Science & TechnologyS


Satellite

Engineers Diagnosing Voyager 2 Data System

Jia-Rui C. Cook
NASA/JPL
Thu, 06 May 2010 09:51 UTC
Image
© NASA/JPLThis artist's rendering depicts NASAs Voyager 2 spacecraft as it studies the outer limits of the heliosphere - a magnetic 'bubble' around the solar system that is created by the solar wind. Image credit: NASA/JPL-Caltech
Engineers have shifted NASA's Voyager 2 spacecraft into a mode that transmits only spacecraft health and status data while they diagnose an unexpected change in the pattern of returning data. Preliminary engineering data received on May 1 show the spacecraft is basically healthy, and that the source of the issue is the flight data system, which is responsible for formatting the data to send back to Earth. The change in the data return pattern has prevented mission managers from decoding science data.

The first changes in the return of data packets from Voyager 2, which is near the edge of our solar system, appeared on April 22. Mission team members have been working to troubleshoot and resume the regular flow of science data. Because of a planned roll maneuver and moratorium on sending commands, engineers got their first chance to send commands to the spacecraft on April 30. It takes nearly 13 hours for signals to reach the spacecraft and nearly 13 hours for signals to come down to NASA's Deep Space Network on Earth.

Comment: On the Voyager main website http://voyager.jpl.nasa.gov, from where the above article is linked, we find additional information:

May 6, 2010: On 22 April 2010 the DSN achieved a nominal carrier and subcarrier acquisition but was unable to frame-sync Voyager 2 telemetry in the routine cruise science/engineering data mode. We commanded to the 40 bps engineering-only data mode by real-time command, achieved frame-sync and found no spacecraft alarm conditions. So far, the only anomalous indication is an incorrect checksum from the Flight Data System (FDS) memory flight software region. We should learn more after we receive and analyze a full FDS memory readout.

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Info

Archaeologists Upset Theory About Easter Island Statues


Scientific Blogging
Thu, 13 May 2010 22:47 UTC
Moai
© Scientific BloggingEaster Island Stones
Archaeologists say they have disproved the fifty-year-old theory underpinning our understanding of how the famous stone statues were moved around Easter Island. Fieldwork led by researchers at University College London and The University of Manchester has shown the remote Pacific island's ancient road system was primarily ceremonial and not solely built for transportation of the figures.

A complex network of roads up to 800-years-old crisscross the Island between the hat and statue quarries and the coastal areas. Laying alongside the roads are dozens of the statues - or moai.

The find will create controversy among the many archaeologists who have dedicated years to finding out exactly how the moai were moved, ever since Norwegian adventurer Thor Heyerdahl first published his theory in 1958. Heyerdahl and subsequent researchers believed that statues he found lying on their backs and faces near the roads were abandoned during transportation by the ancient Polynesians.
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Info

Uncovering Nottingham's hidden medieval sandstone caves


The University of Nottingham
Thu, 13 May 2010 19:42 UTC
Image
© Unknown
The very latest laser technology combined with old fashioned pedal power is being used to provide a unique insight into the layout of Nottingham's sandstone caves - where the city's renowned medieval ale was brewed and, where legend has it, the country's most famous outlaw Robin Hood was imprisoned.

The Nottingham Caves Survey, being carried out by archaeologists from Trent & Peak Archaeology at The University of Nottingham, has already produced extraordinary, three dimensional, fly through, colour animation of caves that have been hidden from view for centuries.
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Info

Herschel Finds a Large Hole in Space

Tudor Vieru
Space.com
Wed, 12 May 2010 19:04 UTC
Space Hole
© ESA / HOPS ConsortiumNGC 1999 is the green tinged cloud towards the top of the image. The dark spot to the right was thought to be a cloud of dense dust and gas until Herschel looked at it.
Researchers announce the discovery of a very peculiar structure in space. Using data from the European Space Agency's (ESA) Herschel Space Observatory, a group of astronomers managed to identify a vast hole in space, located in a region of the Universe that they previously thought should have been filled with a vast gas cloud, of enormous density. This is only the latest in a string of very interesting discoveries by Herschel. The amazing observational power on the largest space telescope ever flown allows experts to peer at the Universe in sensitive infrared wavelengths, Space reports.

"No one has ever seen a hole like this. It's as surprising as knowing you have worms tunneling under your lawn, but finding one morning that they have created a huge, yawning pit," explains Tom Megeath, who was a member of the research team behind the investigation. He is based at the University of Toledo, in Ohio. According to scientists, it may be that analyzing this cosmic structure in more detail could provide additional clues as to what exactly happens to stars when they reach the end of their burning cycle.
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Satellite

The Ever-Growing Problem of Space Junk

Noel Brinkerhoff, David Wallechinsky
AllGov.com
Thu, 13 May 2010 18:45 UTC
Space Junk
© NASALow Earth Orbit View of Space Junk
So much debris has collected in orbit around the earth that British scientists are now predicting collisions involving operational satellites could occur every five years in the coming decades.

The growing problem became glaringly apparent last year in February when two satellites collided for the first time. One was an active U.S. communications satellite and the other an inoperable Russian satellite. The two smashed into each other northern Siberia while going more than 25,000 m.p.h. The smash-up produced 1,400 catalogued pieces of new space debris, adding to the thousands more already floating around the planet.

In January 2007, China produced 150,000 pieces of debris, including 2,700 that were trackable, when it tested a ballistic missile by destroying a weather satellite. In February 2008, the U.S. used a ballistic missile to destroy a spy satellite, but less debris was created because the strike happened closer to Earth, and most of the debris was burned up in the atmosphere.
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Saturn

Have Aliens Hijacked Voyager 2 Spacecraft?


The Daily Telegraph
Thu, 13 May 2010 03:27 UTC
Voyager 2
© UnknownThe spacecraft late last month began sending science data 8.6 billion miles to Earth in a changed format that mission managers could not decode
It left Earth 33 years ago, now it's claimed the Voyager 2 spacecraft may have been hijacked by aliens after sending back data messages NASA scientists can't decode.

NASA installed a 12-inch disk containing music and greetings in 55 languages in case intelligent extraterrestrial life ever found it.

But now the spacecraft is sending back what sounds like an answer: signals in an unknown data format!

The best scientific minds have so far not been able to decipher the strange information - is it a secret message?

Comment: While the change in the data format may only be a symptom of a failing craft, the timing of this release is quite interesting. It remains to be seen whether the story is quickly discounted - or if it is a precursor to more "revelations" about our place in the Universe.

In the meantime, things on Jupiter are looking interesting, too:
BIG NEWS! Jupiter loses one of its belts

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Info

DNA 'Spiderbot' is on the Prowl


Agence France-Presse
Wed, 12 May 2010 19:09 UTC
DNA Robot
© AFPThe molecular robot is just four nanometres -- four billionths of a metre -- in diameter.
Paris - Scientists on Wednesday announced they had created a molecular robot made out of DNA that walks like a spider along a track made out of the chemical code for life.

The achievement, reported in the British journal Nature, is a further step in nanoscale experiments that, one day, may lead to robot armies to clean arteries and fix damaged tissues.

The robot is just four nanometres -- four billionths of a metre -- in diameter.

Milan Stojanovic of New York's Columbia University, who led the venture, likens the nanobot to "a four-legged spider."

The beast moves along a track comprising stitched-together strands of DNA that is essentially a pre-programmed course, in the same way that industrial robots move along an assembly line.

The track exploits one of the basic characteristics of DNA. A double-helix molecule, DNA comprises four chemicals which pair in rungs.

By "unzipping" the DNA, one is left with one side of the strand whose rungs can then be paired up with matching rungs.

In other words, the track can be used rather like the teeth in a clockwork mechanism. A cog can move around the teeth, provided it meshes with them.

By using strands that correspond to sequences in the track, the robot can be made to walk, turn left or right as it is biochemically attracted to the next matching stretch.
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Info

Ancient DNA Set to Rewrite Human History

Rex Dalton
Nature
Wed, 12 May 2010 18:54 UTC
Discovery that some humans are part-Neanderthal reveals the promise of comparing genomes old and new.

The worlds of ancient and modern DNA exploration have collided in spectacular fashion in the past few months. Last week saw the publication of a long-awaited draft genome of the Neanderthal, an archaic hominin from about 40,000 years ago.[1] Just three months earlier, researchers in Denmark reported the genome of a 4,000-year-old Saqqaq Palaeo-Eskimo[2] that was plucked from the Greenland permafrost and sequenced in China using the latest technology.

Neanderthal
© Nature PHOTOLIBRARYNeanderthals once bred with Homo sapiens.
As researchers compare these ancient genomes with the ever-expanding number from today's humans, they expect to gain insights into human evolution and migration - with more discoveries to come as they decipher DNA from other branches of the human evolutionary tree. "For the first time, ancient and modern genetic research is going hand in hand," says Eske Willerslev, whose team at the University of Copenhagen led the Palaeo-Eskimo sequencing project. "It is really a fantastic time."
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Telescope

Death of a star in 3 dimensions

Dr. Hannelore Hämmerle
Max-Planck-Gesellschaft
Wed, 12 May 2010 11:48 UTC
Image
© MPAThis is a three-dimensional explosion simulation at about 0.5 seconds after core ignited. The bluish, almost transparent surface is the shock front with an average radius of 1900 km.
New computer models show in detail how supernovae obtain their shape

This release is available in German.

Massive stars end their lives in gigantic explosions, so called supernovae, and can become - for a short time - brighter than a whole galaxy, which is made up of billions of stars. Although supernovae have been studied theoretically by computer models for several decades, the physical processes happening during these blasts are so complex that until now astrophysicists could only simulate parts of the process and so far only in one or two dimensions. Researches at the Max Planck Institute for Astrophysics in Garching have now carried out the first fully three-dimensional computer simulations of a core collapse supernova over a timescale of hours after the initiation of the blast. They thus could answer the question of how initial asymmetries, which emerge deep in the dense core during the very early stages of the explosion, fold themselves into inhomogeneities observable during the supernova blast.
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Magnify

Mysterious Mayan ceremonial head found at Tak´alik Ab´aj

Barbara Schieber
Australia's Business and World News
Wed, 12 May 2010 11:36 UTC
Image
© Tak' alik Ab' aj National Project, Ministry of Culture and Sports of Guatemala.
Guatemala - Discovery of an extraordinary offering of a jadeite mosaic miniature ceremonial head underscores the importance and political power at the beginning of Early Classic of the ancient Maya city Tak'alik Ab'aj

Tak'alik Ab'aj is an ancient pre-Hispanic city situated in El Asintal, Department of Retalhuleu at the pacific piedmont of Guatemala. This important long distance trade and cosmopolitan cultural center is transcendent because of its long history which endured 1700 years (800 B.C. - 900 A.D). At its beginnings Tak'alik Ab'aj interacted and participated with the Olmec culture, and at its surmise, was one of the protagonists in the development of the early Maya culture. This particularity in addition to the extraordinary production of sculpture programs during these two important cultural periods, make Tak'alik Ab'aj unique in the history of Mesoamerica.
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