Tuesday, September 30, 2008

GRACE & GOCE



A gravity model of the Earth constructed with data from GRACE. Credit: University of Texas Center for Space Research and NASA


It is all about gravity these days. First came GRACE (Gravity Recovery and Climate Experiment) and then we'll have GOCE (Gravity field and steady-state Ocean Circulation Explorer). I'll reveal the difference right away: GRACE measures time variations while GOCE measures the static gravity field. Both are equally important for a number of societal application and both are hot on the satellite scene this fall. Well, actually amazing science results have come out based on data from GRACE ever since it was launched in 2002. In particular the increased resolution is stunning and continue to enthuse the scientists. One of my colleagues, Srinivas Bettanpur at the University of Texas, has increased the spatial resolution beyond our wildest dreams and provides now researchers with an instrument that can estimate mass changes with a spatial resolution of less than 322 km (200 miles) – a lot better than first anticipated.

Most recently (today), the first results from the unprecedented high accuracy measurements of Greenland ice variations was announced. Lets back up a little and introduce GRACE in somewhat more details first. The German-American GRACE consist in fact of two satellites and these twin satellites are used to make precise measurements of gravity-field changes on Earth. As gravity is directly related to mass, these data can be used to plot changes in the earth's water balance, such as the disappearance of the ice caps. Major breakthroughs from GRACE include establishing the rapid loss of ice mass in recent years from Greenland and Antarctica, and major changes in water storage in China's Yangtze River and other water sources.

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German-American GRACE (Gravity Recovery and Climate Experiment) satellites, two satellites that have been orbiting the earth behind each other since mid-2002. Credit: GRACE


GOCE will map the reference shape of our planet – the geoid - with unprecedented resolution and accuracy. The spatial resolution for instance, will be 100 km (for comparison note that the much improved spatial resolution of Grace is 322 km). The satellite realizes a broad range of fascinating new possibilities for the fields of oceanography, solid Earth physics, geodesy and sea-level research, and significantly contribute to furthering our understanding of climate change. A more detailed description of the usefulness of a good geoid can be found in 10 reasons why Al Gore needs the geoid”.

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The sleek aerodynamic design of GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) immediately sets it apart from most other satellites. This unique five-metre long spacecraft has none of the usual moving parts. The satellite together with its sensor, system of supporting instrumentation and control elements actually form a single composite gravity-measuring device. Credits: ESA - AOES Medialab

Within the last 10 years an improved knowledge of the geoid has revolutionized height determination on land by GNSS satellites, allowing heights to be determined with an accuracy of better than 2 cm in several countries. For marine areas a similar improvement is expected to take place giving oceanographers access to valuable information on ocean circulation from satellite altimetry.

GRACE and GOCE will to some extent complement each other and GOCE may even improve the performance of GRACE. As for all remote sensing techniques, a ground segment to assist and calibrate the data is imperative.

Unfortunately GOCE has been delayed. The original launching date this fall was on the same day they fired up the Large Hadron Collider, 10th September but the event has been postponed and it is now set to 5th October 2008.



Greenland lost an average of 195 cubic kilometres of ice per year between 2003 and 2008, which is enough to cause an annual increase in the global sea level of half a millimetre, or 5 cm over the course of the next century. Credit: GRACE


Back to the news of the day. Based on GRACE data researchers can now present a more detailed map of mass loss – the ice melting - in Greenland. Researchers from TU Delft joined forces with the Center for Space Research (CSR) in Austin, Texas, USA, to develop a method for creating an accurate picture of Greenland's shrinking ice cap. On the strength of this method, it is now estimated that Greenland is accountable for a half millimeter-rise in the global sea level per year. They point out, however, that long-term observations are needed to compile a reliable estimate of Greenland's contribution to the rising sea level during the next century. Due to the high spatial resolution it is possible to plot the loss of mass per region, thereby providing new insight into the patterns of ice loss. These findings will be published in the scientific journal Geophysical Research Letters in early October.

Ladybirds of Australia




Lady Bugs



Ladybirds of Australia.







Jules Verne




Jule Verne on Fire






First images of Jules Verne ATV re-entry over the Pacific Ocean

Who cares, you might ask. Well, this deorbit burning of Jules Verne, the European service vehicle that just left ISS, will teach us a lot about how we can dispose some of the future space junk that could be orbiting our planet. We send up an awful lot of satellites and spacecrafts and we have to clean up the mess somehow since the junk represent a danger to the multimillion dollars equipment we invest in space. Disposal of used spacecraft will at least not add on to the ordeal already swirling around. :-)

Watch the movie.




Monday, September 29, 2008

Wind




Energy Gone With The Wind



I am all supportive of alternative energy, to put it mildly. Testing various ways of producing energy is necessary. I hope we do not make the same mistakes we've done with hydropower though, and hurt the environment on the way. A wind mill might look nice on pictures like the one above, but I am afraid that the visual pollution is underestimated in the alternative energy projects be it on and off shore.




Jules Verne




Jules Vernes Last Minutes



Before it burns up in the atmophere.



Jules Verne left the International Space Station 5. September and is on fire right this minute!




Jules Vernes Deorbit Burn




Taikonauts




Picnic in Space



As you can see going to space, go for an EVA (Extra Vehicular Activity) and land in a funny capsule in Inner Mongolia is a piece of cake or rather just like a picnic, for the Chinese taikonauts. What is all the fuzz about!?! ;-)




Martian Bedrock





Martian Bedrock Information





Credit: NASA




On a string




String Vibrations



Credit: Andrew Davidhazy




Sunday, September 28, 2008

Stars




Infant Stars



Credit: NASA, ESA and A. Nota (STScI/ESA)


In the Small Magellanic Cloud we can see star formation from gravitational collapse. The infant stars are very young stars that have not yet started their hydrogen burning.

Spectacular!



Swan Veil




A Cygnus Loop



Credit: ESA & Digitized Sky Survey (Caltech)


A supernova explosion left a cosmic veil in the Cygnus constellation. Thank you for that! :-)






Science Art




Polymizing



Photo: Jenna Eun

More extraordinary science art here,.





Saturday, September 27, 2008

Vela Nebula




Vela



Credit: Davide De Martin, Skyfactory

The Vela nebula is a supernova remnant. The supernova explosion left a pulsar.




Chinese EVA




Taikonauts EVA



Chinese Spacewalking!







China in Space




Chinese Space Snacking






What most people fail to appreciate when it comes to space exploration is the importance of a sound ground segment. For precise navigation we depend on good knowledge of our own planet, especially a geodetic reference frame. On the image we see a telescope in Inner Mongolia getting ready to assist the descent of Shenzhou-7. We can't have the taikonauts choking on space snacks just because we didn't know the exact whereabouts of Shenzhou, can we? :-)




Creation of the Universe




Evolution - The Really Big Picture



Watch Star Stories



You gotta read this story, or at least play with the multimedia Star Stories. This is one of if not THE best story about how the universe came about that I've seen up until now.
Pretty neat stuff! Makes me totally happy and content. :-)

With all the scientific evidence embedded in Star Stories, it is a miracle that there are people actually believing the universe was literally created in a week, just out of the blue (even as much as I love blue I cannot give credit to blue for the universe).




Thursday, September 25, 2008

Magnetic Neutronstar




Stellar Magnet



Credit: ESO/L.Cal├žada

Magnetars
Magnetars are young neutron stars with an ultra-strong magnetic field a billion billion times stronger than that of the Earth. The twisting of magnetic field lines in magnetars give rise to 'starquakes', which will eventually lead to an intense soft gamma-ray burst.

Like I've said before, we still do not understand magnetic fields well enough. And they are the coolest! :-)





Supernova




A Wild Cousin of A Supernova



Credit: X-ray (NASA/CXC/Columbia/F.Bauer et al); Visible light (NASA/STScI/UMD/A.Wilson et al.)

SN 1996cr in Circinus Galaxy


A web of telescopes discovered this wild thing exploding near us (astronomically speaking of course, otherwise, we'd be evaporated....-)).


The Arctic




Arctic Conservation Area



Cartographer: Hugo Ahlenius, UNEP/GRID-Arendal





Colliding Planets




Smashing Planets



Credit: Lynette R. Cook

Artistic rendering depicts planets colliding in a sun-like binary system about 300 light-years from Earth, in the constellation Aries.



Colliding Equals






Wednesday, September 24, 2008

Sunspots




The Return of Sunspots - Again



Credit: SOHO Consortium, EIT, ESA, NASA





Finally, we see a serious sunspot again on the surface of the Sun. The solar cycle 24 has been a little slow turning the magnetic engines on (or something :-)) so we have so far just seen some freckles earlier this year. No "real" sunspot has surfaced. The fact that we are surprised by this only shows that there are still unsolved mysteries in space, including on our very own star, the Sun.








Solar wind




Solar Wind Slows Down




Credits: ESA/Dave Hardy

Ulysses





Credits: McComas et al. GRL, 2008

Variation in the solar wind as observed by Ulysses over a solar cycle.



Data from Ulysses shows that the solar wind is at an all time low* leaving our solar system less protected from the rest of the universe.





* lowest in 50 years, but before that we didn't measure it the way we do today so I say all time. :-)

Space




JavaScripters Cyberrape Space



Starburst galaxy M82 by NASA, ESA, and The Hubble Heritage Team (STScI/AURA)

I have absolutely nothing against javascripts or fine producers of such, but come on, give space a little credit at least. To me the [nice] illustrations looks very much like Hubble images. Give space som credit, will you - you cyberraping geeks! :-D

Stellare, on an eternal mission securing adequate funding of space agencies!




Saturn




Saturn Abstraction



Cedit: NASA/JPL/Space Science Institute




Tuesday, September 23, 2008

Equinox




Autumnal Equinox

astronomy

Photo: Tunc Tezel

Starting with winter solstice 2007 this image shows daily trails of the sun on: winter solstice, vernal equinox and summer solstice.



2008 September 22. 15:44 UTC









Martian Polar Caps




Martian Meteorology



Credits: ESA/ Image Courtesy of F. Altieri (IFSI-INAF) and the OMEGA team

Martian south polar cap at the end of northern winter on the Red Planet. The cap appears clearly asymmetric, its centre being displaced by 3° from the geographic pole.




Explains Polar Cap Asymmetry.





Credits: ESA - D. Ducros

ESAs Mars Express




Distant Gamma-ray outburst




Long(est) Distance Gamma-rays



Credit: NASA/Swift/Stefan Immler (left) and MPE/GROND (right)






Iranian Sky




Scriptures in the Night



Photo: Babak Tafreshi, an young Iranian astronomy photographer.




Chinese cave








Photo: Ian Sewell

Reed Flute Cave in Guilin, China was discovered during the Tang Dynasty almost 1,300 years ago.

Monday, September 22, 2008

Mapping Titan






Photobucket


Photobucket

Credit: ESO




Sunday, September 21, 2008

The Seven Sisters




Pleiades



Credit: Davide De Martin & the ESA/ESO/NASA Photoshop FITS Liberator



The Hubble Telescope - collection




Hubble Telescope



The Hubble telescope is named after the American astronomer Edwin Hubble



European Hubble site



American Hubble site



The Hubble Heritage



Hubble at NASA



Hubble at ESA



Space Telescope Science Institute


All my Hubbles...