Science & Technology
LOS ANGELES - NASA's Phoenix spacecraft has discovered evidence of past water at its Martian landing site and spotted falling snow for the first time, scientists reported Monday. Soil experiments revealed the presence of two minerals known to be formed in liquid water. Scientists identified the minerals as calcium carbonate, found in limestone and chalk, and sheet silicate.
© European Space Agency
One of the first images of the re-entry of the European Space Agency's space freighter, Jules Verne, over the Pacific Ocean
One of the first images of the re-entry of the European Space Agency's space freighter, Jules Verne, over the Pacific Ocean
The planned burn followed the craft's six-month mission to the space station to provide the crew there with a fresh shipment of food, fuel and supplies. The crew reloaded the freighter with 2.5 tonnes of garbage before launching it back into space.
© Science/AAAS
A large band of ancient rocks in northern Quebec, known as the Nuvvuagittuq greenstone belt, has produced what may be the oldest rock on Earth – at 4.28 billion years old
A large band of ancient rocks in northern Quebec, known as the Nuvvuagittuq greenstone belt, has produced what may be the oldest rock on Earth – at 4.28 billion years old
Finding the oldest rocks on Earth is important because they should help scientists solve one of geology's great mysteries: how the surface of our planet was transformed from the ocean of magma that existed in the Hadean - the earliest era in Earth's history - into the floating tectonic plates we have today.
Rather than building stronger ocean-based structures to withstand tsunamis, it might be easier to simply make the structures disappear.
A collaboration of physicists from the Centre National de la Recherche Scientifique (CNRS) and Aix-Marseille Universite in France and the University of Liverpool in England have conducted laboratory experiments showing that it's possible to make type of dike that acts as an invisibility cloak that hides off-shore platforms from water waves. The principle is analogous to the optical invisibility cloaks that are currently a hot area of physics research.
© M. Farhat, S. Enoch, S. Guenneau and A.B. Movchan
Laboratory experiments show that obstacles arranged in fluids in certain patterns can effectively make objects they surround invisible to waves. If it works as well in in scaled-up versions, it could lead to new ways to protect ocean-based platforms and coasts from devastating tsunamis.
Laboratory experiments show that obstacles arranged in fluids in certain patterns can effectively make objects they surround invisible to waves. If it works as well in in scaled-up versions, it could lead to new ways to protect ocean-based platforms and coasts from devastating tsunamis.
Dark energy is at the heart of one of the greatest mysteries of modern physics, but it may be nothing more than an illusion, according physicists at Oxford University.
The problem facing astrophysicists is that they have to explain why the universe appears to be expanding at an ever increasing rate. The most popular explanation is that some sort of force is pushing the accelerating the universe's expansion. That force is generally attributed to a mysterious dark energy.
Although dark energy may seem a bit contrived to some, the Oxford theorists are proposing an even more outrageous alternative. They point out that it's possible that we simply live in a very special place in the universe - specifically, we're in a huge void where the density of matter is particularly low. The suggestion flies in the face of the Copernican Principle, which is one of the most useful and widely held tenants in physics.
© NASA/STScI/Ann Feild
Changes in the rate of expansion since the universe's birth 15 billion years ago. The more shallow the curve, the faster the rate of expansion. The curve changes noticeably about 7.5 billion years ago, when objects in the universe began flying apart at a faster rate. Astronomers theorize that the faster expansion rate is due to a mysterious, dark force that is pulling galaxies apart.
Changes in the rate of expansion since the universe's birth 15 billion years ago. The more shallow the curve, the faster the rate of expansion. The curve changes noticeably about 7.5 billion years ago, when objects in the universe began flying apart at a faster rate. Astronomers theorize that the faster expansion rate is due to a mysterious, dark force that is pulling galaxies apart.
Although dark energy may seem a bit contrived to some, the Oxford theorists are proposing an even more outrageous alternative. They point out that it's possible that we simply live in a very special place in the universe - specifically, we're in a huge void where the density of matter is particularly low. The suggestion flies in the face of the Copernican Principle, which is one of the most useful and widely held tenants in physics.
New Mexico scientists discover fossilized remains of Typothorax with protective spikes
Don't call them perverts, but when two New Mexico paleontologists found a spiked opening on a fossilized 210 million-year-old animal - - in a place the sun doesn't generally shine -- they realized they had discovered something exciting.
The creature, called a Typothorax, appears to have had a protective cover over its naughty bits, although the actual purpose of the spikes hasn't quite been determined, they said.
"Is it an ancient chastity belt? Is it a clasper-type adaptation used in sexual activity? We just don't know yet," said Andy Heckert, an assistant geology professor at Appalachian State University in North Carolina and former geosciences collection manager at the New Mexico Museum of Natural History and Science.
Don't call them perverts, but when two New Mexico paleontologists found a spiked opening on a fossilized 210 million-year-old animal - - in a place the sun doesn't generally shine -- they realized they had discovered something exciting.
The creature, called a Typothorax, appears to have had a protective cover over its naughty bits, although the actual purpose of the spikes hasn't quite been determined, they said.
"Is it an ancient chastity belt? Is it a clasper-type adaptation used in sexual activity? We just don't know yet," said Andy Heckert, an assistant geology professor at Appalachian State University in North Carolina and former geosciences collection manager at the New Mexico Museum of Natural History and Science.
Gold jewelry, weapons and pottery are found near Pella, birthplace of the kingdom's legendary leader Alexander the Great.
Archaeologists have unearthed gold jewelry, weapons and pottery at an ancient burial site near Pella in northern Greece, the birthplace of Alexander the Great, the Culture Ministry said this week.
The excavations at the vast cemetery uncovered 43 graves dating from 650 to 279 BC, shedding new light on the early development of the Macedonian kingdom, which stretched as far as India under Alexander's conquests.
© Greek Culture Ministry
Jewelry found in a woman’s grave at Pella, northern Greece, dates to between 650 and 279 BC. Under Alexander’s conquests, Macedonia stretched as far as India.
Jewelry found in a woman’s grave at Pella, northern Greece, dates to between 650 and 279 BC. Under Alexander’s conquests, Macedonia stretched as far as India.
The excavations at the vast cemetery uncovered 43 graves dating from 650 to 279 BC, shedding new light on the early development of the Macedonian kingdom, which stretched as far as India under Alexander's conquests.
A protein required for the earliest steps in embryonic development also plays a key role in solidifying fear memories in the brains of adult animals, scientists have revealed. An apparent "hub" for changes in the connections between brain cells, beta-catenin could be a potential target for drugs to enhance or interfere with memory formation.
The results are published online this week and appear in the October issue of Nature Neuroscience.
The protein beta-catenin acts like a Velcro strap, fastening cells' internal skeletons to proteins on their external membranes that connect them with other cells. In species ranging from flies to frogs to mice, it also can transmit early signals that separate an embryo into front and back or top and bottom.
The results are published online this week and appear in the October issue of Nature Neuroscience.
The protein beta-catenin acts like a Velcro strap, fastening cells' internal skeletons to proteins on their external membranes that connect them with other cells. In species ranging from flies to frogs to mice, it also can transmit early signals that separate an embryo into front and back or top and bottom.
Mathematicians at UCLA have discovered a 13-million-digit prime number, a long-sought milestone that makes them eligible for a $100,000 prize.
The group found the 46th known Mersenne prime last month on a network of 75 computers running Windows XP. The number was verified by a different computer system running a different algorithm.
"We're delighted," said UCLA's Edson Smith, the leader of the effort. "Now we're looking for the next one, despite the odds."
The group found the 46th known Mersenne prime last month on a network of 75 computers running Windows XP. The number was verified by a different computer system running a different algorithm.
"We're delighted," said UCLA's Edson Smith, the leader of the effort. "Now we're looking for the next one, despite the odds."
NASA's Mars Reconnaissance Orbiter has revealed hundreds of small fractures exposed on the Martian surface that billions of years ago directed flows of water through underground Martian sandstone.
Researchers used images from the spacecraft's High Resolution Imaging Science Experiment, or HiRISE, camera. Images of layered rock deposits at equatorial Martian sites show the clusters of fractures to be a type called deformation bands, caused by stresses below the surface in granular or porous bedrock.
"Groundwater often flows along fractures such as these, and knowing that these are deformation bands helps us understand how the underground plumbing may have worked within these layered deposits," said Chris Okubo of the U.S. Geological Survey in Flagstaff, Ariz.
Visible effects of water on the color and texture of rock along the fractures provide evidence that groundwater flowed extensively along the fractures.
© NASA/JPL-Caltech/Univ. of Arizona
Dense clusters of crack-like structures called deformation bands form the linear ridges prominent in this image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.
Dense clusters of crack-like structures called deformation bands form the linear ridges prominent in this image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.
"Groundwater often flows along fractures such as these, and knowing that these are deformation bands helps us understand how the underground plumbing may have worked within these layered deposits," said Chris Okubo of the U.S. Geological Survey in Flagstaff, Ariz.
Visible effects of water on the color and texture of rock along the fractures provide evidence that groundwater flowed extensively along the fractures.
