Science & Technology
Sand dunes on Mars are monsters - around 10 times as big as the largest on Earth. That's because low gravity gives Martian sand grains a lot more bounce.
The latest edition of the Oxford English Dictionary boasts 22,000 pages of definitions. While that may seem far from succinct, new research suggests the reference manual is meticulously organized to be as concise as possible - a format that mirrors the way our brains make sense of and categorize the countless words in our vast vocabulary.
"Dictionaries have often been thought of as a frustratingly tangled web of words where the definition of word A refers users to word B, which is defined using word C, which ends up referring users back to word A," said Mark Changizi, assistant professor of cognitive science at Rensselaer Polytechnic Institute. "But this research suggests that all words are grounded in a small set of atomic words - and it's likely that the dictionary's large-scale organization has been driven over time by the way humans mentally systematize words and their meanings."
"Dictionaries have often been thought of as a frustratingly tangled web of words where the definition of word A refers users to word B, which is defined using word C, which ends up referring users back to word A," said Mark Changizi, assistant professor of cognitive science at Rensselaer Polytechnic Institute. "But this research suggests that all words are grounded in a small set of atomic words - and it's likely that the dictionary's large-scale organization has been driven over time by the way humans mentally systematize words and their meanings."
Researchers at the University of Cincinnati and Florida State University have confirmed evidence of domesticated sunflower in Mexico - 4,000 years before what had been previously believed.
|
| ©University of Cincinnati |
| Wild sunflowers in Nuevo Leon in the foothills of the Sierra Madre Oriental mountains. |
Stem cell researchers at UCLA were able to grow functioning cardiac cells using mouse skin cells that had been reprogrammed into cells with the same unlimited properties as embryonic stem cells.
The finding is the first to show that induced pluripotent stem cells or iPS cells, which don't involve the use of embryos or eggs, can be differentiated into the three types of cardiovascular cells needed to repair the heart and blood vessels.
The finding is the first to show that induced pluripotent stem cells or iPS cells, which don't involve the use of embryos or eggs, can be differentiated into the three types of cardiovascular cells needed to repair the heart and blood vessels.
As a powerful electrical storm rages on Saturn with lightning bolts 10,000 times more powerful than those found on Earth, the Cassini spacecraft continues its five-month watch over the dramatic events.
Scientists with NASA's Cassini-Huygens mission have been tracking the visibly bright, lightning-generating storm--the longest continually observed electrical storm ever monitored by Cassini.
Saturn's electrical storms resemble terrestrial thunderstorms, but on a much larger scale. Storms on Saturn have diameters of several thousand kilometers (thousands of miles), and radio signals produced by their lightning are thousands of times more powerful than those produced by terrestrial thunderstorms.
Scientists with NASA's Cassini-Huygens mission have been tracking the visibly bright, lightning-generating storm--the longest continually observed electrical storm ever monitored by Cassini.
|
| ©NASA/JPL/Space Science Institute |
| It is no Great Red Spot, but these two side-by-side views show the longest-lived electrical storm yet observed on Saturn by NASA's Cassini spacecraft. The view at left was created by combining images taken using red, green and blue spectral filters, and shows Saturn in colors that approximate what the human eye would see. The storm stands out with greater clarity in the sharpened, enhanced color view at right. |
Saturn's electrical storms resemble terrestrial thunderstorms, but on a much larger scale. Storms on Saturn have diameters of several thousand kilometers (thousands of miles), and radio signals produced by their lightning are thousands of times more powerful than those produced by terrestrial thunderstorms.
Using NASA's Rossi X-ray Timing Explorer (RXTE) satellite, a team of four astronomers has discovered a timing mechanism that tells them exactly when a superdense star will let loose incredibly powerful explosions.
"We found a clock that ticks slower and slower, and when it slows down too much, boom! The bomb explodes," says team leader Diego Altamirano of the University of Amsterdam in the Netherlands.
The explosions occur on a neutron star, which is a city-sized remnant of a giant star that exploded in a supernova. But despite the neutron star's small size, it contains more material than our sun. The neutron star is not alone in space. It has a companion star, and the two objects orbit each other every 3.8 hours. This double-star system is known as 4U 1636-53 for its sky coordinates in the Southern Hemisphere.
"We found a clock that ticks slower and slower, and when it slows down too much, boom! The bomb explodes," says team leader Diego Altamirano of the University of Amsterdam in the Netherlands.
|
| ©NASA |
| A thermonuclear explosion as it engulfs an entire neutron star. |
The explosions occur on a neutron star, which is a city-sized remnant of a giant star that exploded in a supernova. But despite the neutron star's small size, it contains more material than our sun. The neutron star is not alone in space. It has a companion star, and the two objects orbit each other every 3.8 hours. This double-star system is known as 4U 1636-53 for its sky coordinates in the Southern Hemisphere.
Enzymes regulating genetic expression can be just as important as the genome itself, increasing evidence shows. The expanding field of epigenetics focuses on the multiple influences on DNA and surrounding molecules that determine whether genes are turned on or off during development and disease processes.
|
| ©Walter Meyers |
| Mercury Sunrise |
There been a lot of media attention over the possibility of asteroids and meteors striking Earth and causing cataclysmic damage, but now some scientists are saying that the planet Mercury (sunrise image above) could also possibly smash into our planet. Huh? That sounds bad.
New Dehli - With the help of local herdsmen , a huge cluster of ancient rock drawings has been unearthed in northern China's Inner Mongolian Autonomous Region.
Over one thousand drawings from the Bronze Era were discovered about 55 kilometers west of Hailiutu county, reports CCTV International.
Most of the pictures are carved on black granite along the mountainsides and they stretch about five kilometers into a valley near the Bayinhudu mountain.
The pictures are based mainly on daily life and involve a wide variety of subjects such as goats, longhorn-deer and dogs.
Some drawings depict hunting scenes and mysterious symbols while some single pieces contain dozens of patterns.
Over one thousand drawings from the Bronze Era were discovered about 55 kilometers west of Hailiutu county, reports CCTV International.
Most of the pictures are carved on black granite along the mountainsides and they stretch about five kilometers into a valley near the Bayinhudu mountain.
The pictures are based mainly on daily life and involve a wide variety of subjects such as goats, longhorn-deer and dogs.
Some drawings depict hunting scenes and mysterious symbols while some single pieces contain dozens of patterns.
A team of astronomers looking at the universe's distant past found nine young, unusually compact galaxies, each weighing in at 200 billion times the mass of the Sun. These young galaxies are the equivalent of a human baby that is 20 inches long, yet weighs 180 pounds.
"Seeing the compact sizes of these galaxies is a puzzle," said Pieter G. van Dokkum of Yale, who led the study. "No massive galaxy at this distance has ever been observed to be so compact, and it is not yet clear how one of these would build itself up to be the size of the galaxies we see today." The findings appeared in the April 10 issue of The Astrophysical Journal Letters.
"Seeing the compact sizes of these galaxies is a puzzle," said Pieter G. van Dokkum of Yale, who led the study. "No massive galaxy at this distance has ever been observed to be so compact, and it is not yet clear how one of these would build itself up to be the size of the galaxies we see today." The findings appeared in the April 10 issue of The Astrophysical Journal Letters.
|
| ©NASA, ESA, A. Feild (STScI) and P. van Dokkum (Yale) |
| This illustration shows the comparative sizes of our Milky Way Galaxy and an ultracompact galaxy, which existed in the early universe. Although the compact galaxy is only a fraction of the size of our Milky Way, it contains the same number of stars. The small, dense galaxy could fit inside the central hub of our Milky Way. |
