The Coconino sun., 1923-05-11
FOUND I'M SPIRAL NEBULA
BY DIR. c. O. LAMPLAND;
is LARGER THAN OUR SUN
Continued from Page One.)

Continued from Page One.)
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nebula in the northern sky near the
Send Of the handle Of the Big Dipper.
The nebula in Centaurus and many
others have been carefully observed
at the Lowell Observatory for many
years for the purpose of detecting any
changes which might occur in them.
With the modern highly improved and
accurate optical instruments used in
the comparisons of photographs of
different dates,fit is possible to de-
tect extremely small differences IN
the details Of such plates.
A few words of explanation may be
added here In connection with the re-
searches on nebulae carried on at
Flagstaff. 1t is perhaps known to
many readers Of this brief sketch that
the chief aim of DR.. Lowell in found
ing the Lowell Observatory was to
carry forward principally irvestiga-
tions relating to the origin and devel-
opment Of the planets and the whole
of our solar system. Modern re-
search has brought out clearly the in
telTelations and overlappings of the
various fields Of investigation in sci
ence. The science Of astronomy has
also experienced to a marked degree
this interdependence in parts Of APP
parently distinct lines of investiga-
ton. Information as, to the course of
evolution Of our system may profi-
tably be- gathered from independent
systems. external to our own.
In astronomy the time factor in
the development Of system must be
very great indeed, and the astrono-
mer must study many objects in or
der to piece together the evolutional
life of any chosen subject of inves-
tigation.
For a long time the celebrated tho
oryi Of Laplace on the development
of our solar system was firmly in
trenched and the forms of the spiral
nebulae seemed to exemplify in vivid
manner this theory Though this the
ory is now known to be no longer ten
able in accounting for the actual de-
velopment of our own system, this
beautiful and at one time plausible
theory has served a most useful pur-
pose in stimulating and directing fur
ther research and leading to wider and
more comprehensive knowledge of the
universe of which our solar system
forms humble part but to us very
important part.
Problems connected with the neb-
ulae, particularly the spiral forms, are
among the most difficult presented to
the astronomer. With the remarkable
I.
instruments and methods the critical
studies of nebulae have in recent years
assumed great Importance. In the
past, Investigations on the stars have
been given more attention than the
nebulae and star clusters. 1t is now
realized that to arrive at a more COM
plete knowledge Of the structure, ex-
tent, and activities of the universe it
is essential that we must acquire
better knowledge of the true nature
of the nebulae of various types and
their possible affiliations with the
great stellar system of hundreds OF
millions Of suns within the reach Of
modern giant telescopes. In spite OF
the rapid and marked advances made
in our researches on the spiral nebulae
it is not at present possible to defin-
itely assign them place in the
scheme of the visible universe now
within reach oil our instrumental
means. Without entering into details
we may say there are two rival the
cries interpreting the meaning OF the
obseryational data at present avail
able. The "island universe" theory
proposed by Sir William Herschel
more than. century and a quarter
ago has again taken on renewed vital
ity in recent years This theory in-
terprets the nebulae as great stellar
systems like our own but situated at
enormously great distances from US.
The other Interpretation is that all
the observed objects, stars, star
clouds, star clusters and nebulae OF
all types, are part and parcel Of one
gigantic system several hundred
thousand light-yearS in diameter. (Let
US recall that the light-year is the dis
tance travelled by light in one year,
1t takes light only about eight min
utes and twenty seconds to traverse
the distance between the earth and the
sun, 93,000,000 miles; or, in more ia
miliar terms, ray of light would en-
circle the earth at the equator about
seven and one half times in one sec.
ond. The nearest fixed star is dis
tant from the solar system about
four and a quarter light-years.
4 1t is scarcely necessary to add that
information from all possible sources
bearing upon the structure, compost
tion, activities and position in space
of the nebulae are of great impor-
tance. It is gratifying to note that
the intense activities of observers
equipped with powerful instruments
are concentrated on these. difficult in
vestigations, and that steady prog
ress is being made. A contribution
of fundamental importance in this
connection was DR.. Slipher's epoch
making Investigations on the speeds,
and the character of the spectra of
nebulae and star clusters, falling with
in the last decade. For some Of the
spiral nebulae he measured velocities
exceeding 1000 miles a second. speeds
previously unheard of among the
heavenly bodies. These results have
been amply confirmed by investigators
at other observatories, and their in
terpretations necessarily introduce