The Hickman courier., 1877-08-10
THE DUMB-BELL NEBULA.

In Vulpecula there IS a re marketable
object called the Dumb-bell nebula, or
star-cloud. 1t cannot be seen well
without a very powerful telescope. 1t
was formerly thought to consist entirely
of small stars, so remote that they
could not be separately discerned; but
it has lately been discovered that the
greater part of this nebula's light comes
from glowing gas. The vastness of the
space occupied by this cloud Of luminous
gas will be derstood-though no
mind can possibly conceive it when
l mention that at the distance of the
nearest of the fixed stars the whole of
our solar system would appear but as
a mere point, even in a powerful tele-
scope. The Dumb-bell nebula covers
quite a large space as seen in such an
instrument. 1t is also, probably, much
farther away than the nearest fixed stars.
1t must, therefore, occupy a region of
space exceeding many times that
through the planets Of cur Solar system
pursue their paths Yet the span of our
earth's path around the sun is fully one
hundred and eighty-four millions of
miles, while Neptune-the remotest
planet of the solar system-travels
thirty times farther from the sun,
having thus an orbit spanning more
than five thousand millions of miles.
\ globe Just fitting the path Of Nep-
tune would contain many quadrillions
Of cubic miIes'-and probably the
Dumb bell nebula exceeds such globe
in volume (or. to speak more exactly,
occupies a space exceeding such a globe
in volume) many millions OF times.
Very strange is the thought that as
tronomers should have been able to find
out what this mighty mass of glowing
gas consists of. Placed yonder amid the
gIories of the milky way, lost to human
vision through its vast remoteness, only
brought within our view at all by means
Of powerful telescopes, and only reveal
ing its true shape when seen with the
most powerful telescopes men have yet |
what at first sight can seem |
more amazing than that men should be |
able to tell what kind Of substance it is |
which gives out the misty luster of that
cloudlet in space? The very light which |
comes to Us from the Dumb-belI nebula
has probably taken hundreds Of years in /
crossing the tremendous space separating T.
Us from that object. Yet that light has
its message truly. Examined /
with that instrument, the spectroscope, |
whose office | lately described in a pa
per on the planet Nenus,-the light of |
the Dumb-bell nebula presents, not the /
streak which comes from |
glowing solid and liquid bodies, but three /
bright lights only. At least three lines /
are seen if the nebula Is examined /
through a fine slit if the field OF view Is
opened there are seen three faint images /
Of the cloudlet. The correct way of /
describing what the spectroscope tells us /
about this object is to say that, instead of /
It's light presenting all the coIors Of the
rainbow, it is found, when sifted by the /
,pectroscope, to contain three colors only, |
Ill of them greenish, but slightly different /
n tint. One of the colors is precisely /
.uch a tint of green as comes with four
,ther colors) from glowing hydrogen gas,
md shows Us that there are enormous
masses of hydrogen in that remote cloud;
mother tint shows, in like manner, that
here are immense masses of nitrogen;
,ut the third tint has not yet been found
o correspond with tint emitted by any
Known substance The skein of light
rom that double Auf.ball has thus been
mraveled by the spectroscope, after
ourneying millions of millions of miles.
nd has been sorted into three tints, two
# which have been matched against the
.nown tints of earthly gases, but the
bird remains as yet unmatched.--Prof. |
2. /. Proctor, st. Nicholas tor August.