Category: Astronomy

Hubble, Chandra, and Spitzer – NASA’s three Great Observatories – teamed up to create this beautiful photograph of supernova remnant N49. Under visible light, this is the brightest remnant in the Large Magellanic Cloud. It has a strange lopsided shape; unusual because most supernova remnants are spherical. The new data from the triplet of telescopes have revealed that the strange shape is happening because the remnant is expanding into a region of denser gas on one side.
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Type 1a supernovae are used to measure distance in the Universe because they explode with the same brightness, detonating when a white dwarf star consumes a specific amount of material from a binary companion. The accuracy of these distance measurements depends on the shape of the blast. New research indicates that Type 1a supernovae explosions start out clumpy and uneven, but a second, spherical blast overwhelms the first creating a smooth residue. This sets the limits of uncertainty on distance measurements that use Type 1a supernovae.
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Astronomers don’t know what dark matter is, but they do know it takes up approximately 25% of the Universe. We can’t see it, but we can measure the effect of its gravity on stars and galaxies. A powerful detector, deep underground in a mineshaft in Minnesota might be able to get to the bottom of the mystery. The Cryogenic Dark Matter Search II project will attempt to detect Weakly Interacting Massive Particles (aka WIMPS). These theoretical particles don’t normally interact with matter, but the occasional rare collision might be detectable.
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Astronomers have discovered a gamma ray source in the sky that acts like a natural clock. The object is called LS 5039, and consists of a massive blue star orbiting an unknown object – possibly a black hole. The two objects orbit each other closely, completing an orbit every four days. With each orbit, the black hole flies through the blue star’s stellar wind, and accelerates particles to gamma ray levels. This is the first time a source of gamma rays has been discovered with such a regular schedule.
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This is an image of galaxy NGC 1313, taken with the FORS instrument at the ESO’s Very Large Telescope. It’s classified as a starburst galaxy, because of the dense regions of furious star formation. NGC 1313 is relatively close to the Milky Way, located only 15 million light-years away. To say it’s forming many new stars is an understatement; NGC 1313 has a rate of star formation 1000x faster than the Milky Way. Galaxies like this usually went through a recent collision with another galaxy, but astronomers can’t find the culprit anywhere near.
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NASA’s Swift satellite has found a galaxy positively popping with supernovae. NGC 1316 has had two supernovae go off in just the last 5 months, and 4 within the 26 years. This makes NGC 1316 one of the most supernova rich galaxies ever discovered. So, what’s going on here? Astronomers know that the galaxy recently merged with a spiral galaxy, which can produce massive stars that explode as supernovae. However, all four supernovae have been Type 1a, which are formed when a white dwarf consumes material from a binary partner star. Perhaps it’s just a coincidence.
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NASA’s most powerful supercomputer has helped researchers simulate the halo of dark matter that surrounds the Milky Way. This dark matter is invisible to our telescopes; however, it does interact with regular matter through its gravity. This new computer simulation shows how the dark matter clumps together into “subhalos” within the larger halo surrounding the Milky Way. This is a bit of a puzzle, since the dark matter doesn’t match the clumping of the satellite galaxies that surround us.
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Dark energy isn’t new, in fact, it’s been around for at least 9 billion years. According to new data gathered by the Hubble Space Telescope, this mysterious force was already working to speed up the expansion of the Universe was only a few billion years old. Hubble measured the light from 24 of the most distant supernovae ever seen, and found that the Universe is further apart than it should be if only gravity was around to slow things down.
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