October 1, 2007, 10:21 PM CT

The dark matter of the universe has a long lifetime

New research from the Niels Bohr Institute presents new information that adds another piece of knowledge to the jigsaw puzzle of the dark mystery of the universe dark matter. The research has just been reported in the scientific journal Physical Review Letters.

The universe consists not just of visible celestial bodies, stars, planets and galaxies. It also has a mystical fellow player dark matter. The astronomers can measure that the dark matter exists in big quantities but no one knows what it is, nobody has seen it. It does not emit light and it does not reflect light. It is invisible. It is a mystery and the scientists have a number of theories.

The dark matter has caused the scientists headaches for decades since it was detected in the 1970s, and there is intense research into the phenomena. It is invisible but it has got mass, and thus it has got gravitation that can be measured. By analysing the galaxies it is possible to weigh them, and it turns out that by far the greatest matter of the collective mass of the galaxy is dark matter.

Just like stars get together in galaxies, the galaxies get together in clusters of galaxies of up to several thousand galaxies. The astrophysicist Signe Riemer-Srensen, PhD student at the Niels Bohr Institute, has analysed two clusters of galaxies that collide......... Posted by: Brooke      Read more         Source

Fri, 28 Sep 2007 01:42:16 GMT

The Moon in Hypersaturated Color

Via ApodVia Apod- Quoted - The Moon in Hypersaturated Color Posted by: Zinzi      Read more     Source

September 18, 2007, 5:33 AM CT

Satellites witness lowest Arctic ice coverage in history

The area covered by sea ice in the Arctic has shrunk to its lowest level this week since satellite measurements began nearly 30 years ago, opening up the Northwest Passage - a long-sought short cut between Europe and Asia that has been historically impassable.

In the mosaic image above, created from nearly 200 images acquired in early September 2007 by the Advanced Synthetic Aperture Radar (ASAR) instrument aboard ESA's Envisat satellite, the dark gray colour represents the ice-free areas while green represents areas with sea ice.

Leif Toudal Pedersen from the Danish National Space Centre said: "We have seen the ice-covered area drop to just around 3 million sq km which is about 1 million sq km less than the prior minima of 2005 and 2006. There has been a reduction of the ice cover over the last 10 years of about 100 000 sq km per year on average, so a drop of 1 million sq km in just one year is extreme.

"The strong reduction in just one year certainly raises flags that the ice (in summer) may disappear much sooner than expected and that we urgently need to understand better the processes involved."

Arctic sea ice naturally extends its surface coverage each northern winter and recedes each northern summer, but the rate of overall loss since 1978 when satellite records began has accelerated......... Posted by: Tyler      Read more         Source

September 12, 2007, 8:09 PM CT

The mysterious ridges at the mouth of Tiu Valles

These images taken by the High Resolution Stereo Camera (HRSC) on board Mars Express show the mouth of the Tiu Valles channel system on the red planet.

The pictures were taken in orbit 3103 on 10 June 2006 with a ground resolution of approximately 16 metres per pixel.

The mouth of Tiu Valles is an estuary-like landform. On Earth, an estuary is the tidal mouth of a river valley, or the end that meets the sea and fresh water comes into contact with seawater. In such an area, tidal effects are evident.

Tiu Valles is located at approximately 27 degree North and 330 degree East. The sun illuminates the scene from the North West, the lower left-hand side in the image.

Tiu Valles originates in the equatorial chaotic terrains at the mouth, at the eastern end of Valles Marineris. The morphology of this chaotic terrain is dominated by large-scale remnant massifs, which are large relief masses that have been moved and weathered as a block. These are randomly oriented and heavily eroded.

From there, the region extends to the north over a distance of 1500 km before terminating in Chryse Planitia. Along with Kasei Valles and Ares Valles, Tiu Valles is one of the major outflow channels entering the Chryse Planitia plain.

The scene in the images covers an area of approximately 140 by 80 km at the mouth of Tiu Valles. The region was made famous in 1997 when rover Sojourner of NASA's Pathfinder mission landed about 600 km south-west of the mapped area......... Posted by: Brooke      Read more         Source

August 27, 2007, 9:16 PM CT

Hot Spots And Fires From Space

Hot spots across Southeastern Europe from 21 to 26 August have been detected with instruments aboard ESA satellites, which have been continuously surveying fires burning across the Earth's surface for a decade.

Working like thermometers in the sky, the Along Track Scanning Radiometer (ATSR) on ESA's ERS-2 satellite and the Advanced Along Track Scanning Radiometer (AATSR) on ESA's Envisat satellite measure thermal infrared radiation to take the temperature of Earth's land surfaces.

Temperatures exceeding 312ºK (38.85ºC) are classed as burning fires by AATSR, which is capable of detecting fires as small as gas flares from industrial sites because of their high temperature. Worldwide fire maps based on this data are available to users online in near-real time through ESA's ATSR World Fire Atlas (WFA).

Smoke from some of the fires included in the WFA fire map was detected during the same period by Envisat's Medium Resolution Imaging Spectrometer (MERIS) optical instrument. While working in Full Resolution mode to provide a spatial resolution of 300 metres, MERIS captured smoke plumes arising from fires raging across Greece's southern Peloponnese peninsula, where fires have claimed the lives of at least 60 people since they began four days ago.

These images are available on ESA's MIRAVI website, which gives access to Envisat's most recently acquired images. MIRAVI, short for MERIS Images RApid VIsualisation, tracks Envisat - the world's largest Earth Observation satellite - around the globe, generates images from the raw data collected by MERIS and provides them online within two hours. MIRAVI is free and requires no registration......... Posted by: Brooke      Read more         Source

August 26, 2007, 10:40 AM CT

Martian Soil Samples Could Have Biological Origin

A new interpretation of data from NASA's Viking landers indicates that 0.1% of the Martian soil tested could have a biological origin.

Dr Joop Houtkooper of the University of Giessen, Gera number of, believes that the subfreezing, arid Martian surface could be home to organisms whose cells are filled with a mixture of hydrogen peroxide and water. In a presentation at the European Planetary Science Congress in Potsdam on Friday 24th August, Dr Houtkooper will describe how he has used data from the Gas Exchange (GEx) experiment, carried by NASA's Viking landers, to estimate the biomass in the Martian soil.

Dr Houtkooper said, "The GEx experiment measured unexplained rises in oxygen and carbon dioxide levels when incubating samples. If we assume these gases were produced during the breakdown of organic material together with hydrogen peroxide solution, we can calculate the masses needed to produce the volume of gas measured. From that, we can estimate the total biomass in the sample of Martian soil. It comes out at little more than one part per thousand by weight, comparable to what is found in some permafrost in Antarctica. This might be detectable by instruments on the Phoenix lander, which will arrive at Mars in May next year".

Dr Houtkooper and his colleague, Dr Schulze-Makuch from Washington State University, suggest that a hydrogen peroxide-water based organism would be quite capable of surviving in the harsh Martian climate where temperatures rarely rise above freezing and can reach -150 degrees Celsius at the poles......... Posted by: Brooke      Read more         Source

August 26, 2007, 10:37 AM CT

Basalt In The Outer Asteroid Belt

Analysis of the chemical make up of two asteroids in the outer asteroid belt has thrown the classification system for these small bodies, which orbit between Mars and Jupiter, into disorder.

Dr Rene Duffard, who is presenting results at the European Planetary Science Congress in Potsdam on Wednesday 22nd August, said, "We appear to have detected basalt on the surface of these asteroids, which is very unusual for this part of the asteroid belt. We do not know whether we have discovered two basaltic asteroids with a very particular and previously unseen mineralogical composition or two objects of non basaltic nature that have to be included in a totally new taxonomic class".

The presence of basalt means that the asteroid must have melted partially at some time in the past, which implies that it was once part of a larger body which had internal heating processes. However, there do not appear to be other basaltic fragments in the region and, from spectral analysis, it is not clear whether the two are fragments of the same parent body or not.

Until recently, most of the known basaltic asteroids, which are classified as V-type, were believed to be fragments of Vesta, the second largest object in the asteroid belt. Since 2001, several V-type asteroids have been identified as not belonging to this Vesta family, including (1459) Magnya, the first basaltic object to be detected in the outer asteroid belt......... Posted by: Brooke      Read more         Source

August 21, 2007, 5:49 PM CT

Hurricane Dean tracked from space

ESA satellites are tracking the path of Hurricane Dean as it rips across the Caribbean Sea carrying winds as high as 260 km/h. The hurricane, which has already claimed eight lives, is forecast to slam into Mexico's Yucatan Peninsula on Tuesday morning.

Dean was upgraded early Tuesday to a Category 5 - the highest on the Saffir-Simpson scale - before pummelling the peninsula. Knowing the strength and path of hurricanes is critical for issuing timely warnings; satellites are the best means of providing data on the forces that power the storm, such as cloud structure, wind and wave fields, sea surface temperature and sea surface height.

Instruments aboard ESA's Envisat and ERS-2 satellites allow them to peer through hurricanes. Envisat carries both optical and radar instruments, enabling scientists to observe high-atmosphere cloud structure and pressure in the visible and infrared spectrum.

The Medium Resolution Imaging Spectrometer (MERIS) optical instrument shows the swirling cloud-tops of a hurricane, while radar instruments such as the Advanced Synthetic Aperture Radar (ASAR) pierce through the clouds to show how the wind fields shape the sea surface and estimate their likely destructive extent.

ERS-2 uses its radar scatterometer to observe the hurricane's underlying wind fields. The scatterometer instrument works by firing a trio of high-frequency radar beams down to the ocean, then analysing the pattern of backscatter reflected up again. Wind-driven ripples on the ocean surface modify the radar backscatter, and as the energy in these ripples increases with wind velocity, backscatter increases as well. Scatterometer results enable measurements not only of wind speed but also of direction across the water surface......... Posted by: Brooke      Read more         Source

August 3, 2007, 10:27 PM CT

Sensors Help Africa Tackle Water Shortage

Zambian water authorities are integrating information based on satellite imagery to alleviate water shortages. With inadequate information causing a number of water-related problems, an ESA project has generated a variety of environmental maps to provide local policy makers with the necessary tools for effective water resource management.

As part of the IWAREMA (Integrated Water Resource management for Zambia) project, funded through ESA's Data User Element, data from ESA's multispectral MERIS sensor aboard Envisat was used to create maps depicting existing water resources, suitable dam locations and land cover. The project is carried out by the Belgium Company GIM (Geographic Information Management) in partnership with the University of Zambia and the Zambian water authorities.

"The results of the IWAREMA project can be used to protect Zambia's ecosystems especially in the Kafue flats where wildlife, agricultural activities, fisheries and tourism compete for regulated water resources," Jack Nkhoma of Zambia's Department of Water Affairs said.

Having access to these maps allows authorities to determine the expansion of urban areas and loss of forest and agricultural areas as well as calculate the risk of erosion, change in water availability and percentage of surface water, which will allow for early flood warnings......... Posted by: Tyler      Read more         Source

August 3, 2007, 10:24 PM CT

The Planet, the Galaxy and the Laser

On the night of 21 July, ESO astronomer Yuri Beletsky took images of the night sky above Paranal, the 2600m high mountain in the Chilean Atacama Desert home to ESO's Very Large Telescope. The amazing images bear witness to the unique quality of the sky, revealing not only the Milky Way in all its splendour but also the planet Jupiter and the laser beam used at Yepun, one of the 8.2-m telescopes that make up this extraordinary facility.

"The images are not composite", emphasises Yuri Beletsky. "The camera was being tracked on the stars, which can be easily noticed if you look at the telescope domes on the image (they look a little fuzzy). The colour of the laser beam on the first image actually looks pretty close to what one can see on the sky with the unaided eye."

Most striking in the images is the wide band of stars called the Milky Way. Spanning more than 100 degrees in the first of these images, it shows the dust and stars that are part of our own Galaxy, a spiral galaxy containing about 100 billion stars.

In the middle of this image, two bright objects are also seen. The brighter of the two is the planet Jupiter. The other is the bright star Antares. Another bright star, Alpha Centauri, one of the closest stellar neighbours to the Sun, is visible at the middle-left edge of the image......... Posted by: Brooke      Read more         Source