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Sonntag, 28. Juni 2015 - 14:15 Uhr

Astronomie-History - 1935: Ziel ist es Funksignale auf den Mond zu senden

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Aus dem CENAP-Archiv:

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Quelle: Modern Mechanix, CENAP-Archiv


Tags: Astronomie 

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Sonntag, 28. Juni 2015 - 14:00 Uhr

Raumfahrt - Start von SpaceX Falcon 9 mit CRS-7

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16.06.2015

Mission Live Updates
Jun 26 - Falcon 9 : CRS-7 Launch site Cape Canaveral AFB, FL
Launch Date Jun 26
From Launch Pad LC-40
Launch Window : 11:09 am EDT (15:09 GMT)
The seventh SpaceX cargo mission to the International Space Station (ISS) under NASA's Commercial Resupply Services contract is scheduled to launch June 26, from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. 
It will be loaded with more than 4,000 pounds of scientific experiments, technology demonstrations and supplies, including critical materials to support science and research investigations that will take place on the space station. 
Also to be carried up to the ISS is IDA-1 International Docking Adapter 1 which will be fitted to the reconfigured ISS to allow the docking of the new crewed spacecraft.
Quelle: AS
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Update: 20.06.2015
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SpaceX moves Space Station resupply launch to June 28
SpaceX CEO Elon Musk could celebrate his 44th birthday with a rocket launch if all goes well on June 28. SpaceX moved the scheduled Falcon 9 launch from Friday, June 26 to Sunday, June 28.The CRS-7 mission is scheduled to take off from Space Launch Complex 40 at Cape Canaveral Air Force Station at 10:21 a.m. EDT on Sunday. If the launch is a “no go” the next launch window is on Monday, June 29 at 9:58 a.m.
The Falcon 9 rocket will carry the Dragon resupply cargo spacecraft filled with more than 5,000 pounds of supplies to the International Space Station. The supplies include science and research material for the in-orbit lab. Also on board are two docking adapters, built by Boeing that will be used by commercial crew spacecraft when they dock at the Space Station.
This will be the seventh cargo mission by SpaceX to the Space Station.
Quelle: Orlando Sentinel
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Update: 25.06.2015
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90 Percent ‘Go’ Forecast for CRS-7
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Weather forecasters from the U.S. Air Force 45th Weather Squadron are predicting a 90 percent chance of favorable weather at the scheduled time for launch of SpaceX CRS-7. Liftoff of the Falcon 9 rocket and Dragon spacecraft is targeted for 10:21 a.m. EDT on Sunday, June 28, from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. This is the company’s seventh cargo delivery mission to the International Space Station under the agency’s Commercial Resupply Services contract.
Launch coverage on NASA Television will begin at 9 a.m. A Sunday launch will result in the Dragon spacecraft arriving at the space station on Tuesday, June 30. Expedition 44 Flight Engineer Scott Kelly of NASA will use the station’s Canadarm2 robotic arm to reach out and capture Dragon at about 7 a.m. Station commander Gennady Padalka of the Russian Federal Space Agency (Roscosmos) will support Kelly as they operate from the station’s cupola. NASA TV coverage of rendezvous and grapple of Dragon will begin at 5:30 a.m. Coverage of Dragon’s installation to the Earth-facing port of the Harmony module will begin at 8:30 a.m.
If the launch does not occur on Sunday, the next launch opportunity would be at 9:58 a.m. on Monday, June 29, resulting in a grapple and berthing on Thursday, July 2.
The Dragon spacecraft will be filled with more than 4,000 pounds of supplies and payloads, including critical materials for the science and research investigations that will occur during Expeditions 44 and 45. Science payloads will offer new insight to combustion in microgravity, perform the first space-based observations of meteors entering Earth’s atmosphere, continue solving potential crew health risks and make new strides toward being able to grow food in space. Research continues to support the twins study and one-year mission investigations with NASA astronaut Scott Kelly. This mission also is launching more than 30 student experiments, all of which are flying to the U.S. National Laboratory managed by the Center for the Advancement of Science in Space (CASIS). The first of two International Docking Adapters for the station will be delivered in Dragon’s unpressurized trunk. The adapters will enable space station docking of commercial crew spacecraft, including the Boeing CST-100 and SpaceX Crew Dragon.
After more than five weeks at the space station, the spacecraft will return with more than 1,400 pounds of cargo, including science experiments, crew supplies, hardware and computer resources, space station hardware, and trash.
In addition to launch coverage, NASA also will host a series of prelaunch news conferences and events on Friday, June 26, and Saturday, June 27, at the agency’s Kennedy Space Center in Florida. All briefings will air live on NASA TV and the agency’s website.
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Update: 26.06.2015
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SpaceX resupply launch, barge landing attempt set for Sunday


A SpaceX Falcon 9 rocket carrying a resupply capsule to the International Space Station is set to launch from Cape Canaveral Air Force Base on Sunday, June 28 at 10:21 a.m. EDT. The aerospace company announced Thursday they will make another barge landing attempt of the rocket booster.
On Thursday the U.S. Air Force weather forecasters predicted a 90 percent chance of favorable weather conditions for the Sunday launch window. If the launch is scrubbed the next available window will be Monday at 9:58 a.m.
SpaceX CRS-7 resupply flight will be loaded with more than 4,000 pounds of supplies and experiments for the astronauts during ISS Expeditions 44 and 45. The crew will perform experiments for the U.S., Japan Aerospace Exploration Agency and the European Space Agency.
This will be the third attempt to land a Falcon 9 booster on a drone ship in the Atlantic Ocean. SpaceX said they have made corrections to the throttle valve that caused the last hard landing on their drone ship “Just Read the Instructions” in April. The company will use a new custom-built drone ship off the coast of Jacksonville on Sunday called “Of Course I Still Love You.” SpaceX CEO Elon Musk named both drone ships for science fiction writer Iain M. Banks' book "The Player Games."
Musk could celebrate his 44th birthday on Sunday with a barge landing if all goes well.
After Falcon 9 launches and Dragon separates it will reach its preliminary orbit and begin a series of thruster firings to reach the Space Station. The capsule should arrive on Tuesday, June 30. Astronaut Scott Kelly and cosmonaut Gennady Padalka will use the station’s robotic arm to capture the spacecraft. Houston ground control will install Dragon to the bottom of the Space Station.
The science payload will include the Meteor Composition Determination investigation for the first space-based observations of meteors entering Earth’s atmosphere. The meteor study will take high-resolution video and photos using a program to search for bright spots. 
Dragon will also carry materials to support more than 30 student research projects. A hypothesis will be tested about pollination stimulation for food crops in low gravity. Another experiment will test a new type of plastic developed to block radiation from the Sun that could be used to protect astronauts on future missions to Mars. The student experiments are managed and supported by Center for the Advancement of Science in Space (CASIS).
The spacecraft will remain docked at the Space Station’s Harmony module for five weeks allowing the crew to unload supplies and load cargo to be sent back to Earth. During this time, a new docking adapter flown up by Dragon will be installed by astronauts for future commercial crew to dock at the Space Station. The spacecraft will return to Earth with more than 1,400 pounds of supplies, science experiments, hardware and trash. Dragon will splash down in the Pacific Ocean off the coast of California.
This will be the seventh resupply mission to the International Space Station by SpaceX under the Commercial Resupply Services contract.
Quelle: Orlando Sentinel
 
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Update: 23.00 MESZ
 
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Quelle: AS
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Update: 27.06.2015 
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Microsoft's HoloLens to Go Into Orbit Atop SpaceX Dragon
 
Microsoft's virtual reality goggles will be on board SpaceX's next launch to the International Space Station. Pictured: NASA and Microsoft engineers test Project Sidekick on NASA’s Weightless Wonder C9 jet.
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When the SpaceX Dragon blasts off for its seventh resupply mission to the International Space Station this weekend, it will be carrying two pairs of Microsoft's HoloLens goggles.
The augmented-reality wearable device, which was first shown off in January at Microsoft's Windows 10 event, hasn't yet hit the consumer market. The astronauts at the International Space Station will be among the first to strap on the goggles and use Sidekick, a technology designed to help them work in space.
"HoloLens and other virtual and mixed reality devices are cutting edge technologies that could help drive future exploration and provide new capabilities to the men and women conducting critical science on the International Space Station," Sam Scimemi, director of the ISS program at NASA, said in a statement.
The hope is the new technology could one day allow astronauts more autonomy as they travel into deep space and experience more communications delays with Earth.
The Sidekick devices have two modes of operation. The first allows astronauts to use Skype to connect with an expert on Earth to help coach them on a task while the second overlays a standalone set of procedures and illustrations.
SpaceX Will Try Ambitious Rocket Landing Again
If all goes according to plan on Sunday, SpaceX will also try for a third time to land its Falcon 9 rocket on a floating barge.
A video from the most recent attempt in April shows the Falcon 9 rocket hitting its target when it returned to Earth but landing too hard for survival. The company said it has since made corrections to the valve that caused the rough landing.
SpaceX CEO Elon Musk has said recycling rockets will "revolutionize access to space."
"If one can figure out how to effectively reuse rockets just like airplanes, the cost of access to space will be reduced by as much as a factor of a hundred," he said.
Quelle: abc-news
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Update: 28.06.2015 / 14.00 MESZ 
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Quelle: NASA

Tags: Raumfahrt 

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Sonntag, 28. Juni 2015 - 10:40 Uhr

Astronomie - Astronomen entwickeln bahnbrechende optische Komponente zur Erfassung von Exoplaneten welche nah an ihren Zentralsternen sind

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Double image of the star beta Centauri taken through an experimental version of the vector-APP coronagraph installed at MagAO. Both images of the star contain a dark region that covers the complete 360 degrees around the central star. In both cases, the binary companion to beta Centauri is easily detected. Coronagraphic phase pattern designed by Christoph Keller (Leiden). Credit Leiden University, University of Arizona
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Double image of the star Eta Crucis taken through the vector-APP coronagraph installed at MagAO. The two main images of the star exhibit D-shaped dark holes on complementary sides. Coronagraphic phase pattern designed by Christoph Keller (Leiden). Credit Leiden University, University of Arizona
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Astronomers from Leiden University (the Netherlands) and the University of Arizona (USA) have successfully commissioned a new type of optic that can reveal the image of an exoplanet next to its parent star. The ‘vector Apodizing Phase Plate’ (vector-APP) coronagraph was installed at the 6.5-m Magellan Clay telescope in Chile in May 2015, and the first observations demonstrated an unprecedented contrast performance very close to the star, where planets are more likely to reside. These results will be presented by PhD student Gilles Otten (Leiden) this Monday afternoon to the scientific community at the "In the Spirit of Lyot" conference held in Montreal at the Marriott Chateau Champlain Hotel.
Almost 2000 exoplanets have been detected to date, but only a handful of those have been imaged directly. Exoplanets are typically more than a million times fainter than and are lost in the glare of their parent star as seen from Earth. To directly image exoplanets and to characterize their atmospheres, astronomical instruments at the world's largest telescopes use coronagraphs to suppress the overwhelming halo of light from the star.
The vector-APP coronagraph[1] uses the wavelike nature of light to cancel out the starlight whilst allowing the planet’s light to shine through.
This manipulation is implemented through a complex phase pattern that can only be manufactured using advanced liquid crystal 3D patterning techniques [2]. This technique creates two images of the star, for which dark D-shaped regions are located on opposite sides of each star image (see Figure 1). In this way, the whole region around the star can be scrutinized for planets. By combining several layers of liquid crystals, the device can be used over a wide range of wavelengths, including the infrared where the contrast between planet and star is more favorable.
On May 6, 2015 a vector-APP coronagraphic device saw first light (at 3.9 microns wavelength, in the infrared range of the spectrum) at the MagAO[3] instrument, attached to the 6.5-m diameter Magellan Clay telescope in Chile. The telescope's integrated adaptive optics system provided the instrument with sharp images of stars, which were consequently split up and modified by the coronagraph to exhibit dark holes in which much fainter planets could be imaged than without the vector-APP coronagraph.
Frans Snik (Leiden University), who invented the principle behind the new vector-APP coronagraph, says:“ It is fantastic to see that after all our design work and lab testing, this new approach works perfectly at the telescope on the very first night!” Gilles Otten adds:“We knew that we were in business as soon as we saw the first picture on the screen in the telescope control room.”
Jared Males (NASA Sagan Fellow, University of Arizona) is excited about the opportunities of the vector-APP: “ With this new coronagraph we are now looking for planets around nearby stars. We have the capacity to directly detect, or rule out, planets smaller than Jupiter. Matthew Kenworthy (Leiden) concludes: “ This new coronagraph technology is also excellent news for the extremely large telescopes currently under construction. Thermal infrared instruments such as the Mid-infrared E-ELT Imager and Spectrograph (METIS) can exploit this new technology and discover new worlds. With a vector-APP coronagraph in the next generation of telescopes, we can search for planets around nearby stars with unprecedented sensitivity.”
The advanced liquid crystal technology that the team adopted also permitted the production of extreme vector-APP designs that are not possible with more traditional manufacturing technologies. These new designs produce dark holes that cover the full 360 degrees around the target stars. The first data from an experimental device already shows the viability of this novel approach (see Figure 2).
Support from the William F. and Elizabeth Lucas Junior Faculty Astronomy Award and the NASA Origins of Solar Systems program made this exciting commissioning possible at the MagAO instrument in Chile. This work was performed in part under contract with the California Institute of Technology (Caltech) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute.
Quelle: NOVA

Tags: Astronomie 

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Sonntag, 28. Juni 2015 - 10:25 Uhr

Astronomie - Unerwarteterweise saugt Kleines Schwarzes-Loch-Monster schnell die umgebenden Materie ein

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Using the Subaru Telescope, researchers at the Special Astrophysical Observatory in Russia and Kyoto University in Japan have found evidence that enigmatic objects in nearby galaxies – called ultra-luminous X-ray sources (ULXs) – exhibit strong outflows that are created as matter falls onto their black holes at unexpectedly high rates. The strong outflows suggest that the black holes in these ULXs must be much smaller than expected. Curiously, these objects appear to be "cousins" of SS 433, one of the most exotic objects in our own Milky Way Galaxy. The team's observations help shed light on the nature of ULXs, and impact our understanding of how supermassive black holes in galactic centers are formed and how matter rapidly falls onto those black holes (Figure 1).

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Figure 1: Multi-color optical image around the ULX "X-1" (indicated by the arrow) in the dwarf galaxy Holmberg II, located in the direction of the constellation Ursa Major, at a distance of 11 million light-years. The image size corresponds to 1,100 × 900 light-years at the galaxy. The red color represents spectral line emission from hydrogen atoms. (Credit: Special Astrophysical Observatory/Hubble Space Telescope)

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X-ray observations of nearby galaxies have revealed these exceptionally luminous sources at off-nuclear positions that radiate about million times higher power than the Sun. The origins of ULXs have been a subject of heated debate for a long time. The basic idea is that a ULX is a close binary system consisting of a black hole and a star. As matter from the star falls onto the black hole, an accretion disk forms around the black hole. As the gravitational energy of the material is released, the innermost part of the disk is heated up to a temperature higher than 10 million degrees, which causes it to emit strong X-rays.
The unsolved key question about these objects asks: what is the mass of the black hole in these bright objects? ULXs are typically more than a hundred times more luminous than known black hole binaries in the Milky Way, whose black hole masses are at most 20 times the mass of the Sun.
There are two different black hole scenarios proposed to explain these objects: (1) they contain very "big" black holes that could be more than a thousand times more massive than the Sun (Note 1), or (2) they are relatively small black holes, "little monsters" with masses no more than a hundred times that of the Sun, that shine at luminosities exceeding theoretical limits for standard accretion (called "supercritical (or super-Eddington) accretion," Note 2). Such supercritical accretion is expected to produce powerful outflow in a form of a dense disk wind.
To understand which scenario explains the observed ULXs researchers observed four objects: Holmberg II X-1, Holmberg IX X-1, NGC 4559 X-7, NGC 5204 X-1, and took high-quality spectra with the FOCAS instrument on Subaru Telescope for four nights. Figure 1 shows an optical multi-color image toward Holmberg II X-1 as observed with Hubble Space Telescope. The object X-1, indicated by the arrow, is surrounded by a nebula (colored in red), which is most likely the gas heated by strong radiation from the ULX.
The team discovered a prominent feature in the optical spectra of all the ULXs observed (Figure 2). It is a broad emission line from helium ions, which indicates the presence of gas heated to temperatures of several tens of thousands of degrees in the system. In addition, they found that the width of the hydrogen line, which is emitted from cooler gas (with a temperature of about 10,000 K), is broader than the helium line. The width of a spectral line reflects velocity dispersion of the gas and shows up due to the Doppler effect caused by a distribution of the velocities of gas molecules. These findings suggest that the gas must be accelerated outward as a wind from either the disk or the companion star and that it is cooling down as it escapes.
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Figure 2: Optical spectra of the four ULXs observed with the Subaru Telescope (from upper to lower, Holmberg II X-1, Holmberg IX X-1, NGC 4559 X-7, NGC 5204 X-1). He II and Hα denote the spectral lines from helium ions and from hydrogen atoms, respectively. (Credit: Kyoto University)
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Distant ULXs and a Similar Mysterious Object in the Milky Way
The activity of these ULXs in distant galaxies is very similar to a mysterious object in our own Milky Way. The team noticed that the same line features are also observed at SS 433, a close binary consisting of an A-type star and most probably a black hole with a mass less than 10 times that of the Sun. SS 433 is famous for its persistent jets with a velocity of 0.26 times the speed of light. It is the only confirmed system that shows supercritical accretion (that is, an excessive amount of accretion that results in a very powerful outflow). By contrast, such features have not been observed from "normal" black hole X-ray binaries in the Milky Way where sub-critical accretion takes place.
After carefully examining several possibilities, the team concluded that huge amounts of gas are rapidly falling onto "little monster" black holes in each of these ULXs, which produces a dense disk wind flowing away from the supercritical accretion disk. They suggest that "bona-fide" ULXs with luminosities of about million times that of the Sun must belong to a homogeneous class of objects, and SS 433 is an extreme case of the same population. In these, even though the black hole is small, very luminous X-ray radiation is emitted as the surrounding gas falls onto the disk at a huge rate.
Figure 3 is a schematic view of the ULXs (upper side) and SS 433 (lower side). If the system is observed from a vertical direction, it's clear that the central part of the accretion disk emits intense X-rays. If SS 433 were observed in the same direction, it would be recognized as the brightest X-ray source in the Milky Way. In reality, since we are looking at SS 433 almost along the disk plane, our line-of-sight view towards the inner disk is blocked by the outer disk. The accretion rate is inferred to be much larger in SS 433 than in the ULXs, which could explain the presence of persistent jets in SS 433.
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Figure 3: Schematic view of ULXs (looking from upper side) and SS 433 (looking from left side). Strong X-rays are emitted from the inner region of the supercritical accretion disk. Powerful winds are launched from the disk, which eventually emit spectral lines of helium ions and hydrogen atoms. (Credit: Kyoto University)
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Such "supercritical accretion" is thought to be a possible mechanism in the formation of supermassive black holes at galactic centers in very short time periods (which are observed very early in cosmic time). The discovery of these phenomena in the nearby universe has significant impacts on our understanding of how supermassive black holes are formed and how matter rapidly falls onto them.
There are still some remaining questions: What are the typical mass ranges of the black holes in ULXs? In what conditions can steady baryonic jets as observed in SS 433 be produced? Dr. Yoshihiro Ueda, a core member of the team, expresses his enthusiasm for future research in this area. "We would like to tackle these unresolved problems by using the new X-ray observations by ASTRO-H, planned to be launched early next year, and by more sensitive future X-ray satellites, together with multi-wavelength observations of ULXs and SS 433," he said.
This work has been published online in Nature Physics on 2015 June 1 (Fabrika et al. 2015, "Supercritical Accretion Discs in Ultraluminous X-ray Sources and SS 433", 10.1038/nphys3348). The research was supported by the Japan Society for the Promotion of Science's KAKENHI Grant number 26400228.
Authors:
Sergei Fabrika (Special Astrophysical Observatory, Russia; Kazan Federal University, Russia)
Yoshihiro Ueda (Department of Astronomy, Kyoto University, Japan)
Alexander Vinokurov (Special Astrophysical Observatory, Russia)
Olga Sholukhova (Special Astrophysical Observatory, Russia)
Megumi Shidatsu (Department of Astronomy, Kyoto University, Japan)
Notes:
Generally, black holes with masses between about 100 and about 100,000 times that of the Sun are called "intermediate-mass black holes," although there is no strict definition for the mass range.
In a spherically symmetric case, matter cannot fall onto a central object when the radiation pressure exceeds the gravity. This luminosity is called the Eddington limit, which is proportional to the mass of the central object. When matter is accreted at rates higher than that corresponding to the Eddington limit, it is called "supercritical (or super-Eddington) accretion." In the case of non-spherical geometry, such as disk accretion, supercritical accretion may happen.
Quelle: Subaru Telescope

Tags: Astronomie 

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Sonntag, 28. Juni 2015 - 08:30 Uhr

Astronomie - Messier 87 hat in der vergangenen Milliarde Jahre eine ganze Galaxie verschlungen

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Die elliptische Galaxie Messier 87 hat in der letzten Milliarde Jahre eine ganze Galaxie mittlerer Größe verschlungen – das ergaben neue Beobachtungen mit dem Very Large Telescope der ESO. Zum ersten Mal gelang es einem Astronomenteam vom Max-Planck-Institut für extraterrestrische Physik in Garching, die Bewegung von 300 leuchtenden Planetarischen Nebel zu verfolgen, um klare Hinweise auf dieses Ereignis zu finden. Außerdem fanden sie Hinweise auf überschüssiges Licht, das aus den Überresten des vollständig zerrissenen Opfers dieses kosmischen Ereignisses stammt.

Astronomen gehen davon aus, dass Galaxien wachsen, indem sie kleinere Galaxien regelrecht verschlingen. Der Nachweis dessen ist allerdings nicht einfach zu beobachten – genauso wie Wasser, das aus einem Glas in einen Teich gegossen wird, sich schnell mit dem Teichwasser mischt, mischen sich die Sterne der Galaxie, die verschlungen wird, mit den ihnen sehr ähnlichen Sternen der größeren Galaxien, ohne auch nur irgendeine Spur zu hinterlassen.
Ein Team aus Astronomen, angeführt von der Doktorandin Alessia Longobardi vom Max-Planck-Institut für extraterrestrische Physik in Garching, hat einen raffinierten Beobachtungstrick angewendet, um eindeutig nachweisen zu können, dass die nahegelegene riesige elliptische Galaxie Messier 87 in der letzten Milliarde Jahre mit einer mittelgroßen anderen Galaxie verschmolzen ist. „Das zeigt, dass auch große, hellleuchtende Strukturen im Universum immer noch in nicht unerheblichem Umfang wachsen – Galaxien sind noch nicht fertig entwickelt“, erklärt Alessia Longobardi. „Ein großer Bereich des äußeren Halos von Messier 87 ist jetzt zweimal so hell als ohne die Kollision.“
Messier 87 befindet sich im Zentrum des Virgo-Galaxienhaufens und ist eine gewaltige Kugel voller Sterne mit einer Gesamtmasse von mehr als einer Billion Sonnenmassen, die etwa 50 Millionen Lichtjahre von uns entfernt ist. Anstatt den Versuch zu unternehmen alle Sterne in Messier 87 unter die Lupe zu nehmen – es sind im wahrsten Sinne des Wortes Milliarden, und sie sind zu lichtschwach und zahlreich um einzeln untersucht zu werden – nahm das Team nur Planetarische Nebel in Augenschein, die leuchtenden Hüllen alternder Sterne. Da diese Objekte sehr hell in einem speziellen Grünton leuchten, sind sie von den umgebenden Sternen gut zu unterscheiden. Mithilfe sorgfältiger Untersuchungen des Lichts durch einen leistungsstarken Spektrografen können Rückschlüsse auf deren Bewegung gezogen werden.
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Genauso wie das Wasser aus dem Glas nicht mehr sichtbar ist, wenn es erst einmal in den Teich geschüttet wurde – aber möglicherweise kleine Wellen und andere Störungen verursacht hat, die sichtbar sind, wenn sich Schmutzpartikel im Wasser befinden – liefern die Bewegungen der Planetarischen Nebel, vermessen mit dem FLAMES-Spektrografen am Very Large Telescope, Hinweise auf die frühere Verschmelzung.
“Wir sind Zeugen eines einzelnen, noch gar nicht so lange zurückliegenden Verschmelzungsereignisses, bei dem eine Galaxie mittlerer Größe durch das Zentrum von Messier 87 gerauscht ist, deren Sterne infolge der enormen gravitativen Gezeitenkräfte nun über eine Region verteilt sind, die 100 Mal größer ist als die ursprüngliche Galaxie”, fügt Ortwin Gerhard, Leiter der Dynamik-Gruppe am Max-Planck-Institut für extraterrestrische Physik in Garching hinzu, einer der Koautoren der Studie, in der die neuen Ergebnisse präsentiert werden.
Das Team untersuchte auch sehr gründlich die Lichtverteilung in den äußeren Bereichen von Messier 87 und fand Hinweise auf zusätzliches Licht, das von den Sternen aus der Galaxie stammt, die angezogen und zerrissen wurde. Diese Beobachtungen haben auch gezeigt, dass durch die zerstörte Galaxie jüngere, blaue Sterne in Messier 87 hinzugekommen sind. Vermutlich handelte es sich also vor ihrem Untergang um eine Spiralgalaxie mit aktiver Sternentstehung.
“Es ist sehr aufregend, Sterne identifizieren zu können, die über Hunderttausende von Lichtjahren im Halo dieser Galaxie verstreut wurden – und trotzdem noch in der Lage zu sein, anhand ihrer Geschwindigkeiten zu erkennen, dass sie zu einer gemeinsamen Struktur gehören. Die grünen Planetarischen Nebel sind wie Nadeln in einem Heuhaufen aus roten Sternen. Aber diese seltenen Nadeln halten Hinweise darüber bereit, was mit den Sternen passiert ist”, stellt Koautorin Magda Arnaboldi von der ESO in Garching abschließend fest.
 
Anmerkungen:
[1] Planetarische Nebel bilden sich, wenn sonnenähnliche Sterne das Ende ihres Lebens erreichen. Sie senden einen den Großteil ihrer Energie in Form von nur wenigen Spektrallinien aus, die hellste darunter liegt im grünen Bereich des sichtbaren Lichts. Daher lassen sich ihre Geschwindigkeiten auch in der großen Entfernung von 50 Millionen Lichtjahren, in der sich Messier 87 befindet, noch einzeln messen. Sie verhalten sich sozusagen wie Leuchttürme aus grünem Licht die und zeigen, wo sie sind und mit welcher Geschwindigkeit sie sich bewegen.
[2] Diese Planetarischen Nebel sind sehr lichtschwach und das Leistungsvermögen des Very Large Telescopes muss vollständig ausgereizt werden, um sie näher untersuchen zu können: Die Lichtmenge, die von einem typischen Planetarischen Nebel im Halo der Galaxie Messier 87 auf der Erde ankommt, entspricht zwei 60-Watt-Glühbirnen auf der Venus.
Die Bewegungen Planetarischer Nebel entlang der Sehlinie zur Earth führen zu Verschiebungen der Spektrallinien aufgrund des Dopplereffekts. Diese Verschiebungen können mit einem empfindlichenen Spektrografen sehr präzise gemessen werden und ermöglichen so die Bestimmung der Geschwindigkeiten der Nebel.
Quelle: Max-Planck-Institut für extraterrestrische Physik 85748 Garching

Tags: Astronomie 

1476 Views

Sonntag, 28. Juni 2015 - 08:00 Uhr

Astronomie - Neue Studie von University of Southern Mississippi, besagt das Universum sich nicht nur ausdehnt, sondern auch schwingend

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Is the Universe Ringing Like a Crystal Glass?
Main Content
ARTICLE | THU, 06/18/2015 - 4:18PM | BY TARA BURCHAM
Many know the phrase “the big bang theory.” There’s even a top television comedy series with that as its title. According to scientists, the universe began with the “big bang” and expanded to the size it is today. Yet, the gravity of all of this matter, stars, gas, galaxies, and mysterious dark matter, tries to pull the universe back together, slowing down the expansion. 
Now, two physicists at The University of Southern Mississippi, Lawrence Mead and Harry Ringermacher, have discovered that the universe might not only be expanding, but also oscillating or “ringing” at the same time. Their paper on the topic has been published in the April 2015 issue of the Astronomical Journal.
In 1978 Arno Allan Penzias and Robert Woodrow Wilson received the Nobel prize for their 1964 discovery of the key signature of this theory, the primal radiation from the early universe known as the “cosmic microwave background” (CMB).
“Then in 1998 the finding that the universe was not only expanding, but was speeding up, or accelerating in its expansion was a shock when it was discovered simultaneously by east coast and west coast teams of astronomers and physicists,” said Mead. “A new form of matter, dark energy, repulsive in nature, was responsible for the speed-up. The teams led by Saul Perlmutter, Adam Riess, and Brian Schmidt won the 2011 Nobel Prize in Physics for that discovery.”
According to Mead and Ringermacher, this change from slowing down to speeding up (the transition time) took place approximately 6 to 7 billion years ago. Since then, Mead and Ringermacher say a vast accumulation of high-tech data has verified the theory to extraordinary accuracy.
Figure 1 is a NASA diagram representing the events of the Big Bang from the beginning of time to the present day as described by the current, accepted model known as “CDM” or Lambda Cold Dark Matter, where the Greek Lambda stands for Einstein’s “cosmological constant”. This cosmological constant is responsible for the acceleration of the universe. The outline of the “bell-shaped” universe represents its expanding size. The transition time is the point in time at which the bell shape shifts from going inward to outward from left to right.
“The new finding suggests that the universe has slowed down and speeded up, not just once, but 7 times in the last 13.8 billion years, on average emulating dark matter in the process,” said Mead. “The ringing has been decaying and is now very small – much like striking a crystal glass and hearing it ring down.”
Figure 2 shows the new finding superposed on the CDM model of Figure 1.  The oscillation amplitude is highly exaggerated, but the frequency is roughly correct. Ringermacher and Mead have determined that this oscillation is not a wave moving through the universe, such as a gravitational wave, but rather it is a “wave of the universe”.
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Ringermacher says the discovery was made accidentally when, through their collaboration on dark matter modeling of galaxies, they found a new way of plotting a classic textbook graph describing the scale of the universe against its age (lookback time) that did not depend on one’s prior choice of models of the universe – as was traditional.
“The standard graph, the Hubble diagram, is constructed by astronomers observing the distances of Type 1A Supernovae that serve as “standard candles” for measuring the expansion of the universe,” said Ringermacher. “Analyzing this new plot to locate the transition time of the universe, we found there was more than one such time – in fact multiple oscillations with a frequency of about 7 cycles over the lifetime of the universe. It is space itself that has been speeding up its expansion followed by slowing down 7 times since creation.”
Mead and Ringermacher say this finding must ultimately be verified by independent analyses, preferably of new supernovae data, to confirm its reality. In the meantime, their work into the “ringing” of the universe continues.
Quelle: The University of Southern Mississippi

Tags: Astronomie sondern auch schwingend 

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Samstag, 27. Juni 2015 - 21:45 Uhr

Astronomie - Sharjah Zentrum für Astronomie-und Weltraum (Vereinigte Arabische Emirate) öffnet für die Öffentlichkeit am 2. Juli

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Facility at University City of Sharjah seeks to renew spirit of scientific enquiry in the Arab world
Those keen on developments to do with space exploration and astronomy can look forward to experiencing first-hand the scientific theories that have helped shape our understanding of the universe at the Sharjah Centre for Astronomy and Space Sciences when it opens to the public on July 2.
The centre was built on the instructions of His Highness Dr Shaikh Sultan Bin Mohammad Al Qasimi, Supreme Council Member and Ruler of Sharjah, to promote and develop education about astronomy and space sciences in the Arab world.
A tour of the two-storey centre located in the University City in Sharjah starts with an educational exhibition that provides visitors with a hands-on learning experience through game-like models.
The exhibition is divided into four sections that highlight the principles of astronomy and physics, early understanding of light behaviour and spectrum, and the formation of the universe to name a few.
The highlight of the centre is its high-tech planetarium that takes the audience through a journey through the cosmos to explore the constellations, the planets and the brightest of stars.
Marwan Anwar Shwaiki, the Planetarium’s manager, said that the planetarium — with a dome spanning a diameter of more than 18 metres — is equipped with a set of high-precision digital projectors and the most advanced MegaStar projector, which can display nearly 10 million celestial bodies. The planetarium can accommodate more than 200 visitors at a time.
In addition to eight other space-related documentaries, the planetarium also displays a short movie titled Deen Al Qayyimah (That is the Correct Religion), which is authored by Shaikh Sultan himself under a title borrowed from a verse in the Quran.
The documentary tells the story of how the universe was created by Allah at the moment of the Big Bang.
Abdul Dayem Kaheel, a visitor at the exhibition and creator of Kaheel7.com website, one the biggest websites on astronomy in the Islamic context with information drawn from it translated into nine languages, commended the 360-degree movie.
“My love for astronomy started from the Quran. God orders us to study astronomy as well as other sciences,” he said. “The space and astronomy centre is one of Shaikh Sultan’s many great cultural developments. I believe that Islamic scholars should come here to learn about astronomy to understand the Quran better.”
RESEARCH CENTRE
Shwaiki said the facility will also be used for research by students from the University of Sharjah.
“We have an astronomical lab that can be used by secondary schools and university students to learn astrophysics. We will also have a space lab for students from the University of Sharjah to build satellites,” he said.
Shwaiki said the centre hopes to create space technology to keep pace with the UAE’s national agenda. He added that he expects the research centre to be functional next year as a course on space technology is introduced in the University of Sharjah.
An astronomical observatory at the complex houses a telescopic system comprising a reflecting telescope of 450 mm diameter connected with a refracting telescope of 180 mm diameter, both devices mounted on one base.
The system is connected to an electronic control network that posts the acquired data on the internet to enable users to access it anywhere in the world. The observatory also has a high-precision spectroscope that enables a research team to study unique phenomena such as unstable and double stars and formulate mathematical models for them.
Academically, the observatory plays a significant role in teaching astronomy and astrophysics to university students, with the programme seeing consistently higher enrolment every semester.
The centre is surrounded by lush green areas that will be open to the public to unwind. Giant structures modelled on the planets of the solar system are spread around the park with the centre’s golden dome representing the sun.
Other public facilities include the Universe in Holy Quran Exhibition, a galactic cafeteria and a souvenir shop.
Quelle: GULF NEWS

Tags: Astronomie 

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Samstag, 27. Juni 2015 - 21:30 Uhr

Raumfahrt - Medizin im Weltall ist völlig anders als auf der Erde

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Preparing to make a house call: Scott Kelly, currently aboard the space station for a one-year stay, checks out spacewalk suit of space doc Kjell Lindgren, who blasts off next month

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Everything's different in zero-g
You may or may not want to go to space, but here’s something certain: you definitely don’t want to get sick there. Ask the crew of Apollo 7, the 1960s mission in which the commander contracted a cold, spread it to the other two astronauts and all three of them spent the entire mission trapped inside a cramped spacecraft, sneezing, hacking and griping at the ground.
And that was just 11 days in Earth orbit. What about a year aboard the International Space Station (ISS)? What about a two-and-a-half-year mission to Mars. And what about something a wee bit more serious than a cold—like appendicitis or a heart attack or a severe injury? Zero-gravity plays all manner of nasty games with the bones, muscles, organs, eyeballs, the brain itself—never mind the infectious risks that come from sealing half a dozen people inside a self-contained vessel, where a virus or bacterium could simply circulate ’round and ’round, from person to person indefinitely.
These are some of the things that will be on the mind of rookie astronaut Kjell Lindgren, who will spend nearly six months aboard the ISS when he lifts off in late July as part of the station’s next three-person crew. Lindgren is not just a well-trained astronaut, but a specialist in aerospace and emergency medicine—just the kind of expert who will increasingly be needed as the human presence in space becomes permanent.
“If we want to go to Mars some day,” Lindgren said in a recent conversation with TIME, “if we want to get further and deeper into the solar system, we need to start thinking about these things, thinking about the capabilities we need to do an appendectomy or take out a gall bladder.”
There will be no gall bladder or appendix takings while Lindgren is aloft. For now, he and the ISS flight doctors back on Earth are taking only space-medicine baby steps, learning the basics about the radical differences between medical care on the Earth and medical care off it. Here are a few of the most vexing problems they have to learn to solve:
1. Where is that kidney again? On Earth, your organs settle into predictable positions. A doctor palpating your liver or thumping your chest knows exactly where things ought to be. In zero-g, not so much. “The organs may be displaced a little bit,” says Lindgren. “They tend to shift up a little more. The heart may have a little bit of a different orientation, which may be reflected on an EKG.” Other kinds of shifting or compression—of the lungs, stomach, bladder and more—can cause problems of their own.
2. Your bones hate space: Without the constant tug of gravity, your skeleton doesn’t work nearly as hard, which causes it to weaken and decalcify. Astronauts spend many hours a week exercising to counteract some of that, but nothing can reverse it completely. When Russia’s Mir space station was still flying, newly arriving cosmonauts were warned not to exchange traditional bear hugs with crew members who had been there for a while. The risk: broken ribs.
3. Your eyes do too: Astronauts who have been in space for long-term stays often find that their vision grows worse, and it doesn’t always bounce completely back when they return to Earth. The problem is caused by fluid shifting upward from the lower body into the head, compressing the optic nerve and distorting the shape of the eyeball. Eye infections and irritation are more common too—for decidedly ick-inducing reasons. “Dust doesn’t settle in the vehicle like it does on Earth,” says Lindgren. “So things that are liberated, little pieces of metal from equipment or maybe dead skin just float around and cause eye irritation.”
4. But your feet will thank you: You know all of those callouses that you’ve built up on your heel and the ball of your foot after a lifetime of walking around? Say goodbye too them. They serve a purpose, which is to cushion your foot against the shock of walking, but since you’re not walking in space, you don’t need them. Just beware when you remove your socks. The callouses don’t tell you when they’re going to slough off, so the wrong move at the wrong time could leave unsightly chunks of you floating around the cabin. (See, e.g., “ick-inducing,” above.)
5. Try not to need stitches: Suturing wounds is one of the most basic things doctors and other medical caregivers learn how to do, but it will take a little extra work in space. On Earth, sutures are simply laid on a tray along with the other equipment. In space, that’s not possible. “Instead of your sterile suture thread laying in a sterile field, now it’s floating around and running into everything,” says Lindgren. While aloft, Lindgren plans to experiment with different techniques to address this problem; no word on which of his five crewmates will volunteer to be the patient.
6. Eat your roughage: Easily the least glamorous part of space travel is the simple business of, well, doing your business. The space toilets aboard the ISS and the shuttle have come a long way from the bags and tubes of the Mercury, Gemini and Apollo era. But the human body hasn’t changed much in that time, and when it comes to keeping the intestines operating, a little gravity can help. One lunar astronaut who, for the sake of legacy and dignity will not be identified here, claimed that one of the best parts about landing on the moon was that things that hadn’t been working at all when he was in zero-g, got moving right away in the one-sixth gravity of the moon. History is made by mortals, and no matter where they are, mortals gotta’ do what mortals gotta’ do.
Quelle: TIME

Tags: Raumfahrt 

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Samstag, 27. Juni 2015 - 21:15 Uhr

Raumfahrt - JAXA plant neue Organisation zu gründen, welche spezialisiert ist für die Erforschung von außerirdischen Materialien

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Japan to launch new group to study extraterrestrial materials

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The Japan Aerospace Exploration Agency plans to launch a new organization Wednesday specializing in the study of extraterrestrial materials to further investigate how the solar system developed, agency officials said Saturday.
JAXA, as the agency is known, will establish the new organization within its Institute of Space and Astronautical Science in Sagamihara, Kanagawa Prefecture.
The group is expected to analyze mineral grains brought back to Earth from the asteroid Itokawa by the Hayabusa probe, as well as rocks taken from asteroid 1999 JU3 by the Hayabusa2, which is expected to arrive in three years and return with the samples by the end of 2020.
It will also likely to study ice and sand brought back from a satellite of Mars by a probe in the early 2020s, they added.
Asteroids are believed to date back to the birth of the solar system, and their composition holds clues as to how the planets developed and how Earth received the water and organic chemicals that allowed life to emerge.
With the new entity, JAXA plans to study asteroid samples to be brought to Earth by the Origin Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) to be launched next year by the NASA, the officials added.
Regolith is the loose material that lies atop bedrock.
JAXA will keep these extraterrestrial materials away from materials on Earth and handle them carefully with special apparatus to be set up in a clean room. They will be stored in containers filled with nitrogen to avoid contact with the atmosphere.
Any rocks brought back from asteroid 1999 JU3 by the Hayabusa2 are expected to contain a tiny amount of organic substances and moisture like those that could have fallen to Earth long ago and facilitated the origin of life.
JAXA also plans to develop a new method for analyzing these samples.
The new study organization is likely to consist of around 10 members and will work with outside organizations, such as the Japan Agency for Marine-Earth Science and Technology and the National Institute of Polar Research.
Quelle: The Japan Times

Tags: Raumfahrt 

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Samstag, 27. Juni 2015 - 21:00 Uhr

Raumfahrt - ISRO Mars Orbiter Mission übersteht Sonnenfinsternis, und sendet wieder Signale

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India's maiden Mars Orbiter Mission survived a 15-day solar eclipse (June 8-22) and emitted signals back to earth, the space agency chief said on Friday.
"Our Orbiter spacecraft has survived the blackout in the Martian atmosphere when sun came in between the red planet and the earth and was cut off from us. Coming out of the eclipse phase, it is communicating signals," Indian Space Research Organisation (Isro) chairman A.S. Kiran Kumar told reporters here.
The 1,340 kg spacecraft was under solar conjunction from June 8 when it went behind the sun and away from the earth due to solar eclipse, which occurs once in 26 months over the red planet.
"The Orbiter's communication signals that were disrupted by the sun's corona (outer atmosphere) during the fortnight-long eclipse got activated and its five payloads (scientific instruments) resumed activities after being on autonomous mode," Kiran Kumar said on the margins of a a global conference on "Science for Society" by alumni of the Indian Institute of Science (IISc).
Noting the spacecraft had withstood a crucial phase of nine months after reaching the Martian orbit, he said the Orbiter would continue to spin around the red planet for years as it had saved enough fuel since its November 5, 2013 launch from Sriharikota spaceport.
"Though the Orbiter's initial lifespan was intended to last six months after entering the Martian orbit (on September 24, 2014), it has been extended since March and is likely to survive many years as it is hardly using any fuel," he said.
Lauding the scientists for the mission's success, he said from the Orbiter's launch till its insertion after a 10-month voyage through the inter-planetary space, the mission did not encounter any untoward incident or deviation, which otherwise would have consumed precious fuel though provision was made for such occurrence.
Noting that the mission's objective of exploration would continue till the spacecraft survives, Kumar said the Orbiter had completed about 100 revolutions around the planet and its five experiments had transmitted enormous data to the space agency's deep space network near here.
"As a bonus of its extended life, we will collect more data and information on the seasons on Mars and its images. Our payloads have found out many things during the last six-nine months, which are being validated," he added.
The Orbiter's Mars Colour Camera had transmitted about 400 images of the red planet till date to the space agency's telemetry tracking and command network (Istrac) in the city, while its spectrometer, Lyman Alpha photometer, thermal infrared imaging spectrometer and methane sensor have relayed data of their findings.
India created history by becoming the first country to have a craft enter the Martian orbit in maiden attempt after a nine-month voyage through the inter-planetary space.
It also became the first Asian country to have entered Mars' sphere of influence (gravity) in maiden attempt, as a similar mission by China failed to succeed in 2011.
The Rs. 450 crores Mars mission was launched November 5, 2013 on board a polar rocket. It had 855kg fuel but consumed about 800kg since then for its orbit-raising exercises undertaken during its nine-month long journey and on entering the Martian sphere.
Scientists at the mission control centre here monitor its orbital movement and check health of its instruments round-the- clock.
Orbiter takes 3.2 earth days or 72 hours, 51 minutes and 51 seconds to go around Mars once while orbiting at a distance of 500km nearest and over 80,000km farthest from its surface.
Quelle: NDTV

Tags: Raumfahrt und sendet wieder Signale 

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