Space & Science discoveries

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Big Venus and small Jupiter: Galileo’s astronomical puzzle is solved after 400 years





Scientists have finally come up with an explanation for a visual illusion that was first identified in the 16 Century by Galileo Galilei who noticed how large the planet Venus appears to the naked eye when compared to Jupiter – which is quite the reverse when seen through a telescope.

Venus is nearer to Earth than Jupiter and therefore appears brighter in the night sky, however this alone cannot account for its larger-than-life appearance. There must be another reason to do with the way the eye perceives light compared to the optical reality of a telescope, scientists said.

Viewed directly with the naked eye, Venus appears to have a “radiant crown” which makes it look eight to ten times bigger than Jupiter even though Jupiter is four times larger when seen from Earth.

Galileo was the first to realise that this radiant crown was something to do with human perception, or, as he described it, an “impediment of our eyes” which the telescope eliminated, but he put it down to some kind of optical interference to the light from the planets as the light entered the human eye.

However, scientists have now shown that the effect is caused by the way the light-sensitive cells at the back of the eye respond to images of different intensity set against a dark background. Venus appears larger because its brighter-than-Jupiter image is much exaggerated by the visual centres of the brain to create a bigger radiant crown than Jupiter’s, according to the study published in the journal Proceedings of the National Academy of Sciences.

They believe the effect influences the way we see everything because the human retina and brain are finely tuned to respond to the contrast between light objects against a dark background. This makes them appear larger than light objects of the same size set against a light background, said Jose-Manuel Alonso of the State University of New York College of Optometry.

“Galileo was the first to say that our eye was distorting reality. He could see that Venus appeared to be much larger than Jupiter when seen with the naked eye and that the opposite was true when he looked through his telescope,” Dr Alonso said.

Galileo said that the effect was some kind of size illusion created by the eyes. “Either because their light is refracted in the moisture that cover the pupil, or because it is reflected from the edges of the eyelids and these reflected rays are diffused over the pupil, or for some other reasons,” Galileo wrote.

The 19 Century German physicist Hermann von Helmholtz came nearer to the truth when he said that the “irradiation illusion”, as he called it, was caused by our sensation of the object and not by the optics of the eye.

“The latest research demonstrates that the sensation Helmholtz used to explain the irradiation illusion is a ‘non-linear’ response of the visual system when objects are presented on dark backgrounds,” Dr Alonso explained.

The edges of a light object appear blurred and this is effectively magnified by the brain so that the entire object appears bigger than it should. Venus, being nearer to Earth, is brighter than Jupiter and so it appears bigger against the dark background of the night sky, he said.

source independent
 
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    A Ring Around The Moon



    You’ve seen pictures of the planet Saturn, surrounded by its system of rings, but would you be surprised if you looked up at night to see a ring around the moon?

    In fact, it’s sometimes possible to see just this. There’s even a folk rhyme about it: When there’s a ring around the moon, rain or snow is coming soon. Is there really, sometimes, a ring around the moon?

    An Optical Illusion

    Unlike Saturn, which has actual, physical rings, the ring you can sometimes see around the moon is merely an optical illusion.

    It’s an effect of our own atmosphere that meteorologists call a “halo effect,” because diffracted light rays create a halo around a bright object.

    How It Works

    Moon halos are caused by tiny ice crystals that have gathered twenty thousand feet above the ground, as thin, wispy clouds. These clouds are so thin, you might not notice them at night, if it weren’t for their effect on the moonlight. Incoming light rays from the moon are bent, or diffracted, by these ice crystals at an angle of 22 degrees.

    This means that in addition to the direct moonlight, you will also see diffracted moonlight in a circle 22 degrees away from the moon. This is about the distance of your fist, held at arm’s length.

    Like a rainbow, this halo can even be slightly colored; red on the inside, and blue on the outside.

    Yes, it can mean that rain or snow is coming soon. Those high, wispy clouds could be the forerunners of storm clouds right behind them.

    source indiana
     
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    Spitzer's Orion




    Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away.

    This stunning false-color view spans about 40 light-years across the region, constructed using infrared data from the Spitzer Space Telescope. Compared to its visual wavelength appearance, the brightest portion of the nebula is likewise centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But the infrared image also detects the nebula's many protostars, still in the process of formation, seen here in red hues. In fact, red spots along the dark dusty filament to the left of the bright cluster include the protostar cataloged as HOPS 68, recently found to have crystals of the silicate mineral olivine within its protostellar envelope.
     
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    Jade Rabbit lunar rover alive after all, says China



    China’s troubled Jade Rabbit lunar rover has come back to life, a day after it was declared dead from a combination of mechanical troubles and extreme cold on the moon, according to state media.

    “It came back to life! At least it is alive and so it is possible we could save it,” the official Xinhua news agency quoted Pei Zhaoyu, spokesman for the lunar programme, as saying on a verified account on Sina Weibo, a Chinese equivalent of Twitter.

    The probe, named Yutu or Jade Rabbit after the pet of Chang’e, the goddess of the moon in Chinese mythology, had ground to a halt with a “mechanical control abnormality” last month, provoking an outpouring of sympathy from weibo users.

    Concerns were raised that the vehicle would not survive the bitter cold of the lunar night. An unverified Weibo user “Jade Rabbit Lunar Rover”, which has posted first-person accounts in the voice of the probe, made its first update since January, when it had declared: “Goodnight, Earth. Goodnight, humans.”

    “Hi, anybody there?” it said on Thursday, prompting thousands of comments within minutes.

    “The Jade Rabbit went into sleep under an abnormal status,” Pei said, according to Xinhua. “We initially worried that it might not be able to bear the extremely low temperatures during the lunar night.”
    Xinhua has said the Weibo account is “believed to belong to space enthusiasts who have been following Yutu’s journey to the moon”. Other reports said amateur radio astronomers had picked up radio downlink signals from the rover.

    The Jade Rabbit was deployed on the moon’s surface on 15 December, several hours after the Chang’e-3 probe carrying it landed. It was the third such soft-landing in history and the first of its kind since a Soviet Union mission nearly four decades ago. Consequently it was a huge source of pride in China.

    China first sent an astronaut into space a decade ago and is the third country to complete a lunar rover mission after the United States and the Soviet Union.

    The landing was a key step forward in Beijing’s ambitious military-run space programme, which includes plans for a permanent orbiting station by 2020 and eventually sending a human to the moon.

    source Guardian
     
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    Supernova scrutiny: Astronomers look inside the heart of a dying star for the first time



    For the first time ever astronomers have been able to look inside the heart of an exploding star, using a space telescope to peer into the radioactive corpse of Cassiopeia A, a star that was once eight times the size of the Sun.

    “This has been a holy grail observation for high energy astrophysics for decades,” said Steven Boggs, chair of physics at UC Berkeley and co-author of the paper published in the journal Nature.

    “For the first time we are able to image the radioactive emission in a supernova remnant, which lets us probe the fundamental physics of the nuclear explosion at the heart of the supernova like we have never been able to do before.”

    Supernovae are a key mechanism in the formation of the Universe as we know it, creating a wide array of ‘heavy’ elements via nucleosynthesis and ejecting this matter deep into the cosmos. In fact, the shock waves from supernovae can even trigger the formation of new stars – making these explosions part of the Universe’s most awe-inspiring ‘life cycle’.

    "People should care about supernova explosions because that's where all the stuff that makes us comes from," Brian Grefenstette, lead author on the paper and a research scientist at the California Institute of Technology, told CNN.

    “All of the iron in your blood and calcium in your bones and teeth, and gold in your wedding band, that all comes from the center of a supernova explosion."


    Superimposed images of the Cas A supernova remnant taken by NASA’s Chandra and NuSTAR orbiting telescopes. Red and green patches are iron and silicon/magnesium, respectively, while blue shows the distribution of titanium. However, although scientists have long known about the importance of supernovae in creating matter, they’ve been unable to get a closer look at the process that causes them to explode.

    Supernovae occur when stars many time the size of our Sun run out of fuel, leaving behind a dense iron core that collapses in on itself, a process that can happen at velocities reaching 70,000 km/s and that causes a shockwave, expelling gas and dust into space. We can see existing stars and supernova remnants but the moments in between are much more mysterious.

    "It's like you blink your eyes twice, and the whole thing has exploded, and we're seeing it three or four hundred years later, preserved in the radioactive ash," said Grefenstette.

    This latest research used the NuSTAR telescope (short for Nuclear Spectroscopic Telescope Array) astronomers have been able to analyse a previously unexamined section of the X-ray spectrum in supernova remnant Cassiopeia A, a well-observed stellar explosion first spotted in 1947.

    Other telescopic arrays such as the Hubble Space Telescope and Chandra X-Ray Observatory are only capable of looking at low-energy X-ray trails from elements like iron, but the NuSTAR was able to map the movement of the high-energy element, titanium-44, within the cosmic explosion of Cassiopeia A.

    The observations captured by NuSTAR have led the astronomers to believe that the explosion was shaped by pressure inside the iron core of the dying star “sloshing” about; an asymmetrical process (below) that could explain why supernova remnants look so crooked compared to the spherical stars they once were.


    Grefenstette compares the process to the top blowing off a pressure cooker, with the subsequent shockwave tearing the matter of the star apart and leaving behind the uneven splashes and smears of matter we now see.

    "We think that these large bubbles, which were formed in the first fraction of a second as the star collapsed, have been preserved for hundreds of years like a fossil record in the radioactive ash of the explosion," said Grefenstette, describing the trails of titanium-44 that have been newly mapped.

    These observations have helped astronomers rule out previous theories about how stars explode, but NuSTAR’s measurements have also raised further questions. The astronomers found that the map of titanium-44 recorded by the telescope does not match up with the map of iron created by other telescopes – even though both elements are supposed to have come from the same ‘bubbles’ of pressure.

    This may mean that there is simply some iron that hasn’t been detected by the telescopes (they can only observe the element when it is hot) or that there some other process within the supernova creating these elements. It is perhaps unsurprising that even when we can look within the heart of a dying star, it creates more questions than answers.

    source Independent
     
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    Astronomers find new dwarf planet - and hints of a much larger one hidden on the edge of the Solar System



    Astronomers have discovered a new small planet at the edge of the Solar System and in the process have received tantalising support for the idea that there may be a much larger planet still waiting to be discovered even further away.

    In a separate development, another team of researchers have startled seasoned sky watchers by finding an asteroid with its own orbiting ring system similar to the famous rings of Saturn.

    The two sets of discoveries, published together in the journal Nature, are both surprising additions to the known Solar System and show that there is still much to be learned about our own cosmic back-yard.

    The new dwarf planet, prosaically named 2012 VP113, has a solar orbit that takes it beyond the furthest known edge of the Solar System but its remote location suggests a gravitational influence from a much larger planet perhaps ten times the size of Earth still waiting to be found, scientists said.

    Only one object, another small planet named Sedna, was previously known to exist in this remote part of the Solar System. However, whereas the outer boundary of Sedna’s orbit is 76 times the distance between the Earth and the Sun, the closet orbit of 2012 VP113 to the Sun is 80 times the distance.

    “This is an extraordinary result that redefines our understanding of our Solar System,” said Linda Elkins-Tanton of Carnegie Institution, which took part in the discovery.

    The new planet is estimated to be 450km in diameter, compared to the 1,000km-wide Sedna, and could be part of a constellation of orbiting objects known as the inner Oort Cloud, which exists beyond the edge of the Kuiper Belt, a band of icy asteroids that orbit further out than the planet Neptune.

    “The search for these distant inner Oort Cloud objects beyond Sedna and 2012 VP113 should continue as they could tell us a lot about how our Solar System formed and evolved,” said Scott Sheppard of the Carnegie Institution, who made the discovery with Chad Trujillo of the Gemini Observatory in Hawaii.

    “Some of these inner Oort Cloud objects could rival the size of Mars or even Earth. This is because many of the inner Oort Cloud objects are so distant that even very large ones would be too faint to detect with current technology,” Dr Sheppard said.



    Meanwhile, a second team of researchers have discovered an icy asteroid surrounded by a double-ring system similar to the rings of Saturn. Only three other planets – Jupiter, Neptune and Uranus – were known to have rings.

    The scientists made the discovery within the 20 seconds it took for the asteroid to pass in front of a distant star. The existence of the rings emerged in the form of two extra dips in light intensity as the rings on each side of the asteroid interrupted the starlight reaching the earth .

    Martin Dominik of the University of St Andrews, who was part of the team, said that the rings around the 250km-wide asteroid, called Chariklo, are seven and three kilometres wide respectively with an eight kilometre gap in between. They were observed by telescopes at seven locations across South America including the European Southern Observatory at La Silla, Chile.

    “We did not even dare to dream about finding a ring, let alone two. That took us by complete surprise, and we actually do not know why they are there,” Dr Dominik said.

    The rings probably consist of pebbles and icy particles formed from some kind of collision with the asteroid in the past. The scientists suggest that the asteroid may be in a similar evolutionary stage to the early Earth, after a Mars-like object collided with it to form a ring of orbiting debris that eventually coalesced into the Moon.

    Felipe Braga-Ribas of the National Observatory in Brazil, who was the lead author of the study, said: “We weren’t looking for a ring and didn’t think small bodies like Chariklo had them at all, so the discovery and the amazing amount of detail we saw in the system came as a complete surprise.”

    “So, as well as the rings, it’s likely that Chariklo has at least one small moon still waiting to be discovered,” Dr Braga-Ribas said.

    source Independent
     
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    Something new under the sun

    A miniature planet sheds light on the extremities of the solar system



    MODERN telescopes can see things billions of light-years away, so it may seem surprising that there remains anything to be discovered in the Earth’s backyard. But there is. On March 27th, for example, in a paper published in Nature, Chadwick Trujillo of the Gemini Observatory, in Hawaii, and Scott Sheppard of the Carnegie Institution for Science, in Washington, DC, announced that they have found a new member of the sun’s retinue, in a part of the solar system of which astronomers know little.

    The object in question, thought to be 450km across and provisionally dubbed 2012VP113, is much farther away than Neptune, the icy world that is the most distant of the sun’s proper planets. Neptune is about 30 astronomical units from the sun (an astronomical unit, or AU, is the average radius of Earth’s orbit, about 150m kilometres). The highly elliptical orbit followed by 2012VP113 brings it no closer to the sun than 80 AU. At its most distant, though this is hard to estimate until more data are available, it may be as much as 500 AU away.

    This orbit puts 2012VP113 much farther out even than the Kuiper belt, a collection of icy asteroids beyond the orbit of Neptune in which Pluto (which was booted out of the planetary club in 2006) makes its home. Instead, the two researchers suggest their find is a member of the inner part of the Oort cloud, a collection of dwarf planets, asteroids and comets thought—but not yet proved—to surround the sun, and which may extend as much as half of the four light-year distance to Alpha Centauri. The Oort cloud is believed to be the source of many comets. But some models of how the solar system works suggest there ought to be a gulf of empty space between the Kuiper belt’s edge and the Oort cloud’s beginning, somewhere around 10,000 AU from the sun. Uncomfortably for those models, 2012VP113 sits in that gap.

    The Oort-cloud-gap theory has already taken one hit. In 2003 Mike Brown, of the California Institute of Technology, discovered a dwarf planet called Sedna, 1,000km across, travelling in an orbit (see diagram) similar to that of 2012VP113—exactly where it should not have been, in other words. Finding one such body could have been a fluke. A second, though, “strongly suggests that the inner Oort Cloud is real”, according to Megan Schwamb, of the Institute for Astronomy and Astrophysics, in Taiwan, who worked with Dr Brown.

    Regardless of whether Sedna and 2012VP113 are part of an inner Oort cloud, their weird orbits need explaining. They have probably not been like that from the start. The sun and its retinue condensed from a rotating disc of gas and dust, and anything produced this way should have ended up in a more-or-less circular orbit, such as those the modern planets follow.

    One idea is that the two eccentrics were kicked into their orbits by a close encounter with Neptune (which is how the Kuiper belt is thought to have been created). That seems unlikely, though, for both are too far from Neptune for its gravity to have had much influence on them.

    Another theory is that they were forced into their current orbits during the solar system’s youth, perhaps by a close encounter with another star that formed in the same nebula as the sun. If so, then they have probably orbited undisturbed ever since, and may thus provide a window onto the earliest years of the solar system.

    Elliptical thinking

    There is, however, a more intriguing possibility. Sedna, 2012VP113 and a handful of smaller objects share similar values of a particular orbital characteristic called the “argument of perihelion”, which describes the angle that their orbits form with the plane of the solar system. Computer models suggest these angles should be randomly distributed. So far, they do not seem to be. And that is a puzzle. According to Drs Trujillo and Sheppard, one possible explanation is that the gravity of something big, distant and unseen is marshalling the orbits of these smaller hunks of rock. The two researchers say their data are compatible with the idea of a giant planet lurking in the far reaches of the solar system.

    “Compatible with” is not the same as “proof of”, of course. Unlike the makers of science-fiction films, most astronomers are sceptical of “Planet X” hypotheses, of which there have been plenty over the years. So far only one has proved correct—Neptune itself, whose existence was inferred in the 19th century from irregularities in the orbit of Uranus. But things should become clearer in the not-too-distant future, when new telescopes more capable of spotting dim, distant objects come into operation. When these get going, they will probably find that Earth’s backyard holds plenty more surprises.

    source economist
     
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    Solar flare captured in incredible Nasa footage


    Nasa’s Solar Dynamics Observatory has released incredible footage of a flare erupting from the sun.

    The powerful bursts of radiation appear in the clip as sudden, swirling, bursts of brightness. Captured on 2 April 2014, the flares reached their peak at 15:05 GMT, according to the space agency.

    “The image shows the flare in a blend of two wavelengths of extreme ultraviolet light: 131 Angstroms and 171 Angstroms, colorized in yellow and red, respectively,” explained Nasa on its website.

    The space agency confirmed that the solar flares were classed at M6.5, or mid-level. The strongest flares are labelled X Class, and are 10 times more powerful than Wednesday’s eruption.

    The ‘M’ corresponds to the strength of the flare, with an ‘M2’ being twice as intense as an M1, an M3 is three times as intense, according to Nasa.

    The agency said that the explosions are not harmful to humans as they cannot penetrate the Earth’s atmosphere.

    However, if intense enough, the clouds of electrons, ions and atoms that are shot into the Earth’s atmosphere during solar flares can sometimes disrupt GPS and communications signals, including mobile phone service.

    The effects usually take around a day or so to materialise.

    How the earth is being impacted can be monitored via the US’ National Ocean and Atmospheric Administration website, Nasa advised.

    source independent
     
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    Hubble unveils a colourful view of the Universe




    Astronomers using the Hubble Space Telescope have captured the most comprehensive picture ever assembled of the evolving Universe — and one of the most colourful. The study is called the Ultraviolet Coverage of the Hubble Ultra Deep Field (UVUDF) project.

    Prior to this survey, astronomers were in a curious position. They knew a lot about star formation occurring in nearby galaxies thanks to UV telescope facilities such as NASA's Galex observatory, which operated from 2003 to 2013. And, thanks to Hubble's near-infrared and visible capability, they had also studied star birth in the most distant galaxies. We see these distant galaxies in their most primitive stages due to the vast amount of time it takes their light to reach us.

    However, between 5 and 10 billion light-years away from us — corresponding to a time period when most of the stars in the Universe were born — there was a lack of the data needed to fully understand star formation. The hottest, most massive and youngest stars, which emit light in the ultraviolet, were often neglected as subjects of direct observation, leaving a significant gap in our knowledge of the cosmic timeline.

    The addition of ultraviolet data to the Hubble Ultra Deep Field using Hubble's Wide Field Camera 3 gives astronomers access to direct observations of regions of unobscured star formation and may help us to fully understand how stars formed. By observing at these wavelengths, researchers get a direct look at which galaxies are forming stars and, just as importantly, where the stars are forming. This enables astronomers to understand how galaxies like the Milky Way grew in size from small collections of very hot stars to the massive structures they are today.

    The patch of sky in this image has been previously studied by astronomers in a series of visible and near-infrared exposures taken from 2004 to 2009: the Hubble Ultra Deep Field. Now, with the addition of ultraviolet light, they have combined the full range of colours available to Hubble, stretching all the way from ultraviolet to near-infrared light. The resulting image, made from 841 orbits of telescope viewing time, contains approximately 10 000 galaxies, extending back to within a few hundred million years of the Big Bang.

    Since the Earth's atmosphere filters most ultraviolet light, this work can only be accomplished with a space-based telescope like Hubble. Ultraviolet surveys like this are incredibly important in planning for the James Webb Space Telescope (JWST) as Hubble is the only telescope currently able to obtain the ultraviolet data that researchers will need to combine with infrared data from JWST.

    The Hubble Ultra Deep Field 2014 image is a composite of separate exposures taken from 2003 to 2012 with Hubble's Advanced Camera for Surveys and Wide Field Camera 3.

    http://www.spacetelescope.org/news/heic1411/
     
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    'Magic island' appears out of nowhere on Titan, Saturn's biggest moon, then quickly disappears


    Scientists are baffled by images of planet-like Titan’s second largest sea, which appear to show an island materialise then disappear



    A “magic island” has mysteriously appeared out of nowhere in one of the hydrocarbon seas on Saturn's giant planet-like moon, Titan, only to later disappear.

    Described as a bright “transient feature” by scientists, it is not clear what the object is, or how it appeared there. Theories include that it could be the result of waves or bubbles, or even buoyant solid matter.

    The sea had appeared flat and completely devoid of features, including waves prior to 2013. But then the object, dubbed “magic island” by scientists, suddenly materialised before vanishing in later images.

    The object was spotted in Ligeia Mare, Titan's second-largest sea, by radar images. The Cassini space probe which captured it has been exploring the Saturnian system since 2004.

    Planetary scientist Jason Hofgartner, from Cornell University in New York City, said: “This discovery tells us that the liquids in Titan's northern hemisphere are not simply stagnant and unchanging, but rather that changes do occur.

    “We don't know precisely what caused this 'magic island' to appear, but we'd like to study it further.”

    Titan is the only object in the universe other than Earth which is known to have proven bodies of stable surface liquid.



    Rather than water, the seas and lakes are however made up of liquid ethane, methane, and propane, and are thought to hold hundreds of times more natural gas and other hydrocarbons than the entire known oil and natural gas reserves on Earth.

    Beneath Titan's thick, hazy atmosphere, scientists have also discovered icy mountains and dunes made from organic “sand”. Like Earth, Titan has seasonal weather systems, with wind and rain carving out landscapes similar to that on our planet.

    It is from this changing in seasons which astronomers believe strange feature may arise.

    The main theories argue that the island like object is the result of waves formed by heavy winds, bubbles formed by gases pushing out from the sea floor or floating solids.

    “Likely, several different processes - such as wind, rain and tides - might affect the methane and ethane lakes on Titan,” said Mr Hofgartner. “We want to see the similarities and differences from geological processes that occur here on Earth.

    “Ultimately, it will help us to understand better our own liquid environments.”

    Huygens, a European Space Agency probe deployed from Cassini, landed on Titan in January 2005 - the first spacecraft landing ever accomplished in the outer Solar System. The craft touched down on a flat, damp, sandy plain covered with ice pebbles.

    source Independent
     
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    Fireballs in space: Amazing video shows Nasa's 'flame extinguishment experiment' in action



    This is what a fireball looks like in space: first there’s ignition, and then a miniature sun blossoms in mid-air. It flares for a second and then fades away, exiting stage-left in a series of pulse like a ghostly jellyfish.

    This amazing footage was captured by astronaut Reid Wiseman and as part of Nasa’s ongoing 'Flame Extinguishment Experiment' - a project dedicated to examining the behaviour of flames in microgravity in order to find better ways to extinguish fires in space.

    Wiseman, who is also responsible for the first Vine from space, posted the clip three days ago with the caption - "Forgot to thank @ISS_Research for this amazing video - floating sphere of fire comes alive in FLEX-2.”

    The fireball itself was created by igniting a small drop of ethanol or heptane in the microgravity of the ISS. While flames on Earth form vertical shapes thanks to the upward pull of hot air, the lack of gravity in orbit around the planet means that fire naturally becomes dome-shaped or spherical.

    Although these flames look tranquil when compared to their flickering, Earth-bound cousins,they're actually much more dangerous - not simply due to their location but also because they survive for longer with less oxygen and are resistant to gas-based extinguishers.

    Nasa's research is not only looking for safer ways to put out fires in space, it's also hoping that observations made onboard the ISS will eventually help engineers here on Earth - especially insights into so-called "cool flames" - fires that burn at lower temperatures producing fewer air pollutants.

    video + source Independent
     
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    NASA gets rare glimpse at black hole





    Scientists have caught a better-than-ever view of the way that black holes can drag space and time around with them as they spin, a finding that could lead to new understanding of Einstein's theory of relativity.

    Nasa’s Nuclear Spectroscopic Telescope Array (NuSTAR) captured the effect when a compact source of X-rays, known as the corona, moved towards the black hole and was pulled into it. That blurred and stretched the X-rays, a phenomenon that is rarely captured and has never been studied in such detail before.

    Some of the light that falls into supermassive black holes is never seen again, but other high-energy light comes from the corona and a disk of superheated material that surrounds it.

    Scientists don’t know the shape and temperature of coronas — though artists have produced sketches of how the formations could look — but know that they contain particles that move close to the speed of light.

    The light shining from the corona lit the part of the black hole that scientists were studying, which the agency described as almost as if a torch had been shone on the exact place they were looking at.

    The black hole involved is known as Markarian 335, and is about 324 million light-years from Earth. The mass of around 10 million of our suns is packed into a space only 30 times as big, and the spinning black hole pulled space and time around with it.

    Studying the blurring could help scientists to better understand black hole coronas, which until now have been mysterious.


    The telescope's findings. The blue line shows what scientists would have expected with no blurring, the yellow if blurring was present, and the white dots show what the telescope captured. Source: NASA/JPL-Caltech/Institute for Astronomy, Cambridge

    It might also help demonstrate some of the effects described in Einstein’s theory of relativity, because of the particles’ speed.

    "NuSTAR's unprecedented capability for observing this and similar events allows us to study the most extreme light-bending effects of general relativity," said Fiona Harrison, who is NuSTAR principal investigator and based at the California Institute of Technology.

    source independent
     
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    'Alien thigh bone' on Mars: Excitement from alien hunters at 'evidence' of extraterrestrial life





    More than two years into the Curiosity rover’s lonely trek across Mars, conspiracy theorists believe they’ve struck gold: an ‘alien thigh bone’ has been spotted on the surface of the red planet.

    For keen alien hunters, the image above - taken by the rover’s MastCam on August 14 – is proof that large animals once roamed Mars, possibly even dinosaurs.

    “Simply put this shows that there were some living things on the Mars (sic),” asserts an anonymous editorial writer at Northern Voices Online, while the popular site UFO Blogger compares the find to previous images of a “fossilized, reptilian spine” and a “human finger”.

    The regularity of these ‘finds’ is of course testament not to the once-flourishing wildlife of Mars, but to the human brain’s remarkable capacity to spot patterns in random noise.

    This was a handy trait for our ancestors when identifying a potential predator among the primeval foliage, but in modern times it’s more likely to lead only to those little ‘huh’ moments when we spot a face in some inanimate object.

    Of course, there is some truth to conspiracy theorists’ hopes of life on Mars, with scientists pointing out last year that the asteroid impact that killed of the dinosaurs could have flung rocks carrying organic matter to the red planet some 66 million years ago.

    Unfortunately, at this point (and for roughly 3 billion years prior) Mars was a barren place with no flowing water. However, if the microorganisms from Earth had hitched a ride to somewhere a little more hospitable, like Europa then it could be a different matter altogether.

    source independent
     
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    ‘Extreme’ solar storm is heading straight for Earth following ‘giant magnetic explosion’ on the Sun





    A massive explosion on the Sun has sent a solar storm heading straight for Earth, experts have said, which may disrupt communications equipment and power grids when it strikes.

    The solar flare registered in the “extreme” band on the scale used by forecasters – a magnitude not seen by observers for a number of years.

    Originating from a collection of sunspots right in the centre of our nearest star, it poses a direct threat because “it’s pointed right at us”, according to experts at the Space Weather Prediction Center in Boulder, Colorado.

    Observed late on Wednesday, the storm is moving towards Earth at a medium-to-fast rate of about 2.5 million mph (4.02 million kph), said forecaster Tom Berger, meaning the soonest it can arrive is early on Friday (US time).

    "There's been a giant magnetic explosion on the sun," Berger said. "Because it's pointed right at us, we'll at least catch some of the cloud" of highly energized and magnetized plasma that can disrupt Earth's magnetic sphere, which sometimes leads to temporary power grid problems,

    Berger nonetheless added that the worst effects of the storm are likely to narrowly miss Earth, passing over the North Pole.

    It could still cause disturbances in satellite and radio transmissions, though, and will have a significant impact on Earth’s magnetic field.

    While a warning has been issued, Berger said “we’re not scared of this one”, and issued a reminder that solar storms don’t directly harm people.

    There is a positive aspect to the storm’s arrival, despite the communications concerns.

    From Friday morning and over the weekend, we can expect the displays of the Northern Lights (Aurora Borealis) to be particularly bright and colourful, and visible unusually far south.

    source independent
     
    EuroMode

    EuroMode

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    Is Pluto about to be reinstated as a planet?





    There were once nine planets. Everyone learned them, sometimes aided by a mnemonic: “My Very Excellent Mother Just Sent Us Nine Pizzas.”

    But back in 2006, the International Astronomical Union (IAU), arbiter of what is and what isn’t a planet, stripped Pluto of its status, saying it was too small to pack sufficient gravitational punch. It was downgraded to a new, second-class status: “dwarf planet.”

    So then there were eight: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, or “My Very Excellent Mother Just Served Us Nachos.”

    The decision did not sit well with the public. Some amateur stargazers and some astronomers thought it rather arbitrary. As the Harvard-Smithsonian Center for Astrophysics put it in a press release, “a dwarf fruit tree is still a small fruit tree, and a dwarf hamster is still a small hamster.”

    But recently the Harvard-Smithsonian Center did something about it: It held a debate — pro and con — and let the audience vote. The result: “Pluto IS a planet.”

    The debate centered around the IAU’s demands of a planet — that it must:

    be in orbit around the Sun,
    be round or nearly round, and
    be shown to have “cleared the neighborhood” around its orbit, be gravitationally dominant in its area — the big kid on the block.
    Pluto was originally kicked out because it did not “clear the neighborhood.” It is indeed small. It has a radius of about 750 miles — less than 20 per cent of the Earth’s radius. Its circumference is about 4,500 miles, which makes it smaller than the moon. You could fly around its equator faster than flying from Washington, DC, to Hawaii.

    According to a release from the centre, Owen Gingerich, who chaired the IAU planet definition committee, presented the historical viewpoint. He said Pluto is a planet, and “a planet is a culturally defined word that changes over time.” Gareth Williams, associate director of the Minor Planet Center, presented the IAU’s viewpoint — that Pluto is not a planet. And Dimitar Sasselov, director of the Harvard Origins of Life Initiative, “presented the exoplanet scientist’s viewpoint.”

    Sasselov argued, among other things, that the criteria for planethood was sun-centric, excluding planets beyond our solar system, or so-called “exoplanets.” He offered an alternative definition: A planet, he argued, is “the smallest spherical lump of matter that formed around stars or stellar remnants.” That opened up a lot of possibilities, one of them clearly being the reinstatement of Pluto.

    When the unrecorded voice vote was taken, Sasselov’s new definition prevailed.

    Of course, the vote doesn’t bind anyone. But, for Pluto enthusiasts, it’s a start.

    source independent
     
    EuroMode

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    Virgin Galactic space rocket crash: Richard Branson’s dream of space tourism suffers setback after Mojave crash kills test pilot





    Sir Richard Branson’s bid to take paying customers into space has suffered a major blow, after a test flight of a Virgin Galactic spacecraft crashed in southern California, with early reports suggesting one pilot had been killed and another seriously injured.

    SpaceShipTwo, the flagship of the British billionaire’s commercial spaceflight venture, took off on a test flight yesterday morning from the Virgin Galactic Base, at the Mojave Air and Space Port, a little under 100 miles north-east of Los Angeles.

    The craft is designed to be carried aloft by a partner plane, called WhiteKnightTwo, to an altitude of 50,000ft, at which point it peels away and fires its rockets to fly on into sub-orbit alone. Witnesses on the ground said shortly after detaching from WhiteKnightTwo, a little past 10am, SpaceShipTwo suffered a mid-air explosion, which Virgin described as an “in-flight anomaly”.

    Two test pilots equipped with parachutes were thought to be on board the spacecraft, and local authorities said one had died, while the other managed to eject from the plane and was transported to hospital with “moderate to major” injuries.

    The incident puts a large dent in the ambitions of Sir Richard and Virgin Galactic, and could prove to be a public-relations disaster for the nascent space-tourism industry as a whole. Virgin Galactic is one of the leading firms in the commercial space race. Yet the launch date for Virgin’s first commercial flight has been repeatedly put back, with some experts sceptical about its chances of launching at all.

    More than 800 prospective space tourists have already parted with around $200,000 (£125,000) for the privilege of being on an early Virgin Galactic flight; the two-hour trips will include five minutes of weightlessness. The passenger list reportedly includes Justin Bieber, Angelina Jolie and Professor Stephen Hawking. Until the accident, Sir Richard and his children were expected to be aboard SpaceShipTwo’s first commercial flight sometime in 2015. Sir Richard tweeted yesterday, “Thoughts with all @virgingalactic & Scaled. I’m flying to Mojave immediately to be with the team”.

    Earlier this year, Virgin Galactic unveiled a partnership with Nasa to undertake a commercial research flight on the spacecraft, which completed its first powered test flight in April 2013. As part of the long-running test programme, the craft’s flights had been edging ever closer to the fringes of space. Before yesterday’s crash, the firm suggested SpaceShipTwo might make its first trip to an outer-space altitude – 62 miles – before the end of this year.

    Yesterday’s flight, conducted by Virgin Galactic’s aerospace partner Scaled Composites, was SpaceShipTwo’s 55th flight, and the 35th time it had detached from its carrier plane to fly alone. However, it was only the fourth time the craft had fired its rockets – the first such test since January. In the meantime, engineers had altered the make-up of its rocket fuel, from a rubber-based to a plastic-based compound, in a bid to improve the performance.



    The last time SpaceShipTwo completed a successful test flight was on 7 October, when it glided unpowered back to the Mojave Space Port from 50,000ft. According to NBC News, yesterday’s flight faced a delay of at least three hours as the Virgin ground team made sure the weather was suitable for a test flight. The twin craft were finally cleared for take-off at 9.19am. WhiteKnightTwo then took 45 minutes to carry SpaceShipTwo to 50,000ft before the two planes split and SpaceShipTwo fired its rockets, apparently with fatal results.

    “Virgin Galactic’s partner Scaled Composites conducted a test flight of SpaceShipTwo earlier today,” said a statement on the Virgin Galactic website. “During the test, the vehicle suffered a serious anomaly resulting in the loss of the vehicle. Our first concern is the status of the pilots, which is unknown at this time.”

    “Space is hard, and today was a tough day,” said George Whitesides, CEO of Virgin Galactic, at a press conference. “We believe we owe to the folks who were flying these vehicles to understand this and to move forward, which is what we’ll do.” WhiteKnightTwo later landed safely.

    source independent
     
    EuroMode

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    Stunning Nasa image reveals surface of Saturn's Titan moon


    The image suggests that one of Titan's seas was once much larger



    US space agency Nasa has released a stunning image revealing the polar seas on one one of Saturn’s moons alongside sun glints for the first time.

    Shot by Nasa’s Cassini spacecraft in late August, the image shows sun light reflecting off Titan's swirling surface.

    Titan is the largest of Saturn’s 53 official moons, and is the second largest moon in the Solar System, after Jupiter’s Ganymede. With a diameter 50 per cent larger that Earth’s moon, Titan is mainly composed of water, ice and rocky material while its atmosphere is largely nitrogen.

    In the past, Cassini has captured separate images of the polar seas and the sun shining against them (as show below), but this is the first time both have been seen together in the same view.


    A specular reflection on Titan (Nasa)


    Hydrocarbon lakes on Titan. (Nasa)

    The sun's glint, also called a specular reflection, appears in the image as the bright area near the 11 o'clock position on the upper left. This mirror-like reflection, known as the specular point, is in the south of Titan's largest sea, Kraken Mare, just north of an island archipelago separating two separate parts of the sea.

    The image is also particularly special because the sun’s glint appears much higher than in has in previous collections of data.

    And when the image was captured, the sun’s glint was so bright that it saturated the detector of Cassini's Visual and Infrared Mapping Spectrometer (VIMS) instrument. Because it was so bright, this glint was visible through the haze at much lower wavelengths than before, down to 1.3 microns.

    From the image, scientists understand that the Kraken Mare sea was larger at some point in the past, but has since evaporated.

    This is revealed by the southern portion of the Kraken mare - the area surrounding the specular feature toward upper left – which has a “bathtub ring” made of material left behind after the methane and ethane liquid evaporated – similarly to the saline crust which remains on a salt flat.

    But the snap is not a photograph, but rather an image comprised of ‘real colour information’ in wavelengths that correspond to atmospheric windows through which Titan's surface is visible, according to Nasa. The unaided human eye would see nothing but haze.

    Cassini captured this image by flying by Titan, with the area seen immediately to the right of the sunglint being the highest resolution data collected. It reveals the labyrinth of channels that connect Kraken Mare to another large sea, Ligeia Mare.

    Ligeia Mare itself is partially covered in its northern reaches by a bright, arrow-shaped complex of clouds. The clouds are made of liquid methane droplets, and could be actively refilling the lakes with rainfall.

    source independent
     
    J. Abizeid

    J. Abizeid

    Well-Known Member

    https://plus.google.com/+NASA/posts/YTXTHAH4XBV?pid=6080796069892177634&oid=102371865054310418159



    Earlier this morning, the European Space Agency's Rosetta Mission deployed its comet lander, "Philae." Seven hours later at 11 a.m. EST, the experiment-laden, harpoon-firing Philae is set to touch down on the surface of comet 67P/Churyumov-Gerasimenko.

    It will be the first time in history that a spacecraft has attempted a soft landing on a comet. Rosetta is an international mission led by the European Space Agency (ESA), with instruments provided by its member states, and additional support and instruments provided by NASA.

    NASA Television will provide live coverage from 9-11:30 a.m. EST of Rosetta scheduled landing of a probe on a comet today. NASA's live commentary will include excerpts of the ESA coverage and air from 9-10 a.m. EST. NASA will continue carrying ESA's commentary from 10-11:30 a.m. EST. ESA’s Philae (fee-LAY) lander is scheduled to touch down on comet 67P/Churyumov-Gerasimenko at 10:35 a.m. EST. A signal confirming landing is expected at approximately 11:02 a.m. EST.

    After landing, Philae will obtain the first images ever taken from a comet's surface. It also will drill into the surface to study the composition and witness close up how a comet changes as its exposure to the sun varies. Philae can remain active on the surface for approximately two-and-a-half days. Its “mothership” is the Rosetta spacecraft that will remain in orbit around the comet through 2015. The orbiter will continue detailed studies of the comet as it approaches the sun and then moves away. NASA has three of the 16 instruments aboard the orbiter.

    Comets are considered primitive building blocks of the solar system that are literally frozen in time. They may have played a part in "seeding" Earth with water and, possibly, the basic ingredients for life.

     
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    EuroMode

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    Black hole as massive as 12 billion suns found, could change theories of how universe began



    A giant black hole, as massive as 12 billion suns, has been found by astronomers and seems to be growing far too fast.

    The black hole is not the biggest that is known, but is far bigger than scientist would expect to be at its age. It got to its huge size 875 million years after the big bang – which scientists wouldn’t expect to happen, since black holes grow as they age and eat other gas and stars that surround them.

    Scientists can only see it at that age – 12.8 billion years ago, and 6 per cent of the age of the current universe – because it is so far away. They also can’t look at it directly, because the power of its gravity sucks everything including light into it – but the team that found it saw it by spotting a quasar, an object that gets lit up as it’s heading into the black hole.


    In a paper reporting their finding, published in Nature and reported in National Geographic, the scientists behind the study say that the finding could change our understanding of how black holes form. It is thought that black holes begin when the first stars collapsed, about 100 million years after the big bang, and that they swelled after that.

    But the newly-found black hole is too big to have happened that way, according to Bram Venemans of the Max Planck Institute for Astronomy, who writes a commentary on the new study.

    Other possibilities include a merging of galaxies, bringing two different black holes together. But that depends on the two having the same mass, or they would have cast each other aside rather than merging.

    Instead, it’s possible that the first stars that helped create those black holes were huge – as much as a million suns packed into one star. If they collapsed early on, they could have “they could jump-start the formation of very large black holes,” said Loeb.

    While that would explain the surprising formulation of the newly-discovered black hole, it depends on such huge stars ever existing. Scientists hope that they can find out whether they did when they send the new James Webb Space Telescope into orbit in 2018

    source independent
     
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