Evening star., 1933-01-25
SOLAR SYSTEMS
AGE IS ESTIMATED
Authority on Gravity Places
1t at Thousand Billion
Years.
The solar system may be a thousand

The solar system may be thousand
billion years old.
Such is the deduction from celestial
mechanics of DR.. Ernest w. Brown,
Yale professor and foremost living su-
thorty on gravity as It affects planetary
motions, announced through the Ma
tional Research Council here. Dr.
Brown will present further aspects OF
the problem Of gravity within the solar
system in the annual Arthur lecture.
under the auspices of the Smithsonian
Institution. which he will deliver at
the National Museum this evening.
Prof Browns deduction Is based on
the inclinations of the orbits of the
eight ma jor planets, which are reSpon
sible for changing seasons and which
are believed to have differed very great
ly. through the operation of mechanical
causes, since the beginning OF time. But
the progress has been so slow, the Yale
astronomer points out in his report to
the National Research Council, that it
can have had no noticeable effect on
the seasons during approximately 100,-
600 GOO years although. in this lnterVa!
Temperate Zone forests have extended
far toward the North Pole. Scme Other
reason must be sought for such COM
paratively recent charges.
Existed Long Ages.
The astronomical estimate Of the age
Of the solar system gives geologisJs
plenty Of time to spare. The utmost
estimate. based on the evidence OF the
disintegration Of radioactive minerals.
presented in the National Research
. In nf 1a nor rf c
only 1000 900, 600 years. But, it Is point
ed cut. the earth must have existed
for long ages between the time it was
torn loose from the sun and the time
when a hard crust was formed, which
would leave geological evidence.
Prof. Brown proceeds on the hypo-
thesis that originally the inclinations
were very large. This would have
meant very great annual changes IN
the climate between Summer and
Winter whereas. at present. the diter-
ences are comparatively slight. Now
the inclinations are small. Calculating
the time necessary for this change to
have taken place. Prof. Brown says:
1T is improbable that the age OF the
system is less than 10000. 900 900 years.
1t is probably - to 100 times older.
These leave the high estimate of two
billion years for the geological age OF
the earth only a small fraction OF the
age of the solar system"
Comparatively Recent.
The calling in of astronomy to pro-
vide evidence Of the earth'S age is the
latest chapter in the solution Of prob
lem which has caused much dispute
since the PRONUNCIATION Of the evolu-
tionary theory in the last century. The
time necessary for life to have de-
veloped to its present stages by the
SLOW sters of evolution was much
greater than could be granted to the
earth by the physics and geology OF the
day. Continuously accumulating evi-
Gence ever since has extended the num-
Der of the earth's birthdays until even
the beginning Of organic evolution may
be considered as comparatively recent.
The planets. bound to the sun by un-
breakabe chains Of gravity. do not
furnish direct evidence of the age OF
the system, Prof Brown says. but they
do furnish q check on the probability
of estimates derived originally from
other sources.
Prof Brown provides check for his
own estimates through deductions frcm
the number of asteroids. or minor
planets lying between the orbits OK
Jupiter and Mars. the total mass OF
which is believed to be diminishing
through the ages as one after another
is caught" by major planeS.