The morning star and Catholic messenger. [volume] (New Orleans [La.]) 1868-1881, 1877-03-25
LIGHT And TIE DISTANCES OF THE
STARS.
{ Scientific American.)
A correepo ndent writes az follows


"One of the New York daily papers gives
an account of a recent lecture delivered by o
Professor Grant ON astronomy, in Great Britain
and reI orts him to have said that some stars
are 30 distant from the earth that light trav-
cling at the rate of 49,, 900 miles o second,
would take half million Of years to reach US,
and that consequently We would observe now
what b adj tr.nspired on such stars half mil
lion Years ago. l. not this last statement to-
tally erroneousf Does not the eye travel
almost instan aneousiy along the line OF direc-
tinn of any objec5 within the range of either
unassisted human or telescope vision an d do
We not accordingly Whist is transporting
now Mt any point within such raugef Please
state whether this view or that Imputed to
Professor Grant is correctr
To point ont the error in our correspon-
dents reasoning, We have only to apply it
to the propagation of sound and to the ear,
and then we may ask, almost in the sam
words: docs not the ear travel almost
simultaneously along the line of direction
Of any sounding object within the range of
either unasslsted or assisted human heat
ing, and do We not accordingly hear what
Is transpiring now az any given point with
in such ranger" We may ask this with
good reason, because the natures of the
propagation of light and sound are identi-
cal, the eye being the organ for the percep-
ton of the fret, the ear that for the per-
ception of the second. Now the fact is
that the eye Tor the sight) travels as little
the hearing) travels toward the sounding
object; both organs merely receive inn
pressions from the luminous or sonorous
lay 8. lie Is perfectly we'll established that
we see astronomical events later than they
occur. and il WAS this fact which Taught us
that light moves with u velocity of IS5 600
miles per second. The eclipseS OF the moons
OF Jupiter revealed to 4 )emer, the ceIe
DRAFTED German astronomer, this fact he
found An lrregularity which no astronO-
mical data could account for, and he OBJ
served that the periods between these
eclipses were ION Ger when the distance be-
tween us and the planet was increasing,
while, inverseIy, the periods became short
er when this distance was Diminishing. He
found at last, by close observation, that
every time that the planet was, say l00,-
600 900 miles further off, we see that eclIp-
500 happen minutes later then they do
when the planet il at its nearest distauce
As 9 minutes is $40 seconds. we have only
to divide $40 into 100 900 600 TO find the
velocity "f light per second, which is very
nearly 1850 miles. This has been
verified atterWard ia various other ways
the velocity of light has been directly
measured (by the help of most Ingenious
and delicate apparatus) by Foucault and
Fresnel while the alteration of the xed
stars, which consists in an apparent dis
placement OF the same, produced by the
yearly motion OF the earth in its orbit, fully
cOrroborates the scientific theory. 1t is,
therefore, a positive fact that We see the
staTs as they were at the time when the
light which reaches us now left them and
we see the suu as be- was 8 minutes ago, the
nearest fixed star ss it was 81 years ago,
aud the pole star as it was 36 yeaIs ago.
OF the other stars, very few are near
enough for US to measure their distances
but most of them ars thousands of times
further off, aud therefore we soc them as
they were thousands of years ago; and
when the telescope reveals, in the depths
of infinite space, stars thousauds of thou
sand times further off still, we are couvinc-
ed that, as their light can only reach us in
millions of years, We see them as they were
mlllions of years ago. Perhaps at that re
mote period, in those unfathomAble dls.
tauCes, blazng suns have been created of
which the lignt has not yet reached us,
and Inverseiy those may have become
extinct of which the light reaches US
now in the samn way rs when the sound
of n gun, exploding at Il great distance,
reaches us, the reat explosion is a thing OF
the past, and may have taken place fifty,
sixty, or more seconds before, according TO
tue distance.
Life is n collection of litale thiups Happi-