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Sonntag, 5. Juni 2016 - 21:45 Uhr

Luftfahrt-History - 1945: Curtiss XP-55 Ascender

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Aus dem CENAP-Archiv:

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Quelle: CENAP-Archiv


Tags: Luftfahrt 

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Sonntag, 5. Juni 2016 - 20:45 Uhr

Raumfahrt - Was braucht es, ein NASA-Astronaut zu werden?

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HOUSTON, TEXAS—
For many aspiring space explorers around the world, becoming an astronaut is a childhood dream.
But have you ever wondered how one becomes a NASA astronaut? As with most things, it begins with filling out an application.
The National Aeronautics and Space Administration (NASA) received a record-breaking 18,300 applications when it announced it was looking to fill its 2017 Astronaut Candidate program.
The U.S. space agency said it will take 18 months to select eight to 14 applicants to join a new class of astronauts. The odds of getting selected are less than 0.08 percent, which makes getting into this program 65 times harder than getting into Harvard University, which has an acceptance rate of 5.2 percent.
No easy task
Selection Manager Anne Roemer said the process is no easy task.
“It’s very hard; we will do it very carefully. It starts by us reviewing all the files to make sure they meet the basic qualifications, and we actually utilize our current team of astronauts to come in and review the files as well," Roemer said.
Applicants must be a U.S. citizen and have a bachelor’s degree in engineering, biological science, physical science, computer science or mathematics. They also need at least three years of related experience or at least 1,000 hours as a jet airplane pilot.
Along with being able to pass a physical, NASA likes applicants to have certain personality traits.
“I think leadership, teamwork, the ability to both work on a team, lead a team, but also be a follower on a team," Roemer said. "Communication certainly plays a role, so it’s some pretty common skills that I think translate into even other professions.”
About 120 applicants will be invited to the Johnson Space Center in Houston for a first round of interviews. About half of them will be invited back for a second round.
Two-year training period
Once astronaut candidates are selected, they must successfully complete a two-year training period.
Roemer said they will learn a "little bit of everything about spaceflight, whether that’s systems training, they also do Russian language training, they will do EVA, Extravehicular Activities (spacewalks) training. They do a little bit of everything in that two-year window before moving into mission specific training.”
This group of astronauts may fly on three new spacecraft that are currently being developed, including NASA’s Orion, which is aimed at deep space exploration. If all goes well, NASA plans to send humans to Mars in the 2030s.
For people who are interested in pursuing a career in space, Roemer offers some advice.
“The piece of advice we always like to tell young folks that are interested is to pick a career that you are passionate and enthusiastic about, because you tend to do well with things you like, and being an astronaut would be the icing on the cake to hopefully otherwise a very fulfilling career," she said.
Since 1959, when the first group of seven astronauts were selected from the military, only 338 others have been chosen as NASA astronauts.
Quelle: Voice of America

Tags: Raumfahrt ein NASA-Astronaut zu werden? 

1367 Views

Sonntag, 5. Juni 2016 - 20:15 Uhr

Raumfahrt - Die Quantenkommunikation im Raum kann technisch machbar sein.

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Quantum weirdness survives space travel
Photons sent to satellite and back maintain cryptography ability
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QUANTUM MESSAGES  Scientists used a telescope (shown) to direct photons to satellites and then measure the photons’ quantum properties on their return. The green laser visible in the image is used to track the location of the satellite. The scheme shows that quantum communication in space may be technologically feasible.
In a feat that demonstrates the feasibility of using satellites to transmit uncrackable quantum messages, scientists have measured the quantum properties of photons sent to space and back again.
Physicists beamed the blips of light up to a satellite that reflected them back to Earth. Upon the photons’ return, the team, led by Paolo Villoresi of the University of Padua in Italy, observed a property known as quantum interference. That confirmed that the particles’ quantum traits remained intact over the 5,000-kilometer space voyage. The team reports the advance in a paper to be published in Physical Review Letters.
The technique could one day lead to quantum cryptography by satellite,allowing users to send snoop-proof encryption keys for encoding secret information. “It’s important for the sake of secure communication and advancement of physics,” says Villoresi. But that’s not the only reason he took on the challenge. “I can more honestly say that it’s cool.”
Quantum interference is a fact of life for tiny particles like photons. Just as ripples in a pond can interfere with one another, increasing or decreasing in height as they collide, quantum particles — which have wavelike properties — can interfere with themselves (SN Online: 9/15/14). This interference amplifies or diminishes the probability that a particle will appear at a particular time or place.
To produce the quantum interference, the scientists first split photons in two — a feat that is possible because quantum mechanical particles can be in two places at once, a state known as a superposition. The scientists sent light pulses through an optical apparatus, designed so that each photon traversed two paths simultaneously before recombining at the other side. But because one of the paths was longer than the other, when a photon came out the other end, it was split into two packets, one lagging a few billionths of a second behind the other. Such a state is known as a temporal superposition.
A satellite-tracking telescope, located at the Matera Laser Ranging Observatory in Italy, then beamed the photons up to an orbiting satellite equipped with reflectors that bounced the photons back in the direction they came from. The photons returned to the telescope and traveled back through the optical setup into a detector. Due to quantum interference, the distribution of the photons’ arrival times differed from that expected in the nonquantum case. And the amount of interference varied depending on the velocity of the satellite — in agreement with scientists’ predictions.
“It’s quite challenging to make these links between a satellite and Earth station,” says physicist Hugo Zbinden of the University of Geneva, who was not involved with the research. Scientists have previously transmitted photons’ quantum properties via satellite, but those photons were in polarization superpositions — the photons’ electric fields were oriented in two directions at once. Temporal superpositions have some advantages over polarization superpositions. For instance, the polarization might be lost when the photon bounces off the satellite, Zbinden says.
The new result indicates that quantum communication can work outside of pristine laboratory environments. “Whether this could survive such long distances and harsh experimental conditions, that was a big question,” saysphysicist Alexander Sergienko of Boston University. “Everybody else is doing this either in the lab or kind of in a quiet environment somewhere.” 
Quelle: ScienceNews

Tags: Raumfahrt 

1353 Views

Sonntag, 5. Juni 2016 - 19:20 Uhr

Raumfahrt - Gift-Ladung durch Russische SS-19 Trägerrakete Re-Entry in kanadische arktische Gewässer

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3.06.2016

Toxic splash? Russian rocket stage to come down in Canada's Arctic waters
Debris from a Russian rocket launch is slated to fall Saturday into Baffin Bay
Environmentalists are angry that a Russian rocket stage potentially carrying highly toxic chemicals is expected to splash down this weekend in a biodiversity hotspot in the Canadian Arctic. 
"The idea of dropping a missile full of toxic chemicals in the Arctic waters off Baffin Island is just as preposterous as drilling for oil there," Greenpeace Arctic campaigner Alex Speers-Roesch said Tuesday.
"Dumping these chemicals from a ship would be a clear violation of international and Canadian law, and it is no more acceptable when it is dumped from the air."
A spokesman from the Canadian government was not immediately available.
An international aviation authority has issued a notice warning that debris from a Russian rocket launch is slated to fall Saturday into Baffin Bay. That's outside Canada's territorial waters but inside an economic zone the country partially controls.
May contain extremely toxic fuel
The space debris is a stage from a rocket set off under Russia's Rokot program, a for-profit service that launches commercial satellites, said Michael Byers, a professor of international law and an Arctic expert at the University of British Columbia.
Byers said Russia is following the rules by informing aviation authorities of the launch and the splashdown. The stage is falling over a remote stretch of water between Greenland and the southern tip of Ellesmere Island.
He notes Rokot uses repurposed Cold-War-era intercontinental ballistic missiles to launch satellites. Those missiles, the SS-19, use hydrazine for fuel.
Hydrazine is known to be extremely toxic — so toxic that technicians working with it have to use pressurized hazmat suits, Byers said.
"The United States has very deliberately moved away from it because of the health and environment risk."
The U.S. last used hydrazine as a launch propellant in its Titan missile program which ended a decade ago.
North Water Polynya at risk
The rocket stage is expected to come down in what is called the North Water Polynya, an 85,000-square-kilometre area of Arctic sea that naturally remains ice free year round.
The open water is a refuge for narwhal, beluga, walrus and bowhead whales. Its plankton-rich waters draw shoals of Arctic cod, providing food for an ecosystem that also supports seals, polar bears and millions of seabirds.
The polynya — the largest in the Arctic — is hunted by Inuit from Canada and Greenland. It's also connected through ocean currents to Lancaster Sound, where the Canadian government is considering creation of a marine protected area.
Byers said little is known about how hydrazine reacts in water, especially when it is cold and ice-choked. Nor is there any information on how much unused hydrazine the rocket stage is likely to hit the water with.
An American rocket stage that came down off the coast of Newfoundland in 2005 released more than two tonnes of a hydrazine-based fuel.
Quelle: CBC-News
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Update: 5.06.2016
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Rokot launch vehicle blasts off from Plesetsk space center
The Force’s Deputy Commander Lt Gen Aleksander Golovko was in charge of the launch
Russia’s Aerospace Force has launched a Rokot carrier rocket from the Plesetsk space center (in northern Arkhangelsk region), Russian Defense Ministry’s press service told TASS on Saturday.
"On Saturday, at 17.00 Moscow Standard Time (15.00 GMT), a combat crew of the Russian Aerospace Force’ Space Troops carried out the successful launch of a Rokot small expendable space launch vehicle with a defense satellite atop in the interests of the Russian Defense Ministry," the press service said adding the Force’s Deputy Commander Lt Gen Aleksander Golovko was in charge of the launch.
"The pre-launch preparations and launch of the Rokot carrier rocket were carried out in a routine mode," the spokesperson said. "Ground services of the Aerospace Force’s Space Troops were supervising the launch and flight of the space vehicle."
Rokot is a space launch vehicle capable of delivering light and medium payloads to orbit. It was created on the basis of the RS-18 (SS-19) intercontinental ballistic missile manufactured by the Khrunichev State Research and Production Center. After the end of the Cold War the missiles were re-purposed by the center to serve as space launch vehicles.
Rokot (also spelled as Rockot) consists of a booster unit - that provides the first and second stages - and the Briz-KM (also spelled as Breeze-KM) upper stage containing the propulsion compartment, the hermetically sealed equipment compartment and the inter-stage compartment.
The first Rokot carrier rocket blasted off from the Plesetsk spaceport on May 16, 2000. As many as 26 launches have taken place since, which lifted 65 spacecraft into low earth orbit.
Quelle: TASS

Tags: Raumfahrt 

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Sonntag, 5. Juni 2016 - 09:30 Uhr

Raumfahrt - ESA Sentinel-1A Satellit konzentriert sich auf die Niederlande und Dänemark

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For a low-lying, densely populated country like the Netherlands, monitoring subsidence is critical. Until recently, tiny displacements in the ground beneath our feet couldn’t be mapped nationally but, thanks to the Sentinel-1 mission, this is now possible.
Focusing on the Netherlands and Denmark, scientists have been using radar images from the  Sentinel-1A satellite to pinpoint where the ground is stable, where it is rising and where it is sinking – and, importantly, by exactly how much.
Images from November 2014 to April 2016 and 2.5 million measurement points were used to compile the map above, which shows subsidence and uplift in the northeast of the Netherlands. Most of these measurements were made around buildings and constructions such as dikes.
Remarkably, these measurements are accurate to a few millimetres. However, within a couple of years this accuracy will improve further, approaching 1 mm/year over the entire country.
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Sentinel-1A has been used to measure subsidence along the shores of the Markermeer in the Netherlands. This map, which is a zoom-in of a larger map, shows the area around the city of Hoorn. Areas where the ground is moving are shown in red, while green areas show where the ground is stable.
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This degree of accuracy, which was not achievable over such a large area before Sentinel-1, is needed for numerous applications such as building and maintaining effective flood defences – an application particularly relevant for the Netherlands.
Ramon Hanssen from Delft University of Technology said, “For a nation largely sitting below sea level, surface deformation is of existential importance for the Netherlands.
“Satellite data from the Sentinel-1 mission helps us to monitor and maintain the high safety standards the Dutch population expects.”
The map at the top shows that some areas, particularly along the western shore of the Ijsselmeer, along the lower causeway that crosses this manmade lake, and some areas close to Groningen in the east, are sinking by as much as 20 mm a year.
Since gas is extracted in this region, monitoring ground deformation here is particularly important.
The zoom-in of the area around Veendam (right) shows subsidence thought to be caused by salt mining activities.
Marking the first milestone towards using Sentinel-1 to map ground movement nationwide, these results are thanks to a study carried out by PPO.labs and Norut though ESA’s Scientific Exploitation of Operational Missions initiative.
“From a technical point of view, these preliminary results clearly demonstrate the potential of such nationwide products. We now have to start preparing systems that can provide standardised products to end users,” said Yngvar Larsen from Norut.
There is huge potential for using standardised ground-deformation information for sectors such as insurance, utility services and construction.
Petar Marinkovic from PPO.labs said, “This unique capability, once a prerogative of larger companies, will now foster growth of small and medium enterprises in the Earth observation market.”
In Denmark, ground deformation affects the sewerage system as pipelines are compromised. As well causing leaky and broken pipes, changes in the surface also affect the way water accumulates and runs off. As a result, Denmark’s utility sector spends of tens of millions of euros every year to modify subsurface water and wastewater pipelines.
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This shows surface deformation resulting from from salt mining activities around Veendam in the province of Groningen in northeast of the Netherlands. The map, which is a zoom-in of a larger map, has been generated using images from the Copernicus Sentinel-1A satellite. Green points show where the land is stable and the orange and red colours indicate subsidence.
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This map shows Thyborøn in Jutland, Denmark, where each coloured square is a measurement of the ground deformation. Green is stable, warmer colours indicate subsidence, and colder colours show uplift. A trend from stable in the west to subsidence in the east can be seen. This causes problems for wastewater pipes in the area. There is also a high rate of subsidence around the harbour. Sentinel-1A images from March 2015 to March 2016 were used to generate this map.
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Understanding land deformation is important for investing in renovations.
Lars Noergaard Holmegaard, CEO of the Danish Lemvig Water and Waste Water Company, said, “If we can incorporate reliable information on land subsidence and uplift in our investment plans for the pipelines, we can focus the renovation activities where they are most needed and secure a functional network while reducing maintenance costs.”
Sentinel-1A, which has been in orbit since April 2014, is clearly paving the way for these new applications.
Moreover, now that its identical twin Sentinel-1B has also been launched, data delivery and coverage will be further improved.  It is expected that the constellation will produce more than 10 terabytes of data per day.
“The open data policy and regular acquisition plan of the Copernicus programme allows research and development to be carried out at tremendous speed, providing results that can affect the world within a few hours after a satellite has gathered data,” noted Dr Marinkovic.
Quelle: ESA

Tags: Raumfahrt 

1498 Views

Samstag, 4. Juni 2016 - 22:15 Uhr

Raumfahrt - ISRO`s MCC-Aufnahmen von Mars-Oberfläche

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This MCC snapshot covers a large region of mars from Coogon valles and Oxia Palus  at the bottom to focas region to the right top. Oxia Palus region has been studied to have abundant clay minerals. This is a map corrected MCC data set that can be overlaid on  existing maps derived from earlier Mars observation missions. High, low albedo regions along with many craters are seen.
This image was captured by MCC on April 14, 2016 from an altitude of 21,924 km and with a resolution of 1.1 km. It covers 2100 x 2100 sq.km area approximately.
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Olympus Mons - a large shield volcano on the planet Mars
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Valles Marineris
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One of the brightest desert regions of Mars called Thymiamata
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This MCC picture portrays a large area of Mars covering almost 1800 km x 1800 km.
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Snapshot of Mars terrain captured from a distance of 26,300 km on Dec 30, 2015.
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Mars full disc image from MOM
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Olympus Mons
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Pictures from Mars Colour Camera (MCC) onboard India’s Mars Orbiter Spacecraft
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Henry Crater -image from MCC
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Quelle: ISRO

Tags: Raumfahrt 

1430 Views

Samstag, 4. Juni 2016 - 20:30 Uhr

Raumfahrt - CNES und DLR erneuern ihre Rahmenvereinbarung für die bilaterale Zusammenarbeit

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At the International Aerospace Exhibition (ILA), which takes places from Wednesday the 1st to Thursday the 4th, june 2016, in Berlin, Jean-Yves Le Gall, President of CNES, the French space agency, and Pascale Ehrebnfreund, Chair of the DLR Executive Board (Deutsches Zentrum für Luft und Raumfahrt), renewed the framework agreement for bilateral cooperation between CNES and DLR.

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Brigitte Zypries, Parliamentary State Secretary at the German Federal Ministry for Economic Affairs and Energy (BMWi) and also German Aerospace Coordinator ; Gerd Gruppe, Member of the DLR Executive Board responsible for the German Space Administration ; CNES President Jean-Yves Le Gall ; Pascale Ehrenfreund, Chair of the DLR Executive Board and Thierry Mandon, French Minister of State for Higher Education and Research. Credits: DLR.

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At the International Aerospace Exhibition (ILA) in Berlin, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and the French space agency (CNES) in the presence of Brigitte Zypries, Parliamentary State Secretary at the German Federal Ministry for Economic Affairs and Energy (BMWi) and also German Aerospace Coordinator, and Thierry Mandon, French Minister of State for Higher Education and Research, renewed their 2002 cooperation agreement on 2 June 2016. The agreement was signed by Pascale Ehrenfreund, Chair of the DLR Executive Board, Gerd Gruppe, Member of the DLR Executive Board responsible for the German Space Administration, and CNES President Jean-Yves Le Gall.
Jean-Yves Le Gall pointed out: “France and Germany are at this time a strong team, in Brussels through Copernicus, Galileo and Horizon 2020; at ESA through launch vehicles, the ISS and science; and in our bilateral relations through MERLIN: an excellent basis to shape successfully future space projects.” 
Prof Ehrenfreund underlined: "Together, DLR and CNES have developed significant space projects in Europe. We will continue this close cooperation in the future in order to actively meet the global challenges that we face.”
In particular, DLR and CNES commit to continuing the close cooperation and coordination in research and technology collaborations, projects at the national level and within the European Space Agency (ESA) and in EU research programmes, as well as in satellite missions and in the operation and use of the International Space Station ISS. The agreement provides for regular meetings, as well as the option of personnel exchanges. The cooperation agreement has a term of five years and will be renewed automatically.
“The two countries will continue to play a leading role in Europe and worldwide in satellite applications, system developments and space exploration,” said Thierry Mandon. “With this agreement, DLR and CNES emphasise the excellent and long-standing cooperation between Germany and France in space,” Brigitte Zypries welcomed the agreement renewal.
Quelle: CNES

Tags: Raumfahrt 

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Samstag, 4. Juni 2016 - 19:30 Uhr

Astronomie - Am 14. September 2015 gab es eine winzige nachhaltig 200 Millisekunde

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NASA's Big Mistake: LIGO's Merging Black Holes Were Invisible After All

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On September 14, 2015, a tiny effect lasting 200 milliseconds passed through the Earth at the speed of light. The entire planet compressed and expanded in two mutually perpendicular directions by less than the width of a proton, oscillating back and forth roughly seven times in that span. And in two detectors separated by 2,000 miles, an interference pattern formed by two isolated lasers, reflected back-and-forth in a vacuum and then brought together again, gave us the telltale explanation for this effect. From 1.3 billion light years away, two black holes some 30 times the mass of the Sun had spiraled into one another, merging together and sending energetic ripples through the fabric of space itself. For the first time, a gravitational wave — one of the oldest unverified predictions of Einstein’s General Relativity — had been directly detected.

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Optical telescopes didn’t see anything, as expected. Merging black holes weren’t anticipated to emit any light, unlike merging stars (which create a larger star), white dwarfs (which create a supernova), or neutron stars (which are thought to create a gamma ray burst); they should only be detectable by their gravitational wave signal. Yet there was a curious possible exception, as a team from NASA’s Fermi satellite claimed to detect gamma rays coincident with this event, offset by a meagre 0.4 seconds. An array of 14 crystal detectors on board — the Gamma-ray Burst detection Monitor (GBM) instrument — detected an unexpected burst of X-rays, and claimed there was only a 0.2% chance of a false positive.
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This image, taken in May 2008 as the Fermi Gamma-ray Space Telescope was being readied for launch, highlights the detectors of its Gamma-ray Burst Monitor (GBM). The GBM is an array of 14 crystal detectors.
Image credit: NASA/Jim Grossmann.
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While NASA was celebrating, however, cautious scientists all over the world were skeptical. Not only would this overthrow the leading theoretical models for black hole mergers, and not only does a 99.8% chance of success correspond only to a 3-σ significance (rather than the 5-σ significance typically required for a discovery in physics), but a complimentary satellite in orbit — the ESA’s INTEGRAL satellite — failed to see the corroborating evidence it should have if this signal were real. On the contrary, INTEGRAL searched through all the data and failed to find any interesting signal coincident with LIGO’s gravitational wave at all. Far from a definitive detection, this conflicting data raised more questions than it answered.
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A marginal detection only is available for the gravitational wave event associated with LIGO’s detection on September 14, 2015. Image credit: D. Bagoly et al., 2016 (submitted to A&A), via http://arxiv.org/abs/1603.06611.
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Thanks to a new paper now available from J. Greiner, J.M. Burgess, V. Savchenko and H.-F. Yu, however, the apparent conflict may at last be resolved. The secret lies in understanding how the GBM instrument aboard NASA’s Fermi satellite actually works. Rather than measuring an absolute signal, it measures a steady, continuous background of photons over a large energy range. The spikes above that background, when they appear, can show us either a real, physical event (like a burst or merger), or they can simply be evidence of a random fluctuation that has no physical origin at all. If you use an imperfect algorithm for discriminating which fluctuations are physical vs. non-physical, you could wind up drawing invalid conclusions about what’s real and what’s phantasmal. The huge advance of the new paper, submitted to the Astrophysical Journal as a Letter, isn’t observational or theoretical, but rather statistical; it more robustly and successfully discriminates between normal noise and a burst of high-energy light from an astrophysical source.
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Various statistical techniques analyzing the Fermi data. The original analysis (purple) shows a signal, but the improved analysis (orange) shows only something consistent with pure noise. Image credit: Figure 5 from J. Greiner, J.M. Burgess, V. Savchenko and H.-F. Yu, 
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Above, you can see a number of different ways of reconstructing the apparent signal coincident with LIGO’s gravitational wave. The original Fermi team’s analysis is shown in purple: a clear detection. However, the superior reconstruction of this new paper is shown in orange, and lines up with both the raw data (blue) and also — more importantly — is consistent with a non-detection, meaning that there is no electromagnetic signal here. According to one of the paper’s authors, J. Michael Burgess, the original paper (claiming a detection) had some statistical flaws his team was able to spot, relating the following:
When I saw the announcement and the paper, the spectrum looked like what I always see as background.
After pulling his team together and developing some new analysis tools, they confirmed their suspicions:
We instantly saw that we got a much different answer. The spectrum of the event was basically zero: nothing there.
The new statistical technique developed by Burgess and his collaborators has proven to be incredibly powerful, successfully pulling out even faint gamma ray signals from noisy data and drastically reducing the number of false positives. By combining this new technique with the existing Fermi data, it should be possible to make huge strides forward in identifying true astrophysical events.
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An artist’s impression of a gamma-ray burst illuminating its host galaxy. Image credit: Gemini Observatory / AURA / Lynette Cook.
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It’s important to remember that there can and will be correlations in the future not only between gravitational waves and gamma rays, but between LIGO and Fermi’s GBM instrument. When asked for comment, Burgess said the following:
GBM is an amazing instrument and its synergy with LIGO provides an amazing way for us to view the Universe. The GBM team has made a huge effort for this, and when a neutron star merger happens nearby, it is very likely GBM and LIGO (and others) will see something… and this will be amazing!
But in order to make sure we aren’t fooling ourselves, we have to do it right. Collaboration between the teams — the Fermi team, the INTEGRAL team, and the gravitational wave teams — are incredibly important. But the necessity of calibrating the signals that multiple observatories will see is essential to getting the right results. Merging black holes may, in fact, sometimes lead to electromagnetic radiation, a possibility which future events will hopefully test. But the golden rule in situations like these is the null hypothesis: in the absence of extraordinary evidence, as is the case here, bet on exactly what the leading physics ideas predict.
Quelle: Forbes Science

Tags: Astronomie 

1427 Views

Samstag, 4. Juni 2016 - 14:45 Uhr

Astronomie - MSU Physiker entwickelt neues Modell für die Geschwindigkeit und Bewegung von Sonneneruptionen

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A Montana State University physicist who has developed a new model that predicts the speed of solar plasma during solar flares, likening it to the path traveled by a thrown baseball, will present his findings at the Solar Physics Division of the American Astronomical Society conference being held this week in Boulder, Colorado.
Sean Brannon, a postdoctoral researcher in the MSU Department of Physics within the College of Letters and Science, developed the model that might help to define how solar flares evolve and provide better ways to predict them. His work could have applications on how to protect power grids and communication technology and aeronautics from the energy released by the flares.
Brannon used data from the NASA Interface Region Imaging Spectrograph satellite, also known as IRIS, which monitors a specific layer of the sun known as the transition region. The transition region is thin, but complex, and separates the sun’s outermost layer, the corona, from an inner layer, the chromosphere. The corona, the chromosphere and the transition region are of great interest and mystery to scientists.
Temperatures in the corona can reach several million degrees Kelvin, far hotter – often by more than a factor of 100 – than any other layer of the sun’s atmosphere. A solar flare arcing through the corona can be more than 10 million degrees Kelvin. This is puzzling and seems counterintuitive since the corona is the furthest layer from the sun and, therefore, should arguably be the coolest.
IRIS spectrograms are made by a process similar to what happens when you shine light through a prism, breaking it into different colors. Each color is formed by a different kind of atom in the solar atmosphere and we can extract all kinds of interesting information about what the plasma is doing based on that spectrum. For example, if the light is more red or blue than we'd expect, then we know that the plasma is moving either away from or toward us,” Brannon said.
Brannon used IRIS’s data to look at the sun’s solar flare process. During a solar flare, plasma from the sun can heat up to millions of degrees Kelvin and evaporate into the corona. There it fills or is funneled into powerful magnetic fields that give it an arcing, loop-like shape, Brannon said.
“We then expect that this hot plasma will cool off over the next several minutes to hours. As it cools, models predict that it should start to drain back out of the loops, resulting in spectral signatures that should be detectable,” Brannon said.
“Up until now, however, there haven't been any published papers analyzing an observation of the entire filling, cooling, and draining process, nor have there been any papers that attempt to model a spectral observation as a signature of the draining,” Brannon said. “The cooling and draining is important to look at, since we'd like to be sure that the plasma we're measuring is evaporated plasma draining back, and not some other source of plasma.”
Brannon devised a simple model to describe the speed at which a blob of plasma falls from the top of an oval-shaped flare loop and how it would appear on an IRIS spectrograph. His results indicate that plasma is draining from the loops at free-fall speeds – similar to the path a baseball follows when thrown. Additionally, the location and timing of the draining plasma matches that which was observed evaporating.
The prediction of large solar flares is important because they can emit vast amounts of energy that can disrupt power grids, satellites, communication technology and aeronautics. For example, in March 1989, a powerful solar flare left millions of Canadians without electricity for about 12 hours, according to NASA.
“The sun really dominates Earth’s environment, climate and space in which Earth lives,” Brannon said. “What the sun does can have very profound impacts on life here on Earth. So, understanding the sun’s processes can help us determine how to protect technology and people.”
MSU Physics Professor Dana Longcope was Brannon’s academic adviser and is national chairman for the Solar Physics Division. Longcope said that while solar flares are unpredictable making it difficult to find one to observe, Brannon was able to identify a specific IRIS observation, enabling him to make his analysis.
“He came up with a very different interpretation of what happens during a solar flare,” Longcope said. “It is one of the most compelling quantitative observations I’ve seen as to what we’d expect to see during a solar flare. It’s a credit to a scientist when they look at the data and they aren’t blinded by what they expect to see, but rather keep an open mind and observe what is actually happening.”
Quelle: Montana State University

Tags: Astronomie 

1449 Views

Samstag, 4. Juni 2016 - 14:30 Uhr

Astronomie - Helle Feuerkugel mit lauten Schlag über Phoenix/USA wahrscheinlich ein Meteor

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3.06.2016 / 7.00 MESZ

Flash of Light, Loud Boom Over Phoenix Skies Likely a Meteor

An expert in meteorites says a bright flashing light and loud boom over the skies in metro Phoenix looks like a single meteor burning up as it entered the Earth's atmosphere at thousands of miles per hour.
Radar footage shows that meteorites — black rocks ranging in size from a pea to a grapefruit — may have fallen to the ground early Thursday near the eastern Arizona community of Cibecue, said Laurence Garvie, curator of the Center for Meteorite Studies at Arizona State University.
"That's what everyone will rush out there to look at," Garvie said.
Garvie said the flashing light across the sky likely wasn't a meteor shower, but rather a random piece of space rock that intersected with the orbit of the Earth.
Video footage shows the skies went from dark to instantly bright — and then grew even brighter.
It produced a loud boom that awoke people who were sleeping.
The flash in the sky finally decreased in intensity and fizzled out.
Vicky Schmid of Snowflake, Arizona, said she was asleep in bed when she and her dogs were awoken by a loud noise.
"I thought somebody was breaking into the house," she said.
She checked her front door camera from an app on her phone and saw video showing an intense burst of light flashing across the sky.
"The funny thing was the (video) clip said that at 3:56 a.m. a visitor was detected," she said.
Quelle: abcNews
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Update: 13.15 MESZ
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Fireball Lights Pre-Dawn Sky over Arizona
This feature was updated at 9:00 p.m. EDT to reflect new data on the size, mass and kinetic energy of the fireball.
For a few seconds early Thursday, night turned into day as an extremely bright fireball lit the pre-dawn sky over much of Arizona, blinding all-sky meteor cameras as far away as western New Mexico.
Based on the latest data, a small asteroid estimated at 5 feet (1-2 meters) in diameter - with a mass of a few tons and a kinetic energy of approximately half a kiloton - entered Earth's atmosphere above Arizona just before 4 a.m. local (MST) time. NASA estimates that the asteroid was moving at about 40,200 miles per hour (64,700 kilometers per hour).
Eyewitness reports placed the object at an altitude of 57 miles above the Tonto National Forest east of the town of Payson, moving almost due south. It was last seen at an altitude of 22 miles above that same forest.
“There are no reports of any damage or injuries—just a lot of light and few sonic booms,” said Bill Cooke in NASA's Meteoroid Environment Office at the Marshall Space Flight Center in Huntsville, Alabama. “If Doppler radar is any indication, there are almost certainly meteorites scattered on the ground north of Tucson.”
The NASA Meteoroid Environments Office (MEO) monitors the small rock (meteoroid) environment near Earth in order to assess the risks posed to spacecraft by these bits of tiny space debris. As part of this effort, it operates a network of meteor cameras within the U.S. that are capable of detecting meteors brighter than the planet Jupiter. Three of these cameras are in southern Arizona.
Cooke notes that he and other meteor experts are having difficulty obtaining data on the June 2 fireball from meteor camera videos, since many of the cameras were almost completely saturated by the bright event.
Meteoroid impacts are a continuously occurring natural process.  Every day, about 80 to 100 tons of material falls upon the Earth from space in the form of dust and meteorites. Over the past 20 years, U.S. government sensors have detected nearly 600 small asteroids, a few meters in size, which have entered the Earth’s atmosphere and created spectacular bolides. The superbolide that impacted over Chelyabinsk, Russia in 2013 is estimated to have been 65 feet (20 meters) in size and released over 800 times the energy of the Arizona fireball. Impacts of that size take place a few times a century, and impacts of larger asteroids are expected to be far less frequent (on the scale of centuries to millennia) but can happen on any day.
NASA’s Planetary Defense Coordination Office is responsible for finding, tracking, and characterizing near-Earth asteroids, identifying potentially hazardous objects, and planning for the mitigation of potential impacts to Earth that could do damage at ground level. More than 14,000 near-Earth asteroids (NEAs) have been discovered since NASA-sponsored efforts began in 1998 to detect, track and catalogue asteroids and comets.
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Video obtained from the NASA meteor camera situated at the MMT Observatory on the site of the Fred Lawrence Whipple Observatory, located on Mount Hopkins, Arizona, in the Santa Rita Mountains.
Credits: NASA/MEO
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This footage from the Sedona Red Rock Cam (part of the EarthCam network) shows how brightly the ground was illuminated during the fireball, which entered the atmosphere over Arizona shortly before 4 a.m. MST on June 2, 2016.
Credits: Sedona Red Rock Cam/EarthCam
Quelle: NASA
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Quelle: YouTube
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Update: 20.45 MESZ
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Meteorit erhellt den Nachthimmel

Am Donnerstag sorgte ein heller Feuerball über dem amerikanischen Bundesstaat Arizona für Aufregung.

Faszinierendes Naturschauspiel: Der Kleinplanet über dem Nachthimmel Arizonas.
Donnerstagnacht erhellte ein Meteorit den Nachthimmel über dem amerikanischen Bundesstaat Arizona. Laut der Nasa handelte es sich dabei um einen Kleinplaneten, der 1–2 Meter gross und ein Paar Tonnen schwer gewesen sei. Dieser hatte sich mit 64'000 km/h auf die Erdoberfläche zubewegt.
Es gebe keinen Hinweis auf Beschädigungen oder Verletzte, verlautete die Nasa in einer Mitteilung. Mehrere Zeugen hätten aber von einem lauten Knall berichtet. Das Expertenteam der Nasa hatte Probleme, Genaueres über den Meteoriten herauszufinden, da viele der Spezialkameras zu sehr vom entstandenen Licht geblendet wurden.
Meteoriteneinschläge sind ein natürliches Vorkommen. Jeden Tag fallen etwa 80 bis 100 Tonnen Weltraummaterie auf die Erde. In den letzten 20 Jahren wurden fast 600 kleine Asteroiden verzeichnet.
Quelle: Basler Zeitung
(Anmerkung: Kleinplanet-Bezeichnung von Redaktion: Basler Zeitung)
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Update: 21.30 MESZ
ASTEROID EXPLODES OVER ARIZONA: On June 2nd just before 4 a.m. MST, a small asteroid hit Earth's atmosphere and exploded over Arizona. The airburst shook the ground below and produced a flash of light 10x brighter than a full Moon. NASA says it was a 3-meter wide space rock from beyond the orbit of Mars. Shortly after the explosion, Mike Lerch walked out the front door of his house in Phoenix on the way to work, and this is what he saw:
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"At first I thought it was a rocket launch," says Lerch. "Now I realize it was debris from the asteroid." Indeed, the smokey remains were widely visible as they twisted in the winds high above Arizona.
The flash itself was so bright, it briefly turned night into day. Marsha Adams sends these before, during, and after shots from Sedona, Arizona:
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"The camera was facing NE so it did not record the asteroid itself," says Adams. "However, the flash cast very distinct shadows, and landscape colors were vivid."
Bill Cooke of NASA's Meteoroid Environment Office says this is the brightest fireball detected in the 8-year history of the NASA's All Sky Fireball Network, an array of cameras that monitors fireball activity across the USA. The fact that the explosion blinded most cameras that saw it initially complicated analysts' efforts to pinpoint its nature and origin. Ultimately, however, they were able to draw firm conclusions: The mass of the asteroid was some tens of tons and it exploded with a kinetic energy of approximately 10 kilotons.
"There are no reports of any damage or injuries—just a lot of light and few sonic booms," says Cooke. "If Doppler radar is any indication, there are almost certainly meteorites scattered on the ground north of Tucson."
Quelle: Spaceweather
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Update: 4.06.2016
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After the asteroid breakup, the hunt begins for the pieces

For a few fleeting seconds about 3:57 a.m. Thursday, the Arizona sky lit up with a bright flash and loud boom as an asteroid broke apart over Payson. The event could land the Center for Meteorite Studies at Arizona State University its "winning lottery ticket," or so its curator hopes.
The center, with what it calls the world's largest university meteorite collection, hopes to be chosen as the institution that gets to analyze and study any recovered pieces from the meteorite that may be found, said Laurence Garvie, the center's curator, on Friday.
Over the past century, pieces from only three meteorites have been recovered in the state, Garvie said.
The first meteorite recovery in Arizona took place in 1912, the second in 1998 and the third in 2009, he said.
This year, Garvie said, pieces from only two meteorites have been recovered in the United States as a whole, one in Florida and one in northern Texas. In 2015, there was only one recovery, in California.
Garvie compared the possibility of being chosen to analyze the recovered meteorite pieces to winning a big lottery drawing among all scientists.
"Yesterday the lottery has been drawn and now they (explorers for the fallen pieces) are going to go out and see who won," Garvie said.
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A security system in Arizona caught a brilliant flash of light from an asteroid burning up in the atmosphere. Video Credit: Susanne Campbell-Vincent
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Amateurs fan out to find fragments
According to Garvie, most meteorites are hunted by amateurs who have the ability to leave immediately for the landing areas and explore for the pieces.
Once pieces have been recovered, the fragments then will be taken to a scientist or organization of the collectors' choice.
"I would hope they will take it to ASU and come to me to do the analysis, but they can go to any other scientist in the U.S," Garvie said.
There is no guarantee that recovery teams will be able to locate the fallen fragments, he said. But some people familiar with the process don't believe it will be exceptionally difficult.
The freshly fallen meteorite broke apart over the eastern part of the state, where the majority of the rocks are red or brown.
The recovery teams will be looking for black, rounded pieces that will stand out against the native rock, Garvie said.
Doppler radar is also expected to help in the discovery, he said, as it should be able to pinpoint approximately where the meteorite shards may have fallen.
A collection of other-worldly objects
The center at ASU has a growing display of rocks and meteorites from all over, including a piece from the meteorite in northern Texas that center officials plan to add to the exhibit very soon, Garvie said.
“Something like this is exciting for both the collectors and scientists. The pieces could be from Mars, the Asteroid Belt or from the moon.”
Laurence Garvie
The university's collection has more than 1,600 samples of different meteorites. The rocks are preserved and displayed for scientific research and education.
The center's display, which is open to the public, is in the Interdisciplinary Science and Technology Building on the university's Tempe campus.
Garvie said that while the most recent recoveries have been identified as ordinary chondrites, pieces from one of the most common classes of meteorites, these findings can't be described as anything but extraordinary. Because they aren't of this earth.
"Something like this is exciting for both the collectors and scientists," Garvie said. "The pieces could be from Mars, the Asteroid Belt or from the moon."
Asteroid vs. meteor: What's the difference?
Livescience.com explains many of the details on its website, as does the American Meteor Society. Here are some of the extraterrestrial basics from those two sources:
Asteroid: An asteroid is a rocky object in space that's smaller than a planet. There are millions of asteroids orbiting the sun, some 750,000 of which are found in the Asteroid Belt, a vast ring of asteroids between the orbits of Mars and Jupiter.
Meteoroid: A general term describing small particles of comets or asteroids that are in orbit around the sun. There's no universally accepted definition (based on size or any other characteristic) that distinguishes a meteoroid from an asteroid — they're simply smaller than asteroids.  If remnants of the parent meteoroid survive the trip through the atmosphere to reach the ground, then these remnants are called meteorites.
Meteor: A meteor is an asteroid or meteoroid or other object that burns and vaporizes upon entry into the Earth's atmosphere; meteors are commonly known as "shooting stars."  Whenever a meteoroid plows into the Earth’s atmosphere, it will create a brief flash of moving light in the sky.
Meteorite: If a meteor survives the plunge through the atmosphere and lands on the Earth's surface, it's known as a meteorite.
Fireball: A fireball is another term for a very bright meteor, generally brighter than magnitude -4, which is about the same magnitude of the planet Venus in the morning or evening sky.
Quelle: az central

Tags: Astronomie 

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