Physicists may have solved a long-standing mystery about sand dunes on Mars. The dunes looks as if they should have been created by the action of wind, but the Martian atmosphere is so still and thin that it was thought impossible for wind to have played a part. New computer simulations suggest that the wind can indeed drive the sand dunes on Mars -- it's just that the dunes are formed far more slowly than back on Earth.
Astronomers have long been puzzled by the sand dunes on Mars, which were first discovered in 1971. The dunes look very much like those on Earth, which suggests they were created by the action of wind. The problem is that the Martian atmosphere is so thin and still -- so how could the wind have played a part?
Even more curious is the fact that successive missions to Mars have not detected any change in the positions of the dunes, whereas the dunes on Earth are shifting constantly. Some scientists have therefore suggested that the dunes were created long ago, when the Martian atmosphere could have been much denser than it is today.
Science & Technology
Tomita's team successfully inserted into a common bacterium Albert Einstein's famous "E equals MC squared" equation and "1905," the year the Nobel Prize-winning physicist published the special theory of relativity.
Charlie Callagan, park ranger and naturalist, knows the rocks well. "You see the rocks and you see the tracks they left behind and it's obvious they've moved," says Callagan.
And there are no footprints, no tire tracks, no sign of someone moving them.
And there are no footprints, no tire tracks, no sign of someone moving them.
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"This is not my day job." So begins Michel Barsoum as he recounts his foray into the mysteries of the Great Pyramids of Egypt. As a well respected researcher in the field of ceramics, Barsoum never expected his career to take him down a path of history, archaeology, and "political" science, with materials research mixed in.
As a distinguished professor in the Department of Materials Science and Engineering at Drexel University, his daily routine consists mainly of teaching students about ceramics, or performing research on a new class of materials, the so-called MAX Phases, that he and his colleagues discovered in the 1990s. These modern ceramics are machinable, thermal-shock resistant, and are better conductors of heat and electricity than many metals-making them potential candidates for use in nuclear power plants, the automotive industry, jet engines, and a range of other high-demand systems.
As a distinguished professor in the Department of Materials Science and Engineering at Drexel University, his daily routine consists mainly of teaching students about ceramics, or performing research on a new class of materials, the so-called MAX Phases, that he and his colleagues discovered in the 1990s. These modern ceramics are machinable, thermal-shock resistant, and are better conductors of heat and electricity than many metals-making them potential candidates for use in nuclear power plants, the automotive industry, jet engines, and a range of other high-demand systems.
Our natural daily 24-hour cycle could be stretched by an extra hour safely and simply by exposure to pulses of bright light, research suggests.
Experts say it could prove useful for astronauts adapting for long-term missions to Mars - where a day lasts an extra 40 minutes.
The team, from universities in the US and France, tested the light treatment successfully on 12 volunteers.
The study features in the Proceeding of the National Academy of Sciences.
Experts say it could prove useful for astronauts adapting for long-term missions to Mars - where a day lasts an extra 40 minutes.
The team, from universities in the US and France, tested the light treatment successfully on 12 volunteers.
The study features in the Proceeding of the National Academy of Sciences.
YouTube's co-founders on Thursday challenged the Pentagon's assertion that soldiers overseas were sapping too much bandwidth by watching online videos, the military's principal rationale for blocking popular Web sites from Defense Department computers.
"They said it might be a bandwidth issue, but they created the Internet, so I don't know what the problem is," Chief Executive Chad Hurley said with a hearty laugh during an interview with The Associated Press.
Hurley, Chief Technology Officer Steve Chen and YouTube spokeswoman Julie Supan emphasized that the online video company is trying to work with the Pentagon in hopes the military will reverse course or at least partially repeal the ban.
"We'd like to explore what's at issue here and talk about what we can do to sort out what's the issue here," Supan said.
"They said it might be a bandwidth issue, but they created the Internet, so I don't know what the problem is," Chief Executive Chad Hurley said with a hearty laugh during an interview with The Associated Press.
Hurley, Chief Technology Officer Steve Chen and YouTube spokeswoman Julie Supan emphasized that the online video company is trying to work with the Pentagon in hopes the military will reverse course or at least partially repeal the ban.
"We'd like to explore what's at issue here and talk about what we can do to sort out what's the issue here," Supan said.
B12 - an essential vitamin for land-dwelling animals, including humans - also turns out to be an essential ingredient for growing marine plants that are critical to the ocean food web and Earth's climate, scientists have found.
The presence or absence of B12 in the ocean plays a vital and previously overlooked role in determining where, how much, and what kinds of microscopic algae (called phytoplankton) will bloom in the sea, according to a study published in the May issue of the journal Limnology and Oceanography.
These photosynthesizing plants, in turn, have a critical impact on Earth's climate: They draw huge amounts of carbon dioxide, a greenhouse gas, from the air, incorporating carbon into their bodies. When they die or are eaten, carbon is transferred to the ocean depths, where it cannot re-enter the atmosphere.
The presence or absence of B12 in the ocean plays a vital and previously overlooked role in determining where, how much, and what kinds of microscopic algae (called phytoplankton) will bloom in the sea, according to a study published in the May issue of the journal Limnology and Oceanography.
These photosynthesizing plants, in turn, have a critical impact on Earth's climate: They draw huge amounts of carbon dioxide, a greenhouse gas, from the air, incorporating carbon into their bodies. When they die or are eaten, carbon is transferred to the ocean depths, where it cannot re-enter the atmosphere.
Historians need not be quite so impressed by Alexander the Great's defeat of the island of Tyre in 332BC. Geological studies of the region show that Alexander's army had help reaching the island, in the form of a natural land-bridge lying just a metre or two below the water's surface.
Alexander the Great was just 23 years old when he stood on the coast of what is now Lebanon, gazing offshore at the tiny Phoenician island city of Tyre, a powerful commercial centre. Alexander knew that Tyre had to be seized before he could safely move south to Egypt and then turn inland to conquer the Persian Empire.
In a determined attack, Alexander's engineers used timber and ruins from the old centre of Tyre on the coast to build a 1-kilometre-long 'mole', or causeway, to the island. Months later, his army broke through the fortress walls and brutally crushed Tyre.
Alexander the Great was just 23 years old when he stood on the coast of what is now Lebanon, gazing offshore at the tiny Phoenician island city of Tyre, a powerful commercial centre. Alexander knew that Tyre had to be seized before he could safely move south to Egypt and then turn inland to conquer the Persian Empire.
In a determined attack, Alexander's engineers used timber and ruins from the old centre of Tyre on the coast to build a 1-kilometre-long 'mole', or causeway, to the island. Months later, his army broke through the fortress walls and brutally crushed Tyre.
A new image from NASA's Spitzer Space Telescope shows infant stars "hatching" in the head of Orion, the famous hunter constellation visible from northern hemispheres during winter nights. Astronomers suspect that shockwaves from a 3-million-year-old explosion of a massive star may have initiated this newfound birth.
The region featured in the Spitzer image is called Barnard 30. It is located approximately 1,300 light-years away and sits on the right side of Orion's head, just north of the massive star Lambda Orionis.
"When we decided to study this region, it was barely known, despite the fact that its properties made it a nice target. Our aim was to carry out a comprehensive study of the region's different properties," said David Barrado y Navascués, of the Laboratorio de Astrofísica Espacial y Física Fundamental in Madrid, Spain, who led the Spitzer observations.
"We now know, thanks to Spitzer, that there is a large population of low-mass stars and brown dwarfs [or failed stars]," he added.
The region featured in the Spitzer image is called Barnard 30. It is located approximately 1,300 light-years away and sits on the right side of Orion's head, just north of the massive star Lambda Orionis.
"When we decided to study this region, it was barely known, despite the fact that its properties made it a nice target. Our aim was to carry out a comprehensive study of the region's different properties," said David Barrado y Navascués, of the Laboratorio de Astrofísica Espacial y Física Fundamental in Madrid, Spain, who led the Spitzer observations.
"We now know, thanks to Spitzer, that there is a large population of low-mass stars and brown dwarfs [or failed stars]," he added.
A Neptune-size planet likely covered in hot - but solid - water has been discovered in a snug orbit around a nearby star, a team of astronomers announced today.
While this planet is not fit for life, the finding suggests astronomers may soon detect habitable planets in similar alien solar systems, said Michaël Gillon of the University of Liège in Belgium.
"We are just at the door of a very exciting era," he said in an email interview.
The exotic water detected on the planet is known to form under extremely high pressure - conditions that can only be replicated on Earth in laboratories.
The planet, called GJ 436 b, orbits a cool, red star at a distance of only 2.5 million miles (4 million kilometers).
While this planet is not fit for life, the finding suggests astronomers may soon detect habitable planets in similar alien solar systems, said Michaël Gillon of the University of Liège in Belgium.
"We are just at the door of a very exciting era," he said in an email interview.
The exotic water detected on the planet is known to form under extremely high pressure - conditions that can only be replicated on Earth in laboratories.
The planet, called GJ 436 b, orbits a cool, red star at a distance of only 2.5 million miles (4 million kilometers).
