Science & TechnologyS


Meteor

Tunguska Event: No answers to fireball mystery

David Hill
Otago Daily Times
Sat, 28 Jun 2008 12:12 UTC


Image
©Unknown
When Russian mineralogist Leonid Kulik made his way to the remote Tunguska River basin, his group found thousands of pine trees lying burned in a radial pattern.

JUNE 30, 1908.

Reindeer graze beside the Podkamennaya or Lower Stony Tunguska River that winds through the Siberian steppes.

The tents of a few herdsmen stand nearby, but hardly anyone else lives in this land of swamps and forests.

7.14 am. Pine trees glow in the summer light. The morning is blue and cloudless.

Then a blinding ball of light rips across the sky, trailing a column of fire.

Some eye-witnesses say the light was red. Others claim it was blue, and cylindrical in shape.

It races down towards the Tunguska River, and explodes.

A spear of fire splits the sky. Explosions boom across the land.

A dark mushroom cloud begins rolling upwards. It will reach a height of 80km: ten times higher than Mt Everest.
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Question

Flashback Fossil DNA tells tales of red-haired Neanderthals

Robert C. Cowen
The Christian Science Monitor
Thu, 08 Nov 2007 16:20 UTC
Paleontologists are surprised to find such diversity; clues also suggest wider migration.

Red headed Neanderthals
©Michael Hofreiter and Kurt Fiust
Some Neanderthals may have had pale skin and red hair similar to that of some modern humans.

Scientists probing Neanderthal remains find important clues in DNA. One recent study suggests some of our extinct cousins had pale skin and red hair. Another investigation finds Neanderthals ranged much farther from Europe into Asia than paleontologists have thought.

The key fact is that at least some Neanderthal fossils yield DNA of high enough quality to tell such tales. Last month, members of an international research team led by Carles Lalueza-Fox at the University of Barcelona in Spain explained in the journal Nature why they think recovering specific DNA sequences from extinct species "can potentially provide information" as to what the species looked like. They backed up this hypothesis with analysis of DNA from two Neanderthal fossils.

They found genetic information similar to, but distinct from, the genes governing skin and hair color in modern humans. They say this "suggests that Neanderthals varied in pigmentation levels" just as we do. That includes the pale skin and red hair that evolved largely in Europe. The team adds that the data suggest this potential "evolved independently in both modern humans and Neanderthals."

Comment: For more articles on this subject see: Red hair a part of of Neanderthal genetic profile, Red hair a legacy of Neanderthal man, Neanderthals 'were flame-haired', Ancient DNA Reveals That Some Neanderthals Were Redheads, and Some Neanderthals were redheads - Bones yield genetic data that adds red hair, light skin and maybe freckles.

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Rocket

As research funds stagnate, science in state of 'crisis'

Amy Ellis Nutt
Star-Ledger
Sun, 29 Jun 2008 01:58 UTC
Once the world's gold standard, American scientific enterprise is in free fall. Short of government funds and strapped for cash, researchers across the country are abandoning promising avenues of scientific investigation and, increasingly, the profession of science itself.
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Bug

Lyme Disease Bacterium Came From Europe Before Ice Age


Science Daily
Sun, 29 Jun 2008 22:13 UTC
Researchers at the University of Bath have discovered that a bacterium that causes Lyme disease originated in Europe, rather than in North America as previously thought.

blacklegged tick
©CDC/ James Gathany; William Nicholson
The blacklegged tick Ixodes pacificus, a known vector for Borrelia burgdorferi, the pathogen responsible for Lyme disease.

The bacterium responsible for Lyme disease, Borrelia burgdorferi, originated in America, or so researchers thought. Now, however, a team from the University of Bath has shown that this bug in fact came from Europe, originating from before the Ice Age.

By understanding the origins of the bacterium and how it has evolved so far researchers hope to be able to predict how it will continue to develop, and so find ways to prevent its spread.
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Evil Rays

Cluster Listens To The Sounds Of Earth


Agence France-Presse
Sun, 29 Jun 2008 21:43 UTC
The first thing an alien race is likely to hear from Earth is chirps and whistles, a bit like R2-D2, the robot from Star Wars. In reality, they are the sounds that accompany the aurora.

Now ESA's Cluster mission is showing scientists how to understand this emission and, in the future, search for alien worlds by listening for their sounds.

Cluster constellation
©ESA
Artist's impression of the Cluster constellation. ESA's mission Cluster consists of four identical spacecraft flying in formation between 19000 and 119000 km above the Earth. They study the interaction between the solar wind and Earth's magnetosphere, or the Sun-Earth connection in 3D.

Scientists call this radio emission the Auroral Kilometric Radiation (AKR). It is generated high above the Earth, by the same shaft of solar particles that then causes an aurora to light the sky beneath.

For decades, astronomers had assumed that these radio waves travelled out into space in an ever-widening cone, rather like light emitted from a torch. Thanks to Cluster, astronomers now know this is not true.

By analysing 12 000 separate bursts of AKR, a team of astronomers have determined that the AKR is beamed into space in a narrow plane. This is like placing a mask over the torch with just a small slit in the middle for light to escape.

"We can now determine exactly where the emission is coming from," says Robert Mutel, University of Iowa, who conducted the three-year study with colleagues. For each of the AKR bursts they analysed, the astronomers pinpointed its point of origin to regions in Earth's magnetic field just a few tens of kilometres in size. These were located a few thousand kilometres above where the light of the aurora is formed.
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Telescope

A Quark Star? Super-luminous Stellar Explosion Observed


Science Daily
Sun, 29 Jun 2008 15:38 UTC
Astronomers recently announced that they have found a novel explanation for a rare type of super-luminous stellar explosion that may have produced a new type of object known as a quark star.

Three exceptionally luminous supernovae explosions have been observed in recent years. One of them was first observed using a robotic telescope at the California Institute of Technology's (Caltech) Palomar Observatory.

supernova explosion
©NASA/CXC/M.Weiss
Illustration of a supernova explosion.

Data collected with Palomar's Samuel Oschin Telescope was transmitted from the remote mountain site in southern California to astronomers via the High-Performance Wireless Research and Education Network (HPWREN), funded by the National Science Foundation (NSF). The Nearby Supernova Factory research group at the Lawrence Berkeley Laboratory reported the co-discovery of the supernova, known as SN2005gj.

Researchers in Canada have analyzed this, along with two other supernovae, and believe that they each may be the signature of the explosive conversion of a neutron star into a quark star.
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Star

NASA to Attempt Historic Solar Sail Deployment


physorg.com
Fri, 27 Jun 2008 14:10 UTC
"Hold your hands out to the sun. What do you feel? Heat, of course. But there's pressure as well - though you've never noticed it, because it's so tiny. Over the area of your hands, it only comes to about a millionth of an ounce. But out in space, even a pressure as small as that can be important - for it's acting all the time, hour after hour, day after day. Unlike rocket fuel, it's free and unlimited. If we want to, we can use it; we can build sails to catch the radiation blowing from the sun."1

These words were spoken not by a NASA scientist but by a fictional character - John Merton - in Arthur C. Clarke's short story The Wind from the Sun. If all goes well, Merton's prophetic words are about to become fact.

NASA researchers, thinking "out of the box" (or maybe "out of the rocket") have long dreamed of the possibility of sailing among the planets with sails propelled by sunlight instead of by wind. Except in works of fiction, though, no one has yet successfully deployed such a sail anywhere beyond Earth.

"There's a first time for everything," says Edward "Sandy" Montgomery of NASA's Marshall Space Flight Center.

Montgomery's team and a team from Ames Research Center (led by Elwood Agasid) hope to make history this summer by deploying a solar sail called NanoSail-D. It will travel to space onboard a SpaceX Falcon 1 rocket, scheduled for launch from Omelek Island in the Pacific Ocean during a window extending from July 29th to August 6th (a back-up extends from August 29th to September 5th).

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Telescope

Charleston resident teams with EIU professor to watch skies for dangerous near-Earth objects

Rob Stroud
JG-TC.com
Fri, 27 Jun 2008 10:16 UTC
CHARLESTON - More than 1,300 square miles of Siberian forest were devastated a century ago by what is thought to have been an asteroid or comet.

As the 100th anniversary of the June 30, 1908 event approaches, astronomy enthusiast Robert Holmes Jr. of Charleston has been using his two professional-grade telescopes to measure potentially hazardous objects that could collide with the Earth.

Image
©JG/T-C
Astronomy enthusiast Robert Holmes Jr. of Charleston has been using his two professional-grade telescopes to measure potentially hazardous objects that could collide with the Earth.

Eastern Illinois University physics professor James Conwell and Holmes have partnered to turn over images collected via the two telescopes to students throughout the world for analysis as part of NASA's Near-Earth Object Program.

Holmes estimated his observatory near Charleston has facilitated the measuring of 5,835 near-earth asteroids during the past year.

"The asteroid or comet that exploded over Tunguska (in Siberia) is very small and we don't typically research objects this small with our telescopes," Holmes said. "We measure asteroids that are 10 times this size, or about 400 feet in diameter or larger."
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Telescope

Flashback Global Warming on Pluto Puzzles Scientists

Robert Roy Britt
Space.com
Wed, 09 Oct 2002 08:32 UTC
In what is largely a reversal of an August announcement, astronomers today said Pluto is undergoing global warming in its thin atmosphere even as it moves farther from the Sun on its long, odd-shaped orbit.

Pluto's atmospheric pressure has tripled over the past 14 years, indicating a stark temperature rise, the researchers said. The change is likely a seasonal event, much as seasons on Earth change as the hemispheres alter their inclination to the Sun during the planet's annual orbit.

They suspect the average surface temperature increased about 3.5 degrees Fahrenheit, or slightly less than 2 degrees Celsius.

Pluto remains a mysterious world whose secrets are no so easily explained, however. The warming could be fueled by some sort of eruptive activity on the small planet, one astronomer speculated.
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Telescope

Flashback Global Warming Detected on Neptune's Largest Moon


Scienceagogo.com
Sun, 28 Jun 1998 08:21 UTC
There may not be much industrial pollution on Neptune's largest moon, but things are hotting up nonetheless...

The Earth is not alone in suffering global warming. According to observations made by NASA's Hubble Space Telescope and several ground-based instruments, temperatures on Neptune's largest moon have increased dramatically since the Voyager space probe swung by in 1989. So much so, in fact, that Triton's surface of frozen nitrogen is turning into gas, making its thin atmosphere denser by the day.

"At least since 1989, Triton has been undergoing a period of global warming," confirms astronomer James Elliot, professor of Earth, Atmospheric and Planetary Sciences at Massachusetts Institute of Technology. "Percentage-wise, it's a very large increase."
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