Astronomers recently calculated the distance to the relatively nearby galaxy M33 (aka the Triangulum Galaxy) as being about 15% further than previously estimated. They analyzed the distance using several telescopes, fine tuning their instruments very carefully. This measurement means that the Hubble constant – which astronomers use to measure distances in the Universe – could be off as well. The Universe might actually be 15% larger than previously believed.
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Dark Energy Mission Chosen
A new space telescope concept has been chosen by NASA to help uncover the source of dark energy; the mysterious force accelerating the expansion of the Universe. Called Destiny, or the Dark Energy Space Telescope, the orbiting observatory would detect and observe more than 3,000 supernovae over the course of 2 years. This data will help astronomers trace back the expansion of the Universe, and calculate if the rate of acceleration has changed over time. If all goes well, it’ll launch in 2013.
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Brown Dwarf Lived Inside Another Star
ESO’s Very Large Telescope has uncovered an interesting stellar pair: a hot white dwarf and a brown dwarf orbiting each other every two hours. In the past, the heavier star was actually a bloated red giant, and the brown dwarf orbited inside its envelope. The friction of moving through the red giant caused the brown dwarf to spiral in to its current position. Finally, the star collapsed down to a white dwarf, leaving the two objects in this embrace.
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Podcast: A Puzzling Difference
Imagine looking at red houses, and sometimes you see a crow fly past. But every time you look at a blue house, there’s always a crow flying right in front of the house. The crow and the house could be miles apart, so this must be impossible, right? Well, according to a new survey if you look at a quasar, you’ll see a galaxy in front 25% of the time. But for gamma ray bursts, there’s almost always an intervening galaxy. Even though they could be separated by billions of light years. Figure that out. Dr. Jason X. Prochaska, from the University of California, Santa Cruz speaks to me about the strange results they’ve found, and what could be the cause.
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Strange Difference Between Gamma Ray Bursts and Quasars
Look at a quasar and a gamma ray burst – two of the most luminous objects in the Universe – and you’re 4 times more likely to see intervening galaxies in front of the burst. This conclusion was reached by astronomers from UC Santa Cruz, who studied more than 50,000 quasars, and a handful of gamma ray bursts. There shouldn’t be a connection between the quasar or burst in the background, and the number of galaxies in the foreground… but there is, and right now that relationship is a complete mystery.
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The Largest Structure in the Universe
Astronomers have used the Subaru and Keck telescopes to discover gigantic filaments of galaxies stretching across 200 million light-years in space. These filaments, formed just 2 billion years after the Big Bang, are the largest structures ever discovered in the Universe. The filaments contain at least 30 huge concentrations of gas, each of which contains 10x the mass of the Milky Way.
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Starburst Galaxy NGC 908
This photograph of galaxy NGC 908 was taken with the European Southern Observatory’s Very Large Telescope. This spiral galaxy was first discovered in 1786 by William Herschel, and is considered a starburst galaxy. Clusters of young, massive stars pepper its spiral arms indicating regions of furious star formation. NGC 908 must have had a recent encounter with another galaxy; the gravitational interaction between the galaxies caused gas clouds to collapse, igniting star formation.
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New View on Pulsars
Pulsars are the rapidly spinning corpses of massive stars. And although they were discovered nearly 40 years ago, they still hold many mysteries. One such mystery: why do pulsars have million-degree hotspots around their poles? New data from ESA’s XMM-Newton X-Ray observatory have cast doubt on the theory that charged particles are colliding with the pulsar’s surface at its poles. XMM-Newton failed to see the X-ray emissions in several old pulsars that should have been very bright if particles were continuously colliding.
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A New View of Quasars
Some of the brightest objects in the Universe are quasars. A mystery for decades, most astronomers now believe quasars are the bright centres of galaxies with actively feeding supermassive black holes. A team of researchers have found evidence that there might be something very different at the heart of these galaxies to cause quasars. Instead of black holes consuming matter, there could be objects with powerful magnetic fields that act like propellers, churning matter back into the galaxy.
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Podcast: Inevitable Supernova
Consider the dramatic binary system of RS Ophiuchi. A tiny white dwarf star, about the size of our Earth, is locked in orbit with a red giant star. A stream of material is flowing from the red giant to the white dwarf. Every 20 years or so, the accumulated material erupts as a nova explosion, brightening the star temporarily. But this is just a precursor to the inevitable cataclysm – when the white dwarf collapses under this stolen mass, and then explodes as a supernova. Dr. Jennifer Sokoloski has been studying RS Ophiuchi since it flared up earlier this year; she discusses what they’ve learned so far, and what’s to come.
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