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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. |
Science & Technology
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.
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.
The case had the makings of an eerie cyber-mystery: A young Alexandria woman told local police she suspected that her ex-boyfriend was tapping into her e-mail inbox from thousands of miles away, reading messages before she could and harassing the senders.
She was right to be suspicious. Her ex had hacked into her e-mail account, either guessing her password or using spyware -- software that can secretly read e-mails and survey cyber-traffic, law enforcement officials said. For months, apparently, he had followed her every online move, part of a pattern of abuse city police are still investigating.
She was right to be suspicious. Her ex had hacked into her e-mail account, either guessing her password or using spyware -- software that can secretly read e-mails and survey cyber-traffic, law enforcement officials said. For months, apparently, he had followed her every online move, part of a pattern of abuse city police are still investigating.
As countless photos from space can attest, Earth is round - the "Blue Marble," as astronauts have affectionately dubbed it. Appearances, however, can be deceiving. Planet Earth is not, in fact, perfectly round.
This is not to say Earth is flat. Well before Columbus sailed the ocean blue, Aristotle and other ancient Greek scholars proposed that Earth was round. This was based on a number of observations, such as the fact that departing ships not only appeared smaller as they sailed away but also seemed to sink into the horizon, as one might expect if sailing across a ball says geographer Bill Carstensen of Virginia Tech in Blacksburg.
This is not to say Earth is flat. Well before Columbus sailed the ocean blue, Aristotle and other ancient Greek scholars proposed that Earth was round. This was based on a number of observations, such as the fact that departing ships not only appeared smaller as they sailed away but also seemed to sink into the horizon, as one might expect if sailing across a ball says geographer Bill Carstensen of Virginia Tech in Blacksburg.
Cluster is providing new insights into the working of a 'space tsunami' that plays a role in disrupting the calm and beautiful aurora, or Northern Lights, creating patterns of auroral dances in the sky.
Generally seen in high-latitude regions such as Scandinavia or Canada, aurorae are colourful curtains of light that appear in the sky. Caused by the interaction of high-energy particles brought by the solar wind with Earth's magnetic field, they appear in many different shapes.
Generally seen in high-latitude regions such as Scandinavia or Canada, aurorae are colourful curtains of light that appear in the sky. Caused by the interaction of high-energy particles brought by the solar wind with Earth's magnetic field, they appear in many different shapes.
Scientists have found one of the largest fields of seafloor vents gushing super-hot, mineral-rich fluids on a mid-ocean ridge that, until now, remained elusive to the ten-year hunt to find them.
"The discovery of the first active vents ever found on an ultraslow-spreading ridge is a significant milestone event," said Jian Lin, leader of a team of Woods Hole Oceanographic Institution (WHOI) scientists who participated in a Chinese expedition to the remote Southwest Indian Ridge in the Indian Ocean in February and March.
Since deep-sea hydrothermal vents were first discovered 30 years ago in the Pacific Ocean, scientists have studied them all along the Mid-Ocean Ridge, a 40,000-mile-long mountain range that zigzags through the middle of the world's ocean basins like a giant zipper. The ridge marks the area where the Earth's giant tectonic plates spreads apart and new ocean crust forms from hot lava rising from deep within Earth's mantle.
"The discovery of the first active vents ever found on an ultraslow-spreading ridge is a significant milestone event," said Jian Lin, leader of a team of Woods Hole Oceanographic Institution (WHOI) scientists who participated in a Chinese expedition to the remote Southwest Indian Ridge in the Indian Ocean in February and March.
Since deep-sea hydrothermal vents were first discovered 30 years ago in the Pacific Ocean, scientists have studied them all along the Mid-Ocean Ridge, a 40,000-mile-long mountain range that zigzags through the middle of the world's ocean basins like a giant zipper. The ridge marks the area where the Earth's giant tectonic plates spreads apart and new ocean crust forms from hot lava rising from deep within Earth's mantle.
