I guess the Hollywood suits just can't resist a dumb idea.lswot wrote:Henry J wrote:They'd also have to avoid inspiring the new technology...
hence my resistance to "prequels"
Physics news
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Xjmt
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Telescope is focus of Ohio town
Monday, August 22, 2005
John Mangels
Plain Dealer Science Writer
Elmore
-- For now, the time machine is in pieces.
They made them here, in a fabrication plant off the main roads, tucked among the lush corn and soybean fields of northwestern Ohio. You might miss it if you didn't know where to look.
Nearly two years. That's how long it took more than 80 Brush Wellman Inc. workers to fashion the heart of the thing -- 18 hexagons made of a hard, strangely lightweight metal, each one about the size and shape of a poker-table top.
Most of them have been swaddled in pink foam and trucked south, to another small-town factory that will do additional work. The final four shipped out last week, after a party to mark the occasion. It's not every day that you make a time machine.
This one will transport scientists billions of years into the past, to nearly the beginning of everything. If the 18 hexagons do their job, the scientists will be able to use them to watch the first stars flare to life and the earliest galaxies begin to form.
Only a telescope of extraordinary design and fidelity could probe that distant epoch. Its mirrors would have to be powerful enough to capture the faintest, most ancient photons of light, light just now trickling into our solar system, long after the stars that emitted it exploded or collapsed into black holes.
The six-sided slabs of metal fashioned at Brush Wellman's plant don't look like mirrors yet. The 18 "blanks," as they're called at this nascent stage, are a lackluster gray, only dimly reflecting the overhead factory lights.
But in the next decade, when they have been meticulously ground and polished, coated with a reflective layer of gold, mounted on a collapsible frame, folded like an origami bird, stuffed into a rocket's nose cone, blasted 940,000 miles into space and unfurled, the mirrors on NASA's James Webb Space Telescope should give scientists an unprecedented view of the very early universe.
"We're looking back to the first objects that formed after the Big Bang," said John Mather, Webb's senior scientist at NASA's Goddard Space Flight Center in Maryland. "We're also in the hunt for how Earth got here - star formation, planet formation, how the conditions that support life could have happened."
The clues lie more than 13.5 billion years in the past, when the universe was about 1 percent of its current age. The earliest stars were just beginning to light the void, blazing to life when gravity and quantum forces ignited gas clouds produced by the Big Bang.
Those massive first-born suns burned bright and fast, consuming themselves in only a few million years. Their violent suicides helped dictate the future of the cosmos. Some stars swallowed themselves, forming the yawning black holes that lurk at the center of many galaxies, including our own Milky Way.
Others blew themselves to bits in supernovas, spewing element- rich clouds that were the grist for more stars, planets and us.
That's the big picture. The devil is in the details: divining how planets, especially Earthlike ones, emerged from rubble; how galaxies assembled and evolved; why the earliest stars were short-lived and massively self- destructive; what shape the universe takes, and the nature of the unseen "dark matter" that seems to fill much of it.
That's where space-based observatories like the Webb tele scope, named for an Apollo-era NASA administrator, come in. Unhampered by Earth's thick, light-polluted atmosphere, they can gaze much more sharply and deeply into space, thus looking far back in time.
The best-known of the space scopes is Hubble, which has been providing spectacular views of distant stars and galaxies since astronauts nudged it from the shuttle bay and into Earth orbit in 1990.
Hubble is equipped to "see" things that emit visible, ultraviolet and near-infrared radiation. But it can't spot the oldest, farthest-away celestial bodies. That's because the universe is swelling outward like an inflating balloon, stretching light from the most distant stars and galaxies into longer wavelengths as the objects speed away from us.
Astronomers call this phenomenon "redshifting" because the resulting light is in the reddish, infrared part of the spectrum.
The Webb telescope's detectors, far more advanced than Hubble's 1980s technology, should be able to snare these weak mid-infrared waves. To prevent the sensors from being swamped, though, they will have to be isolated from other sources of infrared radiation, or heat - that means nearby objects in space, and even the telescope's own electronic equipment.
NASA's solution? Park the observatory in an orbit nearly a million miles out, at a spot where Earth, sun and moon are roughly aligned, so a tennis court-sized umbrella can block their heat output simultaneously. The shade will keep most of the telescope at a frigid minus 378 degrees Fahrenheit.
The location is good for stargazing but is too distant for the space shuttle to reach if any repairs are needed. So Webb's builders know they have to get everything right the first time. There will be no chance for the embarrassing but necessary 1993 mission where astronauts installed instruments to correct for Hubble's distorted mirror.
"It was obvious we had to do everything well," said Keith Smith, manager of Brush Wellman's Elmore plant.
The design of Webb's light- gathering mirror posed major challenges. It had to be big but not heavy, to avoid huge launch costs. And it couldn't warp in extreme cold or the telescope would be useless.
NASA chose beryllium over glass, the material Hubble's mirror is made of. The metal is stiff, so it dampens vibration - important for a stable view - and expands and shrinks uniformly, lessening the risk of distortion in the brutal cold of deep space. With beryllium, Webb's 21-foot-wide mirror is six times the area of Hubble's, but weighs about one-third of Hubble's 2,200 pounds.
Rather than a single sheet, Webb's mirror is split into 18 hexagons that allow it to be folded to fit in a rocket, then blossom once in space.
Lead mirror contractor Ball Aerospace & Technologies Corp. turned to Cleveland-based Brush Wellman for the $18 million job of making the mirror blanks. Brush Wellman's beryllium components can be found in everything from Formula One race cars and military attack helicopters to NASA's robotic Mars rovers.
Each of the blanks started as beryllium hydroxide, a white, sticky powder the consistency of talc, extracted from ore in a Utah mine. The toxic powder is poured into a steel mold, heated to 1,832 degrees, and compressed with argon gas to squeeze out voids between the tiny beryllium particles and "lock" them together.
The process takes three days. At the end, workers use acid to dissolve the mold. The six-sided beryllium slab is sawed in half lengthwise to create two mirror blanks. Each is scanned with X rays to check for defects that might cause distortion.
Axsys Technologies Inc. in Cullman, Ala., will spend a year drilling a honeycomb of holes in the back of each blank, shaving its weight from 600 pounds to less than 46. "By the time they're finished, you could lift it over your head," NASA's Mather said.
Tinsley Laboratories Inc., of Richmond, Calif., will take another year to grind and polish the mirror surfaces to their final, ultra-precise shape. Then, there will be extensive testing under spacelike conditions to ensure that Webb's vision will be 20-20.
Engineering changes and a debate about which rocket will carry Webb have swelled the projected cost from $825 million to $4.5 billion and will delay its launch by at least a year, to 2012.
A NASA team is reviewing cost-cutting options, although Webb scientists have advised against reducing the size of the mirror.
Brush Wellman workers point with pride to their completion of the blanks ahead of schedule. "We weren't the bottleneck," said Webb project manager Larry Hattan. "There were a lot of eyes in our direction."
Which is what you would expect when people get around a big mirror.
To reach this Plain Dealer reporter:
jmangels@plaind.com, 216-999-4842
© 2005 The Plain Dealer
© 2005 cleveland.com All Rights Reserved.
Monday, August 22, 2005
John Mangels
Plain Dealer Science Writer
Elmore
-- For now, the time machine is in pieces.
They made them here, in a fabrication plant off the main roads, tucked among the lush corn and soybean fields of northwestern Ohio. You might miss it if you didn't know where to look.
Nearly two years. That's how long it took more than 80 Brush Wellman Inc. workers to fashion the heart of the thing -- 18 hexagons made of a hard, strangely lightweight metal, each one about the size and shape of a poker-table top.
Most of them have been swaddled in pink foam and trucked south, to another small-town factory that will do additional work. The final four shipped out last week, after a party to mark the occasion. It's not every day that you make a time machine.
This one will transport scientists billions of years into the past, to nearly the beginning of everything. If the 18 hexagons do their job, the scientists will be able to use them to watch the first stars flare to life and the earliest galaxies begin to form.
Only a telescope of extraordinary design and fidelity could probe that distant epoch. Its mirrors would have to be powerful enough to capture the faintest, most ancient photons of light, light just now trickling into our solar system, long after the stars that emitted it exploded or collapsed into black holes.
The six-sided slabs of metal fashioned at Brush Wellman's plant don't look like mirrors yet. The 18 "blanks," as they're called at this nascent stage, are a lackluster gray, only dimly reflecting the overhead factory lights.
But in the next decade, when they have been meticulously ground and polished, coated with a reflective layer of gold, mounted on a collapsible frame, folded like an origami bird, stuffed into a rocket's nose cone, blasted 940,000 miles into space and unfurled, the mirrors on NASA's James Webb Space Telescope should give scientists an unprecedented view of the very early universe.
"We're looking back to the first objects that formed after the Big Bang," said John Mather, Webb's senior scientist at NASA's Goddard Space Flight Center in Maryland. "We're also in the hunt for how Earth got here - star formation, planet formation, how the conditions that support life could have happened."
The clues lie more than 13.5 billion years in the past, when the universe was about 1 percent of its current age. The earliest stars were just beginning to light the void, blazing to life when gravity and quantum forces ignited gas clouds produced by the Big Bang.
Those massive first-born suns burned bright and fast, consuming themselves in only a few million years. Their violent suicides helped dictate the future of the cosmos. Some stars swallowed themselves, forming the yawning black holes that lurk at the center of many galaxies, including our own Milky Way.
Others blew themselves to bits in supernovas, spewing element- rich clouds that were the grist for more stars, planets and us.
That's the big picture. The devil is in the details: divining how planets, especially Earthlike ones, emerged from rubble; how galaxies assembled and evolved; why the earliest stars were short-lived and massively self- destructive; what shape the universe takes, and the nature of the unseen "dark matter" that seems to fill much of it.
That's where space-based observatories like the Webb tele scope, named for an Apollo-era NASA administrator, come in. Unhampered by Earth's thick, light-polluted atmosphere, they can gaze much more sharply and deeply into space, thus looking far back in time.
The best-known of the space scopes is Hubble, which has been providing spectacular views of distant stars and galaxies since astronauts nudged it from the shuttle bay and into Earth orbit in 1990.
Hubble is equipped to "see" things that emit visible, ultraviolet and near-infrared radiation. But it can't spot the oldest, farthest-away celestial bodies. That's because the universe is swelling outward like an inflating balloon, stretching light from the most distant stars and galaxies into longer wavelengths as the objects speed away from us.
Astronomers call this phenomenon "redshifting" because the resulting light is in the reddish, infrared part of the spectrum.
The Webb telescope's detectors, far more advanced than Hubble's 1980s technology, should be able to snare these weak mid-infrared waves. To prevent the sensors from being swamped, though, they will have to be isolated from other sources of infrared radiation, or heat - that means nearby objects in space, and even the telescope's own electronic equipment.
NASA's solution? Park the observatory in an orbit nearly a million miles out, at a spot where Earth, sun and moon are roughly aligned, so a tennis court-sized umbrella can block their heat output simultaneously. The shade will keep most of the telescope at a frigid minus 378 degrees Fahrenheit.
The location is good for stargazing but is too distant for the space shuttle to reach if any repairs are needed. So Webb's builders know they have to get everything right the first time. There will be no chance for the embarrassing but necessary 1993 mission where astronauts installed instruments to correct for Hubble's distorted mirror.
"It was obvious we had to do everything well," said Keith Smith, manager of Brush Wellman's Elmore plant.
The design of Webb's light- gathering mirror posed major challenges. It had to be big but not heavy, to avoid huge launch costs. And it couldn't warp in extreme cold or the telescope would be useless.
NASA chose beryllium over glass, the material Hubble's mirror is made of. The metal is stiff, so it dampens vibration - important for a stable view - and expands and shrinks uniformly, lessening the risk of distortion in the brutal cold of deep space. With beryllium, Webb's 21-foot-wide mirror is six times the area of Hubble's, but weighs about one-third of Hubble's 2,200 pounds.
Rather than a single sheet, Webb's mirror is split into 18 hexagons that allow it to be folded to fit in a rocket, then blossom once in space.
Lead mirror contractor Ball Aerospace & Technologies Corp. turned to Cleveland-based Brush Wellman for the $18 million job of making the mirror blanks. Brush Wellman's beryllium components can be found in everything from Formula One race cars and military attack helicopters to NASA's robotic Mars rovers.
Each of the blanks started as beryllium hydroxide, a white, sticky powder the consistency of talc, extracted from ore in a Utah mine. The toxic powder is poured into a steel mold, heated to 1,832 degrees, and compressed with argon gas to squeeze out voids between the tiny beryllium particles and "lock" them together.
The process takes three days. At the end, workers use acid to dissolve the mold. The six-sided beryllium slab is sawed in half lengthwise to create two mirror blanks. Each is scanned with X rays to check for defects that might cause distortion.
Axsys Technologies Inc. in Cullman, Ala., will spend a year drilling a honeycomb of holes in the back of each blank, shaving its weight from 600 pounds to less than 46. "By the time they're finished, you could lift it over your head," NASA's Mather said.
Tinsley Laboratories Inc., of Richmond, Calif., will take another year to grind and polish the mirror surfaces to their final, ultra-precise shape. Then, there will be extensive testing under spacelike conditions to ensure that Webb's vision will be 20-20.
Engineering changes and a debate about which rocket will carry Webb have swelled the projected cost from $825 million to $4.5 billion and will delay its launch by at least a year, to 2012.
A NASA team is reviewing cost-cutting options, although Webb scientists have advised against reducing the size of the mirror.
Brush Wellman workers point with pride to their completion of the blanks ahead of schedule. "We weren't the bottleneck," said Webb project manager Larry Hattan. "There were a lot of eyes in our direction."
Which is what you would expect when people get around a big mirror.
To reach this Plain Dealer reporter:
jmangels@plaind.com, 216-999-4842
© 2005 The Plain Dealer
© 2005 cleveland.com All Rights Reserved.
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Henry J
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Physicists Entangle Photon and Atom in Atomic Cloud
(Oh what an entangled web we weave?)Quantum communication networks show great promise in becoming a highly secure communications system. By carrying information with photons or atoms, which are entangled so that the behavior of one affects the other, the network can easily detect any eavesdropper who tries to tap the system.
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lswot
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Henry J
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Earth's core rotates faster than its crust, scientists say
(Well, that's getting to the core of why people get dizzy sometimes, huh? Spinning wheels spin...)Scientists have ended a 9-year-old debate by proving that Earth’s core rotates faster than its surface, by about 0.3 to 0.5 degree per year.
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