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Le télescope spatial japonais Hitomi en perdition un mois après son lancement. Ce mastodonte à un demi-milliard d'euros environ aurait perdu plusieurs morceaux pour une raison encore inconnue.

Le télescope spatial japonais Hitomi en perdition un mois après son lancement

Les ingénieurs de la JAXA tentent de reprendre le contrôle du satellite. Que s'est-il passé? Un mois seulement après son lancement réussi le 17 février dernier, l'agence spatiale japonaise (JAXA) a perdu samedi le contact avec son télescope spatial Astro-H, rebaptisé Hitomi (pupille en japonais) après son lancement, comme le veut la tradition. L'orbite du gigantesque insecte métallique de 2,7 tonnes et 14 mètres de long a été modifiée de 5 km (il se situe à moins de 600 km d'altitude). D'après les observations effectuées depuis le sol, cinq débris l'accompagnent désormais dans sa course. Deux scénarios sont possibles.

La JAXA essaye depuis ce week-end de reprendre le contrôle de son satellite. Si les choses en restaient là, le gâchis serait immense. Calendrier julien, multiples de 400, mécanique céleste : pourquoi y a-t-il un 29 février ? Le | • Mis à jour le | Par Gary Dagorn Les années bissextiles sont le moyen le plus simple qu’ont trouvé les Romains pour coordonner imparfaitement le calendrier sur la durée de l’année solaire, c’est-à-dire sur l’intervalle de temps pour que le Soleil, vu de la Terre, retourne à la même position en suivant le rythme des saisons (par exemple entre deux équinoxes de printemps ou entre deux solstices d’été).

Calendrier julien, multiples de 400, mécanique céleste : pourquoi y a-t-il un 29 février ?

Une année solaire dure environ 365,25 jours. Pour compenser cette différence, on intercale un jour après le 28 février tous les quatre ans. L’année bissextile, introduite par Jules César en 46 avant J. -C. avec la réforme du calendrier julien et reconduite dans le calendrier grégorien, dont on se sert encore, a vu ses règles de calcul évoluer. Entre - 46 et 1582, lorsque le calendrier julien était en vigueur, une année était bissextile si elle était un multiple de quatre. La mécanique céleste étant complexe, elle ne se plie jamais à la régularité du calendrier humain. Visible Light From A Black Hole Spotted For The First Time Ever.

In a cosmic first, astronomers have spotted visible light coming from a black hole during a violent outburst of energy.

Visible Light From A Black Hole Spotted For The First Time Ever

The discovery, made from observations of a nearby black hole binary called V404 Cygni, suggests other black holes could be studied in this way – with nothing more than a backyard telescope. This research was led by astronomers from Kyoto University, published in Nature, and presented at the American Astronomical Society meeting in Florida this week. On June 15, 2015, the black hole "woke up" after 26 years of being dormant, emitting an outburst of energy. Usually, astronomers observe these events in other wavelengths such as X-rays or gamma-rays. A Map Of The Entire Universe In One Image. If you ever happen to embark on a cosmic journey to the outer reaches of the universe, you may want to take along a copy of this map, which was created by musician and artist Pablo Carlos Budassi and encapsulates the entire cosmos in a single, mind-blowing image.

A Map Of The Entire Universe In One Image

In order to create this incredible cartographic masterpiece, Budassi combined images from several of NASA’s telescopes and rovers with logarithmic maps of the universe created by astronomers from Princeton University. Logarithmic maps are able to encapsulate huge areas within manageable graphics since they decrease in scale as they move outwards from the center of the image, meaning that the objects in the middle of the map are shown in a much larger scale than those at the edges. Cosmic 'web' seen for first time. The hidden tendrils of dark matter that underlie the visible Universe may have been traced out for the first time.

Cosmic 'web' seen for first time

Cosmology theory predicts that galaxies are embedded in a cosmic web of "stuff", most of which is dark matter. Astronomers obtained the first direct images of a part of this network, by exploiting the fact that a luminous object called a quasar can act as a natural "cosmic flashlight". Details of the work appear in the journal Nature. The Universe's "Missing Matter" Found Within Superheated Cosmic Web Filaments. Everything you can see around you is composed of “ordinary matter.”

The Universe's "Missing Matter" Found Within Superheated Cosmic Web Filaments

Looking at the remnant radiation of the Big Bang, the cosmic microwave background (CMB), scientists have calculated that this matter consists of only five percent of the entire universe. Hayabusa 2 Captures Stunning Image Of Earth And The Moon. If you’ve ever pondered how the Earth and Moon might look from a distance of three million kilometers (1.9 million miles), then wonder no more, as the Japanese Aerospace eXploration Agency’s (JAXA) Hayabusa 2 asteroid explorer has managed to capture an incredible image of the two bodies in a single shot.

Hayabusa 2 Captures Stunning Image Of Earth And The Moon

Taken on November 26, the image was recorded by the vessel’s optical navigation telephoto camera (ONC-T), and shows most of the Earth’s eastern hemisphere, with the Moon in orbit as if suspended by an enormous celestial rope. Scientist Claims He Has Found Evidence Of Other Universes. A new study submitted to the Astrophysical Journal has claimed to have found evidence of interactions between our universe and other universes by looking at the cosmic microwave background (CMB).

Scientist Claims He Has Found Evidence Of Other Universes

The scientist discovered an anomaly associated with some regions of the CMB, and he believes it is evidence for alternate universes. NASA Releases Stunning Half-Hour Ultra HD Video Of The Sun. NASA has created its first few ultra-high definition videos, and the results are truly spectacular.

NASA Releases Stunning Half-Hour Ultra HD Video Of The Sun

Among the items released is a jaw-dropping 30-minute portrait of the Sun, which was put together from data captured by the Solar Dynamics Observatory (SDO). Launched in early 2010, the SDO observes the Sun around the clock, capturing images in ten different wavelengths, each of which highlights a different temperature of solar material. By observing these multiple types of radiation, NASA is able to keep tracks on a number of facets of solar activity, such as solar flares and streams of electrified plasma called coronal loops. By putting it all together in stunning 4K resolution, NASA has created an image of the Sun as you’ve never seen it before. Rare Double Star System Seen In Final Death Throes Before It Explodes. An incredible stellar system has been found where two stars are so close that their surfaces are overlapping.

Rare Double Star System Seen In Final Death Throes Before It Explodes

It is the hottest and most massive double star system ever seen, and provides a rare glimpse into what is believed to be a relatively brief cosmic event. The system is known as VFTS 352, found 160,000 light-years away in the Tarantula Nebula by the European South Observatory's Very Large Telescope. Both of the stars are nearly identical in size, with a combined mass 57 times greater than the Sun, meaning one is not sucking material from the other – rather, they are likely sharing 30% of their material. This has led to a “bridge” forming between their two connected surfaces. What Is The Biggest Star In The Universe? The universe is a big place, and it is home to a lot of big objects. For humans, contemplating even the size of Earth can be a struggle. It can be even more uncomfortable to consider that the planet under our feet is barely a speck when compared to the star it rolls its constant path around: the Sun. What Is The Biggest Star In The Universe?

Project Apollo Archive’s albums. Ces incroyables photos de la NASA prises sur la Lune. Here's What Would Happen To Your Brain If You Took A Trip To Mars. How Accurate Is The Martian? 9 Things The Movie Got Right And Wrong. "The Martian" is hitting cinemas right about now, and already it is being heralded as one of the most scientifically accurate sci-fi films of all time. We’ve seen the movie, and we’ve got to say, it’s amazing how far we’ve come since "Armageddon" (shudder). NASA has been so impressed, they've been using the movie as a marketing campaign for their own, actual manned missions to Mars in the 2030s. Based on the book of the same name by Andy Weir, itself praised for its accuracy, director Ridley Scott asked NASA to check the film and ensure everything in it was correct – or as correct as can be.

But just how did they do? Here we pick through the science in the movie, with the help of a few experts, to see if "The Martian" is deserving of its accolades. Be warned, though, there are some spoilers in this post. The dust storm. Check Out These Spectacular New Images Of Pluto. NASA just released their new images of Pluto and they are stunning. The header image above features Pluto’s crescent and was captured on July 14th by New Horizons Ralph/Multispectral Visual Imaging (MVIC) camera and downlinked on September 13. In it we see the incredible Plutonian landscape backlit by the Sun. “This image really makes you feel you are there, at Pluto, surveying the landscape for yourself,” said New Horizons Principal Investigator Alan Stern, in a statement. “But this image is also a scientific bonanza, revealing new details about Pluto’s atmosphere, mountains, glaciers and plains.”

Scientists Detect The Oldest, Most Distant Galaxy Known So Far. After spending years searching the cosmos, a research team from CalTech may have found the oldest and most distant galaxy yet. As part of its search, the team combed through data collected by the Hubble Space Telescope and the Spitzer Space telescope, and ultimately identified the galaxy EGS8p7 as a target to investigate further. The team then performed a spectrographic analysis of EGS8p7 using the Keck Observatory’s multi-object spectrometer for infrared exploration (MOSFIRE) to calculate its redshift. Redshift is a result of the Doppler effect – like when an ambulance drives by and the siren fades as it passes. In astronomy, instead of sound waves, light from the galaxy is stretched and shifted towards the red end of the spectrum as it moves farther away. Based on the data collected, the team estimates that EGS8p7 is over 13.2 billion years old, meaning it was formed only around 600 million years after the Big Bang.

A Brief History Of Everything, With Neil deGrasse Tyson. Kepler-452b: Earth's Bigger, Older Cousin. NASA will host a news teleconference at noon EDT Thursday, July 23 to announce new discoveries made by its planet-hunting mission, the Kepler Space Telescope. The first exoplanet orbiting another star like our sun was discovered in 1995. Exoplanets, especially small Earth-size worlds, belonged within the realm of science fiction just 21 years ago. Today, and thousands of discoveries later, astronomers are on the cusp of finding something people have dreamed about for thousands of years -- another Earth. The briefing participants are: John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington Jon Jenkins, Kepler data analysis lead at NASA's Ames Research Center in Moffett Field, California Jeff Coughlin, Kepler research scientist at SETI Institute in Mountain View, California Didier Queloz, professor of astrophysics at Cambridge University, United Kingdom.

First Close-Up Photograph Of Pluto's Surface Released. Just 24 hours after receiving confirmation that the New Horizons spacecraft survived its encounter with the Pluto system, NASA released the first close-up view of Pluto’s surface. The high-resolution image is just one segment of a larger mosaic of the lower left portion of Pluto’s “heart.” The region – now officially dubbed Tombaugh Regio after the man who discovered the icy world – features a mountain range similar to the Rocky Mountains with peaks towering as high as 3,500 meters (11,000 feet) above the surface and composed of water ice.

The mountains are young and thought to have formed no more than 100 million years ago – which makes them very young when compared to the age of the Solar System. Mountains on an isolated small body in the far reaches of the Solar System was a surprise, and it’s still too early to determine how they formed. New Super-Hubble Telescope Could Find out if we are Alone in the Universe. When it comes to astronomy, bigger is almost always better. Although the iconic Hubble Space Telescope is set to be eclipsed by a telescope three times its size in 2018, the James Webb Space Telescope (JWST), astronomers have already proposed an even more impressive space observatory that would put both of them to shame.

And tantalizingly, it could reveal how rare or common life is in the Universe. Hubble Detects Massive Gas Halo Surrounding Andromeda Galaxy. The nearest large galaxy to our own has a halo that stretches out for a million light-years around it and almost half way to the Milky Way, The Hubble Telescope has observed. Missing 'Galactic Dinosaurs' Found Hiding In Plain Sight. It’s long been presumed that millions of ancient compact spherical galaxies, abundant in the early universe about 11 billion years ago but scarce now, collided and formed much larger clouds of stars with little form. Missing 'Galactic Dinosaurs' Found Hiding In Plain Sight.

The sun is now virtually blank during the weakest solar cycle in more than a century « Vencore Weather. Breathtaking 3D Model Of The Pillars Of Creation. Hubble Offered A Rare, Ring-Side Seat At The Death Of A Star. Could Tau Ceti Be Humanity's Next Home? NASA : La sonde New Horizons débute son exploration de Pluton et envoie des images en couleur. La sonde New Horizons a commencé à explorer Pluton après plus de neuf ans de voyage et 4,8 milliards de kilomètres parcourus.

C’est vers le 14 juillet que la sonde de la NASA sera au plus proche de cette planète naine plus petite que la Lune. Espace: En ratant son atterrissage, Philae a fait faire un bond à la science. Afin d'être publiée, votre note : La naissance de la Lune serait bien due à une collision entre la Terre et sa sœur jumelle Théia. Astronomers Track Birth Of A Giant.

Large Hadron Collider Could Detect Extra Dimensions. VIDEO. La sonde Dawn a un rendez-vous historique avec la planète naine Cérès. Travel Through The Solar System At The Speed Of Light. Researchers Claim To Have Found Evidence of Dark Matter In Inner Milky Way. Beagle-2 lander found on Mars / Mars Express. Planetary Alignment On Jan 4, 2015 Will Decrease Gravity For 5 Minutes Causing Partial Weightlessness. Sky Watching Event Guide For 2015. The Next 209 Seconds Will Blow Your Mind. Internet aux autres 3 milliards : la constellation de satellites au complet. This Is What Astronauts See As They Re-Enter Earth's Atmosphere. Is There a Parallel Universe That's Moving Backwards in Time? Every Ship That Has Carried Humans Into Space Scaled Into One Chart. "TOP 10 REASONS Why We Know the Earth is Round" Debunked. TOP 10 REASONS Why We Know the Earth is Round.

Astronomers Spot Massive Blue Stars Beginning To Merge. Scientists Recreate First Spark Of Life. Ariane 6 prête au lancement. Why We Should Mine The Moon. Philae à l'assaut de sa comète ! Philae Sends Back First Images, But Problems Mean Its Mission Could Soon Be Over. Expanding Fireball from a Nova Explosion Spotted for the First Time. «La conquête spatiale peut continuer à faire rêver si on y met les moyens» WMAP Big Bang CMB Test. Unbelievable Facts About Our Universe. Unusual Organic Molecule Discovered At The Heart Of The Milky Way. Hawking Believes The Higgs Field Could Wipe Out The Universe—Should We Be Worried? Impact: Earth! Time-Lapse Footage From ISS Gives Spectacular Aerial View of Earth at Night. What Would Happen To Your Body In Space Without A Spacesuit?

JWST : Momentum Trim Tab. Massive Asteroids Battered Early Earth. Earth Narrowly Missed A Potentially Devastating Solar Superstorm In 2012. How many habitable planets are there in the galaxy? - Bad Astronomy.

Un océan immense au centre de la Terre. Vie extraterrestre ? . Sous la lune de Saturne, un océan. VIDEO - Un astéroïde à anneaux découvert dans notre système solaire. Nasa : votez pour votre combinaison spatiale préférée ! EN IMAGES. "Houston, on a un reportage !" A Kourou, le satellite Gaia s'élance pour réaliser un panorama 3D de la Voie lactée - Espace. En vidéo : l'impact étonnamment lumineux d'un astéroïde sur la Lune. Video: How to Put a Star Into a Bottle. Les Américains franchissent une étape vers la fusion nucléaire.

Inflation : les ondes gravitationnelles du Big Bang enfin découvertes ? Big Bang: une découverte "essentielle" mais "incomplète" Une simulation retrace en deux minutes 13 milliards d'années d'histoire de l'Univers. Big Bang : les ondes gravitationnelles d'Einstein enfin détectées. Big Bang: Une théorie qui ne convainc pas encore tous les scientifiques.