New-York tribune., 1900-07-29
CELESTIAL COLLISION.
A NEBULA SET ON FIRE BY A DARK
SUN.

Ions of years ago, but which flying through |
space at a tremendous velocity, ran into a dust
cloud of enormous extent. Although the latter
was so cool as to be utterly invisible before
ard was almost inconceivably attenuated, fric
ton developed enough heat to render the sur
face of the globe incandescent. The latter
cooled off in n few months, and cannot now be
dscerned. The dust cloud, however, shone
brilliantly at the time, and has continued to do
SO ever since. Although these facts have only
just been discovered. it is probable that the
catastrophe occurred a century or more ago.
Full details will probably never be received. |
But there is reason to suspect that the dead |
sun was from thrce-fourths of a million to two |
million miles in diameter, and was rushing
along at speed Of from twenty-five million to |
forty million miles day. Even so, it took sew
eral weeks to traverse the cloud"
The foregoing paragraph is liberal but
fairly accurate translation of announcement |
sent out last week from the Harvard College |
Observatory. The official bulletin says that |
Mrs. Fleming, whose duty it is to scrutnze |
photographs Of stars and star spectra, has re- |
Gently found several plates the image Of a |
star not before known in the constellation of
AQuia. Ninety-siX plates, exposed to the same |
region between August 81, 1886, and Novem- |
her J. 1898, showed trace of the star; but |
between April 21, 1899, and October 27 of the |
same year it appears eighteen times. On the |
first of these dates the nova ht31 the bright |
ness of a seventh magnitude star, but by the |
end of October it had faded to the tenth magni- |
tude. Direct observation with a telescope less
than fortnight ago showed that the object is |
still visible, but its magnitude is between 11.5 |
and l.. 1t is added that the spectrum of the |
nova is like that of gaseous nebula."
The appearance of a star where none was |
known before has been recorded at least half |
dozen times in the last thirty-fve years. one
was seen in Corona in 1866, in Cygnus in |
1876, one in Andromeda in 1850 and one in |
Auriga in 1892. These were detected by direct |
observation. But a star in Norma, like |
that now discovered in Aquia, found by |
inspection of Photographic plates, conducted
for different purpose.
These interesting objects blaze up suddenly. but |
Boon subside either sappearing entirely or else
becoming faint to be barely discernble |
Nova Cygni sank from the third to the seventh
magnitude in less than d year and then was
lost to view altogether, So were two or three
others. Nova Aurge threatened to behave in
the same manner but six months after its dis
covery. when il had sunk to the sixteenth mag
nitude, it suddenly to the tenth, and has
remained there to the present time. 1t now
resembles planetary nebula' object hav-
ing too fuzzy edge to be regarded a star and
yet practically glObular Most nebUlae are ex-
ceedingly irregular in form
Many theories have been offered to account for
these abrupt and temporary blazes Of light 1t
has been supposed that a sphere having a
molten interior, but a solid crust, had burst and
allowed its contents to escape and to produce a
tremendous conhagration. body in a similar
condition, if nit by another, might be heated by
the impact enough to yield similar results Sir
Norman Lockyer fances that temporary stars
are produced by a collision between two meteor
swarlns VogePs notion is that the phenomenon
is due to the invasion Of the visible heavens
by a dark sun from remote space, attended by
a family Of planets. He imaSines that The mem
bers Of the groups would be so disturbed bv
the attraction of other celestial bodies near
which they passed as to be set abumping against
one another. Thus. he thinks enough heat
would be developed to render the dark sun in
iandescent and to Yaporize the satellites
Seeliger's theory. which has not been uni
versally accepted but which has met with much
favor, is outlined in the opening paragraph Of
his article When considers how wide
~ scattered are the particles composing a
nebula, or celestial dust cloud ne is inclined to
doubt whether friction could ca use so vast an
illumination. But the tremendous velocity of
some Of the runaway stars must also be re-
membered. Observations made soon after the
new star in Aurga was discovered gave indi
cations of a relative speed there of $40 miles a
second or 10000 GOO miles day!
That two or more bodies are concerned in tho T
development of new stars has been denon