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Latest Activity: 12 hours ago
Cosmology - Astrophysics - Astronomy
Hubble Wallpaper - Awesome Hubble Images
Started by Michel. Last reply by Michel May 15.
Started by doone. Last reply by doone Apr 19.
Started by Dallas the Phallus. Last reply by Onyango Makagutu Apr 15.
Started by Dallas the Phallus. Last reply by Dallas the Phallus Apr 14.
Started by Michel. Last reply by Onyango Makagutu Apr 9.
How to find your very own supernova
What is dark energy?
The E-Cat is back, and people are still falling for it!
Messier Monday: A Hyper-Smooth Globular Cluster, M5
Weekend Diversion: Against Scientific Racism
To Blob, or not to Blob, that is the question:
Explanation: No, they are not alive -- but they are dying. The unusual blobs found in the Carina nebula, some of which are seen floating on the upper right, might best be described as evaporating. Energetic light and winds from nearby stars are breaking apart the dark dust grains that make the iconic forms opaque. Ironically the blobs, otherwise known as dark molecular clouds, frequently create in their midst the very stars that later destroy them. The floating space mountains pictured above by the orbiting Hubble Space Telescope span a few light months. The Great Nebula in Carina itself spans about 30 light years, lies about 7,500 light years away, and can be seen with a small telescope toward the constellation of Keel (Carina).
Explanation: When does Mars act like a liquid? Although liquids freeze and evaporate quickly into the thin atmosphere of Mars, persistent winds may make large sand dunes appear to flow and even drip like a liquid. Visible on the above image right are two flat top mesas in southern Mars when the season was changing from Spring to Summer. A light dome topped hill is also visible on the far left of the image. As winds blow from right to left, flowing sand on and around the hills leaves picturesque streaks. The dark arc-shaped droplets of fine sand are called barchans, and are the interplanetary cousins of similar Earth-based sand forms. Barchans can move intact a downwind and can even appear to pass through each other. When seasons change, winds on Mars can kick up dust and are monitored to see if they escalate into another of Mars' famous planet-scale sand storms.
Explanation: Except for the rings of Saturn, the Ring Nebula (M57) is probably the most famous celestial band. Its classic appearance is understood to be due to perspective - our view from planet Earth looks down the center of a roughly barrel-shaped cloud of glowing gas. But expansive looping structures are seen to extend far beyond the Ring Nebula's familiar central regions in this intriguing composite of ground based and Hubble Space Telescope images with narrowband image data from Subaru. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the gaseous shroud represents outer layers expelled from the dying, once sun-like star at the nebula's center. Intense ultraviolet light from the hot central star ionizes atoms in the gas. Ionized oxygen atoms produce the characteristic greenish glow and ionized hydrogen the prominent red emission. The central ring of the Ring Nebula is about one light-year across and 2,000 light-years away. To accompany tonight's shooting stars it shines in the northen constellation Lyra.
Apr. 19, 2012
Jason Palmer at the BBC:
The mystery surrounding the source of the highest-energy particles known in the Universe has grown deeper.
The particles, known as cosmic rays, can show up with energies a million times higher than the biggest particle accelerators on Earth can produce.
Astrophysicists believed that only two sources could make them: supermassive black holes in active galaxies, or so-called gamma ray bursts.
A study in Nature has now all but ruled out gamma ray bursts as the cause.
Gamma ray bursts (GRBs) are the brightest events we know of, though their sources remain a matter of some debate. They can release in hours more energy than our Sun will ever produce.
Computer models predict that GRBs could be the source of cosmic rays - mostly subatomic particles called protons, accelerated to incredibly high speeds.
But they were also predicted to produce a stream of neutrinos, the slippery subatomic particlesrecently brought to fame in claims of faster-than-light travel.
So researchers at the IceCube neutrino telescope went looking for evidence of neutrino arrival that coincided with measurements of gamma ray bursts detected by the Fermi and Swift space telescopes.
But it found none - suggesting that active galactic nuclei, where supermassive black holes reside, are likely to be the source.
Posted by Abbas Raza at 01:08 PM | Permalink |
Podcast: Space Chronicles; Neil DeGrasse Tyson
NASA has been sending Americans into space for half a century. But now that proud chapter is history. With the end of the space shuttle program, we have no way of launching astronauts in an American spacecraft from American soil for at least a decade, and maybe longer.
Astrophysicist Neil DeGrasse Tyson has big problems with that and he writes about them in his new book Space Chronicles: Facing the Ultimate Frontier. Neil DeGrasse Tyson is the director of the Hayden Planetarium in New York City and he recently spoke to Living on Earth’s Steve Curwood about space exploration, science education, and the role of discovery.
Apr. 18, 2012
Explanation: Antares is a huge star. In a class called red supergiant, Antares is about 850 times the diameter of our own Sun, 15 times more massive, and 10,000 times brighter. Antares is the brightest star in the constellation of Scorpius and one of the brighter stars in all the night sky. Located about 550 light years away, Antares is seen on the left surrounded by a yellowish nebula of gas which it has itself expelled. Radiation from Antares' blue stellar companion helps cause the nebular gas to glow. Far behind Antares, to the lower right in the above image, is the globular star cloud M4, while the bright star on the far right is Al Niyat.
Apr. 16, 2012
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