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Frequent climate fluctuations on the world
Planets abound in the galaxy. Over the past decade, scientists have discovered giant planets mostly by radial velocity techniques that detect the spectral shift in a star's light caused by the to and fro tug of an unseen planetary companion.
This method has detected more than 200 planets, dominantly large close-in planets called "hot Jupiters" that are inhospitable to life as we know it.
In the near future, with the launch of NASA's Kepler Mission in 2008, we'll have the tools to seek evidence of Earth-size planets in the habitable zone of distant stars.
The search for life beyond Earth is the search for a good place to live, a habitable planet, in orbit about a long-lived star where life may arise and evolve. The first place we looked was at stars like our own Sun, a middle-sized, middle-aged star. G-Stars like the Sun are stable for about 10 billion years, which is a good long time for planets to form, and life to evolve. We also expected to find solar systems like our own with small terrestrial planets near the star, and larger gaseous planets farther out. This particular pre-conception was discarded with the discovery of hot Jupiters on 4-day orbits about their stars.
This method has detected more than 200 planets, dominantly large close-in planets called "hot Jupiters" that are inhospitable to life as we know it.
In the near future, with the launch of NASA's Kepler Mission in 2008, we'll have the tools to seek evidence of Earth-size planets in the habitable zone of distant stars.
The search for life beyond Earth is the search for a good place to live, a habitable planet, in orbit about a long-lived star where life may arise and evolve. The first place we looked was at stars like our own Sun, a middle-sized, middle-aged star. G-Stars like the Sun are stable for about 10 billion years, which is a good long time for planets to form, and life to evolve. We also expected to find solar systems like our own with small terrestrial planets near the star, and larger gaseous planets farther out. This particular pre-conception was discarded with the discovery of hot Jupiters on 4-day orbits about their stars.
Hurtling through a cosmic dust cloud a mere 400 light-years away, the lovely Pleiades or Seven Sisters star cluster is well-known in astronomical images for its striking blue reflection nebulae. At visible wavelengths, the starlight is scattered and reflected by the dust, but in this portrait in infrared light by the Spitzer Space Telescope, the dust itself glows.
The false color image spans about 1 degree or seven light-years at the distance of the Pleiades, with the densest regions of the dust cloud shown in yellow and red hues. Exploring this young, nearby cluster, the Spitzer data have revealed many cool, low mass stars, brown dwarfs or failed stars, and possible planetary debris disks. Want to see the Pleiades tonight? Look near Venus, the brilliant evening star in the west just after sunset.
The false color image spans about 1 degree or seven light-years at the distance of the Pleiades, with the densest regions of the dust cloud shown in yellow and red hues. Exploring this young, nearby cluster, the Spitzer data have revealed many cool, low mass stars, brown dwarfs or failed stars, and possible planetary debris disks. Want to see the Pleiades tonight? Look near Venus, the brilliant evening star in the west just after sunset.
Suggestions in regard to robotic rights seem to be flying off the shelves these days, but an engineer at the Naval Surface Warfare Centre has concocted an interesting set of guidelines catering to autonomous killbots of the future. Most likely, it's just a matter of time before machine-on-machine violence becomes commonplace, and John Canning's "Concept of Operations for Armed Autonomous Systems" outlines just how lethal robots should handle themselves when faced with potentially deadly conflicts.
Interestingly, the document suggests the the bots should be allowed to make their own decisions when it comes to blasting or forgiving fellow robots, but before they pull the trigger on a human, it should request guidance from a flesh 'n blood friendly.
Interestingly, the document suggests the the bots should be allowed to make their own decisions when it comes to blasting or forgiving fellow robots, but before they pull the trigger on a human, it should request guidance from a flesh 'n blood friendly.
For the first time ever, NASA researchers have successfully demonstrated in the laboratory that a space telescope rigged with special masks and mirrors could snap a photo of an Earth-like planet orbiting a nearby star. This accomplishment marks a dramatic step forward for missions like the proposed Terrestrial Planet Finder, designed to hunt for an Earth twin that might harbor life.
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| ©NASA/JPL-Caltech |
| Three simulated planets -- one as bright as Jupiter, one half as bright as Jupiter and one as faint as Earth -- stand out plainly in this image created from a sequence of 480 images captured by the High Contrast Imaging Testbed at JPL. A roll-subtraction technique, borrowed from space astronomy, was used to distinguish planets from background light. The asterisk marks the location of the system's simulated star. |
We learn better when the material meshes with what we already know, according to a new study of rats that researchers say could help explain human learning.
The earliest life on Earth might have been just as purple as it is green today, a scientist claims.
Ancient microbes might have used a molecule other than chlorophyll to harness the Sun's rays, one that gave the organisms a violet hue.
Chlorophyll, the main photosynthetic pigment of plants, absorbs mainly blue and red wavelengths from the Sun and reflects green ones, and it is this reflected light that gives plants their leafy color. This fact puzzles some biologists because the sun transmits most of its energy in the green part of the visible spectrum.
"Why would chlorophyll have this dip in the area that has the most energy?" said Shil DasSarma, a microbial geneticist at the University of Maryland.
Ancient microbes might have used a molecule other than chlorophyll to harness the Sun's rays, one that gave the organisms a violet hue.
Chlorophyll, the main photosynthetic pigment of plants, absorbs mainly blue and red wavelengths from the Sun and reflects green ones, and it is this reflected light that gives plants their leafy color. This fact puzzles some biologists because the sun transmits most of its energy in the green part of the visible spectrum.
"Why would chlorophyll have this dip in the area that has the most energy?" said Shil DasSarma, a microbial geneticist at the University of Maryland.
In 2008, scientists will, for the very first time, create a continual profile of ice thickness in the Arctic, extending from the Canadian coast across the North Pole to Siberia. At the core of the project lies the crossing of the North Pole by zeppelin. The airship will be equipped with an electromagnetic sensor developed at the Alfred Wegener Institute for Polar and Marine Research, one of the 15 research centres within the Helmholtz Association. The sensational project of French physician Jean-Louis Etienne is financed by the French oil company Total and will be presented in Berlin on April 5.
Background
The extent of sea ice cover in the Arctic Ocean is declining strongly. This reduction in the North represents a stark contrast to sea ice cover in the Antarctic where even a slight increase is detectable. "There is almost no information about regional distribution of ice thickness in the Arctic and Antarctic", explains Dr Christian Haas, geophysicist at the Alfred Wegener Institute. "This lack of knowledge is a consequence of major methodological problems associated with measuring ice floes of only several metres thickness, and of the logistical difficulties of venturing into the central Arctic." The development of ice cover in the polar oceans represents one of the key questions in climate research, and hence is among the core research topics during the International Polar Year 2007 / 2008.
Background
The extent of sea ice cover in the Arctic Ocean is declining strongly. This reduction in the North represents a stark contrast to sea ice cover in the Antarctic where even a slight increase is detectable. "There is almost no information about regional distribution of ice thickness in the Arctic and Antarctic", explains Dr Christian Haas, geophysicist at the Alfred Wegener Institute. "This lack of knowledge is a consequence of major methodological problems associated with measuring ice floes of only several metres thickness, and of the logistical difficulties of venturing into the central Arctic." The development of ice cover in the polar oceans represents one of the key questions in climate research, and hence is among the core research topics during the International Polar Year 2007 / 2008.
Solar storms, which are expected to get worse over the next five years, could threaten China's national defence and communications satellite systems, said the National Satellite Meteorological Center (NSMC) on Tuesday.
Astronomers have long known that the Sun's "activity" rises and falls in cycles that last roughly 11 years each. Now a team of scientists from China and India has developed a theoretical model of solar activity that suggests that the next cycle, which is due to begin in about 2011, will be relatively mild. The model -- the first to confirm predictions based purely on experimental records of solar activity -- is good news because high levels of activity can disrupt satellite communications.
The fact that the Sun goes through cycles of activity was first noticed in the 18th century when astronomers began charting the number of cool, dark patches or "sunspots" on the solar surface where magnetic activity is intense. However, in the mid-1970s -- when the first accurate data of the Sun's polar magnetic field started being recorded -- astronomers found evidence for a possible link between the minimum value of the field in one cycle and the peak field of the next cycle. If such a link does exist, one could then predict the strength of future cycles based on past data. Indeed, the polar field is so low in the current solar cycle that the next cycle is predicted to be the weakest for 100 years.
The fact that the Sun goes through cycles of activity was first noticed in the 18th century when astronomers began charting the number of cool, dark patches or "sunspots" on the solar surface where magnetic activity is intense. However, in the mid-1970s -- when the first accurate data of the Sun's polar magnetic field started being recorded -- astronomers found evidence for a possible link between the minimum value of the field in one cycle and the peak field of the next cycle. If such a link does exist, one could then predict the strength of future cycles based on past data. Indeed, the polar field is so low in the current solar cycle that the next cycle is predicted to be the weakest for 100 years.
