Where is all the missing matter? That question has plagued astronomers for decades, because the Universe looks emptier than it should, given current theories about its makeup. Most of the Universe (70%) appears to be composed of Dark Energy, the mysterious force which is causing the Universe’s rate of expansion to increase. Another 25% of the Universe is Dark Matter, an unknown substance which cannot be seen, but has been theorized to explain the otherwise inexplicable gravitational forces which govern the formation of galaxies. That leaves Baryonic Matter – all the normal ‘stuff’ like you, me, the trees, the planets, and the stars – to make up just 5% of the Universe. But when astronomers look out into the sky, there doesn’t even seem to be enough normal matter to make up 5%. Some of the normal matter is missing!Continue reading “A New Technique to Find Cold Gas Streams That Might Make up the Missing (Normal) Matter in the Universe”
Fast-Radio Bursts (FRBs) are one of the most puzzling phenomena facing astronomers today. Essentially, FRBs are brief radio emissions from distant astronomical sources whose cause remains unknown. In some cases, FRBs that have been detected that have been repeating, but most have been one-off events. And while repeating sources have been tracked back to their point of origin, no single events have ever been localized.
Until now. Using the Australian Square Kilometer Array Pathfinder (ASKAP) and other radio telescopes from around the world, an Australian-led team of astronomers managed to confirm the distance to an intense radio burst that flashed for just a thousandth of a second. The constitutes the first non-repeating FRB to be traced back to its source, which in this case was a galaxy located 4 billion light-years away.Continue reading “A Fast Radio Burst has Finally Been Traced Back to its Source: the Outskirts of a Galaxy 4 Billion Light-Years Away”
Fast Radio Bursts (FRBs) have become a major focus of research in the past decade. In radio astronomy, this phenomenon refers to transient radio pulses coming from distant cosmological sources, which typically last only a few milliseconds on average. Since the first event was detected in 2007 (the “Lorimer Burst”), thirty four FRBs have been observed, but scientists are still not sure what causes them.
With theories ranging from exploding stars and black holes to pulsars and magnetars – and even messages coming from extra-terrestrial intelligences (ETIs) – astronomers have been determined to learn more about these strange signals. And thanks to a new study by a team of Australian researchers, who used the Australia Square Kilometer Array Pathfinder (ASKAP), the number of known sources of FRBs has almost doubled.
In 1974, astronomers detected a massive source of radio wave emissions coming from the center of our galaxy. Within a few decades time, it was concluded that the radio wave source corresponded to a particularly large, spinning black hole. Known as Sagittarius A, this particular black hole is so large that only the designation “supermassive” would do. Since its discovery, astronomers have come to conclude that supermassive black holes (SMBHs) lie at the center of almost all of the known massive galaxies.
But thanks to a recent radio imaging by a team of researchers from the University of Cape Town and University of the Western Cape, in South Africa, it has been further determined that in a region of the distant universe, the SMBHs are all spinning out radio jets in the same direction. This finding, which shows an alignment of the jets of galaxies over a large volume of space, is the first of its kind, and could tell us much about the early Universe.
Three of 36 antennas of the ASKAP array. Credit: Alexander Cherney
The Australian Square Kilometer Array Pathfinder (ASKAP) is now standing tall in the outback of Western Australia, and will officially be turned on and open for business on Friday, October 5, 2012 . This large array is made up of 36 identical antennas, each 12 meters in diameter, spread out over 4,000 square meters but working together as a single instrument. ASKAP is designed to survey the whole sky very quickly, and astronomers expect to do studies of the sky that could never have been done before.
Below is a beautiful timelapse of the the ASKAP array. The photographer who put the video together, Alexander Cherney says the footage seen here may be quite unique because after the telescope testing phase is completed, any electronic equipment including cameras may not be used near the telescope.
ASKAP provides a wide field-of-view with a large spectral bandwidth and fast survey speed with its phased-array feed or “radio camera,” rather than ‘single pixel feeds’ to detect and amplify radio waves. This new technology allows telescopes to scan the sky more quickly than with traditional methods covers 30 square degrees – a thousand times the size of the full Moon in the sky.
“This will make ASKAP a very powerful survey radio telescope, a 100 times more powerful than any previous survey telescope,” said Brian Boyle, director of the SKA for Australia’s national science agency, speaking to Universe Today in interview earlier this year.
It will provide excellent coverage in a southern hemisphere location, and the radio quiet site at the Murchison Radio Observatory will make it an unprecedented synoptic telescope, according to the ASKAP website, and scientists expect to make advances in understanding galaxy formation and the evolution of the Universe.
While ASKAP will provide advances on its own, later, the dishes will be combined with 60 additional dishes to form part of the world’s largest radio telescope, The Square Kilometer Array. Construction of the SKA is due to begin in 2016.
You can see what the ASKAP looks like anytime by going to their webcam, plus there will be a webcast of the opening ceremonies on Friday at 12 noon – 1pm Western Australian Standard Time, which is 04:00 GMT Friday October 5, 2012 in GMT (midnight US EDT).