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Sonntag, 31. August 2014 - 22:45 Uhr

Astronomie - Rote Sprites über New Underwood, South Dakota

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RED SPRITES AND GREEN GRAVITY WAVES: As northern summer comes to a close, electrical storms are rumbling across the USA. After nightfall, red sprites can be seen dancing across the cloudtops. On Aug. 20th, Tom A. Warner photographed these speciments above New Underwood, South Dakota:.

On the night of Aug 20th, intense storms developed in north central South Dakota, along with an ongoing mesoscale convective complex in south central North Dakota. Skies cleared out to the west and offered a chance to capture some sprites from the northern activity. I did a time-lapse from western South Dakota and captured not only sprites, but also observed convectively-generated air glow gravity waves which are luminosity ripples in the air glow region which is present due to chemiluminescence near the mesopause around 85 km. These ripples are thought to be caused by the cyclical overshooting updrafts of strong thunderstorm complexes which push momentum upward in a localized area. These air glow gravity waves, which are currently being studied by lightning research scientists, are believed to be capable of modifying the luminosity patterns of transient LUMINOUS events such as elves and halos. Canon 5D Mark III, ISO 3200, f/2, 24 mm, 10 sec exposures
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"On the night of Aug 20th, intense storms developed in north central South Dakota," says Warner. "Skies cleared out to the west and offered a chance to capture some sprites from the northern activity."
He saw not only sprites, but also green-glowing gravity waves. The waves are, literally, the ripple effect of a powerful thunderstorm on the mesosphere some 80 km above Earth's surface. From space, these waves look like a giant atmospheric bull's eye. From the ground, they appear to be green ripples in the sky, as shown in Warner's images.
Left to themselves, gravity waves would be invisible to the human eye. We see them, however, because they are colored green by an aurora-like phenomenon called "airglow." Airglow is caused by an assortment of chemical reactions in the upper atmosphere driven mainly by solar ultraviolet radiation. Gravity waves rippling away from the central axis of a thunderstorm cause temperature and density perturbations in the upper atmosphere. Speaking simplistically, those perturbations alter the chemical reaction rates of airglow, leading to more-bright or less-bright bands depending on whether the rates are boosted or diminished, respectively.
Inhabiting the upper reaches of Earth's atmosphere alongside meteors, noctilucent clouds and some auroras, sprites and mesospheric gravity waves are true space weather phenomena. Now is a good time to see them.
Quelle: Spaceweather

Tags: Astronomie South Dakota 

2330 Views

Sonntag, 31. August 2014 - 16:15 Uhr

Luftfahrt - Google testet bereits Liefer Drohnen in Australien

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Project Wing Drone Delivers Google
In rural Australia, a drone delivers dog treats to a farmer. The robot is a PROOF of concept, part of Project Wing by Google X. The program is designed to show that delivery drones are possible, and it seems to be doing just that. Next for Google: figuring out the path from proven prototype to everyday utility.
The drone is a tail-sitter, taking off vertically with its body perpendicular to the ground. At rest, it looks like a tiny spaceship from a 1930s comic BOOK. It’s a type of Vertical Takeoff or Landing (VTOL) rarely done with humans on board, because that transition, from vertical to horizontal and back again, is difficult for onboard human pilots to manage. For the drone it works fine, and the design lets the wing fly fast like a plane. It also means the drone can hover, and that’s where the delivery mechanism of Project Wing shines:
Mechanical engineer Joanna Cohen, trained at Cal Tech and MIT, designed the contraption. It consists of a few key parts. The first is the winch itself, which spools out the hi-grade fishing line. The second is the “egg,” the little gadget that goes down with the package, detects that it has reached the ground, releases the delivery, and signals that it should be cranked BACK UP to the hovering UAV. If something goes wrong, there is an emergency release mechanism at the top of the line—“basically a razor blade,” Cohen told me—that allows the UAV to cut and fly.
A working delivery mechanism is the first step for the service. With the prototype in place, the next challenge is creating an infrastructure for drones so that they can travel safely through skies without hitting other vehicles. Google’s driverless car program is an obvious touchstone for this project, but it’s a limited one. Cars on roads travel in close proximity and only move in two dimensions. Aircraft operate in vast, empty skies, and do so on three AXES. Training a car to sense and avoid other cars is simpler than doing the same for an aircraft. Still, Google’s development and prior experience with cars is a strong sign that this work will continue and ultimately yield fruit. Michael Toscano, CEO of the Association for Unmanned Vehicle Systems International, said that
Google’s announcement of its planned UAS DELIVERY SERVICE further demonstrates the potential of UAS technology. It also highlights how this technology will revolutionize industries and the importance of the FAA keeping the integration process on track.
It’s worth noting that Google tested this technology IN AUSTRALIA first. While the FAA clearly wants drones to sense and avoid other aircraft, its been slow to implement changes and create a regulatory framework that lets innovation like this happen stateside. If the drone INDUSTRYwants to change the world, it’ll need an FAA that lets it deliver. Watch the drone in action below, and read more about Project Wing at The Atlantic.
Quelle: PS

2131 Views

Sonntag, 31. August 2014 - 12:30 Uhr

Raumfahrt - CubeSat-Missionen öffnen neue Türen...

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THE FUTURE OF CUBESATS 
To investigate climate change, scientists and engineers at NASA’s Goddard Space Flight Center are develop- ing the IceCube satellite, which will be no larger than a loaf of bread. In 2016, this satellite will mature technology that scientists will use to analyze cloud ice in the atmosphere.
“We’re using IceCube to test a radiometer that we want to fly on a big space mission,” said Jeffrey Piepmeier, associate head of Goddard’s Microwave Instruments and Technology Branch. “Climate scientists have never used this frequency to measure cloud ice from space before.”
The project highlights a growing trend toward testing instru- ments and running scientific experiments aboard CubeSats. “Every pound that you send into space costs a phenomenal amount of money,” said Todd Bonalsky, an electrical engineer at Goddard. “Hence in the investment in CubeSats, which are tiny, complete satellites that are cheaper and easier to build than their larger counterparts.”
Bonalsky’s Dellingr CubeSat is slated to launch in March 2015. Employing a magnetometer system Bonalsky miniatur- ized for CubeSat use, Dellingr will measure magnetic fluctua- tions to help scientists better understand how space weather affects Earth. Dellingr will be the first CubeSat to fly this type of science grade magnetometer system.
Scientists however face a number of challenges when working on CubeSats. Because of their size, CubeSats cannot power many of NASA’s formidable scientific instruments, and there are limits to what can be miniaturized. The Hubble Space Telescope for example uses a mirror nearly eight feet wide to capture light and translate it into images that a smaller mirror could not produce.
Doug Rowland, a solar scientist at NASA, faced this dilemma when gathering data from his Firefly CubeSat. He built it to investigate the correlation between lightning and gamma radiation, but his CubeSat can only download 20 milliseconds slots of data to Earth each day. “The Firefly just doesn’t have enough electrical power to simultaneously run its GPS re- ceiver, its communications antenna and our experiment at the same time,” Rowland said. “On a big spacecraft, you’d have a thousand times as much data, at least, and you’d have other ways to transmit the data down to Earth.”
Despite such drawbacks, the size and cost of CubeSats open up new strategies for scientific investigations. In conventional missions, every component must function exactly as designed, but, depending on the mission, a single CubeSat is expend- able.
“Instead of pouring money into one big satellite, we try to make a swarm,” said Robert Clayton, a Goddard intern from Dartmouth College. “It’s okay if we lose two or three from our swarm of 20. We instead focus on making each CubeSat as cheap and reproducible as possible.”
CubeSats can thus slash a scientific mission’s budget and allow scientists to measure multiple data points that would be unobtainable otherwise.
Using multiple spacecraft for a single mission is by no means a novel concept. The Solar Terrestrial Relations Observatory for example is a pair of nearly identical observatories that trace solar matter as it flows from the sun. However losing one of these expensive observatories would spell catastrophe for the mission, as opposed to losing one CubeSat in a swarm.
Advances in the mobile phone industry opened the door
for smaller solar panels and more efficient batteries. NASA develops such technology both to advance methods of cost- effective data collection and to test technology that will lead to larger missions down the road. Pioneering CubeSat missions may open new doors in the future of space exploration. n
Opposite: Three cans of soda would fill the Firefly CubeSat to the brim. But don’t let its size fool you—NASA has big plans for these tiny satellites. Photo credit: NASA/Goddard/Bill Hrybyk
Below: Todd Bonalsky holds the solar panel that will power the Dellingr satellite. Photo credit: NASA/Goddard/kristen Basham
Quelle: NASA

Tags: Raumfahrt 

2273 Views

Sonntag, 31. August 2014 - 11:45 Uhr

Luftfahrt - NASA-Studie Flugsystem GL-10 Greased Lightning

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Testing Electric Propulsion
On Aug. 19, National Aviation Day, a lot of people are reflecting on how far aviation has come in the last century. Could this be the future – a plane with many electric motors that can hover like a helicopter and fly like a plane, and that could revolutionize air travel?
Engineers at NASA's Langley Research Center in Hampton, Va., are studying the concept with models such as the unmanned aerial system GL-10 Greased Lightning. The GL-10, which has a 10-foot wingspan, recently flew successfully while tethered. Free-flight tests are planned in the fall of 2014.
This research has helped lead to NASA Aeronautics Research Mission Directorate efforts to better understand the potential of electric propulsion across all types, sizes and missions for aviation.
Quelle: NASA

Tags: Luftfahrt 

2090 Views

Sonntag, 31. August 2014 - 11:00 Uhr

Raumfahrt - Die Funken fliegen, wie NASA die Grenzen der 3-D-Drucktechnologie pusht

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Engineers just completed hot-fire testing with two 3-D printed rocket injectors. Certain features of the rocket components were designed to increase rocket engine performance. The injector mixed liquid oxygen and gaseous hydrogen together, which combusted at temperatures over 6,000 degrees Fahrenheit, producing more than 20,000 pounds of thrust.

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NASA has successfully tested the most complex rocket engine parts ever designed by the agency and printed with additive manufacturing, or 3-D printing, on a test stand at NASA's Marshall Space Flight Center in Huntsville, Alabama.
NASA engineers pushed the limits of technology by designing a rocket engine injector --a highly complex part that sends propellant into the engine -- with design features that took advantage of 3-D printing. To make the parts, the design was entered into the 3-D printer's computer. The printer then built each part by layering metal powder and fusing it together with a laser, a process known as selective laser melting.
The additive manufacturing process allowed rocket designers to create an injector with 40 individual spray elements, all printed as a single component rather than manufactured individually. The part was similar in size to injectors that power small rocket engines and similar in design to injectors for large engines, such as the RS-25 engine that will power NASA's Space Launch System (SLS) rocket, the heavy-lift, exploration class rocket under development to take humans beyond Earth orbit and to Mars.
"We wanted to go a step beyond just testing an injector and demonstrate how 3-D printing could revolutionize rocket designs for increased system performance," said Chris Singer, director of Marshall's Engineering Directorate. "The parts performed exceptionally well during the tests."
Using traditional manufacturing methods, 163 individual parts would be made and then assembled. But with 3-D printing technology, only two parts were required, saving time and money and allowing engineers to build parts that enhance rocket engine performance and are less prone to failure.
Two rocket injectors were tested for five seconds each, producing 20,000 pounds of thrust. Designers created complex geometric flow patterns that allowed oxygen and hydrogen to swirl together before combusting at 1,400 pounds per square inch and temperatures up to 6,000 degrees Fahrenheit. NASA engineers used this opportunity to work with two separate companies -- Solid Concepts in Valencia, California, and Directed Manufacturing in Austin, Texas. Each company printed one injector.
"One of our goals is to collaborate with a variety of companies and establish standards for this new manufacturing process," explained Marshall propulsion engineer Jason Turpin. "We are working with industry to learn how to take advantage of additive manufacturing in every stage of space hardware construction from design to operations in space. We are applying everything we learn about making rocket engine components to the Space Launch System and other space hardware."
Additive manufacturing not only helped engineers build and test a rocket injector with a unique design, but it also enabled them to test faster and smarter. Using Marshall's in-house capability to design and produce small 3-D printed parts quickly, the propulsion and materials laboratories can work together to apply quick modifications to the test stand or the rocket component.
"Having an in-house additive manufacturing capability allows us to look at test data, modify parts or the test stand based on the data, implement changes quickly and get back to testing," said Nicholas Case, a propulsion engineer leading the testing. "This speeds up the whole design, development and testing process and allows us to try innovative designs with less risk and cost to projects."
Marshall engineers have tested increasingly complex injectors, rocket nozzles and other components with the goal of reducing the manufacturing complexity and the time and cost of building and assembling future engines. Additive manufacturing is a key technology for enhancing rocket designs and enabling missions into deep space.
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Quelle: NASA

2134 Views

Samstag, 30. August 2014 - 23:40 Uhr

Astronomie - Hubble sieht Licht und Dunkelheit im Universum

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This new NASA/ESA Hubble Space Telescope image shows a variety of intriguing cosmic phenomena.
Surrounded by bright stars, towards the upper middle of the frame we see a small young stellar object (YSO) known as SSTC2D J033038.2+303212. Located in the constellation of Perseus, this star is in the early stages of its life and is still forming into a fully-grown star. In this view from Hubble’s Advanced Camera for Surveys(ACS) it appears to have a murky chimney of material emanating outwards and downwards, framed by bright bursts of gas flowing from the star itself. This fledgling star is actually surrounded by a bright disk of material swirling around it as it forms — a disc that we see edge-on from our perspective.
However, this small bright speck is dwarfed by its cosmic neighbor towards the bottom of the frame, a clump of bright, wispy gas swirling around as it appears to spew dark material out into space. The bright cloud is a reflection nebula known as [B77] 63, a cloud of interstellar gas that is reflecting light from the stars embedded within it. There are actually a number of bright stars within [B77] 63, most notably the emission-line star LkHA 326, and it nearby neighbor LZK 18.
These stars are lighting up the surrounding gas and sculpting it into the wispy shape seen in this image. However, the most dramatic part of the image seems to be a dark stream of smoke piling outwards from [B77] 63 and its stars — a dark nebula called Dobashi 4173. Dark nebulae are incredibly dense clouds of pitch-dark material that obscure the patches of sky behind them, seemingly creating great rips and eerily empty chunks of sky. The stars speckled on top of this extreme blackness actually lie between us and Dobashi 4173.
Quelle: ESA/NASA

Tags: Astronomie 

2138 Views

Samstag, 30. August 2014 - 16:30 Uhr

UFO-Forschung - IFO-Universität: Ufo-Queen Venus

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Venus: The debunker’s myth?
Arecent posting by Kevin Randle on his blog, revealed that Brad Sparks has begun to question various “debunker’s” attempts to use Venus as a source of UFO reports. He specifically made the accusation that Allan Hendry either created a hoax or was fooled into repeating a lie told by an FAA official.
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Hoax, exaggeration, or true story?
Kevin Randle’s blog entry, written by Brad Sparks, took issue with a quote that appears in Allan Hendry’s UFO Handbook. On page 27 and 102, Hendry makes the following quote from an FAA official at the Detroit airport:
Do you know how many times we’ve cleared Venus to land?1
Sparks says the answer to this question is “Zero” because Venus would never respond to any attempt to give clearance so it can neverbe“clearedtoland”. HealsonotesthatthereisnocasenumberforthisincidentinHendry’sbooksoitwasneverreallyinves- tigated.
I think Sparks is taking the quote far too literally in his commentary. It appears to have been a poor choice of words by the official or Hendry simply misquoted him. The statement seems to have been made in a joking manner to reflect the observation by Hendry that he was aware that Venus had been misidentified by air traffic controllers. Apparently, Sparks found no humor in it.
In the NOVA program, “The case for the UFOs”, Hendry repeats this story with a slightly different description:
I suppose my favorite Venus story was the time that I was working with Air Traffic Controllers at a large metropolitan airport here in the United States, who were expecting the arrival of a flight in the eastern sky during dawn hours. And...uh... when they caught sight of Venus out the control tower windows, they started radioing to the planet, “clearance to land”.2
So, it really was not a matter of giving clearance but attempting to give clear- ance for Venus to land.
It wasn’t just Hendry that was guilty of repeating this story. Dr. Hynek also made a similar statement. In an interview with Barb Martinec, which ap- peared in the La Grange Suburban Life Citizen on November 4, 1978, Hynek was quoted as giving the following statement:
An air traffic controller told me ‘You’d be surprised how many times we’ve given Venus permission to land, “he said.3
Was he basing this on what Hendry told him or was he making the statement based on his personal experience? We don’t know but it seems that Air Traffic Controllers confusing Venus with an approaching aircraft is something that both Hendry and Hynek believed had happened.
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Some examples of Venus being mistaken for something other than a celestial object. Going from top to bottom and left to right we see that Venus was mistaken for an airship4, a Japanese plane at night5, a high altitude balloon6, A Zeppelin7, Japanese Balloon Bombs8, and Apollo 16/a piece of the moon/or an object going to strike the moon9.
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Sparks has suggested that because there are no specifics of these events, the case may be a hoax perpetrated by Hendry or the air traffic controller. The objective of this hoax was to humiliate UFO witnesses. I agree with Sparks that there are no specifics here and it is nothing more than an anecdotal claim. However, to draw the conclusion that this was some sort of hoax, without any evidence other than belief, is not looking at this objectively.
I find it hard to believe that Hendry, Hynek, or the unnamed Air Traffic Controller/FAA official were thinking of ways to humiliate UFO witnesses when they made this statement. It seems more likely that the individual was telling Hendry or Hynek that they sometimes did confuse Venus for the landing lights of an airplane.
A brief history of Venus misidentified
Venus started to play a role as a misidentified object starting with the advent of the aviation era (see newspaper clippings above). During the airship wave of 1897, there were several reports that were made that indicated Venus was a source. Witnesses, who heard about these “airships” in the news papers, went outside in the evening, looked up, and saw the planet prominent in the west- ern evening sky. Like today, the “man in the street”, was probably not aware of what was visible in the evening sky. When you look for an “airship” with an electric light and see a bright light in the sky, it was easy to draw the conclusion that Venus was the “airship” light. Venus does not explain all the airship sightings but there are too many coincidences to ignore the possibility that some of these sightings were of Venus.
During both World Wars, Venus was misidentified as a plane, balloon, or Zeppelin. Witnesses were more than willing to believe that Venus was a hostile aircraft of some kind. There are examples of ships and bomber crews attempting to shoot down Venus thinking it was some sort of enemy aircraft. Nervous airmen, sailors, and civilians, who were concerned about enemy aircraft saw the planet and determined it to be what they feared.
My first exposure to how Venus could be misidentified occurred shortly after I began to become involved in amateur astronomy. 
On April 16, 1972, Apollo 16 had been launched and was on its way to the moon. That evening, Venus was close to the crescent moon. I remember seeing this and reading the papers the next day, where many people across the nation thought they had seen the Apollo 16 capsule on the way to the moon. Others thought it was something else. Like the examples involving the airship waves and World Wars, people saw what they wanted to see. Is it any surprise that people, who want to see UFOs are going to misidentify Venus as a UFO or, in the case of Hendry/Hynek’s anecdote, a potential aircraft lining up for a landing?
On April 16, 1972, Apollo 16 had been launched and was on its way to the moon. That evening, Venus was close to the crescent moon. I remember seeing this and reading the papers the next day, where many people across the nation thought they had seen the Apollo 16 capsule on the way to the moon. Others thought it was something else. Like the examples involving the airship waves and World Wars, people saw what they wanted to see. Is it any surprise that people, who want to see UFOs are going to misidentify Venus as a UFO or, in the case of Hendry/Hynek’s anecdote, a potential aircraft lining up for a landing?
Venus as a UFO report generator
Sparks’ article seems to imply that whatever Hendry wrote about UFOs can not be trusted. This would include the fact that a great many of Hendry’s UFO cases were determined to be stars and planets. Venus being a UFO report generator is not just something that has been mentioned only by Hendry. I have found several prominent UFOlogists agree with this conclusion over the years based on their own personal experience.
Jaques Vallee - No single object has been misinterpreted as a ‘flying saucer’ more often than the planet Venus.10
Raymond Fowler - The four brightest planets - Venus, Jupiter, Mars and Saturn - are also often reported as UFOs. Of these four, Venus is the chief culprit....11
Frank Salisbury - Many of the UFOs I have studied have turned out to be the planet Venus; other stars and planets have sometimes accounted for other UFOs. 12
It has been my opinion that when Venus is prominent in the evening sky a certain percentage of UFO reports are probably caused by it. However, is this just an opinion or is it a fact? Unfortunately, the Mutual UFO Network (MUFON) and National UFO Reporting Cen- ter (NUFORC), who have UFO databases available on-line, do not list any conclusions to their investigations of these UFO reports. In order to see how often Venus was possibly reported as a UFO, I chose to examine these databases.
I went to the NUFORC and MUFON web sites to examine the reports between October 1 and 14, 2013. As an additional test, I exam- ined the reports submitted to NUFORC between March 7 and 17th of 2012. During that time period, Jupiter and Venus were close together (see image above) and, in my opinion, should have generated a significant number of UFO reports that would be easy to identify. The results were interesting.
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Many of these raw reports are missing additional data that could positively identify the source. I tried to take an objective approach in my numbers and I would like to point out that in my first pass of the NUFORC October 1-14 cases, I identified 35 potential Venus sightings. However, after closer examination of the sighting descriptions, I determined that only 15 were “probably Venus” (note: Probably means in my subjective opinion). Many of the others did not contain sufficient information to indicate Venus was the source or the descriptions indicated the report was not Venus.
As one final test, I decided to sample the ten day period from November 26 to December 5th using the NUFORC database16. During this time period, Venus was approaching greatest brilliancy. Out of 210 reports I examined, 19 were probably Venus. This is roughly nine percent, indicating that the percentage of UFO reports generated by Venus is a function of when Venus is most prominent.
Larry Hatch’s UFO database
Larry Hatch’s database is a collection of raw UFO reports, which he has attempted to analyze for trends. One of his most interest- ing comparisons is his plot of the number of UFO sightings with the proximity of Venus to the Earth. Using a database of 16976 reports, we discover that when Venus was at superior and inferior conjunction with the sun, the number of UFO reports dropped significantly (679 and 633). 17
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Using these numbers, one could draw the conclusion that Venus appears to play a significant role in the number of UFO sightings when it is most prominent. The spikes of sightings around greatest brilliancy are significant and appear to agree with my ten day sample in late November/early December 2013.
Still the queen of UFOs
Based on what many UFO investigators seem to indicate, and what these raw numbers appear to reveal, Venus does appear to play a significant role in producing UFO reports. This does not mean that all UFO reports are produced by Venus. To suggest such is folly. It just means that Venus is something that has to be considered as a potential source when it is visible. There is little reason to reject Hendry’s findings about Venus in his book. We can, and should, question the story about air traffic controllers at- tempting to clear Venus to land but, based on what we know about Venus and UFO reports, we should not consider it a hoax.
More importantly, to ignore Venus as a potential source in any UFO sighting, especially when the witness does not mention seeing it, is ignoring what is known about how witnesses often mistake Venus for something other than a celestial object. When a UFO report is generated, the first thing a UFO investigator should ask is, “Could it have been Venus?”
Quelle: SUNlite 1/2014

Tags: UFO-Forschung 

2179 Views

Samstag, 30. August 2014 - 11:03 Uhr

Astronomie - Samstag früh, Near-Earth Object (NEO) 2002 CU11 im Teleskop zu sehen

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The track of the NEO through Taurus during its closest approach on 30 August (times BST). AN graphic by Greg Smye-Rumsby.
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Early Saturday morning, the Near-Earth Object (NEO) 2002 CU11 has a close shave with our planet, passing within 13.5 lunar distances or 5,191,046 kilometres.
Soon after its discovery 12 years ago by the one-metre Lincoln Near-Earth Asteroid Research (LINEAR) telescope it was recognised as a potentially hazardous object. It's thought to have a 1-in-9,400 chance of hitting the Earth in 2049.
The asteroid is around 730 metres in diameter and at its brightest on 30 August it will be magnitude +13.9, bright enough to be visible in a 200-250-mm telescope. CCD imagers can follow it up to close approach at 4.14am BST (0314 UT) when it's moving towards the southern border of Taurus and almost 30 degrees above the south-eastern horizon from the UK.
Quelle: AN

1964 Views

Samstag, 30. August 2014 - 10:48 Uhr

Astronomie - Astrophysiker entdecken radioaktives Kobalt in Supernova-Explosion

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A group of astrophysicists, including researchers from MIPT, have DETECTED the formation of radioactive cobalt during a supernova explosion, lending credence to a corresponding theory of supernova explosions. Details are given in the journal Nature, one of the most cited scientific publications in the world.
The article’s main author, Yevgeny Churazov (Space Research Institute of the Russian Academy of Sciences), together with his co-authors, including Sergei Sazonov of the Space Research Institute and MIPT, REPORTED the results of their analysis of data collected with the INTEGRAL gamma-ray orbital telescope, which they used to detect the radioactive isotope cobalt-56(56Co).
Isotope 56Co has a half-life of just 77 days, and does not exist in normal conditions. However, during a giant thermonuclear explosion of a supernova, this short-lived radioactive isotope is produced in large quantities.
RADIATING cobalt was registered at the supernova SN2014J, located 11 million light-years from Earth.
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A radioactive decay chain and the spectrum obtained by the INTEGRAL observatory. Note the scale of the vertical axis – about one gamma quantum an hour per 1cm2! Image courtesy of the press service of the Nuclear Research Institute.
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Astrophysicists never obtained similar spectra before. The reason was the rarity of explosions at such a distance – 11 million light-years is a large value on the galactic scale (the diameter of a galaxy is about 100,000 light-years, the distance between stars is a few light-years), but on an intergalactic scale it is a relatively short distance. There are SEVERAL hundreds of galaxies within a radius of ten million light-years; supernovae produce explosions like this (type Ia explosions) once every few centuries in a galaxy. For example, a type Ia supernova last exploded in the Milky Way in 1606.
SN2014J was registered on January 21, 2014 by astronomer Steve Fossey and a group of students from UNIVERSITY COLLEGE London in the galaxy M82. Fossey reported the discovery, and several observatories, including INTEGRAL, started observations immediately. Russian researchers spent a million seconds of their quota for the use of the INTEGRAL telescope to study the supernova. In addition to the spectra, they obtained data on how the brightness of RADIATION changes over time.
According to a theory that was developed earlier, during an explosion of the Ia type, the remnants of a star barely radiate in the gamma range the first dozens of days. The star’s shell is opaque in this region of the spectrum; a supernova begins to produce gamma RADIATION only after the outer layer becomes sufficiently rarefied. By that time, radioactive nickel-56 with a half-life of 10 days, synthesized during the explosion, transforms into radioactive cobalt-56, the lines of which were detected by the researchers.
The essence of spectral analysis remains unchanged whatever the nature of RADIATION. For light, X-rays and even radio waves, scientists first plot a graph of a spectrum, or the relationship of intensity and frequency (or, equivalently, wavelength: wavelength is inversely proportional to frequency).
The graph’s shape indicates the nature of the source of RADIATION and through what environment the radiation has passed. Spectral lines, or sharp peaks on such graphs, correspond to certain events like the emission or absorption of quanta by atoms during transition from one energy level to another.
During formation, cobalt-56 had a surplus of energy, exhausted in the form of gamma rays with energies of 847 keV and 1237keV; other isotopes produced radiation with quanta of different energies and thus could not be confused with cobalt-56.
The data collected by the INTEGRAL telescope also allowed the researchers to assess how much radioactive cobalt was emitted during the explosion – the equivalent of about 60% of the Sun’s mass.
Over time, cobalt-56 turns into the most common isotope of iron, 56Fe.56Fe is the most common isotope because it can be obtained from nickel emitted during supernovae explosions (nickel turns into cobalt, and cobalt turns into iron).
Thus, the new results BACK UP simulations of supernovae explosions and also confirm that our planet consists of matter that has gone through thermonuclear explosions of an astronomical scale.
MIPT’s press service would like to thank the press service of the Space Research Institute and personally Olga Zakutnaya. This article is based on a press release provided by the institute.
Quelle: Moscow Institute of Physics and Technology

Tags: Astronomie 

2077 Views

Samstag, 30. August 2014 - 10:35 Uhr

Astronomie - Stardust Mission enthüllt Geheimnisse des Raumstaubs

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This story was originally reported by Kate Greene of Berkeley National Laboratory.
The first analysis of space dust collected by a special collector onboard NASA's Stardust mission and sent back to Earth for study in 2006 suggests the tiny specks open a door to studying the origins of the solar system and possibly the origin of life itself.
This is the first time synchrotron light sources have been used to look at microscopic particles caught in the path of a comet. The Advanced Photon Source, the Advanced Light Source, and the National Synchrotron Light Source at the U.S. Department of Energy's Argonne, Lawrence Berkeley and Brookhaven National Laboratories, respectively, enabled analysis that showed that the dust, which likely originated from beyond our solar system, is more complex in composition and structure than previously imagined.
"Fundamentally, the solar system and everything in it was ultimately derived from a cloud of interstellar gas and dust," says Andrew Westphal, physicist at the University of California, Berkeley's Space Sciences Laboratory and lead author on the paper published this week in Science titled "Evidence for interstellar origin of seven dust particles collected by the Stardust spacecraft". "We're looking at material that's very similar to what made our solar system."
The analysis tapped a variety of microscopy techniques including those that rely on synchrotron radiation. "Synchrotrons are extremely bright light sources that enable light to be focused down to the small size of these particles while providing unprecedented chemical identification," said Hans Bechtel, principal scientific engineering associate at Berkeley Lab.
The APS helped the researchers create a map of the locations and abundances of the different elements in each tiny particle, said Argonne physicist Barry Lai, who was involved with the analysis at the APS.
"The Advanced Photon Source was unique in the capability to perform elemental imaging and analysis on such small particles — just 500 nanometers or less across," Lai said. (That is so small that about 1,000 of them could fit in the period at the end of a sentence.) "This provided an important screening tool for differentiating the origin of each particle."
Researchers used the scanning transmission x-ray and Fourier transform infrared microscopes at the ALS. The X-ray microscope ruled out tens of interstellar dust candidates because they contained aluminum, not found in space or other substances and possibly knocked off the spacecraft and embedded in the aerogel. The infrared spectroscopy helped to identify sample contamination that could ultimately be subtracted later.
"Almost everything we've known about interstellar dust has previously come from astronomical observations — either ground-based or space-based telescopes," says Westphal. But telescopes don't tell you about the diversity or complexity of interstellar dust, he says. "The analysis of these particles captured by Stardust is our first glimpse into the complexity of interstellar dust, and the surprise is that each of the particles are quite different from each other."
Westphal, who is also affiliated with Berkeley Lab's Advanced Light Source, and his 61 co-authors, including researchers from the University of Chicago and the Chicago Field Museum of Natural History, found and analyzed a total of seven grains of possible interstellar dust and presented preliminary findings. All analysis was non-destructive, meaning that it preserved the structural and chemical properties of the particles. While the samples are suspected to be from beyond the solar system, he says, potential confirmation of their origin must come from subsequent tests that will ultimately destroy some of the particles.
"Despite all the work we've done, we have limited the analyses on purpose," Westphal explains. "These particles are so precious. We have to think very carefully about what we do with each particle."
Between 2000 and 2002, the Stardust spacecraft, on its way to meet a comet named Wild 2, exposed the special collector to the stream of dust coming from outside our solar system. The mission objectives were to catch particles from both the comet coma as well as from the interstellar dust stream. When both collections were complete, Stardust launched its sample capsule back to earth where it landed in northwestern Utah. The analyses of Stardust's cometary sample have been widely published in recent years, and the comet portion of the mission has been considered a success.
This new analysis is the first time researchers have looked at the microscopic particles collected en route to the comet. Both types of dust were captured by the spacecraft's sample-collection trays, made of an airy material called aerogel separated by aluminum foil. Three of the space-dust particles (a tenth the size of comet dust) either lodged or vaporized within the aerogel while four others produced pits in the aluminum foil leaving a rim residue that fit the profile of interstellar dust.
Much of the new study relied on novel methods and techniques developed specifically for handling and analyzing the fine grains of dust, which are more than a thousand times smaller than a grain of sand. These methods are described in twelve other papers available now and next week in the journal of Meteoritics & Planetary Science.
One of the first research objectives was to simply find the particles within the aerogel. The aerogel panels were essentially photographed in tiny slices by changing the focus of the camera to different depths, which resulted in millions of images eventually stitched together into video. With the help of a distributed science project called Stardust@home, volunteer space enthusiasts from around the world combed through video, flagging tracks they believed were created by interstellar dust. More than 100 tracks have been found so far, but not all of these have been analyzed. Additionally, only 77 of the 132 aerogel panels have been scanned. Still, Westphal doesn't expect more than a dozen particles of interstellar dust will be seen.
The researchers found that the two larger dust particles from the aerogel have a fluffy composition, similar to that of a snowflake, says Westphal. Models of interstellar dust particles had suggested a single, dense particle, so the lighter structure was unexpected. They also contain crystalline material called olivine, a mineral made of magnesium, iron, and silicon, which suggest the particles came from disks or outflows from other stars and were modified in the interstellar medium.
Three of the particles found in the aluminum foil were also complex, and contain sulfur compounds, which some astronomers believe should not occur in interstellar dust particles. Study of further foil-embedded particles could help explain the discrepancy.
Westphal says that team will continue to look for more tracks as well as take the next steps in dust analysis. "The highest priority is to measure relative abundance of three stable isotopes of oxygen," he says. The isotope analysis could help confirm that the dust originated outside the solar system, but it's a process that would destroy the precious samples. In the meantime, Westphal says, the team is honing their isotope analysis technique on artificial dust particles called analogs. "We have to be super careful," he says. "We're doing a lot of work on analogs to practice, practice, practice."
The Advanced Photon Source is currently in the process of designing a proposed upgrade that would increase its ability to do such analyses, Lai said.
"With the APS upgrade, we would be able to increase the spatial resolution and to image faster — effectively scanning a larger area of the aerogel in a shorter time," he said.
Since just over half of the aerogels have been checked for particles, there are plenty more waiting to be analyzed.
This research was supported by NASA, the Klaus Tschira Foundation, the Tawani Foundation, the German Science Foundation, and the Funds for Scientific Research, Flanders, Belgium. In addition to ALS, the research made use of the National Synchrotron Light Source at Brookhaven National Laboratory and the Advanced Photon Source at Argonne. All three x-ray light sources are DOE Office of Science User Facilities.
Quelle: Argonne National Laboratory

Tags: Astronomie 

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