Evening star., 1962-12-27
Mariner Shows Venus
Lacks Magnetic Field

coSmlc rays must beat down
evenly on all parts of Venus
atmosphere, Mr.. Coleman sug-
gested. On earth, the magnetic
shield set up by the Van Allen
Belt cuts down cosmic ray PEN
etration sharply except at the
poles.
1t does not necessarily follow
that heavy cosmic radiation at
the top of Venus atmosphere
would make the planets sur
face uninhabitable, Mr.. Cole
man said. The thick atmosphere
itself might be an effective
shield, he explained, leaving
open the possibility that some
form Of life exists on the
planet.
The instruments used to
gauge Venus magnetism were
sensitive to a level about No.
000th of the earth's magnetic
field. Mr.. Coleman said there
was no doubt that they were
working during the fly-by.
Throughout Mariners 109-
day passage across 180 million
miles, these instruments made
readings Of magnetism in in
terplanetary space. These were
low by earthly standards, but
fluctuated enough to indicate
that changes existed from time
to time and place to place. IN
expectedly, no such change was
noted as the space craft scooted
past the planet.
Maybe Different
Mr.. Coleman conceded the
possibility that Venus might
have q magnetic field of a diff
ferent sort from that Of earth,
At certain points on Venus
surface, magnetism might be
even greater than the average
on earth, he explained. The
magnetic field was not evident
out as far as Mariner-21, 800
mileS--he explained.
But the absence Of an earthly
magnetic field probably means
Venus has no Van Allen Belt"
of trapped radiation, and this
in turn means there probably
are no aurora borealis OF
Northern Lights such as are OBJ
served on earth. he said. The
aurora" on Venus may be an
overall phenomenon, obServa-
BILE at the Equator as readily
as at the Poles, Mr.. Coleman
suggested.
This might account for the
so-called "ashen light" which
sometimes illuminates the dark
side Of Venus when that planet
is observed from earth. This
strange light has long puzzled
astronomers, some of whom
thought it might be evidence OF
great thunderstorms in the
clouds which overlie Venus
surface.
Two other scientists reported
on satellite experiments at the
same meeting. DR.. John Lindsay
Of Goddard Space Flight Gen.
ter, Greenbelt, Md, told OF
findings from an "orbitine
solar observatory" launched
last March 7 from Cape Can.
averal, Fla.
The orbiter has "sent bacl
more data on the behavior ant
composition Of the sun thai
any single major ground-base
observatory and all previou
rocket, balloon and satellit
flights combined" DIR. Lindsa,
said. f
1t is helping to unlock thI
mystery of how the sun crates
the earth's ionosphere, which
is important to radio trans.
mission, he added.
Another bountiful scientific
chaos has come from "Alou-
ette," a Canadian-built satel-
lite orbited by the National
Aeronautics and Space Admin
istration from California last
September. DR.. John Chapman
of the Canadian Defense Re-
search Accommodation Es-
tabliShment, Ottawa, reported
on Allouette's findings.
The satellite has sent back
$4,000 readings on the uppel
atmosphere as viewed from
above. These readings, taker
from all over the globe by Q
satellite that orbits over th {
North and South Poles severa
times a day, compare with "a
few dozen" observations taker
hitherto nv soIindinO rocIrats