What is the fastest a dolphin can swim? Near the surface, no more than 54 kilometres per hour. Why? Because it hurts it to swim faster.
Those are the findings of a pair of researchers from the Israel Institute of Technology in Haifa. But tuna, they say, do not suffer the same problem.
Gil Iosilevskii and Danny Weihs carried out a series of calculations to model the tail and fins of fish such as tuna and mackerel, and cetaceans such as dolphins. The aim was to determine what limits the maximum speed at which these creatures can swim.
Science & Technology
For the eager prankster, nothing beats April Fools' Day, a light-hearted tradition that's several hundred years old.
"A lot of people think [April Fools' Day] is just obnoxious, and just wish it would stop," said Alex Boese, curator of the Museum of Hoaxes in San Diego, California.
"But people who love pranks really love the day and refuse to give up the tradition. They're the ones who keep it alive."
Boese notes, however, that the number of pranks in the home and at the office has decreased in recent years in the United States, and has been replaced by large institutionalized media hoaxes, he said.
"A lot of people think [April Fools' Day] is just obnoxious, and just wish it would stop," said Alex Boese, curator of the Museum of Hoaxes in San Diego, California.
"But people who love pranks really love the day and refuse to give up the tradition. They're the ones who keep it alive."
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| ©Hulton Archive/Getty Images |
| Street kids tie a kite to an elderly man's hair on April Fools' Day in a 1770 painting.
Many historians believe the day of pranks originated in 1500s France, when country dwellers did not realize the start of the New Year had been moved from April to January - making them "April fools." |
Boese notes, however, that the number of pranks in the home and at the office has decreased in recent years in the United States, and has been replaced by large institutionalized media hoaxes, he said.
A massive whirling vortex recently discovered over Saturn's south pole has features that are similar to hurricanes on Earth and unlike anything astronomers have seen before, a new study finds.
The polar vortex was first discovered by NASA's Cassini spacecraft on Oct. 11, 2006, as it flew over the gas giant's south pole. The mass of swirling clouds took scientists by surprise.
"This is something we have never seen before," said study team leader Ulyana Dyudina of Caltech. "Before Cassini, we didn't know such a feature could exist on the poles."
The polar vortex was first discovered by NASA's Cassini spacecraft on Oct. 11, 2006, as it flew over the gas giant's south pole. The mass of swirling clouds took scientists by surprise.
"This is something we have never seen before," said study team leader Ulyana Dyudina of Caltech. "Before Cassini, we didn't know such a feature could exist on the poles."
PRESS RELEASE
SIMON P. WORDEN, BRIGADIER GENERAL, USAF
Deputy Director for Operations
United States Space Command
Peterson AFB, CO
July 10, 2002
The opinions and concepts expressed are those of the author and do not necessarily represent the position of the Department of Defense or the United States Space Command
Introduction
A few weeks ago the world almost saw a nuclear war. Pakistan and India were at full alert and poised for a large-scale war - which both sides appeared ready to escalate into nuclear war. The situation was defused - for now! Most of the world knew about this situation and watched and worried. But few know of an event over the Mediterranean in early June of this year that could have had a serious bearing on that outcome. U.S. early warning satellites detected a flash that indicated an energy release comparable to the Hiroshima burst. We see about 30 such bursts per year, but this one was one of the largest we've ever seen. The event was caused by the impact of a small asteroid - probably about 5-10 meters in diameter on the earth's atmosphere. Had you been situated on a vessel directly underneath the intensely bright flash would have been followed by a shock wave that would have rattled the entire ship and possibly caused minor damage.
SIMON P. WORDEN, BRIGADIER GENERAL, USAF
Deputy Director for Operations
United States Space Command
Peterson AFB, CO
July 10, 2002
The opinions and concepts expressed are those of the author and do not necessarily represent the position of the Department of Defense or the United States Space Command
Introduction
A few weeks ago the world almost saw a nuclear war. Pakistan and India were at full alert and poised for a large-scale war - which both sides appeared ready to escalate into nuclear war. The situation was defused - for now! Most of the world knew about this situation and watched and worried. But few know of an event over the Mediterranean in early June of this year that could have had a serious bearing on that outcome. U.S. early warning satellites detected a flash that indicated an energy release comparable to the Hiroshima burst. We see about 30 such bursts per year, but this one was one of the largest we've ever seen. The event was caused by the impact of a small asteroid - probably about 5-10 meters in diameter on the earth's atmosphere. Had you been situated on a vessel directly underneath the intensely bright flash would have been followed by a shock wave that would have rattled the entire ship and possibly caused minor damage.
There is a major meteor shower next month, the Lyrids, peaking on the evening of April 21. Unfortunately, an almost-full moon will shine in the sky all night, making viewing conditions less than ideal for seeing many meteors.
The radiant is between Lyra and Hercules but won't even begin to rise until 9:30 p.m., when the moon is well up in the eastern sky. Fortunately, there are many other science-related events going on right here in the Islands to satisfy your celestial appetite.
The radiant is between Lyra and Hercules but won't even begin to rise until 9:30 p.m., when the moon is well up in the eastern sky. Fortunately, there are many other science-related events going on right here in the Islands to satisfy your celestial appetite.
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| ©Unknown |
| Is this the smell of danger? |
The human nose has evolved to sniff out the smell of danger, according to research published today.
Scientists found volunteers who were previously unable to differentiate between two similar scents learnt to tell them apart when given electric shocks alongside just one of them.
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| ©Chris Walker / Chicago Tribune |
| The Amundsen-Scott station, where scientists are scanning space for evidence of dark energy.
Understanding it could explain the history and future of the universe. |
Anywhere on Earth this would be a big telescope, as tall as a seven-story building, with a main mirror measuring 32 1/2 feet across. But here at the South Pole, it seems especially large, looming over a barren plain of ice that gets colder than anywhere else on the planet.
Scientists built the instrument at the end of the world so they can search for clues that might identify the most powerful, plentiful but elusive substance in the universe: dark energy.
Europe's "Jules Verne" freighter is about to start practice docking manoeuvres at the space station.
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| ©ESA |
For the first time, physicists have been able to identify individual returning photons after firing and reflecting them off of a space satellite in orbit almost 1,500 kilometres above the earth. The experiment has proven the possibility of constructing a quantum channel between Space and Earth.
Research in the New Journal of Physics, discusses the feasibility of building a completely secure channel for global communication, via satellites in space, all thanks to advances in quantum mechanics.
The research team, led by Paolo Villoresi and Cesare Barbieri from Padova University, Italy, has taken intricate steps to fire photons directly at the Japanese Ajisai Satellite. The researchers have been able to prove that the photons received back at the Matera ground-based station, in southern Italy, are the same as those originally emitted.
Research in the New Journal of Physics, discusses the feasibility of building a completely secure channel for global communication, via satellites in space, all thanks to advances in quantum mechanics.
The research team, led by Paolo Villoresi and Cesare Barbieri from Padova University, Italy, has taken intricate steps to fire photons directly at the Japanese Ajisai Satellite. The researchers have been able to prove that the photons received back at the Matera ground-based station, in southern Italy, are the same as those originally emitted.
Despite leaders' best intentions, and contrary to common depictions of abundance and wealth, ancient Egyptians might not have had the most desirable conditions or lifestyles. Art records from the city of Amarna have long depicted prosperity; however new evidence reveals otherwise.
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| ©Gerbil |
| The unusual features of Pharaoh Akhenaten, who founded the city commonly known today as Amarna, are seen here in this family group |
