quantities.
All during this time the space guard radio station on the dark side of Mercury sends a continuous storm warning, never an instant’s break, giving a running account of how the weather looks on the Sun.
. . . and suddenly it stops.
Maybe it’s a power failure and the stand-by transmitter will cut in. Maybe it’s just a “fade” and the storm hasn’t broken yet and transmission will resume with reassuring words.
But it may be that the first blast of the storm has hit Mercury with the speed of light, no last-minute warning at all, and the station’s eyes are knocked out and its voice is swallowed up in enormously more powerful radiation.
The officer-of-the-watch in the control room can’t be sure and he dare not take a chance. The instant he loses Hermes Station he slaps a switch that starts a big clock with just a second hand. When that clock has ticked off a certain number of seconds—and Hermes Station is still silent—the general alarm sounds. The exact number of seconds depends on where the ship is, how far from the Sun, how much longer it will take the first blast to reach the ship after it has already hit Hermes Station.
Now here is where a captain bites his nails and gets gray hair and earns his high pay . . . because he has to decide how many seconds to set that clock for. Actually, if the first and worst blast is at the speed of light, he hasn’t any warning time at all because the break in the radio signal from Hermes and that first wave front from the Sun will reach him at the same instant. Or, if the angle is unfavorable, perhaps it is his own radio reception that has been clobbered, and Hermes Station is still trying to reach him with a last-moment warning. He doesn’t know.
But he does know that if he sounds the alarm and chases everybody to shelter every time the radio fades for a few seconds, he will get people so worn out and disgusted from his crying “Wolf!” that when the trouble really comes they may not move fast enough.
He knows, too, that the outer hull of his ship will stop almost anything in the electromagnetic spectrum. Among photons (and nothing else travels at speed-of-light) only the hardest X-radiation will get through to passenger country and not much of that. But traveling along behind, falling just a little behind each second, is the really dangerous stuff—big particles, little particles, middle-sized particles, all the debris of nuclear explosion. This stuff is moving very fast but not quite at speed-of-light. He has to get his people safe before it hits.
Captain Darling picked a delay of twenty-five seconds, for where we were and what he expected from the weather reports. I asked him how he picked it and he just grinned without looking happy and said, “I asked my grandfather’s ghost.”
Five times while I was in the control room the officer of the watch started that clock . . . and five times contact with Hermes Station was picked up again before time ran out and the switch was opened.
The sixth time the seconds trickled away while all of us held our breaths . . . and contact with Hermes wasn’t picked up again and the alarm sounded like the wakeful trump of doom.
The Captain looked stony-faced and turned to duck down the hatch into the radiation shelter. I didn’t move, because I expected to be allowed to remain in the control room. Strictly speaking, the control room is part of the radiation shelter, since it is just above it and is enclosed by the same layers of cascade shielding.
(It’s amazing how many people think that a captain controls his ship by peering out a port as if he were driving a sand wagon. But he doesn’t, of course. The control room is inside, where he can watch things much more accurately and conveniently by displays and instruments. The only viewport in the Tricorn is one at the top end of the main axis, to allow passengers to look out at the stars. But we have never been headed so that the mass of the ship would protect
All during this time the space guard radio station on the dark side of Mercury sends a continuous storm warning, never an instant’s break, giving a running account of how the weather looks on the Sun.
. . . and suddenly it stops.
Maybe it’s a power failure and the stand-by transmitter will cut in. Maybe it’s just a “fade” and the storm hasn’t broken yet and transmission will resume with reassuring words.
But it may be that the first blast of the storm has hit Mercury with the speed of light, no last-minute warning at all, and the station’s eyes are knocked out and its voice is swallowed up in enormously more powerful radiation.
The officer-of-the-watch in the control room can’t be sure and he dare not take a chance. The instant he loses Hermes Station he slaps a switch that starts a big clock with just a second hand. When that clock has ticked off a certain number of seconds—and Hermes Station is still silent—the general alarm sounds. The exact number of seconds depends on where the ship is, how far from the Sun, how much longer it will take the first blast to reach the ship after it has already hit Hermes Station.
Now here is where a captain bites his nails and gets gray hair and earns his high pay . . . because he has to decide how many seconds to set that clock for. Actually, if the first and worst blast is at the speed of light, he hasn’t any warning time at all because the break in the radio signal from Hermes and that first wave front from the Sun will reach him at the same instant. Or, if the angle is unfavorable, perhaps it is his own radio reception that has been clobbered, and Hermes Station is still trying to reach him with a last-moment warning. He doesn’t know.
But he does know that if he sounds the alarm and chases everybody to shelter every time the radio fades for a few seconds, he will get people so worn out and disgusted from his crying “Wolf!” that when the trouble really comes they may not move fast enough.
He knows, too, that the outer hull of his ship will stop almost anything in the electromagnetic spectrum. Among photons (and nothing else travels at speed-of-light) only the hardest X-radiation will get through to passenger country and not much of that. But traveling along behind, falling just a little behind each second, is the really dangerous stuff—big particles, little particles, middle-sized particles, all the debris of nuclear explosion. This stuff is moving very fast but not quite at speed-of-light. He has to get his people safe before it hits.
Captain Darling picked a delay of twenty-five seconds, for where we were and what he expected from the weather reports. I asked him how he picked it and he just grinned without looking happy and said, “I asked my grandfather’s ghost.”
Five times while I was in the control room the officer of the watch started that clock . . . and five times contact with Hermes Station was picked up again before time ran out and the switch was opened.
The sixth time the seconds trickled away while all of us held our breaths . . . and contact with Hermes wasn’t picked up again and the alarm sounded like the wakeful trump of doom.
The Captain looked stony-faced and turned to duck down the hatch into the radiation shelter. I didn’t move, because I expected to be allowed to remain in the control room. Strictly speaking, the control room is part of the radiation shelter, since it is just above it and is enclosed by the same layers of cascade shielding.
(It’s amazing how many people think that a captain controls his ship by peering out a port as if he were driving a sand wagon. But he doesn’t, of course. The control room is inside, where he can watch things much more accurately and conveniently by displays and instruments. The only viewport in the Tricorn is one at the top end of the main axis, to allow passengers to look out at the stars. But we have never been headed so that the mass of the ship would protect
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