Nov 7, 2015 12:51 AM
We Need A Better Way To Get Into Space
http://www.space.com/31052-its-not-rocke...space.html
EXCERPT: . . . we won’t be heading to the stars in a rocket. Rockets are a terrible way of getting to space. There’s a saying in orbital mechanics: getting to orbit is halfway to anywhere. Orbit is the easiest way of going permanently to space. It’s a big first step on the way to leaving the gravity of earth behind. Being in orbit means you are balanced – between gravity pulling you down and your own momentum flinging you into outer space. You stay at the same height going round the Earth because you’re moving forward so fast that the Earth drops away below you at the same speed you fall into it. Slowing down a little returns you to the surly bonds of gravity. But speed up just a little and you can leave earth all together. Orbit is the gateway to the solar system, the galaxy, the universe. Unfortunately, this gateway happens to be about 100 miles off the floor and moving at about 20,000 mph.
[...] A UK company called Reaction Engines is working on what it calls the SKYLON spaceplane. [...] The SKYLON project relies on the development of its SABRE engine. The unique engine functions as either a plane engine or a rocket engine. The vehicle can take off from a runway like a plane (efficient) and fly as high and as fast as possible. Then the SKYLON plane switches its engines into rocket mode for the rest of its journey. The design shows enough promise that the European Space Agency and the UK Space Agency both recently invested in the concept. The company claims test flights could happen by 2019....
- - - - - - - -
Alien Megastructure? SETI Spies No Intelligent Signals
http://news.discovery.com/space/alien-li...151106.htm
EXCERPT: After all the public excitement surrounding the star KIC 8462852 and its weird transit signal as spotted by NASA’s Kepler Space Telescope, the SETI Institute decided to expedite plans to point a powerful radio antennae at the nearby star in the hope of detecting any artificial transmissions emanating from that location. Sadly (or not, depending on how you view the discovery of an intelligent alien civilization living in our cosmic backyard), the first pass drew a blank. So, is this “case closed” for the possibility of an alien megastructure around KIC 8462852? Well, not really, but it does make a vanishingly slim chance of aliens even more vanishingly slim....
- - - - - - - -
Unlocking the mysteries of 'little starlets'
http://www.eurekalert.org/pub_releases/2...110615.php
RELEASE: Despite being discovered 20 years ago, very little is known about brown dwarfs - notably why they fail to grow into stars. Scientists say part of the answer probably lies in the physics of how dense plasmas merge inside them. Now researchers, led by the York Plasma Institute at the University of York and the UK's Science and Technology Facilities Council's (STFC) Central Laser Facility, have created "lumps" of plasma to recreate the conditions similar to those found deep inside brown dwarfs. They were able to do this using one of the world's most powerful lasers, STFC's Vulcan Petawatt that is based at their Oxfordshire laser laboratory, to create the first test of resistivity and viscosity found in brown dwarfs.
Brown dwarfs bridge the gap between very low mass stars and planets and share characteristics with both. Despite being numerous across the immensity of space, these little "starlets" are hard to spot because they are small and cool in temperature so tend to be faint and difficult to record. But by measuring the x-rays emitted from these objects, the researchers were able to build up a profile of how dense plasmas form inside brown dwarfs. The results, published in Nature Communications, pave the way towards furthering our understanding of these celestial objects.
Professor Nigel Woolsey, from the Department of Physics at York, said: "Brown dwarfs are really difficult to observe because they are cool and our atmosphere absorbs the emissions from cool objects. One of the issues you have in brown dwarfs with dense matter is how this material comes together and how hot it gets. This basic research is furthering our understanding of matter in extreme environments and furthering our understanding of exotic objects. We think, but we don't know because we can't see them, but we think there are lots of brown dwarfs about. There is a suggestion there is at least as many brown dwarfs as there are stars. There's more than a billion stars in our galaxy."
Lead author, Dr Nicola Booth, an alumna of York and now an experimental research scientist at STFC's Central Laser Facility, added: "The Vulcan Petawatt laser is one of the few places on Earth where we can produce conditions close to those at the centre of a brown dwarf. "We hope that with the predicted future observations of brown dwarfs, our experiments can help with the understanding of how energy is transported in these 'starlets'."
It is hoped NASA's premier observatory, the James Webb Space Telescope, currently under construction in the U.S will help scientists understand brown dwarfs in the future.
- - - - - - - -
GMRT discovers a dying, giant radio galaxy 9 billion light years away!
http://www.eurekalert.org/pub_releases/2...110615.php
RELEASE: A team of astronomers working at the National Centre for Radio Astrophysics (NCRA, TIFR), Pune have discovered, using the Giant Metrewave Radio Telescope (GMRT), an extremely rare galaxy of gigantic size. This galaxy -- located about 9 billion light years away towards the constellation Cetus -- emits powerful radio waves and has an end to end extent of a whopping 4 million light years! Such galaxies with extremely large 'radio size' are appropriately called giant radio galaxies.
How do galaxies with an optical size of a hundred thousand light years produce radio emission several million light years in extent? It is argued that the presence of a super massive black hole at the centre of the galaxy drives large scale jets of hot plasma in diametrically opposite directions which eventually give rise to large radio lobes (see the image). While radio galaxies with size less than a million light years are common, giant radio galaxies are extremely rare, even more so, at large cosmic distances where only a handful have been discovered so far. This newly discovered galaxy known by its scientific name 'J021659-044920' is the newest member of this elite group.
Under some special circumstances, the central black hole may stop producing the radio jet, and then the bright radio lobes fade away, within a few million years, due to lack of replenishment. What makes J021659-044920 special, is that it has been caught in this dying phase, where the radio jet appears to have switched off and the radio lobes have started fading. The fading of the lobes is caused by their losing energy in two ways, one, by emitting radio waves which show up as the gigantic radio lobes and two, by transferring energy to photons from the cosmic microwave background via a process known as inverse Compton scattering. This latter mechanism leads to faint X-ray emission, which is seen to emanate from the radio lobes of this galaxy. Such dying radio objects are best studied using a low frequency radio telescope such as the GMRT. The GMRT, the world's largest radio telescope facility operating at low radio frequencies, is an array of 30 fully steerable, 45 metre diameter antennas, spread out over a 30 km region around Khodad, near Narayangaon town of Pune district in western India. The GMRT was built and is operated by National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research and has been in operation since 2002.
For their analysis, the team combined their GMRT observations with previous observations made with a slew of international ground and space based telescope facilities -- XMM-Newton Space Telescope in X-ray, the Japanese Subaru telescope in optical, UK's Infrared Telescope in near-infrared, NASA's Spitzer Space Telescope in mid-infrared and the Jansky Very Large Array (USA) in high frequency radio bands. By using data from multiple telescopes spanning across the electromagnetic spectrum, they were able to carry out a comprehensive and incredibly detailed analysis of the physical conditions around this distant galaxy. The properties of the magnetic field in the region between galaxies in the distant universe can be understood with these observations.
http://www.space.com/31052-its-not-rocke...space.html
EXCERPT: . . . we won’t be heading to the stars in a rocket. Rockets are a terrible way of getting to space. There’s a saying in orbital mechanics: getting to orbit is halfway to anywhere. Orbit is the easiest way of going permanently to space. It’s a big first step on the way to leaving the gravity of earth behind. Being in orbit means you are balanced – between gravity pulling you down and your own momentum flinging you into outer space. You stay at the same height going round the Earth because you’re moving forward so fast that the Earth drops away below you at the same speed you fall into it. Slowing down a little returns you to the surly bonds of gravity. But speed up just a little and you can leave earth all together. Orbit is the gateway to the solar system, the galaxy, the universe. Unfortunately, this gateway happens to be about 100 miles off the floor and moving at about 20,000 mph.
[...] A UK company called Reaction Engines is working on what it calls the SKYLON spaceplane. [...] The SKYLON project relies on the development of its SABRE engine. The unique engine functions as either a plane engine or a rocket engine. The vehicle can take off from a runway like a plane (efficient) and fly as high and as fast as possible. Then the SKYLON plane switches its engines into rocket mode for the rest of its journey. The design shows enough promise that the European Space Agency and the UK Space Agency both recently invested in the concept. The company claims test flights could happen by 2019....
- - - - - - - -
Alien Megastructure? SETI Spies No Intelligent Signals
http://news.discovery.com/space/alien-li...151106.htm
EXCERPT: After all the public excitement surrounding the star KIC 8462852 and its weird transit signal as spotted by NASA’s Kepler Space Telescope, the SETI Institute decided to expedite plans to point a powerful radio antennae at the nearby star in the hope of detecting any artificial transmissions emanating from that location. Sadly (or not, depending on how you view the discovery of an intelligent alien civilization living in our cosmic backyard), the first pass drew a blank. So, is this “case closed” for the possibility of an alien megastructure around KIC 8462852? Well, not really, but it does make a vanishingly slim chance of aliens even more vanishingly slim....
- - - - - - - -
Unlocking the mysteries of 'little starlets'
http://www.eurekalert.org/pub_releases/2...110615.php
RELEASE: Despite being discovered 20 years ago, very little is known about brown dwarfs - notably why they fail to grow into stars. Scientists say part of the answer probably lies in the physics of how dense plasmas merge inside them. Now researchers, led by the York Plasma Institute at the University of York and the UK's Science and Technology Facilities Council's (STFC) Central Laser Facility, have created "lumps" of plasma to recreate the conditions similar to those found deep inside brown dwarfs. They were able to do this using one of the world's most powerful lasers, STFC's Vulcan Petawatt that is based at their Oxfordshire laser laboratory, to create the first test of resistivity and viscosity found in brown dwarfs.
Brown dwarfs bridge the gap between very low mass stars and planets and share characteristics with both. Despite being numerous across the immensity of space, these little "starlets" are hard to spot because they are small and cool in temperature so tend to be faint and difficult to record. But by measuring the x-rays emitted from these objects, the researchers were able to build up a profile of how dense plasmas form inside brown dwarfs. The results, published in Nature Communications, pave the way towards furthering our understanding of these celestial objects.
Professor Nigel Woolsey, from the Department of Physics at York, said: "Brown dwarfs are really difficult to observe because they are cool and our atmosphere absorbs the emissions from cool objects. One of the issues you have in brown dwarfs with dense matter is how this material comes together and how hot it gets. This basic research is furthering our understanding of matter in extreme environments and furthering our understanding of exotic objects. We think, but we don't know because we can't see them, but we think there are lots of brown dwarfs about. There is a suggestion there is at least as many brown dwarfs as there are stars. There's more than a billion stars in our galaxy."
Lead author, Dr Nicola Booth, an alumna of York and now an experimental research scientist at STFC's Central Laser Facility, added: "The Vulcan Petawatt laser is one of the few places on Earth where we can produce conditions close to those at the centre of a brown dwarf. "We hope that with the predicted future observations of brown dwarfs, our experiments can help with the understanding of how energy is transported in these 'starlets'."
It is hoped NASA's premier observatory, the James Webb Space Telescope, currently under construction in the U.S will help scientists understand brown dwarfs in the future.
- - - - - - - -
GMRT discovers a dying, giant radio galaxy 9 billion light years away!
http://www.eurekalert.org/pub_releases/2...110615.php
RELEASE: A team of astronomers working at the National Centre for Radio Astrophysics (NCRA, TIFR), Pune have discovered, using the Giant Metrewave Radio Telescope (GMRT), an extremely rare galaxy of gigantic size. This galaxy -- located about 9 billion light years away towards the constellation Cetus -- emits powerful radio waves and has an end to end extent of a whopping 4 million light years! Such galaxies with extremely large 'radio size' are appropriately called giant radio galaxies.
How do galaxies with an optical size of a hundred thousand light years produce radio emission several million light years in extent? It is argued that the presence of a super massive black hole at the centre of the galaxy drives large scale jets of hot plasma in diametrically opposite directions which eventually give rise to large radio lobes (see the image). While radio galaxies with size less than a million light years are common, giant radio galaxies are extremely rare, even more so, at large cosmic distances where only a handful have been discovered so far. This newly discovered galaxy known by its scientific name 'J021659-044920' is the newest member of this elite group.
Under some special circumstances, the central black hole may stop producing the radio jet, and then the bright radio lobes fade away, within a few million years, due to lack of replenishment. What makes J021659-044920 special, is that it has been caught in this dying phase, where the radio jet appears to have switched off and the radio lobes have started fading. The fading of the lobes is caused by their losing energy in two ways, one, by emitting radio waves which show up as the gigantic radio lobes and two, by transferring energy to photons from the cosmic microwave background via a process known as inverse Compton scattering. This latter mechanism leads to faint X-ray emission, which is seen to emanate from the radio lobes of this galaxy. Such dying radio objects are best studied using a low frequency radio telescope such as the GMRT. The GMRT, the world's largest radio telescope facility operating at low radio frequencies, is an array of 30 fully steerable, 45 metre diameter antennas, spread out over a 30 km region around Khodad, near Narayangaon town of Pune district in western India. The GMRT was built and is operated by National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research and has been in operation since 2002.
For their analysis, the team combined their GMRT observations with previous observations made with a slew of international ground and space based telescope facilities -- XMM-Newton Space Telescope in X-ray, the Japanese Subaru telescope in optical, UK's Infrared Telescope in near-infrared, NASA's Spitzer Space Telescope in mid-infrared and the Jansky Very Large Array (USA) in high frequency radio bands. By using data from multiple telescopes spanning across the electromagnetic spectrum, they were able to carry out a comprehensive and incredibly detailed analysis of the physical conditions around this distant galaxy. The properties of the magnetic field in the region between galaxies in the distant universe can be understood with these observations.
