Bristol news. [volume] (Bristol, Va. & Tenn.) 1867-189?, 1874-02-03
SCIENTIFIC
SIZE, DISTANCE, AMP SUE
STANCE or THE FIXED
STARS.
Fifth Lecture OF Mr.. Proctor.
course on AStrOnOmy-Distan-
ccS beyond measurement and
magnitudes beyond under
stand:mg-GUcsscS ut the
Architecture of the
Heavens.

Mr., Proctor said, How large are
tire stars ~ 70 learn that their dis
taHct must be known. Or all the stars
the distance of only nine or ten WAS
knOwIi TIT all accurately, aud the dis
lance Of but one could be considered
absolutely known. The problem was
one of stupendous difficulty In de-
ternIn ing the suns distance observers
were posted as far part as they could
bc got on this earth But so immense
was the distance of this nearest star
that the ObSeI walton of its diSplace-
uirnt must be made from opposite
sides of the Carth's orbit, that MAS from
POINTS $50 90. 900 miles apart. And
with that enormous. change of posi-
ton no star, except some nIne or ten,
changed 80 far as man could see by an
Iota It's position against The sky aud
Alpha Ceniaur, he first tiitt was
found To change, changed 20 slightly
that one could hardly illustrate it. a
line drawn from the eaIth To that star
would change less i'll apparent posi-
tiuu while the earth moved lS3 000,-
QUO GU of pace than tie minute
hand Oi "A watch moved in l-200 of n
second Or il the line from the star To
! Inc tdikn we're ltiS iillHNlc manu- VI II
mighty clock, in 200 of Il sccgnd the
pointer of That hand would pass oNeI
iS3. UOU, 800 miles. Well. it had been
found that this star was 100000 tincs
further away Il an the sun. There
was another star whose distance had
been delermined-6f. Cygni- Once II
was held To he three times as far away
as the first now il MIS- known To lac
! but IwIcc as far away. That seemed
| Ia have hGpu a Tremendous error, ana
! yet the astronomer : error IN measure
ment was only Une-third of the dis
! lance which the minute Eand of a
watch would traverse in the l-2'O part
of "a second. With the distance
! known. how was the size If Il star Ia
! he learned? There was no disk To lie
| measured, for in the b. st telescope the
nearest star appeared only as n point
All light. The only methOd WAS 10y
mpasurii9 the amount Oi light t ON
th;. stars. The brightness uf Alpha
Centauri was l,17.0JO. UD0, eco of tie
suns brightness, Ii the sun we're
moved 10 the position of this star--tu
Il distance that would Ice 1000 times
IT. plcsvut d.stanc5--its brightness
would be reduced to ,40.O..O,WO,OOO of
! it's pres.ut brightness. The star. then,
To shine as il did must lie sonit Thin"
more Than one and half times as great
as the sun and he five times as great ia
volume, surprising The surface al boill
| To have The SRme intrinsic BRIGHTNESS.
| The king of stars aud SUNS WAS the
glorious star Sirius. as far as stars ami
suns were measured and known. lie
was four times as bright as Alpha
Ceiitauri ana yet five times as Far oil.
! Being five hines ~ far off and of the
same size he should be OILY one
! twp.ftv-ff,h as bright. Being four
| times a. bright as he was. thereiui e. one
| hundred times brighter than If he
were of the same size. that Is, lac was
one hundred times as lIr-e. Three
thousand times The light of the sun
came fIom him, and his volume was
OOO times that OF the sun. 80 We
haG rjseT: at cnce into a higher order
of sums than our own. But after All,
how did We know that Sirius vas
soIid like our sun. Why not rallftf
s,pDose that he was mere a"Cl"IEe-
ration o; ga on matter, bright and
ditFuse rs me matter in u comets tall.
m. next lesson came from the spec
troscoue. The sun gave spectrum oi
sulid or liquid matter shining through
vapors that cut OF a part OF the light.
Ii the stars, any or all them, gave
similar spectra,. we sirOHfG Know HAT
they were lmdies like lie sun. (The
room was here daFkened and specira
obtained from different stars were
thrown on fhe screen.( The Spectrum
of Sirius showed four lines of hydro
gen, indicating deep atmosphere OF