The sun. [volume] (New York [N.Y.]) 1833-1916, 1894-03-27
How Far on il the Sun?

A little new light has recently been
thrown on the problem Of the distance OF
the sun. This Is the great yardstick of
astronomy. For more than century every
effort has been made to ascertain the dis
lance as accurately as possible. Methods
direct and indirect have been employed.
Considering the fact that the knowledge
thus sedulously pursued can serve no
utilitarian purpose. the generous expendi-
ture In the pursuit does credit to the intel
lectual aspirations Of the human race. From
the time OF Capt. Cooks expedition to the
Society Islands to observe the transit OF
Venus In 1853 until the present day. mil
lions of dollars have been spent In this effort
TO drop O sounding line to the sun.
CoPERSIcUs believed that the sun was not
more than 5000 900 miles away. There were
philosophers before the Christian era who
knew as much as that. For several years
past we have been assured that the distance
could not be far from 81. SOC. 600 miles. But
almost a century ago. LAPLACE assumed a
parallax for the sun which gave almost
exactly that distance. Since his time vari-
GUS astronomers have attacked the problem,
and their results have varied from 81, 900 600
to 81. 250. 900 miles. the difference between
these extreme estimates being nearly as
great as tho entire distance was believed
to be by the founders Of astronomy.
Yet these facts carry no challenge to the
soundness Of modern astronomical methods.
or the substantial correctness OF the re-
suits attained by them. The distance OF
the sun Is not yet known with absolute
accuracy. for the same reason that tho
height OF Mount st. Elias or of Mount
Everest has not yet been exactly ascer-
tained. But the limits OF error are known.
and In the future we shall not see estimates
OF the suns distance varying by millions Of
miles. II series OF wires should be cut.
each agreeing In length with one OF the re-
cent measures OF the solar parallax. and all
should then be- stretched from the earth
toward the sun. every one OF them would
end In the sun. though none might stop
precisely at its centre.
As to the recent light upon this prob
lem. it is furnished by the results OF OBJ
servations by officials Of the United States
Coast Survey at the Sandwich Islands. to
determine the constant OF alteration OF the
stars. BY this is meant the amount of dis
placement that the stars undergo in conse-
auence Of the fact that We are looking at
still. but Is moving IN an orbit around the
sun at the rate Of about 1879 miles in a
second. Light travels 1858 miles in a
second. The ratio OF the velocity OF the
flying earth TO that OF light measures the
displacement in the position OF the stars
that is called their alteration. But. mani
testify. II We can learn precisely how
far the earth travels in second. we
shall know Just how long its orbit
is. We know that the earth takes
one year. or, more exactly. 81 .55s. $50 sec
onds. TO go once around that orbit. II. then,
We can find out with rigorous accuracy how
far 1t goes In a second. We can at once cal
culate not only the length OF the orbit. but
the distance Of the sun. which depends di-
reetly upon the size OF the orbit. OF course.
allowance must be made for the fact that
the orbit. instead Of being a circle. is an
sllipse, and that consequently the eaTth's