|
Greenhouse
Asteroid?
Ice Volcanoes on
Enceladus!
Studying Stardust, Pluto's Moons!
The
Other Side of the Sun! |
| Greenhouse
Asteroid? |
 |
University of
Leicester News Release
March 14, 2006 - A new theory to explain global warming was revealed at a
meeting at the University of Leicester (UK) and is being considered for
publication in the journal "Science First Hand".
The controversial theory has nothing to do with burning fossil fuels and
atmospheric carbon dioxide levels. According to Vladimir Shaidurov of the
Russian Academy of Sciences, the apparent rise in average global
temperature recorded by scientists over the last hundred years or so could
be due to atmospheric changes that are not connected to human emissions of
carbon dioxide from the burning of natural gas and oil.
Shaidurov explained how changes in the amount of ice crystals at high
altitude could damage the layer of thin, high altitude clouds found in the
mesosphere that reduce the amount of warming solar radiation reaching the
earth's surface.
Shaidurov has used a detailed analysis of the mean temperature change by
year for the last 140 years and explains that there was a slight decrease
in temperature until the early twentieth century. This flies in the face
of current global warming theories that blame a rise in temperature on
rising carbon dioxide emissions since the start of the industrial
revolution.
Shaidurov, however, suggests that the rise, which began between 1906 and
1909, could have had a very different cause, which he believes was the
massive Tunguska Event, which rocked a remote part of Siberia, northwest
of Lake Baikal on the 30th June 1908.

Trees felled by the Tunguska blast. Photograph from Kulik's
1927 expedition. (Photo N. A. Strukov, 1928) |
The Tunguska Event,
sometimes known as the Tungus Meteorite is thought to have resulted from
an asteroid or comet entering the earth's atmosphere and exploding. The
event released as much energy as fifteen one-megaton atomic bombs. As well
as blasting an enormous amount of dust into the atmosphere, felling 60
million trees over an area of more than 2000 square kilometres.
Shaidurov suggests
that this explosion would have caused "considerable stirring of the
high layers of atmosphere and change its structure." Such meteoric
disruption was the trigger for the subsequent rise in global temperatures.
Global warming is thought to be caused by the "greenhouse
effect". Energy from the sun reaches the earth's surface and warms
it, without the greenhouse effect most of this energy is then lost as the
heat radiates back into space.
However, the
presence of so-called greenhouse gases at high altitude absorb much of
this energy and then radiate a proportion back towards the earth's
surface. Causing temperatures to rise.
Many natural gases and some of those released by conventional power
stations, vehicle and aircraft exhausts act as greenhouse gases. Carbon
dioxide, natural gas, or methane, and chlorofluorocarbons (CFCs) are all
potent greenhouse gases.
Carbon dioxide and
methane are found naturally in the atmosphere, but it is the gradual rise
in levels of these gases since the industrial revolution, and in
particular the beginning of the twentieth century, that scientists have
blamed for the gradual rise in recorded global temperature. Attempts to
reverse global warming, such as the Kyoto Protocol, have centred on
controlling and even reducing CO2 emissions.
However, the most potent greenhouse gas is water, explains Shaidurov and
it is this compound on which his study focuses. According to Shaidurov,
only small changes in the atmospheric levels of water, in the form of
vapour and ice crystals can contribute to significant changes to the
temperature of the earth's surface, which far outweighs the effects of
carbon dioxide and other gases released by human activities. Just a rise
of 1% of water vapour could raise the global average temperature of
Earth's surface more then 4 degrees Celsius.

Asteroid collision with Earth (NASA) |
The role of water
vapour in controlling our planet's temperature was hinted at almost 150
years ago by Irish scientist John Tyndall. Tyndall, who also provided an
explanation as to why the sky is blue, explained the problem: "The
strongest radiant heat absorber, is the most important gas controlling
Earth's temperature. Without water vapour, he wrote, the Earth's surface
would be 'held fast in the iron grip of frost'." Thin clouds at high
altitude allow sunlight to reach the earth's surface, but reflect back
radiated heat, acting as an insulating greenhouse layer.
Water vapour levels are even less within our control than CO2 levels.
According to Andrew E. Dessler of the Texas A & M University writing
in 'The Science and Politics of Global Climate Change', "Human
activities do not control all greenhouse gases, however. The most powerful
greenhouse gas in the atmosphere is water vapour, he says, "Human
activities have little direct control over its atmospheric abundance,
which is controlled instead by the worldwide balance between evaporation
from the oceans and precipitation."
As such, Shaidurov has concluded that only an enormous natural phenomenon,
such as an asteroid or comet impact or airburst, could seriously disturb
atmospheric water levels, destroying persistent so-called 'silver', or
noctilucent, clouds composed of ice crystals in the high altitude
mesosphere (50 to 85km). The Tunguska Event was just such an event, and
coincides with the period of time during which global temperatures appear
to have been rising the most steadily - the twentieth century. There are
many hypothetical mechanisms of how this mesosphere catastrophe might have
occurred, and future research is needed to provide a definitive answer.
Professor Vladimir Shaidurov is an expert in Numerical Analysis and
Mathematical Modelling, and the Corresponding member of Russian Academy of
Sciences. For development of multigrid methods he achieved the highest
Russian prize in science (together with Profs Fedorenko and Bachvalov) -
the State Prize (2004). He visited University of Leicester in April 2005.
Shaidurov's paper "Atmospheric hypotheses of Earth's global
warming" is available online at http://arxiv.org/abs/physics/0510042
University of Leicester - http://www.leicester.ac.uk |
| Ice
Volcanoes on Enceladus! |

Saturn’s moon Enceladus. (NASA) |
Max Planck Society
News Release
March 14, 2006 - Scientists from the Max Planck Institute for Nuclear
Physics and the University of Potsdam have found ice volcanoes - or what
could be called "ice geysers" - on the surface of Saturn’s
moon Enceladus.
They made the discovery using a combination of computer simulations and
measurements from the dust detector on the space probe CASSINI. The ice
volcanoes are located at geologically young, warm structures in the icy
moon’s southern polar region. The ice particles probably are created
from steam deep in crevices.
Volcanic activity is now known to exist in three bodies in our solar
system: Enceladus, Earth, and Jupiter’s moon Io (Science, March 10,
2006).
Saturn’s E ring, the largest ring around any planet in our solar system,
is not only remarkable for its huge size. What is also astounding is that
current optical measurements show it to be made of ice particles of nearly
equal size - a radius of 0.3 to 2 micrometres.
The icy moon Enceladus was, however, expected to feed the ring with
significantly larger pieces. The ring’s mass distribution must thus
somehow be tied up with the dynamics of the particles. Until now, however,
scientists did not know how. Directly measuring ice particles near
Enceladus promised to deliver a better understanding of the E Ring’s
complex nature.
On July 14, 2005, the CASSINI space probe came within 175 kilometres of
Enceladus, which is suspected of being the source of Saturn’s E Ring.
This made it possible to measure dust distribution deep inside the area of
Enceladus’ gravitational pull. The scientists could thus investigate how
the moon refreshed the ring with dust particles.

An artificially colored image of Saturn’s moon Enceladus. Clearly
visible over the southern polar region are dust fountains, caused
by ice volcanic activity (lower left corner). (NASA) |
Until now, it was
assumed that new ice particles were created by interplanetary
micrometeorites, or ring particles themselves, bombarding the moon’s
surface. In this model, most of the fresh particles form a nearly isotopic
dust cloud around the moon. In the other model, faster particles feed the
ring. Indeed, the dust detector on the space probe GALILEO had already
discovered dust clouds surrounding Jupiter’s Galilean moons.
Measurements from
the High Rate Detector (HRD) of CASSINI’s "Cosmic Dust
Analyser" (CDA), taken by scientists from the Max Planck Institute
for Nuclear Physics in Heidelberg and the University of Chicago are
however not consistent with this assumption. Observations showed that the
maximum rate of impact was reached before the probe moved to its closest
point to Enceladus.
This can only be explained if there exists a strong anisotropic - that is,
directionally dependent - dust distribution on the moon.
The dust detector was not the only instrument which came to show
unexpected discoveries. Photographs of Enceladus’ southern polar region
clearly showed geologically young structures. Infrared images also
indicated a warmer area - a "hot spot" - in that southern
region.
This led scientists from the University of Potsdam to model dust
distribution on the moon under the assumption that there is an additional,
tightly confined, dust source on its surface. The models indicated a
contained dust source in the southern polar region. This turned out to be
consistent with the probe’s measurements.
This convincing match between models and HRD measurements (see image 2)
led the Cassini camera team to look for, and find, volcanic activity.
Enceladus is thus the second moon in our solar system where volcanic
activity has been discovered
Max Planck Society - http://www.mpg.de/english |
| Studying
Stardust |

This image illustrates one of several ways scientists have begun
extracting comet particles from the Stardust spacecraft's collector.
First, a particle and its track are cut out of the collector
material,
called aerogel, in a wedge-shaped slice called a keystone. A
specialized silicon pickle fork is then used to remove the keystone
from the remaining aerogel for further analysis. (NASA/ JPL-
Caltech/ University of California, Berkeley) |
University of
Washington News Release
March 13, 2006 - Scientists analyzing recent samples of comet dust have
discovered minerals that formed near the sun or other stars. That means
materials from the innermost part of the solar system could have traveled
to the outer reaches, where comets formed.
"The interesting thing is we are finding these high-temperature
minerals in materials from the coldest place in the solar system,"
said Donald Brownlee, a University of Washington astronomer who is
principal investigator, or lead scientist, for NASA's Stardust mission.
Among the finds in material brought back by Stardust is olivine, a mineral
that is the primary component of the green sand found on some Hawaiian
beaches.
It is among the
most common minerals in the universe, but finding it in comet Wild 2 could
challenge a common view of how such crystalline materials form.
Olivine is a compound of iron, magnesium and other elements, in which the
iron-magnesium mixture ranges from being nearly all iron to nearly all
magnesium. The Stardust sample is primarily magnesium.
Many astronomers believe olivine crystals form from glass when it is
heated close to stars, Brownlee said. One puzzle is why such crystals came
from Wild 2, a comet that formed beyond the orbit of Neptune when the
solar system began some 4.6 billion years ago.

This image shows a comet particle collected by the
Stardust spacecraft. The particle is made up of the
silicate mineral forsterite, which can found on Earth
in gemstones called peridot. It is surrounded by a thin
rim of melted aerogel, the substance used to collect
the comet dust samples. The particle is about 2
micrometers across. (NASA) |
"It's certain
such materials never formed inside this icy, cold body," Brownlee
said.
The comet traveled the frigid environs of deep space until 1974, when a
close encounter with Jupiter brought it to the inner solar system. Besides
olivine, the dust from Wild 2 also contains exotic, high-temperature
minerals rich in calcium, aluminum and titanium.
"I would say these materials came from the inner, warmest parts of
the solar system or from hot regions around other stars," Brownlee
said.
"The issue of the origin of these crystalline silicates still must be
resolved. With our advanced tools, we can examine the crystal structure,
the trace element composition and the isotope composition, so I expect we
will determine the origin and history of these materials that we recovered
from Wild 2."
Brownlee is among scientists presenting the first concrete findings from
the Stardust sample this week at the annual Lunar and Planetary Science
Conference in League City, Texas.
Stardust's captured dust from comet Wild 2 in January 2004, and the
sample-return capsule parachuted to the Utah desert on Jan. 15 to complete
the seven-year mission. The samples from Wild 2 were taken to the National
Aeronautics and Space Administration's Johnson Space Center in Houston,
and from there they have been sent to about 150 scientists around the
world, who are using a variety of techniques to determine the properties
of the comet grains.

A heart-shaped comet particle extracted from aerogel.
Returned to Earth by Stardust. (NASA/JPL) |
The grains are very
tiny, most much smaller than a hair's width. But there appear to be
thousands of them embedded in the unique glassy substance called aerogel
that was used to snare the particles propelled from the body of the comet.
A grain of 10 microns – one-hundredth of a millimeter – can be sliced
into hundreds of samples for scientists to study.
"It's not much, but still it's so much that we're almost
overwhelmed," Brownlee said, noting that his lab has only worked on
two particles so far. "The first grain we worked on, we haven't even
cut into the main part of the particle yet."
The material, which came from the very outer edges of the solar system,
has been preserved since the start of the solar system in the deep freeze
of space 50 times farther away from the sun than Earth is. Brownlee
believes the material will provide key information about how the solar
system was formed.
"A fundamental question is how much of the comet material came from
outside the solar system and how much of it came from the solar nebula,
from which the planets were formed," he said. "We should be able
to answer that question eventually."
High-resolution images available through this release at http://www.uwnews.org
or at http://www.nasa.gov/stardust |
| The
World's Fastest Robot! |
Fatronik
News Release
March 14, 2006 - Fatronik has launched the most rapid robot in the world
at the BIEMH (International Machine-Tool Biennial) in Bilbao.
What is involved here is a high-performance handling robot the structure
of which is basically four actuators working in a coordinated manner with
the goal of achieving maximum dynamic performances.
The robot has four degrees of freedom, displacements along three
translations and rotates on its vertical axis. It is a cylinder with a
diameter of 1200mm and a height of 250mm. Its rotational capacity covers
±200º, which enables positioning an object in any orientation-position.
This robot is characterized by its high dynamics, with accelerations of
15G, enabling it to pick up and position over 200 items per minute. Its
workload capacity is aimed at the manipulation of variously shaped objects
up to a weight of 2 Kg.

Quickplacer - not pretty, but pretty fast. |
This robot is aided
by a vision system capable of guiding its movements. The vision system,
available in both black and white and in color, is responsible for
locating the shape and the orientation-position of the objects and, as a
function of the received programming, gives orders for the robots
movements. It is also possible to co-ordinate the whole system with moving
belts in such a way that the robot can pick up a moving object and also
position it on a moving belt.
Novelty
The Quickplacer robot is the most rapid in the world. Its high
acceleration and braking capacity, 5 times more than that of a Formula 1
racing car, makes it world leader in production capacity.
It special structure and the characteristics of the elements make its
speed and acceleration optimum, increasing productivity by 20% with
respect to currently existing solutions.
Application
The technological structure and capacities of this robot make it ideal for
handling tasks in a multitude of sectors such as in food and agriculture,
the hygiene sector, beauty care, health care or electronic components.
Its design is optimized for small-sized objects – up to 2 Kg – in very
varied tasks. The possible tasks to which this robot can be applied are as
varied as the following:
• Positioning of chocolates in individually-shaped places
• Packaging of bars of chocolate/turron
• Packaging of biscuits individually or in groups
• Quality control in the processing of vegetables (combined with a
colour vision system)
• Packaging of peppers
• Packaging of lipstick bars
• Packaging of baby towelettes
• Feeding various products (fish, meat, CDs,…) to flowpack machines.
Fatronik - http://www.fatronik.com |
| Pluto’s
Moons |

This pair of NASA Hubble Space Telescope images shows the motion of
Pluto's satellites between February 15th and March 2nd, 2006. (NASA) |
Johns Hopkins
University Applied Physics Laboratory News Release
March 10, 2006 - Using new Hubble Space Telescope observations, a research
team led by Dr. Hal Weaver of the Johns Hopkins University Applied Physics
Laboratory and Dr. Alan Stern of Southwest Research Institute has found
that Pluto’s three moons are essentially the same color – boosting the
theory that the Pluto system formed in a single, giant collision.
Publishing their findings in an International Astronomical Union Circular
(No. 8686), the team determined that Pluto’s two “new” satellites,
discovered in May 2005 and provisionally called S/2005 P 1 and S/2005 P 2,
have identical colors to one another and are essentially the same, neutral
color as Charon, Pluto’s large moon discovered in 1978.
All three satellites have surfaces that reflect sunlight with equal
efficiency at all wavelengths, which means they have the same color as the
Sun or Earth's moon. In contrast, Pluto has more of a reddish hue.
The new observations were obtained March 2 with the high-resolution
channel of the Hubble’s Advanced Camera for Surveys. The team determined
the bodies’ colors by comparing the brightness of Pluto and each moon in
images taken through a blue filter with those taken through a green/red
filter.

Pluto, Charon and the two new moons. Credit: NASA,
ESA,
A. Stern(SwRI) and Z. Levay (STScI) |
"The high
quality of the new data leaves little doubt that the hemispheres of P1 and
P2 that we observed have essentially identical, neutral colors," says
Weaver.
The new results further strengthen the hypothesis that Pluto and its
satellites formed after a collision between two Pluto-sized objects nearly
4.6 billion years ago. “Everything now makes even more sense,” says
Stern. “If all three satellites presumably formed from the same material
lofted into orbit around Pluto from a giant impact, you might well expect
the surfaces of all three satellites to have similar colors.”
The researchers hope to make additional Hubble color observations, in
several more filters, to see if the similarity among the satellites
persists to longer (redder) wavelengths.
They have proposed
to obtain compositional information on the new satellites by observing
them at near-infrared wavelengths, where various ice and mineral
absorptions are located. The researchers also hope to better refine the
orbits of P1 and P2 and measure the moons’ shapes and rotational
periods.
The Hubble observations were made in support of NASA’s New Horizons
mission to Pluto and the Kuiper Belt. New Horizons launched on Jan. 19,
2006, and will fly through the Pluto system in July 2015, providing the
first close-up look at the ninth planet and its moons.
Stern leads the
mission and science team as principal investigator; Weaver serves as the
mission’s project scientist. The Johns Hopkins University Applied
Physics Laboratory, Laurel, Md., manages the mission for NASA’s Science
Mission Directorate and operates the New Horizons spacecraft.
For more information on the mission, visit http://pluto.jhuapl.edu |
| The
Other Side of the Sun |

The sun that we see. (NASA) |
Stanford University
News Release
March 13, 2006 - The hidden face of the sun is fully visible for the first
time, thanks to a new technique developed at Stanford University.
Only half of the sun--the near side--is directly observable. The far side
always faces away from Earth and is therefore out of view. But the new
technology allows anyone with a computer to download images of the entire
solar surface--an important advance with practical applications, say
researchers, because potentially damaging solar storms that form on the
far side now can be detected days, or even weeks, before they wreak havoc
on Earth.
"Sunspots, solar flares and other active regions on the surface of
the sun emit radiation that can interfere with orbiting satellites,
telecommunications and power transmission," says Philip Scherrer,
research professor in the Stanford Department of Physics.
"This new
method allows more reliable warning of magnetic storms brewing on the far
side that could rotate with the sun and threaten the Earth."

This image shows two active regions crossing
the solar east limb in November 2003. The right
side, in yellow, are white light images showing
sunspots. The left side (blue) shows the prediction
of sunspots on the farside. Since the white light
observations are images made "straight on", they
are stretched into blurry lines when they are
projected to show the view over the limb. This is
simply because we do not have a camera above
the east limb (yet). (Stanford University) |
It takes about 27
days for the sun to rotate on its axis, so an active region that forms on
the far side can remain hidden for up to 13 days, surprising Earth-bound
observers when it finally rotates into view.
That's what
happened in October 2003, when active regions from the back side suddenly
appeared on the eastern edge of the sun, spewing X-rays, ultraviolet
radiation and high-energy particles into space.
"We were not
able to make a public prediction about the intensity of that activity,
because at the time we could only image about a quarter to a third of the
far side," Scherrer says. "The new method allows us to see the
entire far side, including the poles."
SOHO mission
Scherrer and his Stanford colleagues study the sun using data from the
Solar and Heliospheric Observatory (SOHO), a research satellite launched
in 1995 by NASA and the European Space Agency. On board SOHO is the
Michelson Doppler Imager (MDI), an electronic instrument that creates
images of the sun's interior by measuring the velocity of sound waves
produced by hot, bubbling gases that well up to the surface--a technique
called acoustic helioseismology.
"Heliosesimology works on the same principle as medical ultrasound,
which can create an image of a fetus inside a pregnant woman,"
Scherrer explains. "In this case, we're looking through a star with
sound waves."
Positioned about 1 million miles above Earth, the SOHO satellite always
faces the visible front side of the sun. In 2000 and 2001, scientists
Charles Lindsey and Doug Braun--now at NorthWest Research Associates
Inc.--developed two techniques that resulted in the first pictures of the
sun's back side. However, both techniques had limitations. One method only
produced images near the center of the far side, while the other was
restricted to views at the edges. To get complete image, researchers would
have to combine both methods, but that proved to be a major technical
challenge.
The problem was finally overcome last summer when a new computer algorithm
was developed by the Stanford SOHO/MDI team in collaboration with Kenneth
Oslund, an undergraduate at the California Institute of Technology. Their
work resulted in the MDI Farside Graphics Viewer, which displays the first
full images of the far side of the sun.
The viewer is available online at http://soi.stanford.edu/press/farside_Feb2006/web
Solar max
"This new method is a vast improvement," Scherrer says. "It
should be especially important during the next solar maximum, which should
begin in 2011, when solar activity will be at its peak."
He points out that during the last "solar max," which lasted
from 2000 to 2003, solar storms temporarily knocked out power in the
northern parts of Sweden and Canada and destroyed a satellite that was
used to verify credit card payments at numerous gas stations in the United
States. Air transportation also can be disrupted when solar radiation
interferes with the operation of Global Positioning System satellites, or
when aircraft that take short cuts over the North Pole have to take longer
routes to prevent passengers and crew from being exposed to intense X-ray
radiation.
"Our goal is to give pilots and air traffic controllers a day or two
notice of a possible solar event," Scherrer says, adding that
missions to Mars and other planets also can be affected when solar storms
interfere with satellite communications to Earth. Last week, researchers
at the National Center for Atmospheric Research in Colorado released new
computer models predicting that the next solar cycle will be 30 to 50
percent stronger than last time.
In 2008, SOHO is scheduled to be replaced by NASA's Solar Dynamics
Observatory (SDO), a more advanced satellite designed to provide new data
about the magnetic forces inside the sun that drive the 11-year solar
cycle. Stanford, the University of Colorado and the Lockheed Martin Corp.
will lead the SDO research effort.
"With cell phones and other devices, we've gotten more and more
dependent on the space environment, so there are real economic reasons for
missions like SOHO and SDO," Scherrer says.
Videos and high-resolution images of the far side of the sun are available
at http://sohowww.nascom.nasa.gov
Stanford University - http://www.stanford.edu |