Evening star. [volume] (Washington, D.C.) 1854-1972, 1914-09-10
SPEED WITH WHICH
THE STARS TRAVEL
They Move Faster as Their
Age Increases-Concentra-
ton in Milky Way.
Prom the London Post.

! From the London Post.
! One of the least applicable characters
tics of the stars is that as their age
| increases they appear to gather speed.
We say that they appear to do so, be-
cause this proposition seems after close
examination to be the justifable infer
ence from the observations made by
Campbell of the Lick Observatory. The
observations are not open to challenge;
they constitute one of the great pieces
of astronomical work, the completion of
which is the gift of American astrono-
mers to the twentieth century, and the
| Inference drawn by the director of the
Lick Observatory, and based on the clas-
sification of the stars he has examined,
is accepted by most astronomers as the
best one
The only question which arises is
whether some other Interpretation than
that or Campbell can be put on the way
IN winch stars of varying distance. bril-
liancy. color. age and speed fall into
types or classes of stars Stars are clas-
slhed according to the characteristics
which We have named, and the spectre
scope, which is the final test applied to
them, gives information of their compo-
sition. and SO, indirectly, of their age
since We are at liberty to suppose that a
star which has more elements is at a
later stage of evolutions than one which
has few. We may say, roughly speaking.
that astronomy divides the stars into six
classes, which. to allow ourselves the
Indulgence of simplicity. We will denomi-
nate as classes 0, l, 2, 3. 4, j. Glass o
contains the hottest stars, the most
primitive stars. the slowest stars: and
in general terms the stage of evolution
the stars have reached. their tempera-
ture, their velocity all run in an orderly
progression through these six classes, o
to i.
The Slower Stars.
There is another characteristic run
ming through the classes. The more
primitive stars. the slower stars, are
concentrated about the Milky Way, and
if the starry universe be regarded as
f1attened sphere in shape the older,
speedier stars seem to have strayed more
and more from the equatorial belt where
they were born to the poles. 1t Is as
sumed that this is the case, and that,
while the younger. slower stars have not
had time to stray. time. opportunity and
Increasing speed have carried the older
stars farther from their birthplace.
IF the orderly progression of age. coin
Gliding with temperature that diminishes
with age. and with brightness that di-
ninishes with falling temperature and
growing years; and If these characters
tics all progressed conformably with in
creasing velocity through all the six
classes-then Campbell's discovery would
be unassailable and we should only be
left to wonder what the ineXplira BILE
force could be that adds enormous
amounts of locomotive power-or, in as
Economical phrase. transitional energy
to star as the years go on. But any
of ind &c ynrlyi y,c
hypothesis-which leaves some gaps that
cannot be got to fit in it-and that is
the case here. The red stars. which are
in a general way. the older stars. and In
some cases must be the oldest-redness
being taken to imply that the star has
sunk from white incandescence to a
sulky glow-these stars do not quite con-
form. especially the stars OF the last class,
or oldest class. Some of these red stars
instead of being dull as well as old, are
extremely bright Consequently, new
Interpretation was put on the appearance
of some of the stars, and this interpreta-
ton, which was at first designed to ac-
count for the breaks and discrepancies in
the orderly progression OF star types has
lately been offered by DR.. H. n. Russell
of Princeton observatory, as an alter
native explanation of the speed of stars
Giant and Dwarf Stars.
Briefly. the idea, which was due also
to Schwartzschild of Potsdam, is that
there are in each class giant stars and
dwarf stars. A star at its birth may be
regarded as a coalescence of primordial
matter. AS the particles Of this mass
fall inward in coalescence under the
action of gravity the mass grows hotter
and hotter, brighter and brighter, till it's
maximum brightness is reached. Then,
when the mass ceases to come under the
law of gases and attains a certain
Change of state it's temperature begins
to fall. 1t is growing older and redder,
maintains that it is only the larger
masses of coalescing matter. the giant
stars. which attain very high temper
ature and, in consequence, conspicuous
whiteness A small coalescing mass a
dwarf star is a poor self-heating affair.
and never gets hot enough to shine to
any purpose Thus We see that in any
class of stars there may be three types
of redness-the redness which arises as
the large star is heating up toward white
ness. the redness which occurs when its
wilderness is again dulling into redness.
and the redness of the small star. which
never rises to anything different. rms
propositton due to Lane and Ritter, Is
used by Russell not merely to explain
the discrepancies in the numbers and
distribution of the red and old stars
but to account for the apparent increase
of velocity. IT, he says, We take for
granted that only very massive stars can
attain an appearance of white youthful
ness-the brightness and whiteness OF
class q for example-we shall nave an
other possible explanation of the appar-
ent increase of velocity In the star