asonable velocity, and should have
accelerated rather more swiftly from the moon's surface than it would
have done from Earth. But it should have remained visible during all its
flight. Its trail should have been a thick red line. Instead, the red
sparks were so far separated--the trail was so attenuated that it was
visible only from a spot near its base. The observatory voice said more
blankly still:

"_Hey! I've picked up the trail! I can't see it nearby, but it seems to
start, thin, about fifty miles up and go on away from there! That
rocket shouldn't ha' gone more than twenty miles! What happened?_"

"_Watch for the microwave signals_," said Jones' voice in Cochrane's
headphones.

The voice from the observatory squeaked suddenly. This was not one of
the highly-placed astronomers, but part of the mechanical staff who'd
been willing to do an unreasonable chore for pay.

"_Here's the blip! It's crazy! Nothing can go that fast!_"

And then in the phones there came the relayed signal of the auto-beacon
in the vanished rocket. The signal-sound was that of a radar pulse,
beginning at low pitch and rising three octaves in the tenth of a
second. At middle C--the middle of the range of a piano--there was a
momentary spurt of extra volume. But in the relayed signal that louder
instant had dropped four tones. Cochrane said crisply:

"Jones, what speed would that be?"

"_It'd take a slide-rule to figure it_," said Jones' voice, very calmly,
"_but it's faster than anything ever went before._"

Cochrane waited for the next beep. It did not come in ten seconds. It
was easily fifteen. Even he could figure out what that meant! A
signal-source that stretched ten seconds of interval at source to
fifteen at reception ...

The voice from the observatory wailed:

"_It's crazy! It can't be going like that!_"

They waited. Fifteen seconds more. Sixteen. Eighteen. Twenty. The beep
sounded. The spurt of sound had dropped a full octave. The
signal-rocket, traveling normally, might have attained a maximum
velocity of some two thousand feet per second. It was now moving at a
speed which was an appreciably large fraction of the speed of light.
Which was starkly impossible. It simply happened to be true.

They heard the signal once more. The observatory's multiple-receptor
receiver had been stepped up to maximum amplification. The signal was
distinct, but very faint indeed. And the rocket was then traveling--so
it was later computed