Page images
PDF
EPUB

most glorious objects in the heavens. "If we suppose this nebula to be one continuous bed of stars of different sizes for its entire extent, it must comprise the enormous number of 30,000,000." The distance, of such nebulae from the earth entirely passes our comprehension. Some astronomers have estimated that a ray of light would require 800,000 years to span the gulf that intervenes. Imagination wearies itself in the attempt to understand these figures. They only teach us something of the limitless expanses of that space in which God is working the mysterious problem of creation.

The annular nebulae, have the form of a ring. There are but four of these "ring universes." In

Fig. 84.

[graphic][ocr errors]

the cut is a representation of one in Lyra—first as seen by Herschel, and having in the centre a nebulous film like a "bit of gauze stretched over a hoop;" second, as shown in Lord Rosse's great telescope, which resolves the filmy parts of the nebula into excessively minute stars, and reveals a fringe of stare

[graphic]

SriBAL CLUSTER IN CANES VKNATICI.

most glorious objects in the heavens. "If we suppose this nebula to be one continuous bed of stars of different sizes for its entire extent, it must comprise the enormous number of 30,000,000." The distance, of such nebulae from the earth entirely passes our comprehension. Some astronomers have estimated that a ray of light would require 800,000 years to span the gulf that intervenes. Imagination wearies itself in the attempt to understand these figures. They only teach us something of the limitless expanses of that space in which God is working the mysterious problem of creation.

The annular nebula have the form of a ring. There are but four of these "ring universes." In

[merged small][graphic][merged small]

the cut is a representation of one in Lyra—first as seen by Herschel, and having in the centre a nebulous film like a "bit of gauze stretched over a hoop;" second, as shown in Lord Eosse's great telescope, which resolves the filmy parts of the nebula into excessively minute stars, and reveals a fringe of stars

[graphic][merged small]

along the edge. Though apparently so small, its dimensions must be enormous. If no further from the earth than 61 Cygni, the diameter would be 2,000,000,000 miles. It is probably immensely further distant.

The spiral or " whirlpool nebulae" are exceedingly curious in their appearance. The most remarkable one is that in Canes Venatici. It consists of brilliant spirals sweeping outward from a central nucleus, and all overspread with a multitude of stars. One is lost in attempting to imagine the distance of such a mass, and the forces which produce such a "tremendous hurricane of matter—perhaps of suns."

Planetary nebulae, by their circular form and pale uniform light, resemble the disks of the most distant planets of our system. Their edges are generally well denned, though sometimes slightly furred. Threefourths of them are in the southern hemisphere. Several have a blue tinge. There is one in Ursa Major, which if located at the distance named before—that of 61 Cygni— would fill a space equal to three times the entire orbit of Neptune. About twenty-five of these "island universes" have been found scattered through the ocean of space. Columbus discovered a new continent, and so immortalized his name; what shall we

[graphic]
[ocr errors]

PLANETARY NEBULA,

« PreviousContinue »