While Sputniks I and II still orbit overhead, scientists around the
world are racing through mountains of data to discover how information
on the movements of the Russians' artificial moons has altered standard
theories of the earth and its atmosphere. Last week scientists at the
Smithsonian Astrophysical Observatory in Cambridge suggested a drastic
revision of an accepted notion of the earth's upper atmosphere: at
about 137 miles altitude, the atmosphere may be almost nine times as
dense as scientists once believed.The Smithsonian scientists calculated the density of the upper
atmosphere by studying the gradually shrinking orbit of Sputnik I.
Under the old theory, Sputnik I should stay up for about 27 months
before aerodynamic drag and gravity pull it down into air dense enough
to destroy it by the heat of friction. But now the Smithsonian
scientists think that the moon will set for good after only 3 months,
flare into destruction sometime around the middle of January.Even under the new theory, the earth's upper atmosphere is still nearly
a vacuum. Rocketeers and missilemen, whose vehicles travel through this
area at tremendous speeds, probably will have to make only minor
adjustments in their plans. But if the Smithsonian's finding checks
out, the perigee for a long-lived satellite
will have to be raised from 140 miles to 180 miles because of the
decelerating drag of air particles at the lower altitude. Anticipated
perigee for Vanguard: a safe 200 miles. Scientists at Washington's
Carnegie Institution are still puzzling over a radio phenomenon of
Sputnik I: a “ghost” signal that registered on their receivers when the
artificial satellite was on the opposite side of the earth. One guess:
under certain ionospheric conditions, the radio waves of Sputnik
traveled back on great circle paths that somehow converged on the
opposite side of the world. Suggests Carnegie's Harry W. Wells: “Energy
from this concentrated area, presumably in the ionosphere, was then
radiated or scattered to the receiving antennas so that the hot spot in
motion appeared as a ghost satellite.”
