Read Online Analog SFF, June 2011 by Dell Magazine Authors - Free Book Online Page B
Authors: Dell Magazine Authors
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She had hoped for the latter—and that he would be open-minded. Only then did it occur to her to ask how open-minded she was.
It was not the time to second-guess herself. And anyway, he would get much the same message from many of the staff. All the more important that she get him to lunch on time. . . .
"Let's skip to the main event,” she said. Because the big dish will knock your socks off.
When she next parked, Marcus, his eyes round, rushed from the car. Everyone did. She gave him time to take it all in: the world's largest birdbath, atop an intricate lattice pyramid, above a round trolley base with sixteen enormous wheels. In addition to a standalone trailer, a built-in shielded room high above the ground held many of the onsite controls. The instrument arm, jutting out from and over the dish, made the telescope that much more impressive.
"The Green Bank Telescope,” she began, pointing up at the enormous paraboloid dish. “Completed in 2000, the GBT replaced the smaller big telescope that collapsed under its own weight from metal fatigue in 1988. The dish's signal-collecting surface measures one hundred meters by one hundred ten meters—longer in both dimensions than a football field. Only that's not a surface, but 2,004 small aluminum surfaces. Automation tilts and warps each panel in real time as the structure moves, to compensate for sagging, thermal gradients, and wind."
" Damn , that's big. What happens if lightning strikes?"
"It happens about four times a year, without incident. The GBT weighs more than sixteen million pounds, about the same as nineteen loaded and fueled jumbo jets. When lightning does strike, that's a lot of metal, with all its metal wheels firmly pressed against the well-grounded steel track. The track is lots of metal too: a circle sixty-four meters in diameter."
She resumed her script. “When tipped such that the instrument arm reaches its highest position, the GBT stands taller than the Statue of Liberty. This is the world's largest fully steerable radio telescope."
Hand to his forehead, shading his eyes, Marcus countered, “Surely Arecibo is bigger."
Because everyone knew the observatory at Arecibo, Puerto Rico. Filmmakers loved it. The first time she remembered seeing the Arecibo dish was in some old James Bond flick. Goldeneye , maybe.
Arecibo's dish was three hundred meters across, its aluminum panels suspended over a mesh of steel cables to form a single surface: way too massive to move. To aim the Arecibo telescope—to the extent it could be aimed—you positioned its suspended instrumentation module using the cables that spanned the dish. None of which mattered. If she failed, Arecibo would face the same problems as Green Bank.
Valerie limited herself to, “Bigger, but not fully steerable.” She pointed at the GBT's base, where the mammoth wheels engaged the circular steel track. “As opposed to our big scope. This whole structure can rotate up to forty degrees a minute, versus one-fourth degree per minute needed to keep pace with Earth's rotation. The dish can tip up and down at as much as twenty degrees per minute. That instrument turret at the end of the arm holds up to eight independent instrument modules, each—"
"Back up,” Marcus said. “Those tipping and turning rates. You're telling me that the GBT can track planets, asteroids, even close-orbiting satellites. Stars and galaxies only move with the Earth's rotation.” She must have looked surprised because he added, “Remember who I work for?"
"Right. And sorry."
"Except asteroids and most planets don't emit radio waves. In the middle of the quiet zone, where my cell phone has no service and NRAO won't even permit digital cameras up close, I can't believe the observatory is pumping out radar pulses so you can read the echoes."
He was quick, which was promising, and he seemed engaged in what she'd had to show him. But around the eyes she saw a touch of . . . something. Suspicion? Was she that
It was not the time to second-guess herself. And anyway, he would get much the same message from many of the staff. All the more important that she get him to lunch on time. . . .
"Let's skip to the main event,” she said. Because the big dish will knock your socks off.
When she next parked, Marcus, his eyes round, rushed from the car. Everyone did. She gave him time to take it all in: the world's largest birdbath, atop an intricate lattice pyramid, above a round trolley base with sixteen enormous wheels. In addition to a standalone trailer, a built-in shielded room high above the ground held many of the onsite controls. The instrument arm, jutting out from and over the dish, made the telescope that much more impressive.
"The Green Bank Telescope,” she began, pointing up at the enormous paraboloid dish. “Completed in 2000, the GBT replaced the smaller big telescope that collapsed under its own weight from metal fatigue in 1988. The dish's signal-collecting surface measures one hundred meters by one hundred ten meters—longer in both dimensions than a football field. Only that's not a surface, but 2,004 small aluminum surfaces. Automation tilts and warps each panel in real time as the structure moves, to compensate for sagging, thermal gradients, and wind."
" Damn , that's big. What happens if lightning strikes?"
"It happens about four times a year, without incident. The GBT weighs more than sixteen million pounds, about the same as nineteen loaded and fueled jumbo jets. When lightning does strike, that's a lot of metal, with all its metal wheels firmly pressed against the well-grounded steel track. The track is lots of metal too: a circle sixty-four meters in diameter."
She resumed her script. “When tipped such that the instrument arm reaches its highest position, the GBT stands taller than the Statue of Liberty. This is the world's largest fully steerable radio telescope."
Hand to his forehead, shading his eyes, Marcus countered, “Surely Arecibo is bigger."
Because everyone knew the observatory at Arecibo, Puerto Rico. Filmmakers loved it. The first time she remembered seeing the Arecibo dish was in some old James Bond flick. Goldeneye , maybe.
Arecibo's dish was three hundred meters across, its aluminum panels suspended over a mesh of steel cables to form a single surface: way too massive to move. To aim the Arecibo telescope—to the extent it could be aimed—you positioned its suspended instrumentation module using the cables that spanned the dish. None of which mattered. If she failed, Arecibo would face the same problems as Green Bank.
Valerie limited herself to, “Bigger, but not fully steerable.” She pointed at the GBT's base, where the mammoth wheels engaged the circular steel track. “As opposed to our big scope. This whole structure can rotate up to forty degrees a minute, versus one-fourth degree per minute needed to keep pace with Earth's rotation. The dish can tip up and down at as much as twenty degrees per minute. That instrument turret at the end of the arm holds up to eight independent instrument modules, each—"
"Back up,” Marcus said. “Those tipping and turning rates. You're telling me that the GBT can track planets, asteroids, even close-orbiting satellites. Stars and galaxies only move with the Earth's rotation.” She must have looked surprised because he added, “Remember who I work for?"
"Right. And sorry."
"Except asteroids and most planets don't emit radio waves. In the middle of the quiet zone, where my cell phone has no service and NRAO won't even permit digital cameras up close, I can't believe the observatory is pumping out radar pulses so you can read the echoes."
He was quick, which was promising, and he seemed engaged in what she'd had to show him. But around the eyes she saw a touch of . . . something. Suspicion? Was she that
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