L'actualité astrophysique
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Are we alone in the universe? Not likely, according to math

Are we alone in the universe? Not likely, according to math | L'actualité astrophysique | Scoop.it
By flipping the question of possible alien life to a question of whether we are unique, researchers find it much more likely the universe has seen many civilisations come and go.
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Research Sheds New Light on Dark Energy

Research Sheds New Light on Dark Energy | L'actualité astrophysique | Scoop.it
Dartmouth researchers shed new light on dark energy and eliminate the possibility that our planet, solar system and galaxy are at the center of the universe.
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Newly Discovered ‘Force Field’ Shields a Colossal Cloud On Its Plunge into Milky Way's Center

Newly Discovered ‘Force Field’ Shields a Colossal Cloud On Its Plunge into Milky Way's Center | L'actualité astrophysique | Scoop.it
               The Smith Cloud, a gigantic streamer of hydrogen gas that is on a collision course with the Milky Way Galaxy, is hurtling toward the Milky Way at more than 150 miles per second and is predicted to impact in approximately 30...
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Astronomers detect habitable zone planet 25,000 light years away, in the galactic bulge

Astronomers detect habitable zone planet 25,000 light years away, in the galactic bulge | L'actualité astrophysique | Scoop.it
A quirk of physics has allowed astronomers to spot a distant exoplanet about 25,000 light years away in a densely packed region of the galaxy known as the galactic bulge. This is notable […]
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Astronomers Discover Misaligned Planets in a Distant Planetary System

Astronomers Discover Misaligned Planets in a Distant Planetary System | L'actualité astrophysique | Scoop.it
In a newly published study, researchers from NASA’s Ames Research Center and Iowa State University detail the discovery of two planets in the Kepler-56 planetary system that orbit the host star at a severe tilt.
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"Making Sense of Our Universe" --How NASA Manages Galaxies of Data from Its Space Missions

"Making Sense of Our Universe" --How NASA Manages Galaxies of Data from Its Space Missions | L'actualité astrophysique | Scoop.it
 
The image above shows the center of the Milky Way, sent from NASA's Spitzer Space Telescope.
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Most Distant Gravitational Lens Helps Weigh Galaxies and Deepens a Galactic Mystery

Most Distant Gravitational Lens Helps Weigh Galaxies and Deepens a Galactic  Mystery | L'actualité astrophysique | Scoop.it
Get larger image formats An international team of astronomers has found the most distant gravitational lens yet a galaxy that, as predicted by Albert Einstein's general theory of relativity, deflects and intensifies the light of an even more...
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"30 Supernovas Per Second in the Universe" (Weekend Feature)

"30 Supernovas Per Second in the Universe" (Weekend Feature) | L'actualité astrophysique | Scoop.it
 
 
         
 
While there is, on average, only one supernova per galaxy per century, there is something on the order of 100 billion galaxies in the observable Universe.
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Scientists Generate Magnetic Field by Using Heat Instead of Electricity

Scientists Generate Magnetic Field by Using Heat Instead of Electricity | L'actualité astrophysique | Scoop.it
In a newly published study, EPFL scientists have for the first time predicted and experimentally verified the existence of the Magnetic Seebeck Effect.
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Une nouvelle technique pour réaliser des réactions de fusion contrôlée aneutronique

Le Laboratoire pour l'Utilisation des Lasers Intenses (LULI) de Polytechnique présente une nouvelle technique pour réaliser des réactions de fusion contrôlée aneutronique dans un article publié par Nature Communications Un nouveau schéma pour...
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NASA funds fuelless laser thruster, could be readying for test launch

NASA funds fuelless laser thruster, could be readying for test launch | L'actualité astrophysique | Scoop.it
This week NASA decided to grant funding to an innovative thruster design that could change the way spacecraft maneuver in orbit, and even how they travel between the stars.
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Astronomers discover a planet traveling through space without a sun

Astronomers discover a planet traveling through space without a sun | L'actualité astrophysique | Scoop.it
Early Wednesday, astronomers at the University of Hawaii at Manoa reported that they found a young planet floating in the void of space without a star to call its own.
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New Device Produces Hydrogen Fuel from Sunlight and Wastewater

New Device Produces Hydrogen Fuel from Sunlight and Wastewater | L'actualité astrophysique | Scoop.it
By combining a microbial fuel cell and a type of solar cell called a photoelectrochemical cell, researchers from UC Santa Cruz have developed a hybrid device that produces hydrogen gas from wastewater and sunlight.
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Kepler Mission --"K2" Signals a New Era in Search for Alien Life in the Milky Way

Kepler Mission --"K2" Signals a New Era in Search for Alien Life in the Milky Way | L'actualité astrophysique | Scoop.it
  Scientists from around the world are gathered this week at NASA's Ames Research Center in Moffett Field, Calif., for the second Kepler Science Conference, where they will discuss the latest findings resulting from the analysis of Kepler Space...
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A Visible Milky-Way Supernova Predicted in Next 50 Years

A Visible Milky-Way Supernova Predicted in Next 50 Years | L'actualité astrophysique | Scoop.it
    Astronomers have calculated the odds that, sometime during the next 50 years, a supernova occurring in our home galaxy will be visible from Earth, calculating the odds to be nearly 100 percent that such a supernova would be visible to...
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It's bigger on the inside: Tardis regions in spacetime and the expanding universe

It's bigger on the inside: Tardis regions in spacetime and the expanding universe | L'actualité astrophysique | Scoop.it

Fans of Doctor Who will be very familiar with the stupefied phrase uttered by all new visitors to his Tardis: "It's...bigger...on the inside." As it turns out, this apparently irrational idea may have something to contribute to our understanding of the universe. A team of cosmologists in Finland and Poland propose that the observed acceleration of the expansion of the universe, usually explained by dark energy or modified laws of gravity, may actually be the result of regions of spacetime that are larger on the inside than they appear from the outside. The researchers have dubbed these "Tardis regions."

 

Perhaps the most surprising cosmological observation of the past few decades was the 1998 discovery by Perlmutter, Schmidt and Riess, that the expansion of the universe has been accelerating for the past five billion years. This result, which won the 2011 Nobel Prize, was quickly corroborated by observation of independent phenomena such as the cosmic background radiation.

 

Why the acceleration is occurring is not currently understood, although it can be described. In terms of conventional cosmological theory, it calls for the existence of a "dark energy," an energy field permeating the universe. However, because gravity attracts normal mass-energy, dark energy would have to have a negative energy density, something unknown as yet in nature. In addition, roughly 75 percent of the contents of the universe have to be made up of dark energy to get the observed acceleration of expansion. Even though dark energy provides a reasonable description of the universal acceleration, its value as an explanation is still controversial. Many have the gut reaction that dark energy is too strange to be true.

 

Professors Rasanen, and Szybkab, of the University of Helsinki and the Jagellonian University at Krakow, together with Rasanen's graduate student Mikko Lavinto, decided to investigate another possibility.

 

The "standard cosmological model," which is the framework within which accelerated expansion requires dark energy, was developed in the 1920s and 1930s. The FLRW metric (named for Friedmann, Lemaître, Robertson and Walker, the major contributors) is an exact solution to Einstein's equations. It describes a strictly homogeneous, isotropic universe that can be expanding or contracting.

 

Strict homogeneity and strict isotropy means that the universe described by an FLRW metric looks the same at a given time from every point in space, at whatever distance or orientation you look. This is a universe in which galaxies, clusters of galaxies, sheets, walls, filaments, and voids do not exist. Not, then, very much like our own Universe, which appears to be rather homogeneous and isotropic when you look at distances greater than about a gigaparsec, but closer in it is nothing of the sort.

Rasanen's research team decided to examine a model universe having a structure closer to ours, in an attempt to look for alternate explanations of the accelerating expansion we see. They took an FLRW metric filled with a uniform density of dust, and converted it into a Swiss cheese model but cutting random holes in it. This has the effect of making the model inhomogeneous and non-isotropic (except very far away), and hence the Swiss cheese model looks more like our own Universe, save for the fact that our Universe does not seem to be full of holes.

 

While Swiss cheese is delicious, a universe with holes is not. To rectify this, Rasanen's team filled in the holes with plugs made from dust-filled exact solutions of Einstein's equation. These plugs are a reasonable model of the region near a sizable body, such as a galaxy. By putting the plugs in the holes, and then smoothing the intersections between them, they obtained a rather uniform spacetime with a lot of smaller blobs of matter dispersed throughout it – a (very) simple analog to the structure of the universe in which we live.


Via Dr. Stefan Gruenwald
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Astronomers Identify First Progenitor of a Stripped Envelope Supernova

Astronomers Identify First Progenitor of a Stripped Envelope Supernova | L'actualité astrophysique | Scoop.it
Using a novel astronomical survey software system, the intermediate Palomar Transient Factory (iPTF), astronomers have identified the first progenitor of a stripped envelope supernova.
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Paris depuis l'espace

Paris depuis l'espace | L'actualité astrophysique | Scoop.it
"Londres et Paris illuminent la nuit européenne" écrit sur Twitter l'astronaute de l'ESA Luca Parmitano.
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Multiple-ExoPlanet System Found with Odd Orbit

Multiple-ExoPlanet System Found with Odd Orbit | L'actualité astrophysique | Scoop.it
 
Using data from NASA's Kepler space telescope, an international team of astronomers has discovered a distant planetary system featuring multiple planets orbiting at a severe tilt to their host star.
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Is 21st-Century Technology Too Primitive to Detect Advanced Extraterrestrial Life? (Weekend Feature)

Is 21st-Century Technology Too Primitive to Detect Advanced Extraterrestrial Life? (Weekend Feature) | L'actualité astrophysique | Scoop.it
              Some of the world's leading astronomers -- including Great Britain's astronomer royal, Sir Martin Rees -- believe aliens, rather than using different radio waves or visible light to signal, may be using an entirely different...
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"Microbial Dark Matter" --The Invisible Infrastructure of Life on Earth

"Microbial Dark Matter" --The Invisible Infrastructure of Life on Earth | L'actualité astrophysique | Scoop.it
                  
 
Is space really the final frontier, or are the greatest mysteries closer to home?
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The Largest Star Known in the Universe -- A Red Supergiant in Death Throes

The Largest Star Known in the Universe -- A Red Supergiant in Death Throes | L'actualité astrophysique | Scoop.it
When the astronomers studied the images of the most massive cluster of stars in our galaxy, Westerlund 1, they spotted something truly unique. Around one of the stars, known as W26, they saw a huge cloud of glowing hydrogen gas,...
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L’arbre évolutif des vertébrés remis en cause ?

L’arbre évolutif des vertébrés remis en cause ? | L'actualité astrophysique | Scoop.it
Tout est venu de la découverte d’un fossile de placoderme, un poisson doté d’une mâchoire articulée aujourd’hui disparu, qui sillonnait les eaux du globe il y a 430 à 360 millions d’années.
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Search for alien life more complicated than thought, scientists say - Space Daily

Search for alien life more complicated than thought, scientists say - Space Daily | L'actualité astrophysique | Scoop.it
Search for alien life more complicated than thought, scientists say
Space Daily
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Comet-Like Activity Discovered in Near-Earth Object Don Quixote

Comet-Like Activity Discovered in Near-Earth Object Don Quixote | L'actualité astrophysique | Scoop.it
Using data from the Spitzer Space Telescope, CfA astronomers discover comet-like activity in Near-Earth Object Don Quixote. Near Earth Objects (NEOs) are asteroids or comets whose orbits sometimes bring them close to the earth’s orbit.
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