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Sonntag, 15. Februar 2015 - 21:45 Uhr

Raumfahrt - ATV-5 Re-Entry Aufnahmen aus dem Innern der Kapsel

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7.02.2015

Next Monday, ESA astronaut Samantha Christoforetti will float into Europe’s space ferry to install a special infrared camera, set to capture unique interior views of the spacecraft’s break-up on reentry.
“The battery-powered camera will be trained on the Automated Transfer Vehicle’s forward hatch, and will record the shifting temperatures of the scene before it,” explains Neil Murray, overseeing the project for ESA.
“Recording at 10 frames per second, it should show us the last 10 seconds or so of the ATV. We don’t know exactly what we might see – might there be gradual deformations appearing as the spacecraft comes under strain, or will everything come apart extremely quickly?
“Our Break-Up Camera, or BUC, flying for the first time on this mission, will complement NASA’s Reentry Break-up Recorder.
“Whatever results we get back will be shared by our teams, and should tell us a lot about the eventual reentry of the International Space Station as well as spacecraft reentry in general.”
Every mission of ESA’s ATV ferry ends in the same way – filled with Space Station rubbish then burning up in the atmosphere, aiming at a designated ‘spacecraft graveyard’ in an empty stretch of the South Pacific.
But the reentry of this fifth and final ATV is something special. NASA and ESA are treating it as an opportunity to gather detailed information that will help future spacecraft reentries.
Accordingly, ATV-5 will be steered into a shallow descent compared to the standard deorbit path.
This ATV’s fiery demise will be tracked with a battery of cameras and imagers, on the ground, in the air and even from the Station itself, and this time on the vehicle itself.
ESA’s camera will not survive the reentry, expected to occur some 80–70 km up, but it is linked to the ‘SatCom’ sphere with a ceramic thermal protection system to endure the searing 1500°C.
Once SatCom is falling free, it will transmit its stored data to any Iridium communication satellites in view.
Plunging through the top of the atmosphere at around 7 km/s, it will itself be surrounded by scorching plasma known to block radio signals, but the hope is that its omnidirectional antenna will be able to exploit a gap in its trail.
If not, signalling will continue after the plasma has cleared – somewhere below 40 km altitude.
Japan’s i-Ball camera managed to gather images of its Station supply ferry breaking up in 2012. Another i-Ball was planned to fly with ATV-5, but was lost in the Antares rocket explosion last October.
Quelle: ESA
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Update: 10.02.2015
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ATV-4-Re-Entry
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ESA’s last Automated Transfer Vehicle will leave the International Space Station on Saturday for its final solo voyage, setting course for a fiery demise that will mark the end of its mission and the programme.
The last of five Automated Transfer Vehicles, Georges Lemaître has had an event-filled mission that has displayed the spacecraft’s versatility. ATV-5 was launched only nine months after predecessor Albert Einstein finished its mission to supply and reboost the orbital complex.
ATV-5 is the heaviest spacecraft ever lofted by an Ariane rocket, and delivered 6617 kg of supplies and experiments to the Station.
Before docking, it flew under the Station to demonstrate new laser and infrared imaging technology that will help future spacecraft to rendezvous with uncontrolled objects.
ESA astronaut Alexander Gerst and Russian cosmonaut Alexander Skvortsov oversaw the automated docking on 12 August and quickly began unloading the many items in its cargo hold. Over the last six months, the crew have unpacked the cargo and in turn have loaded ATV-5 with rubbish.
Meanwhile, mission controllers in Toulouse, France, have commanded oxygen, air, fuel and water to pump into the Station’s tanks.
In October Georges Lemaître was the first ATV to push the Station out of the way of space debris using a special manoeuvre requiring less preparation than usual. It repeated the trick just two weeks later.
Last month ATV-5 took the Station into a lower orbit, slowing their orbital speed after the outpost had turned around. This rare manoeuvre had not been performed since 2008, by the first ATV, and will allow other supply spacecraft to bring heavier cargo to the Station.
ATV-5 was set to enter the atmosphere at the end of February in a new, shallow dive that would have allowed NASA and ESA teams to observe the spacecraft closely and learn from its reentry.
However, one of the four power chains failed last week, leading it to switch automatically over to its ‘failsafe’ system. ATV is designed to continue its normal mission with one failure, and can still be controlled safely even with two.
The increased risk of a second failure in the 13 days of free flight before the 27 February reentry, and the impossibility of shortening this phase because of heavy Station traffic and other ATV operational constraints, has led ESA to cancel the shallow reentry.
As a result, George Lemaître will follow the standard reentry profile around 30 hours after undocking, just like its predecessors.
Two experiments are ready in ATV’s cargo hold: both will monitor the temperature and record other information as it reenters in a  controlled dive, transmitting recorded data to researchers.
“The ATV team has worked tirelessly for five missions in a row,” says ATV-5 mission manager Massimo Cislaghi.
“While teams are sincerely disappointed not to conduct the planned shallow reentry, the revised plan doesn’t alter the programme’s overall success.
“The ATVs are large and complex spacecraft and they have achieved every goal, demonstrating Europe’s technical expertise and the skill of teams at ESA, France’s CNES space agency and the many industrial partners.”
While this is the last of the ATV flights, the knowhow and technology that have gone into the series will soon fly again as early as 2017 to power NASA’s Orion spacecraft with the European Service Module, paving the way for the next era in  space exploration.
Quelle: ESA
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Update: 14.02.2015
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Europe's Final ATV Cargo Ship Leaves Space Station Saturday: Watch Live

An unmanned European space ship as big as a double-decker bus will leave the International Space Station tomorrow, signaling the end of a line of cargo ships that had delivered supplies to astronauts since 2008.
Packed with astronaut trash, the European Space Agency's (ESA) fifth and last Automated Transfer Vehicle (ATV-5) will undock from the orbiting outpost Saturday morning (Feb. 14) at 8:41 a.m. EST.
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Timeline: Abdocken von ATV-5:
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Saturday 14 Feb
07:34 Start undocking critical phase
08:52 ISS hooks opening
13:16 ATV wakeup
13:34 Demerging
13:40 Earliest possible separation
13:44 SEPARATION
13:45 ATV departure manouevre (thruster burn)
13:59 ATV leaves the ISS 'approach ellipsoid' (critical area around Station)
16;06 End of undocking critical phase
16:30 Operations briefing at ATV-CC - last one ever?
Quelle: ESA
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Abdocken von ATV-5 - 13.42 MEZ LIVE
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14.15 MEZ
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Re-Entry : Sonntag, 15.02.2015
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Quelle: NASA-TV / ESA
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Update: 23.00 MEZ
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Sam and Sasha ‘at the controls’ of final ATV docking
Posted on 14 Feb 2015 by julien
ESA astronaut Samantha Cristoforetti just Tweeted these two images of ATV-5's undocking.
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Top-Video von ATV-5 Abdocken von ISS-Crew  hier: https://vine.co/v/OPTIKrLqITn
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Quelle: ESA
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Update: 15.02.2015
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The ATV control centre in Toulouse, France, commands the craft throughout their missions. Credit: CNES/M. Pedoussaut
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Sunday 15 Feb /Time GMT
11:30 Start of reentry critical phase
11:30 Start of reentry manoeuvre operations
14:30 DEO1 First deorbit manoeuvre
15:56 Tank switch
17:26 DEO2 Second deorbit manoeuvre
17:57 Tumbling (expected until 18:11; includes final loss of signal)
18:12 Impact (expected)
18:26 Final ATV-CC team briefing
18:57 End of reentry critical phase
 
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Quelle: ESA
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Abschied vom ATV: Raumfahrzeug "Georges Lemaître" verglüht über dem Südpazifik

Es ist ein Abschied für immer: Am 15. Februar 2015 ist um 19.04 Uhr mitteleuropäischer Zeit das fünfte und letzte europäische Raumfahrzeug ATV (Automated Transfer Vehicle) mit dem Namen "Georges Lemaître" kontrolliert in die Erdatmosphäre eingetreten und verglüht. Zuvor hatte es Nachschub und Experimente zur Internationalen Raumstation ISS transportiert sowie deren Bahn angehoben und korrigiert. Mit seinem Ausscheiden ist zwar die Ära der ATV-Transporter zu Ende - doch ihr Knowhow wird im europäischen Servicemodul der US-amerikanischen Raumkapsel Orion weiterleben.
Feuriges Finale im Taumelflug
Einen Tag zuvor, am 14. Februar, hatte ATV-5 um 14.40 Uhr mitteleuropäischer Sommerzeit vom russischen Swesda-Modul  der Raumstation abgedockt und Kurs auf die Erde genommen. Zwei gezielte Bremsmanöver sorgten vor dem Wiedereintritt dafür, dass der 20-Tonnen-Transporter in einem steilen Winkel in die Erdatmosphäre eintauchte, um dann zu verglühen. Das zusätzliche Zünden der Steuerdüsen brachte das Fahrzeug zum Taumeln und erleichterte so das Auseinanderbrechen in kleinere Einzelteile. Drei Wiedereintritts-Experimente zeichneten während des so genannten Reentries Daten auf, wie beispielsweise die Temperaturentwicklung, und sendeten diese zur Erde. Eines davon ist der schon zuvor eingesetzte "Reentry Break up Recorder" - eine Art Flugschreiber, der mechanische Lasten aufzeichnet. Er wurde jetzt von einer optischen und einer Infrarot-Kamera ergänzt. Diese übermittelten die Bilder vom Beginn des Wiedereintritts bis zum Auseinanderbrechen des ATV.
Der ursprünglich von der Europäischen Weltraumorganisation ESA geplante "Shallow Reentry", ein Wiedereintritt in die Erdatmosphäre mit flachem Winkel, wurde aus Sicherheitsgründen nicht durchgeführt. Vor einigen Tagen war eine Batterie in einem der vier redundanten Energieversorgungsstränge ausgefallen.
LIRIS verbessert das automatische Andocken
Am 30. Juli 2014 mitteleuropäischer Sommerzeit war ATV-5 mit eine Ariane-5-Trägerrakete vom Weltraumbahnhof Kourou in Französisch-Guayana zur ISS gestartet. An Bord befanden sich dabei Nachschub an Wasser, Treibstoff, Atemluft und Lebensmittel, der vom Deutschen Zentrum für Luft- und Raumfahrt (DLR) entwickelte Schmelzofen EML sowie die ebenfalls aus Deutschland stammende Experimente MagVector, Spacetex und WiseNet. Vor dem Andocken an die Raumstation am 12. August, das der deutsche ESA-Astronaut Alexander Gerst und der russische Kosmonaut Alexander Skvortsov überwachten, wurden erstmalig die neuen Rendezvous-Sensoren LIRIS (Laser InfraRed Imaging Sensors) am ATV getestet. Diese weiterentwickelte Kombination aus Laser- und Infrarot-Technologie soll zukünftige robotische Anwendungen, wie etwa die Entsorgung von Weltraummüll, ermöglichen und optimieren helfen.
Umittelbar nach dem Andocken begann die Crew mit dem Entladen des Transporters. Das mit über 300 Kilogramm größte der Experimente, den elektromagnetischen Levitator EML, baute Alexander Gerst ins "European Drawer Rack" des Columbus-Labors ein und begann mit dem Testbetrieb. In dem Schmelzofen, in dem metallische Legierungen frei schwebend aufgeschmolzen und analysiert werden können, sollen in den kommenden Monaten Experimente mit 18 verschiedenen Metallproben durchgeführt werden. EML liefert dabei hochgenaue Daten, die beispielsweise die Simulation von Gießvorgängen in der Metallproduktion entscheidend verbessern können.
ATV ist Geschichte, mit Orion geht es weiter
Mit "Georges Lemaître“ gehört das letzte ATV der Vergangenheit an - doch seine Technologie lebt weiter: Sie wird im europäischen Servicemodul ESM der US-amerikanischen Raumkapsel Orion verwendet. ESM ist dort für Energie, Antrieb und Temperaturkontrolle der Raumkapsel, aber auch für die Lagerung von Versorgungsgütern verantwortlich. Das Servicemodul ist außerdem ein so genanntes Barter-Element, das heißt, es sichert den Europäern Nutzungsrechte auf der ISS in den Jahren 2017 bis 2020.
Orion soll erstmals 2018 unbemannt getestet werden und zunächst den Mond, in zukünftigen Missionen aber auch Objekte im erdfernen Weltraum, wie etwa Asteroiden, erforschen. Mit dem ESM steuert die ESA erstmalig ein solch hochkomplexes und kritisches Element zu einer wichtigen US-Mission bei - ein großer Vertrauensbeweis, der durch das erfolgreiche ATV-Programm erst ermöglicht wurde. Entwickelt und gebaut wird ESM, wie auch zuvor das ATV, vom Raumfahrtunternehmen Airbus Defence and Space in Bremen.
Das Ende einer Ära
Mit seinem fünften erfolgreichen Flug habe das ATV alle Erwartungen an das Programm mehr als erfüllt, sagt Volker Schmid, ATV-Programmverantwortlicher beim Raumfahrtmanagement des Deutschen Zentrums für Luft- und Raumfahrt (DLR): "Der europäische Raumtransporter führte alle vollautomatischen Flüge und Andockmanöver in bisher nicht erreichter Präzision durch - allein das punktgenaue Andocken an die ISS bei 28.000 Stundenkilometern war eine große Herausforderung, die es zu meistern galt. Zudem ist ATV das größte und komplexeste Raumfahrzeug, das bislang für den Raumtransport eingesetzt wurde." ATV-1 "Jules Verne" startete 2008 zur Raumstation. Danach folgten "Johannes Kepler" (2011), "Edoardo Amaldi" (2012), "Albert Einstein" (2013) und "Georges Lemaître" (2014). Insgesamt wurden bei den fünf Flügen 31,5 Tonnen Fracht zur ISS transportiert. Mit den ATV-Flügen hat Europa seine Beteiligung an den allgemeinen Betriebskosten der ISS abgeleistet. Dadurch erhalten deutsche und andere europäische Astronauten, Wissenschaftler und Ingenieure entsprechende Nutzungszeit auf der ISS.
Mit dem Bau und der Entwicklung des ATV habe die europäische Raumfahrtindustrie wichtige Kenntnisse und Fähigkeiten sammeln und ihren hohen Technologiestandard unter Beweis stellen können, erläutert DLR-Experte Volker Schmid: "Deutschland war dabei federführend am Programm beteiligt und hat rund 48 Prozent der Beiträge des insgesamt drei Milliarden teuren Programms finanziert." Für de unter Federführung von Airbus Defense & Space in Bremen gebauten Transporter haben 30 Firmen aus zehn europäischen Ländern Leistungen erbracht, weitere Beiträge stammten aus Russland und den USA. Auch das DLR war maßgeblich am Programm beteiligt: So betreute das DLR Raumfahrtmanagement das Programm, beim deutschen Raumfahrtkontrollzentrum beim DLR in Oberpfaffenhofen wurde die Kommunikation zwischen dem ISS-Kontrollzentrum in Moskau und dem ATV-Kontrollzentrum in Toulouse koordiniert, und das DLR in Göttingen hatte die ATV-Steuerdüsen mitentwickelt.
Quelle: DLR

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Mission: A multi-instrument airborne campaign to monitor the shallow reentry of ESA's 5th, and final, Automated Transfer Vehicle over the south Pacific ocean to better understand the physics of the end of life International Space Station de-orbit and the physics of shallow uncontrolled reentries.

Ten of the 31-person strong ATV5 team during upload, ready to deploy in a next opportunity. From left to right: Ron Dantowitz (Dexter Southfield), Fabian Zander (U. Stuttgart), Ferdinand Fahlbush (Astos), Thomas Marynowski (U. Stuttgart), Marek Kozubal (Dexter Southfield), Stefan Loehle (U. Stuttgart), Peter Jenniskens (SETI Institute), Sven Weikert (Astos), Dave Buttsworth (U. Southern Queensland), and Forrest Gasdia (Embry Riddle Aeronautical University).

As a final effort to be prepared for the next shallow reentry opportunity, our team met at 4 am this morning to perform instrument checks, using calibration lamps at the far end of the darkened hangar. Later that morning the instruments and their racks were unloaded and readied for shipment home. It was a very sad moment to walk one last time through the DC8 aircraft, making sure nothing was left behind. The last item to collect was our mission logo sign at the bottom of the stairs.

Our flight has been postponed. This morning, we investigated the possibility of performing a daytime reentry observation campaign to Tahiti on Sunday February 15. Jim calculated the new observation point and found it was not far from where we would have been on Feb 27, even closer to Tahiti. We made sufficient progress with the DC8 preparations to not have a significant show stopper there either.
However, the objective of the ATV5 Reentry Observation Campaign was to study the physics and dynamics of shallow reentries relevant to the ISS de-orbit and it was decided this morning that the remaining funds for such a study be better saved for a next observation attempt during a future controlled reentry of another (necessarily smaller) spacecraft. Those already arrived at AAOF are finishing work today and tomorrow to improve our instrument installations so we are ready for this next opportunity.
Quelle: SETI INSTITUTE

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Update: 21.45 MEZ 

 
Sam CristoforettiVerifizierter Account
‏@AstroSamantha
Good bye #ATV5! Arrivederci ATV5! 
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Great view of ATV-5 smoke trail
Posted on 15 Feb 2015 by Daniel
And on board the ISS, astro Terry also grabbed an amazing photo of ATV-5 reentry!
Terry W. Virts        ✔ @AstroTerry
Final view #ATV5 Georges Lemaître entering Earth's atmosphere. It was surprising to see how high the smoke trail was. 
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ATV forever
This was the last image shown on the ATV Control Centre's main screen after the last reentry ever of an Automated Transfer Vehicle. The technology in ATV will go to space again in 2017 on NASA's Orion spacecraft.
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Last screen shown at the ATV control centre before being switched off.
Quelle: ESA

Jamais l'ATV-CC avait été aussi rempli. Crédits : CNES/Frédéric Maligne

 


Tags: Raumfahrt 

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Sonntag, 15. Februar 2015 - 11:15 Uhr

Astronomie - Daniel Inouye K Sonnenteleskop, als DKIST bekannt, wird auf dem Haleakala Berg in Maui, Hawaii errichtet

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Science Cases for DKIST
Spectral vs. Spatial Diagnostics The Sun sustains life on Earth and impacts human endeavors in space through variations in its radiative, magnetic and particle output as caused by magnetic activity. The solar atmosphere is controlled by magnetic fields. The Daniel K. Inouye Solar Telescope (DKIST) is the first major instrument designed by the astronomical community in all of its aspects as a tool for magnetic remote sensing. Its collecting area, spatial resolution, wavelength performance and integral focal plane instrumentation are all targeted for understanding how magnetic fields affect the physical properties of the Sun. DKIST will be the largest leap in ground-based solar capabilities since Galileo's telescope.
DKIST will be a four-meter off-axis reflecting telescope, which will have the spatial, temporal, spectral resolution and dynamic range that is needed to see and measure the basic magnetic structures (magnetic fibrils) at the solar surface and into the outer atmosphere. Currently much of the magnetic field is invisible. We therefore will depend on the DKIST for quantifying, understanding, and predicting the consequences of such magnetism on solar-terrestrial and astrophysical plasmas.
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The DKIST addresses the basic questions: What is the nature of solar magnetism; how does that magnetism control our star; and how can we model and predict its changing outputs that affect the Earth? DKIST will observe solar plasma processes and magnetic fields with unprecedented resolution in space and time. It will provide critical information needed to solve the mysteries associated with the generation, structure, and dynamics of the surface magnetic fields, which govern the solar wind, solar flares, and short-term solar variability. Used in combination with space-based and other ground-based solar observing assets, DKIST will underpin a revolution in our understanding of the sun.
The following pages provide short descriptions of just some of the critical science topics scientists will use the DKIST to address and solve.
Flux Tubes: The Building Blocks of Solar and Stellar Magnetic Fields
Solar Granulation Observations have established that the photospheric magnetic field is organized in small fibrils or flux tubes (associated with the bright g-band points seen in the photo). These structures are mostly unresolved by current telescopes. Flux tubes are the most likely channels for transporting energy into the upper atmosphere, which is the source of UV and X-ray radiation from the Sun, which in turn affects the Earth's atmosphere. Detailed observations of these fundamental building blocks of stellar magnetic fields are crucial for our understanding not only of the activity and heating of the outer atmospheres of late-type stars, but also of other astrophysical situations such as the accretion disks of compact objects, or proto-planetary environments. The diffraction limited resolution of DKIST will be 0."03 at 500nm and 0."08 at 1.6 microns. At this resolution DKIST will provide the required spectroscopy and polarimetry at an angular resolution to explore the enigmatic flux tube structures.
Magnetic Field Generation, Local Dynamos and the Solar Cycle
Small Scale Dynamo To understand solar activity and solar variability, we need to understand how magnetic fields are generated and how they are destroyed. The 11-year sunspot cycle and the corresponding 22-year magnetic cycle are still shrouded in mystery. Global dynamo models that attempt to explain large-scale solar magnetic fields are based on mean field theories. Dynamo action of a more turbulent nature in the convection zone may be an essential ingredient to a complete solar dynamo model. Local dynamos may produce the small-scale magnetic flux tubes recently observed to cover the entire Sun. This "magnetic carpet" continually renews itself on a time scale of a few days at most and its flux may be comparable to that in active regions. The DKIST will make it possible to directly observe such local dynamo action at the surface of the Sun. The DKIST will measure the turbulent vorticity and the diffusion of small-scale magnetic fields and determine how they evolve with the solar cycle. The DKIST will address the following fundamental questions: How do strong fields and weak fields interact? How are both generated? How do they disappear? Does the weak-field component have global importance and what is its significance for the solar cycle? The DKIST will address these fundamental questions by resolving individual magnetic flux tubes and observing their emergence and dynamics. It will measure distribution functions of field strength, field direction and flux tube sizes and compare these with theoretical models. The DKIST will observe plasma motions and relate them to the flux tube dynamics.
Magnetic and Current Helicity and its Relevance to the Dynamo Problem
Twisted Magnetic Fields Helicity plays a fundamental role in evolution and topology of solar magnetic fields on different spatial and temporal scales. Helicity is essential for the effective operation of a dynamo. On the other hand, excessive helicity may suppress the dynamo action. To ensure efficient operation of the dynamo, helicity has to be removed from the dynamo region and transported to the coronal. On their way to the surface magnetic fields can accumulate addition helicity by interacting with turbulence in the convection zone.
Interaction of Magnetic Fields and Mass Flows
Sunspot Fine StructuresIn sunspots, the total magnetic field is large enough to completely dominate the hydrodynamic behavior of the local gas, a regime very different from that of the rest of the solar photosphere. Numerical simulations and theoretical models predict dynamical phenomena, such as oscillatory convection in the strong-field regions of sunspot umbrae, flows at the speed of sound along penumbral filaments and oscillations and wave phenomena. To verify the predictions of numerical simulations of sunspots and ultimately answer such fundamental questions as "Why do sunspots exist?" require an extremely capable instrument. High-resolution (<0.1 arcsec) vector polarimetry combined with high sensitivity (requires high photon flux) and low-scattering optics are required. Understanding the interaction of magnetic flux and mass flows is crucial for our understanding of the behavior of magnetic fields from the scales of planetary magnetospheres, to star-forming regions, to supernova remnants, to clusters of galaxies. Sunspots allow us to test those theories in a regime where magnetic fields dominate mass flows.
Flares and Mass Ejections
H-alpha FlareIt is commonly believed that solar flares represent a process of rapid transformation of the magnetic energy of active regions into the kinetic energy of energetic particles and plasma flows and heat. Detection of variations of magnetic field associated with solar flares has been one of the most important problems of solar physics for many years. Such detection would provide direct evidence of magnetic energy release in the flares. An important goal for the DKIST will be to study the small-scale processes in solar flares. The DKIST will also provide a new set of tools, in particular in the infrared, to measure magnetic fields at higher layers of the atmosphere. There is limited observational evidence that the distribution of electric currents and current helicity inside an active region varies with flares. Highly uniform sequences of high-resolution vector magnetograms of an active region before and after a flare are required to address this important issue.
Coronal mass ejections (CMEs) originate in large-scale magnetic arcades known as helmet streamers. These structures are known to contain twisted magnetic fields. According to the prevailing view, the arcade becomes dynamically unstable when its fields are twisted beyond some critical point. Field line footpoint motions in the photosphere have long been considered efficient ways to supply (or drain) magnetic shear and energy into (from) the coronal field. MHD simulations have identified critical magnetic shear conditions above which the arcade field will form current sheets, and magnetic reconnection processes will occur to cause active phenomena such as flares, CMEs, and prominence formation and eruption. It is thus important to measure field line footpoint motions and, if possible, the magnetic shear in active regions as well. Although measurements of the footpoint motion (in particular the horizontal plasma flow velocity) have improved considerably, the DKIST will offer unprecedented high spatial and temporal resolution in measuring the field line footpoint motion.
More recently this view has been challenged by models in which the arcade emerges as a twisted flux rope or models in which small-scale photospheric reconnection events inject helicity into the corona. These hypothesized reconnection events occur when small (0."1) photospheric flux elements cancel along the active region's magnetic neutral line. This model seems to contradict those models in which CMEs result from excessive twist in the arcade. Detailed observations of the flux emergence can reveal whether the emerging flux is introducing magnetic twist into the arcade, or changing the arcade's topology through footpoint cancellation. Only with higher spatial resolution vector measurements and good temporal resolution as will be provided by the DKIST, however, can it be established, for example, that the rate and orientation of these cancellations is consistent with an observed change in the twist of the overlying arcade. Such observations are critical to distinguishing between competing models.
Inhomogeneous Stellar Atmospheres
Limb Spectrum of Solar CO LinesMeasurements of CO absorption spectra near 4.7µm show surprisingly cool clouds that appear to occupy much of the low chromosphere. Only a small fraction of the volume apparently is filled with hot gas, contrary to classical static models that exhibit a sharp temperature rise in those layers. The observed spectra can be explained by a new class of dynamic models of the solar atmosphere. However, the numerical simulations indicate that the temperature structures occur on spatial scales that cannot be resolved with current solar infrared telescopes. A test of the recent models requires a large-aperture solar telescope that provides access to the thermal infrared. Such observations would further explore the dynamical basis of the thermal bifurcation process, a fundamental source of atmospheric inhomogeneities in late-type stars. Spicules, the forest of hot jets that penetrate from the photosphere into the chromosphere, are clearly a MHD phenomenon that is not understood nor adequately modeled. Their role in the mass balance of the atmosphere is uncertain. Combined with UV observations (like those of TRACE), the DKIST will allow us to resolve their nature.
Magnetic Fields and Stellar Coronae
Coronal LoopsThe origin and heating of the solar corona, and the coronae of late-type stars, are still mysteries. Most of the proposed scenarios are based on dynamic magnetic fields rooted at the 0.1-arcsec scale in the photosphere. However, none of the processes has been clearly identified by observations or theory. EUV and X-ray observations have gained in importance, but ground-based observations are still critical, not only to determine the forcing of the coronal fields by photospheric motions, but also for the measurement of the coronal magnetic field strength itself. This is important for developing and testing models of flares and coronal mass ejections, which propel magnetic field and plasma into inter-planetary space and induce geomagnetic disturbances. In particular, precise measurements of the coronal magnetic field strength and topology are needed in order to distinguish between different theoretical models. The DKIST with its large aperture, low scattered light characteristics, and the capability to exploit the solar infrared spectrum will provide these critical measurements.
Quelle: DKIST
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Northumbria to help build world’s biggest solar telescope in £220 million project
Experts from Northumbria University, Newcastle are taking part in an international project to build the world’s biggest and most revolutionary solar telescope.
The $344 million (£220m) Daniel K Inouye Solar Telescope, to be known as DKIST, will be situated on Haleakala Mountain in Maui, Hawaii, and aims to unlock the secrets of the Sun. With a four-metre diameter primary mirror, the super-telescope will be able to pick up unprecedented detail on the Sun’s surface – the equivalent of being able to examine a £1 coin from a distance of 100km. It is hoped that DKIST will address fundamental questions at the core of contemporary solar physics. This will be achieved via high-speed spectroscopic and magnetic measurements of the solar photosphere, chromosphere and corona.
Northumbria’s Solar Physics research group will play a lead role in developing software to understand data from the telescope. Dr Richard Morton, Leverhulme Trust Early Career Research Fellow in the Department of Mathematics and Information Sciences, is the project lead at Northumbria.
He said: “DKIST is an exciting project that will revolutionise our understanding of the Sun and how it influences our lives. The Solar Physics research group at Northumbria will develop software to probe data from DKIST, providing key insight into the physical mechanisms responsible for energy transfer in the Sun's atmosphere and how this relates to solar variability and the generation of space weather, including solar flares, which can be hazardous to our technologically-advanced society.”
Northumbria University’s Pro Vice-Chancellor for Research and Innovation, Professor George Marston, said: “We are delighted to be one of eight UK universities helping to support the construction of the world’s most powerful solar telescope. Northumbria’s role in this international project clearly demonstrates the University’s ongoing commitment to driving scientific breakthroughs and technological innovation through the excellence of our world-class research and the expertise of our academics.”   Professor Marston, who spent two years as a Resident Research Associate at NASA Goddard Space Flight Center near Washington DC, added: “The DKIST will address fundamental questions in contemporary solar physics;  in addition, solar activity drives ‘space weather’ and has profound effects on Earth’s climate and global communications, highlighting the relevance of the research to important societal issues.” 
Eight UK institutes will be working as a consortium on DKIST. The project is led by Queen's University Belfast and includes Armagh Observatory, Northumbria University, University College London, and the Universities of Glasgow, Sheffield, St. Andrews and Warwick. The consortium will partner with Belfast-based company and Queen’s University spinout Andor Technology and the Science and Technology Facilities Council. It will oversee the development and delivery of the cameras, and take the lead in supporting the UK solar physics community in their use of DKIST by providing a set of processing tools for DKIST data, synthetic observations to validate diagnostic approaches, and support for developing observing proposals. DKIST is funded by the US National Science Foundation with £2.5m of funding for the cameras provided by the Science and Technology Facilities Council.Northumbria recently launched its Think Physics project to inspire more young people, especially girls and under-represented groups, to engage with Science, Technology, Engineering and Mathematics (STEM) from Early Years to Higher Education and into their careers. The University also recently announced an investment of £6.7 million in STEM facilities, co-funded by the Higher Education Funding Council for England (HEFCE), to help drive world-class research and teaching across STEM disciplines, and an increased flow of highly-employable graduates into industry. Northumbria University provides undergraduate and postgraduate courses in Physics and Physics with Astrophysics.
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Quelle:Northumbria University
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World’s biggest solar telescope to be built with Sheffield expertise
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• New telescope will provide unprecedented insight into physics of the surface and atmosphere of the Sun
• A consortium of universities, including Sheffield, are building cameras for the ‘super telescope’ based in Hawaii 
• Sheffield scientists will help UK solar physics community access facility 
• Telescope will improve the forecasting of space weather hazards
The world’s biggest and most revolutionary solar telescope is being built with the help of researchers from the University of Sheffield.
Led by Queens University Belfast, the Sheffield team is building cameras for the £344 million super telescope which will be situated in Hawaii.
The Daniel K Inouye Solar Telescope (DKIST), which will be launched in 2019, is being constructed by the US National Solar Observatory on Haleakala mountain in Maui, Hawaii. With a four-metre diameter primary mirror, the telescope will be able to pick up unprecedented detail on the surface of the Sun – the equivalent of being able to examine a £1 coin from 100kms away.
It is hoped that DKIST will address fundamental questions at the core of contemporary solar physics via high-speed (sub-second timescales) spectroscopic and magnetic measurements of the solar photosphere, chromosphere and corona – the different layers of the Sun’s atmosphere. The project will be mainly funded by the US National Science Foundation.
Professor Michail Balikhin from the University of Sheffield said: “The development of this telescope provides great potential for us to make earlier forecasts of space weather hazards, such as identifying solar winds which can cause huge disruption to life on Earth. 
Our Space System Laboratory in Sheffield has a well-established track record in space weather forecasting using a spacecraft situated about 1.5 million km from our planet. At the moment this enables us to identify space weather, such as solar wind velocities, approximately one hour before they reach Earth, but once this telescope is built we may be able to significantly extend this time.”
Dr Viktor Fedun from the University’s Solar Wave Theory Group added: “The new high-resolution cameras used by the telescope will provide an unprecedented amount of solar image data. Researchers at Sheffield will use their leading expertise in numerical modelling of plasma processes to develop new algorithms and numerical techniques to process the data observed from the new telescope which will be really impactful to the UK science community and beyond.”
Professor Robertus von Fay-Siebenburgen (a.k.a Erdelyi), Head of SP2RC (Solar Physics and Space Plasma Research Centre) at the University of Sheffield, said: “This is a fantastic opportunity to significantly improve the forecasting of Space Weather. In 1989 a particularly large amount of energetic solar plasma material was ejected from the Sun towards the Earth, which damaged satellites and electrical transmission facilities, as well as caused disruption to communications systems. The understanding and prediction of space weather is vitally important in the age of human exploration of the Solar System and the development of this new telescope will enable us to predict space weather events much earlier.
“It’s also a great facility for early career scientists in the UK and will pave the way for Sheffield to remain at the forefront of solar plasma research.”
The consortium will oversee the development and delivery of the cameras, and take the lead in supporting the UK solar physics community in their use of DKIST by providing a set of processing tools for DKIST data, synthetic observations to validate diagnostic approaches, and support for developing observing proposals.
Quelle: The University of Sheffield
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Tags: Astronomie als DKIST bekannt Hawaii errichtet 

2035 Views

Sonntag, 15. Februar 2015 - 10:33 Uhr

Raumfahrt - Deep Space Climate Observatory (DSCOVR) - Update

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New Lockheed Martin Instrument Gives ‘Big Picture’ Of Earth’s Evolving Climate

The EPIC instrument is 30-centimeter (11.8 inch) telescope that measures 10 channels of ultraviolet and visible areas of the spectrum. It’s one example of a series of instruments Lockheed Martin has developed for NASA and NOAA to reveal more about our planet, including the Global Lightning Mapper for the GOES-R satellite.

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A new Lockheed Martin [NYSE: LMT] instrument is about to make a world of difference for climate scientists. Launched successfully today aboard the Deep Space Climate Observatory (DSCOVR) spacecraft, the Earth Polychromatic Imaging Camera (EPIC) will provide imaging of the entire sunlit side of Earth in one view, something that hasn't been done before from a satellite.
Today, real-time Earth images are patched together from various satellites. With the whole-disk image—one that shows the entire face of the planet in one shot— scientists will have a broad view of the planet’s atmosphere at work. Using EPIC, scientists can monitor clouds and atmospheric particles moving across hemispheres, which will improve models for storms, droughts, dust, pollution and global climate.
“Never before has one instrument been able to capture the entire face of the Earth, to see weather at work on a global scale,” said Joe Mobilia, EPIC program manager at Lockheed Martin. “Even though EPIC will operate over a million miles away, it will deliver data about our atmosphere and vegetation that scientists have been waiting for. Climate affects every person, so better knowledge of atmospheric processes is essential to understanding what’s happening in the world around us.”
The instrument measures and tracks ozone amounts, aerosol particulates, cloud height, vegetation properties and ultraviolet radiation.
EPIC is a NASA-supplied instrument installed on the National Oceanic and Atmospheric Administration (NOAA) DSCOVR spacecraft. While other parts of DSCOVR will focus on space weather, this optical payload will gaze at Earth’s atmosphere to monitor weather events. It will be placed far into space, at a fixed orbiting position between the Earth and sun so it can capture the wide view of the planet in sunlight.
EPIC’s 30-centimeter (11.8 inch) telescope measures 10 channels of ultraviolet and visible areas of the spectrum. Despite its distance, EPIC images will have a resolution of between 25 and 35 kilometers (15.5 to 21.7 miles).
Lockheed Martin has helped NASA and NOAA reveal more about our planet through Earth science instruments developed, produced and tested by scientists and engineers at the Advanced Technology Center in Palo Alto, California. For example, the Global Lightning Mapper instrument aboard NOAA’s next weather satellite, GOES-R, will examine the atmosphere for earlier storm warning. The company continues to develop other climate-monitoring capabilities from space, such as observing and assessing greenhouse gases.   
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EPIC will provide incredible views of the sunlit side of our planet, like this image, which is the result of a patchwork of satellite photos. With EPIC, one image will replace the puzzle pieces of previous whole-disk images of the Earth. (Image: NASA)
Quelle:Lockheed Martin Corporation

Tags: Raumfahrt 

2015 Views

Samstag, 14. Februar 2015 - 18:38 Uhr

Raumfahrt - Virgin Galactic LauncherOne neues Zwei-Stufen-Orbital-Trägerraketen System

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Virgin Galactic to open Long Beach satellite launcher plant

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Virgin Galactic, the space tourism company founded by British billionaire Richard Branson, has leased a new 150,000-square-foot facility in Long Beach that will house design and manufacturing of the company's small satellite launch vehicle, LauncherOne.
LauncherOne is a new two-stage orbital launch vehicle being designed by Virgin Galactic specifically to launch commercial or governmental satellites that weigh 500 pounds or less. Much like SpaceShipTwo, the company's reusable vehicle for space tourism, LauncherOne is designed to be launched from the WhiteKnightTwo carrier aircraft, which the company says will give customers the ability to avoid crowded and expensive launch ranges while also picking the launch location best suited for their mission.
Located at the Long Beach Airport, this new facility will allow easy transportation of rockets and of customers' satellites using WhiteKnightTwo, Virgin Galactic said.
"The technical progress our team has made designing and testing LauncherOne has enabled a move into a dedicated facility to produce the rocket at quantity," Virgin Galactic Chief Executive George Whitesides said in a statement. "With New Mexico's magnificent Spaceport America for our commercial spaceflight operations, our Mojave facilities for WhiteKnightTwo and SpaceShipTwo production, and now our new facility in Long Beach for LauncherOne, we are building capability to serve our expanding customer community."
Virgin Galactic said it aims to price LauncherOne as "the lowest in the nation or perhaps the world" and has already attracted the interest of numerous small satellite manufacturers and operators. Among them is the recently announced OneWeb project designed to deliver broadband services to areas of the world not currently served by terrestrial networks.
Quelle: L.A.BIZ

Tags: Raumfahrt 

630 Views

Samstag, 14. Februar 2015 - 18:00 Uhr

UFO-Forschung - Venus und Jupiter am frühen Abendhimmel

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Die letzten Tage haben in vielen Regionen klare Witterung in den Abendstunden gebracht und so manchen Heimkehrer grelle Lichter am Himmel sehen lassen. Da unsere UFO-Meldestelle in den letzten Tagen viele Anrufe bekommen hat, gerade Gesternabend als am Westhimmel Venus und am Osthimmel Jupiter sehr hell strahlten alleine über 15 besorgte und neugierige Anrufe, wollen wir Ihnen für Heuteabend astronomische Hilfe geben:

Heuteabend können Sie bei klarer Witterung am Westhimmel (wo die Sonne untergeht) nach Sonnenuntergang Venus  hellstrahlend erblicken:

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Blick heuteabend gegen 18.30 MEZ und nachfolgend Fotos von Venus wie es am klaren Himmel wirkt:

Venus in der Abenddämmerung:

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Planeten wie Venus und Jupiter können im ersten Augenblick für Flugzeuge gehalten werden, da die Leuchtkraft wie Flugzeuglandescheinwerfer wirken können, nur das sie sich nicht so schnell bewegen, nur sachte nach rechts wie alle andere Sterne am Himmel.

Ist der Himmel dunkler geworden fällt die Strahlkraft der Planeten wie hier bei Venus noch mehr auf...

Hier schöner Vergleich zu Straßenlaternen und oben im Bild Venus...

Hier ist Venus kurz vor Untergang knapp am Horizont zu sehen.

Und am Osthimmel können Sie heuteabend Jupiter sehen welcher in Strahlkraft derzeit mit Venus mithalten kann:

Blick heuteabend gegen 18.30 MEZ am Osthimmel: Jupiter und weiter rechts davon Sirius welcher in weißbläulicher Strahlkraft vertreten ist, nachfolgend Aufnahme von Jupter am frühen Abend:

Fotos: CENAP-Archiv

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Update: 14.02.2015 

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Auch heute gilt unser astronomischer Hinweis für die Planeten Venus am Westhimmel und Jupiter mit Sirius am Osthimmel:

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Tags: UFO-Forschung 

2089 Views

Samstag, 14. Februar 2015 - 13:00 Uhr

Raumfahrt - Mars-One: Auswahl von 100 Bewerbern für die Einwegfahrt zum Roten Planeten wird noch bekannt gegeben

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Some have said it’s a pie-in-the-sky idea, but it’s not: it’s a pie-on-Mars idea. And, for the moment at least, it is beyond Nasa’s reach.
First there were 200,000 people who wanted to give up life on Earth and travel to Mars – and not return. They included doctors, lawyers, students and, of course, scientists. Yesterday, they were being whittled down to a shortlist of 100, to be announced on Monday. Just 24 of them will get to leave Earth.
The name of the organisation that could be the first to put humans on the Red Planet is Mars One – as in “one-way”. It will launch people into space, land them on Mars and attempt to keep them alive for the length of their natural lives – but it won’t be bringing them back.
The critics of Mars One number almost as many as those willing to die on the red planet. “There are so many unknowns with this mission, and so many possible ways the whole endeavour could fall apart,” wrote Amy Shira Teitel in Physics Focus when the mission was announced.
“It will be an interesting mission to follow, but I suspect it will be another in the growing list of old and abandoned Mars plans that have been forgotten by everyone save a handful of historians.”
The project was dreamt up by Bas Lansdorp, a Dutch entrepreneur, who says he has “never been one to let bold ventures intimidate him”. Arno Wielders, the project’s chief technical officer, has been involved in space telescopes and ozone-monitoring projects since gaining an MSc in physics at the Free University of Amsterdam in 1997. But the prospect of sending crews to Mars has defeated the brightest minds in the world. It has also defeated governments with the deepest pockets on Earth.
Explaining how the seemingly unachievable could be achieved, Mars One says: “Much of what was learned from Skylab, Mir and the International Space Station has resulted in vital data, experiences with systems and related know-how – all of which are applicable to living on Mars.”
True, perhaps, but there is still the matter of transporting crews of four to Mars – a journey of at least 33 million miles (the planet’s maximum separation from Earth is 249 million miles). Then they will have to be landed safely, and resources found to keep them alive.
First, though, the two dozen candidates, broken into six teams of four people, will spend nine years training and preparing, while competing against each other to determine which group will leave for Mars first. To help fund the estimated £4bn trip (so far only £500,000 has been raised), their experiences will be broadcast in a new reality television show.
Maggie Lieu: "I’m very open to having a baby on Mars … My baby could be the first ever Martian: we’d be the Adam and Eve of Mars"
Sixty-three of the remaining hopefuls have PhDs, and 12 are doctors. They include lawyers, pilots, veterans and businessmen. They come from all over the world. The youngest is 18, the oldest 71.
Among the 36 Britons is Ryan MacDonald, 20, a physics student at Oxford University. “By going to Mars I suspect I could accomplish much more for science than I could as one of seven billion people on Earth,” he told ITV last month.
Maggie Lieu, 24, from Coventry, told BBC’s Newsbeat yesterday that she was unconcerned about leaving her friends and family for good. “It’s true I’ll never be able to see [them] ever again in person, but I’ll be able to see their pictures, I’ll still have access to the internet.”
She added: “I’m very open to having a baby on Mars. I think it would be really exciting to be the mother of the first ever baby born there. My baby could be the first ever Martian: we’d be the Adam and Eve of Mars.”
Nasa has no public plans to attempt a human landing on Mars until the 2030s, and it will only be sending experienced astronauts. Mars One, by contrast, is happy to train non-astronauts.
By 2018 a communication satellite will have been launched into Mars’ orbit, Mars One says. Two years later a rover will be launched, and in 2022 cargo will the sent to Mars for the crew to live in. The first crew will land in 2025 and a second a year later. Who the members of that crew will be will become clearer next week.
Quelle:The independent

Tags: Raumfahrt 

1746 Views

Samstag, 14. Februar 2015 - 09:31 Uhr

Astronomie - Jupiter könnte als Gegenkontrollen bei Exoplaneten dienen

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Researchers analysed light that bounced back from Ganymede — seen here nearly disappearing behind Jupiter in a Hubble Space Telescope image — after filtering through the Jovian atmosphere.
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Astronomers have observed Jupiter for centuries. But a study that looks at the gas giant as if it were an exoplanet could help to make more reliable interpretations of the atmospheres of bodies orbiting stars hundreds of light years away1. The results largely confirm the conventional picture of Jupiter, but also reveal some surprises — including clouds of ice crystals previously unheard of on the planet.
The hundreds of planets now known to orbit stars other than our own are almost never directly visible in telescopes. In a handful of cases, however, astronomers have been able to learn about their make-ups, by interpreting how starlight filters through their atmospheres as it skirts the planets while they cross between their parent stars and Earth.
But low resolution and experimental noise mean that such results, which are usually only possible for large planets orbiting bright stars, are often disputed2. “The models give us answers, but we don’t always know if we can believe those answers or not,” says Tyler Robinson, an astronomer at NASA’s Ames Research Center near Mountain View, California.
Now astrophysicist Pilar Montañés-Rodríguez at the Astrophysics Institute of the Canary Islands in Tenerife and her colleagues have devised a way to apply the idea to studying Jupiter. The technique used for exoplanet atmospheres does not immediately translate to Jupiter, because its orbit never takes it between Earth and the Sun. So, instead of looking directly at sunlight filtered through Jupiter’s atmosphere, the team analysed light reflected back from the Jovian moon Ganymede when Jupiter passed between it and the Sun — in other words, when the planet partially eclipsed the Sun as seen from Ganymede.
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By examining the absorption and emission of light passing through Jupiter’s atmosphere at different wavelengths, seen with the European Southern Observatory's Very Large Telescope in Paranal, Chile, and the William Herschel Telescope at the La Palma Observatory in Spain's Canary Islands, the team built up a picture of the chemical make-up of the Jovian atmosphere.
That spectrum shows that Jupiter is a methane-rich planet wrapped in a layer of cloud that scatters light and makes it harder to see more detailed composition. Both findings agree with direct observations, says Enric Pallé, a colleague at the Astrophysics Institute of the Canary Islands and a co-author on the paper, which was posted on the pre-print server arXiv on 7 February1.
Rosetta Stone
Comparing the spectrum of that light with what astronomers already know about the gas giant gives scientists a ‘Rosetta Stone’ for translating results about distant alien worlds, says Montañés-Rodríguez.
“It’s an extremely clever idea and spectacularly carried out,” says Sara Seager, an astronomer at the Massachusetts Institute of Technology in Cambridge.
The findings should boost astronomers’ confidence that similar hazes found on many of the exoplanets whose atmospheres have been studied so far are real and not due to a confounding effect, such as activity on the parent star, he says. These clouds often obscure other elements, and dissecting the results on Jupiter could help astronomers to tease more out of existing spectra, Pallé adds.
A surprising detail that emerged from the study was that Jupiter’s upper atmosphere includes a layer of ice crystals. Pallé says that this finding will probably prove controversial because the planet is known to have very little water vapour, but he suggests that comets could have deposited the water at some point in the planet’s history. The authors also found traces of sodium on Jupiter, which they similarly attribute to comet debris, or possibly to the result of matter flowing into the planet from the atmosphere of another moon, Io.
That Jupiter viewed in this way does not appear the same as in direct observations — its spectrum does not show its swirling clouds of ammonia in the lower atmosphere that are visible in reflected light, for example — is not a failure of the method, notes Seager. But it does show that “each technique tells you something different”, she says.
In 2009, Pallé’s group used a similar technique to study Earth during a partial lunar eclipse, by analysing the light filtered through its atmosphere and reflected back from the Moon3. The group plans to do the same with other planets in the Solar System.
Quelle: nature

Tags: Astronomie 

2001 Views

Freitag, 13. Februar 2015 - 23:00 Uhr

Astronomie - Unser galaktisches Zentrum rauscht mit rund 3 Millionen Kilometern pro Stunde durch das All

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At a time when our earliest human ancestors mastered walking upright the heart of our Milky Way galaxy underwent a titanic eruption, driving gases and other material outward at 2 million miles per hour.
Now, at least 2 million years later, astronomers are witnessing the aftermath of the explosion: billowing clouds of gas towering about 30,000 light-years above and below the plane of our galaxy.
The enormous structure was discovered five years ago as a gamma-ray glow on the sky in the direction of the galactic center. Astronomers have since observed the balloon-like features in X-rays and radio waves, but needed NASA's Hubble Space Telescope to measure for the first time the velocity and composition of the mystery lobes. They now seek to calculate the mass of the material being blown out of our galaxy, which could help determine the cause of the outburst.
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Hubble maps velocity and composition of mysterious lobes expanding from our galaxy. Image Credit: NASA, ESA, A. Fox and A. Feild (STScI)
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Although astronomers have seen gaseous streams of charged particles blowing from the cores of other galaxies, this is a unique opportunity for a close-up view of our galaxy's own fireworks.
"When you look at the centers of other galaxies, the outflows appear much smaller because the galaxies are farther away," said Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland, lead researcher of the study. "But the outflowing clouds we're seeing are only 25,000 light-years away in our galaxy. We have a front-row seat. We can study the details of these structures. We can look at how big the bubbles are and can measure how much of the sky they are covering."
Fox's results will be published in The Astrophysical Journal Letters and will be presented at the American Astronomical Society meeting in Seattle, Washington.
The giant lobes, dubbed Fermi Bubbles, initially were spotted using NASA's Fermi Gamma-ray Space Telescope. The detection of high-energy gamma rays suggested that a violent event in the galaxy's core violently launched energized gas into space.
To provide more information about the outflows, Fox used Hubble's Cosmic Origins Spectrograph (COS) to study the ultraviolet light from a distant quasar, a galaxy with a bright active nucleus, that lies behind the base of the northern bubble. Imprinted on that light as it travels through the lobe is unique information about the velocity, composition, and temperature of the expanding gas inside the bubble.
Fox's team was able to measure that the gas on the side of the bubble closer to Earth is moving towards us and the gas on the far side is travelling away. COS spectra show that the gas is rushing from the galactic center at roughly 2 million miles an hour, or 3 million kilometers an hour.
"This is exactly the signature we knew we would get if this was a bipolar outflow," explained Rongmon Bordoloi of the Space Telescope Science Institute, a co-author on the science paper. "This is the closest sightline we have to the Galaxy's center where we can see the bubble being blown outward and energized."
The COS observations also measure the composition of the material being swept up in the gaseous cloud. COS detected silicon, carbon, and aluminum, indicating that the gas is enriched in the heavy elements produced inside stars and represents the ancient remnants of star formation.
COS measured the temperature of the gas at approximately 17,500 degrees Fahrenheit, which is much cooler than most of the super-hot gas in the outflow, thought to be at about 18 million degrees Fahrenheit. "We are seeing cooler gas, perhaps interstellar gas in our galaxy’s disk, being swept up into that hot outflow," Fox explained.
This is the first result in a survey of 20 faraway quasars whose light passes through gas inside or just outside the Fermi Bubbles – like a needle piercing a balloon. An analysis of the full spectrum of the light sample will yield the amount of mass being ejected. The astronomers can then compare the outflow mass with the velocities at various locations in the bubbles to determine the amount of energy needed to drive the outburst and possibly the origin of the explosive event.
One possible cause for the outflows is a star-making frenzy near the galactic center that produces supernovas which blow out gas. Another scenario is a star or a group of stars falling onto the Milky Way's super-massive black hole. When that happens, gas superheated by the black hole is ejected deep into space.
Because the bubbles are young compared to the age of our galaxy, and believed to be a short-lived phenomenon, the bubbles may be evidence for a repeating event in the Milky Way's history. Whatever the trigger is, it likely occurs episodically, perhaps only when the black hole gobbles up a concentration of material.
"It looks like the outflows are a hiccup," Fox said. "There may have been repeated ejections of material that have blown up, and we're catching the latest one. By studying the light from the other quasars in our program, we may be able to detect the ancient remnants of previous outflows."
Galactic winds are common in star-forming galaxies, such as M82, which is furiously making stars in its core. "It looks like there's a link between the amount of star formation and whether or not these outflows happen," Fox said. "Although the Milky Way overall currently produces a moderate one to two stars a year, there is a high concentration of star formation close to the core of the galaxy."
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.
NASA is exploring our solar system and beyond to understand the universe and our place in it. We seek to unravel the secrets of our universe, its origins and evolution, and search for life among the stars.
Quelle: NASA

Tags: Astronomie 

1736 Views

Freitag, 13. Februar 2015 - 22:45 Uhr

Astronomie - Ein Smiley für Hubble

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Hubble Sees A Smiling Lens
In the center of this image, taken with the NASA/ESA Hubble Space Telescope, is the galaxy cluster SDSS J1038+4849 — and it seems to be smiling.
You can make out its two orange eyes and white button nose. In the case of this “happy face”, the two eyes are very bright galaxies and the misleading smile lines are actually arcs caused by an effect known as strong gravitational lensing.
Galaxy clusters are the most massive structures in the Universe and exert such a powerful gravitational pull that they warp the spacetime around them and act as cosmic lenses which can magnify, distort and bend the light behind them. This phenomenon, crucial to many of Hubble’s discoveries, can be explained by Einstein’s theory of general relativity.
In this special case of gravitational lensing, a ring — known as an Einstein Ring — is produced from this bending of light, a consequence of the exact and symmetrical alignment of the source, lens and observer and resulting in the ring-like structure we see here.
Hubble has provided astronomers with the tools to probe these massive galaxies and model their lensing effects, allowing us to peer further into the early Universe than ever before. This object was studied by Hubble’s Wide Field and Planetary Camera 2 (WFPC2) and Wide Field Camera 3 (WFC3) as part of a survey of strong lenses.
A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Judy Schmidt.
Image Credit: NASA/ESA
Caption: ESA

Tags: Astronomie 

1976 Views

Freitag, 13. Februar 2015 - 20:15 Uhr

Astronomie - Sollte man Grüße senden an außerirdischen Zivilisationen auch wenn sie Klingonen, oder einfach nur schlechte Gesellschaft wäre?

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Should we beam greetings to alien civilizations even though they might be Klingons, or just bad company?

Frank Drake, 84, founder of SETI and creator of thee Drake Equation, shown Feb. 12, 2015, at the American Association for the Advancement of Science convention in San Jose, Calif. 

In one of the first news conferences of this year's American Association for the Advancement of Science (AAAS) annual meeting in San Jose, we learned that there's a raging debate going on between those who want to send signals into outer space to communicate directly and actively with alien civilizations and those who think that's cockamamie and potentially dangerous.
This followed press conferences on how we're dumping plastic in the ocean in heinous quantities and how we're facing the serious prospect of "mega-droughts" lasting 35 years or longer in the American Southwest and Great Plains. One might infer that we are a civilization in need of help, and some folks apparently want to look for that help in outer space — a move that one of the news conference participants, astrophysicist and science fiction writer David Brin, called a form of prayer.
The presser was in advance of a formal science session Friday at which the panelists will detail their views more fully. The advocates for "Active SETI" include Seth Shostak and Douglas Vakoch of the SETI (Search for Extraterrestrial Intelligence) Institute, which is just up Route 101 in Mountain View. With few exceptions, SETI has traditionally been a "passive" enterprise. The searchers scan the heavens for radio signals, primarily, though more recently there have been optical searches as well.
The first SETI experiment was conducted at Green Bank, W.Va., in 1960 by radio astronomer Frank Drake, he of the famous Drake Equation, which creates a way to estimate (or guess) the number of communicative civilizations in our galaxy. SETI searches have failed to pick up a signal from a sentient source. That doesn't mean the aliens aren't out there; it could be that they communicate with a technology with which we are unfamiliar.
Vakoch suggested that it's time to go on the offensive.
"Active SETI is a reflection of SETI growing up as a discipline," Vakoch said. "It may just be the approach that lets us make contact with life beyond Earth."
He acknowledged the fears, and cited a much-reported line from Stephen Hawking: "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans." But Vakoch said this is not an argument against active SETI: "Any civilization that has the ability to travel between the stars can already pick up our accidental radio and TV leakage.”
"It's too late to worry about that," said Shostak. As Shostak put in an article titled "Are transmissions into space dangerous?":
"We have already sent signals into space that will alert the aliens to our presence with the transmissions and street lighting of the last 70 years. These emissions cannot be recalled."
But Brin said our leakage  is not a very robust signal compared to what the advocates of active SETI are envisioning. He said this "barn door excuse" (that our signals are already out the door and the aliens can already detect "I Love Lucy") is bogus. He brought up the Fermi Paradox. "Where are they?" asked the great physicist Enrico Fermi at lunch one day at Los Alamos; by Fermi's calculations, given the rate of technological progress in our own civilization, alien visitors who are much more advanced should be common in our galaxy and should have showed up already or somehow revealed themselves. Brin said there are roughly 100 scenarios to explain why we haven't made contact so far. Roughly a dozen of them are unpleasant scenarios, though he did not detail what he meant by that. He did say that we don't know that altruism is the norm in nature.
Vakoch then said Brin is being inconsistent, because he has collaborated on a message that will be carried into space by the New Horizons spacecraft after its fly-by of Pluto later this year.
"No one is going to get it!" Brin interjected. (The spacecraft will journey into the near-void of interstellar space for eons.)
More of this will play out Friday at the full session. Meanwhile, in the back of the room, none other than Frank Drake himself listened to the news conference, and he took time outside the room to talk to this reporter about the history of SETI.
He's not a fan of active SETI, he said — even though he did it in the past. In 1974, he used the ceremonial dedication of a rebuilt Arecibo radio telescope in Puerto Rico to send an encoded message to Messier 13, the Great Globular Cluster in Hercules. It was just a proof of concept stunt, brief, and aimed at stars clustered 25,000 light years away. He took some flak for that from the Astronomer Royal, Martin Ryle, who thought it was reckless.
Said Drake of active SETI: "I think it’s a waste of time at the present. It's like somebody trying to send an e-mail to somebody whose e-mail address they don’t know, and whose name they don’t know.”
Quelle: The Washington Post

Tags: Astronomie 

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