyche 16 could make every inhabitant of planet Earth a billionaire, a recent study on this most expensive asteroid in the galaxy casts doubt …
Undoubtedly the ancient nucleus of a dead planet, the asteroid Psyche 16, discovered in 1854 (!), Has fed all fantasies for decades.
It is because the profusion of metals (nickel, iron, gold …) that make up this enormous asteroid could make … every inhabitant of planet Earth a billionaire. By itself, the celestial object « weighs » 700 quintillions of dollars (700 billion billion dollars …).null
Suffice to say that the sending of a NASA probe scheduled for 2022 (arrival scheduled for 2026) is fraught with challenges.
94% less metallic than expected
But now, a new study published in the Planetery Science Journal comes to shake up the certainties. Psyche 16 would in fact be a heap of rubble less « metallic than expected by about 94% » and with « 35% vacuum ».
These « more recent telescopic observations suggest the additional presence of pyroxene (material present in eruptive rocks) with a low iron content and exogenous carbonaceous chondrites (iron present in oxidized form) on the asteroid’s surface. »
According to the authors of the study, « Psyche is composed at best of 82.5% metal, 7% low-Fe pyroxene and 10.5% carbonaceous chondrite by weight. »
On reading this study, we understand that the virtual fortune of each inhabitant of our planet therefore seems to have evaporated. NASA’s mission will therefore be particularly monitored from 2022.
Released by Wikileaks in October 2016, the emails from this Democrat, former campaign manager for Hillary Clinton, show that he was simply passionate about extraterrestrial life.
Your question relates to an email released in October 2016 by Wikileaks , which was addressed to John Podesta, Hillary Clinton’s campaign manager for the 2016 presidential election, also a former White House chief of staff to Bill Clinton and former adviser to President Obama. Victim of a phishing on his personal Gmail address, more than 20,000 emails received and sent have been revealed. The authenticity of these exchanges has not been contested. John Podesta accused Russia of being behind the hack and blamed Wikileaks for harming Hillary Clinton’s election campaign.
The email you send to us, dated March 5, 2015, is signed by Edgar D. Mitchell (deceased in 2016), posing as the « sixth man to walk on the moon » as the « Apollo astronaut 14 ” and as the “ Scientific Director and Founder of Quantrek ” . The sender’s e-mail address corresponds to that of Terri Mansfield, a relative of the astronaut, also director of a task force for peace with extraterrestrial intelligences.
Author of books on the subject
In this email addressed to John Podesta and his assistance Eryn Sepp, the former astronaut takes advantage of the fact « that [John Podesta no longer works] at the White House » to offer them « a one-to-one meeting to discuss zero point energy and Disclosure [of the existence of extraterrestrials] ” . He talks about his knowledge of aliens, which he said would be peaceful, since they « hovered nonviolently over Phoenix and other sites, waiting for help, as they hovered over them. could very easily have destroyed the city with their uses of consciousness ” .
Scrutinized by American journalistsduring the last month of the presidential campaign, emails from John Podesta do not demonstrate that there is extraterrestrial life as some internet users want to believe, but instead show that the Clinton and Obama advisor is passionate by the subject, exchanging readily with interlocutors convinced that extraterrestrial life is a reality. Indeed, John Podesta and his assistants had about thirty exchanges with astronaut Edgar D. Mitchell, who even wanted to meet Barack Obama. Emails leaked by Wikileaks also show the same amount of posts with Tom Delonge, the former Blink-182 guitarist turned alien enthusiast, who has produced books and documentaries on the subject.
The interest of Hillary Clinton’s campaign manager in flying saucers, however, was not revealed by Wikileaks, since an investigation published by the Washington Postin April 2016 already returned to his obsession with Area 51 when he was advisor to Bill Clinton, and his requests under George Bush and Barack Obama to declassify government information regarding unidentified flying objects. The American daily also highlighted its statements on CNN, where it promised that Hillary Clinton,« If she is elected president, when she takes office, she will seek the declassification of as many documents as the United States federal government has, and I think that is a commitment that she intends to keep and which I intend to make him respect. «