NASA officials say the space agency is capable of finding nearly all the asteroids that might pose a devastating hit to Earth, but there isn't enough money to pay for the task so it won't get done.
The cost to find at least 90 percent of the 20,000 potentially hazardous asteroids and comets by 2020 would be about $1 billion, according to a report NASA will release later this week. The report was previewed Monday at a Planetary Defense Conference in Washington.
Congress in 2005 asked NASA to come up with a plan to track most killer asteroids and propose how to deflect the potentially catastrophic ones.
Science & Technology
To David Morrison, a senior scientist at NASA, the Earth orbits the sun in a sort of cosmic shooting gallery. More than 1 million asteroids spin around the sun, and it is Morrison's job to figure out which of these bodies of rock, dust and metal could come crashing down on Earth.
Right now, NASA is tracking 127 asteroids that have a very small chance of striking the planet. That number is about to get a lot higher. Stronger telescopes, and a new mandate from Congress, will allow scientists to detect thousands of smaller asteroids more likely to hit Earth. And scientists are plotting ways to stop them, from "gravity tractors" to solar ray guns.
Right now, NASA is tracking 127 asteroids that have a very small chance of striking the planet. That number is about to get a lot higher. Stronger telescopes, and a new mandate from Congress, will allow scientists to detect thousands of smaller asteroids more likely to hit Earth. And scientists are plotting ways to stop them, from "gravity tractors" to solar ray guns.
An underwater survey off San Diego has revealed geological details of how sand builds up along Southern California's continental shelf and could help resource managers to locate deposits to rebuild beaches, according to a report by scientists at Scripps Institution of Oceanography at UC San Diego.
The newly acquired data show the depth of sand levels along 10 kilometers (6.2 miles) of shoreline from La Jolla Cove north to Torrey Pines State Beach and how the sediments are distributed on the shallow, gently sloping seabed adjacent to the shoreline.
The scientists also identified an area of the seafloor uplifted offshore of Torrey Pines State Park that results from a jog in the Rose Canyon fault, similar to the uplift that created Mount Soledad. This uplifted area appears to play a major role in the accumulation of sand in the area, according to Leah Hogarth, a Scripps graduate student and lead author of the article in the journal Geology of the Geological Society of America.
The newly acquired data show the depth of sand levels along 10 kilometers (6.2 miles) of shoreline from La Jolla Cove north to Torrey Pines State Beach and how the sediments are distributed on the shallow, gently sloping seabed adjacent to the shoreline.
The scientists also identified an area of the seafloor uplifted offshore of Torrey Pines State Park that results from a jog in the Rose Canyon fault, similar to the uplift that created Mount Soledad. This uplifted area appears to play a major role in the accumulation of sand in the area, according to Leah Hogarth, a Scripps graduate student and lead author of the article in the journal Geology of the Geological Society of America.
Livermore researchers have moved one step closer to being able to turn on and off the decay of a nuclear isomer.
The protons and neutrons in a nucleus can be arranged in many ways. The arrangement with the lowest energy is called the ground state and all others are called excited states. (This is analogous to the ground and excited states of electrons in an atom except that nuclear excited states are typically thousands of times higher in energy.) Excited nuclear states eventually decay to the ground state via gamma emission or to another nucleus via particle emission. Most excited states are short-lived (e.g., billionth of a second). However, a few are long-lived (e.g., hours) and are called isomers.
Turning the decay on and off is key to using isiomers as high-energy density storage systems such as batteries.
Researchers at Livermore studied an isomer of Thorium-229. This isomer is unique in that its excitation energy is near optical energies, implying that one day scientists may be able to transition Th229 nuclei between the ground and isomeric states using a table-top laser.
"This would then be the first time human control would be exerted over nuclear levels," said Peter Beiersdorfer, an LLNL physicist and co-author of a paper that appears in the April 6 issue of Physical Review Letters. "This only works if the laser is tuned to exactly the correct energy."
The protons and neutrons in a nucleus can be arranged in many ways. The arrangement with the lowest energy is called the ground state and all others are called excited states. (This is analogous to the ground and excited states of electrons in an atom except that nuclear excited states are typically thousands of times higher in energy.) Excited nuclear states eventually decay to the ground state via gamma emission or to another nucleus via particle emission. Most excited states are short-lived (e.g., billionth of a second). However, a few are long-lived (e.g., hours) and are called isomers.
Turning the decay on and off is key to using isiomers as high-energy density storage systems such as batteries.
Researchers at Livermore studied an isomer of Thorium-229. This isomer is unique in that its excitation energy is near optical energies, implying that one day scientists may be able to transition Th229 nuclei between the ground and isomeric states using a table-top laser.
"This would then be the first time human control would be exerted over nuclear levels," said Peter Beiersdorfer, an LLNL physicist and co-author of a paper that appears in the April 6 issue of Physical Review Letters. "This only works if the laser is tuned to exactly the correct energy."
A lifelong obsession leads to the mysterious hedecatope - a seemingly impossible geometric form that, in its own small way, links together the whole universe.
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| ©Computer model courtesy of Carlo Sequin |
| In this 3-D slice of the four-dimensional
hendecatope, colored beams represent the edges of triangles; some triangles are left out for simplicity. |
A serene orb of ice is set against the gentle pastel clouds of giant Saturn. Rhea transits the face of the gas giant, whose darkened rings and their planet-hugging shadows appear near upper right.
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| ©NASA/JPL/Space Science Institute |
The microeconomic law of diminishing marginal utility states that while accumulating a good - pretzels, pencils, nickels, whatever - each successive unit of that good will be less satisfying to acquire than the one before it. Finding a shiny quarter on the street is a real thrill. But, if you are carrying around a bag of coins, acquiring another one does not seem nearly as exciting. In fact, would you even bother to pick it up?
That hesitation is what researchers at the University of Cambridge in England were banking on when they designed a study to see if the haves catch on more slowly than the have-nots when it comes to reward-based learning. Reporting in the current issue of Neuron, the scientists reveal that when a small sum of money is on the line, poorer people learn quickly how to maximize their profits, leaving their wealthier counterparts in the dust.
That hesitation is what researchers at the University of Cambridge in England were banking on when they designed a study to see if the haves catch on more slowly than the have-nots when it comes to reward-based learning. Reporting in the current issue of Neuron, the scientists reveal that when a small sum of money is on the line, poorer people learn quickly how to maximize their profits, leaving their wealthier counterparts in the dust.
Economists who yearn for the redistribution of wealth in an ideal society are up against history. According to a recent study, the uneven distribution of wealth in a society appears to be a universal law that holds true for economies in many different societies, from ancient Egypt to modern Japan and the U.S. This distribution may reflect a simple natural law analogous to a 100-year-old theory describing the distribution of energy in a gas.
Scientists Arnab Chatterjee and Bikas Chakrabarti from the Saha Institute of Nuclear Physics, along with Sitabhra Sinha of the Institute of Mathematical Sciences, both in India, have analyzed a variety models explaining different sets of data, and found striking similarities. The results show that the poorer majority of the population follows one distribution, while a small proportion of the wealthiest people veers off in a tail following a power-law distribution, in essence reflecting how "the rich get richer."
The studies included large sets of data from sources such as income tax returns and net values of assets in societies including Japan, the U.S., the UK, India, and nineteenth century Europe. The data, taken from a large number of recent publications by several groups, represented a variety of different economies and stages of development. Generally, the lower 90% of the population (in terms of income) followed a log-normal distribution, characterized by an initial rapid rise in population followed by a rapid fall as income increased.
Scientists Arnab Chatterjee and Bikas Chakrabarti from the Saha Institute of Nuclear Physics, along with Sitabhra Sinha of the Institute of Mathematical Sciences, both in India, have analyzed a variety models explaining different sets of data, and found striking similarities. The results show that the poorer majority of the population follows one distribution, while a small proportion of the wealthiest people veers off in a tail following a power-law distribution, in essence reflecting how "the rich get richer."
The studies included large sets of data from sources such as income tax returns and net values of assets in societies including Japan, the U.S., the UK, India, and nineteenth century Europe. The data, taken from a large number of recent publications by several groups, represented a variety of different economies and stages of development. Generally, the lower 90% of the population (in terms of income) followed a log-normal distribution, characterized by an initial rapid rise in population followed by a rapid fall as income increased.
Scientists have solved a decades-long mystery of a red glow that permeates our Milky Way Galaxy and other galaxies.
The red glow is most prominent in a strange, dying star called the Red Rectangle, named for the bizarre structure that surrounds it.
The red light, astronomers now say, radiates from invisibly small clusters of dust that are now believed to glow because of newly described molecular forces that oppose each other on very small scales.
The glow, called the Extended Red Emission (conveniently ERE for short) has been known but inexplicable for more than 30 years. Researchers suspected carbon-rich molecules called polycyclic aromatic hydrocarbons (PAHs) were the culprit. These clusters of molecules form a structure that looks like chicken wire; they are measured on a scale of billionths of a meter, far too small to see.
The red glow is most prominent in a strange, dying star called the Red Rectangle, named for the bizarre structure that surrounds it.
The red light, astronomers now say, radiates from invisibly small clusters of dust that are now believed to glow because of newly described molecular forces that oppose each other on very small scales.
The glow, called the Extended Red Emission (conveniently ERE for short) has been known but inexplicable for more than 30 years. Researchers suspected carbon-rich molecules called polycyclic aromatic hydrocarbons (PAHs) were the culprit. These clusters of molecules form a structure that looks like chicken wire; they are measured on a scale of billionths of a meter, far too small to see.
New solar cells developed by Massey University don't need direct sunlight to operate and use a patented range of dyes that can be impregnated in roofs, window glass and eventually even clothing to produce power.
