But again, other nebulae present an appearance suggestive of an opposite condition.
The Structure of Nebulae Yet the new instruments, while leaving so much untold, have revealed some vastly important secrets of cosmic structure.
The linking of nebulae with stars, so clearly evidenced by all these modern observations, is, after all, only the scientific corroboration of what the elder Herschel's later theories affirmed.
Continued condensation may make the stellar mass hotter and more luminous for a time, but eventually leads to its liquefaction, and ultimate consolidation--the aforetime nebulae becoming in the end a dark or planetary star.
The conclusion seems warranted that comets are in point of fact minor nebulae that are drawn into our system; or, putting it otherwise, that the telescopic nebulae are simply gigantic distant comets.
More extended studies showed, it is true, that some nebulae give the continuous spectrum of solids or liquids, but the different types intermingle and grade into one another.
Nebulae are vast cometary clouds, with particles more or less widely separated, giving off gases through meteoric collisions, internal or external, and perhaps glowing also with electrical or phosphorescent light.
Also, the closest affinity is shown between nebulae and stars.
They enable finite man to tell what the earth, sun and stars, meteors, comets and nebulae are composed of.
Nebulae can be seen here that are invisible in many other instruments of equal or greater aperture.
Unfortunately, these nebulae are far beyond the reach of an opera-glass, but it is worth while to know where this curious region is, even if we can not behold the wonders it contains.
The reader should not expect to be able to see the nebulae in the Pleiades with an opera-glass.
We shall presently see some examples of star-clusters and nebulae with which the instruments we are using are better capable of dealing than with the one described above.
Also the northern spiral nebulae were photographed, exhibiting an extraordinary wealth of detail in apparent star formation.
He has also photographed with the Crossley reflector many nebulae with lanes or dark streaks crossing them longitudinally through or near the center.
A search was made for additional spirals among the smaller nebulae along the Galaxy, but without success.
This new method is adding extensively to our knowledge of stellar luminosities and distances, and even the vast distances of globular clusters and spiral nebulae are becoming known.
Campbell and Moore of the Lick Observatory have investigated seventy-three planetary nebulaewhich exhibit the phenomena of star-streaming, and have motions which are characteristic of the stars.
Several of the supposedly variable nebulae are found to be unchanging.
There are perhaps fifteen thousand nebulae in all that have been catalogued, described, and photographed.
Regrettably so in case of the nebulae, because the numerous photographs of the brighter nebulae taken since 1880 when Draper got the first photograph of the nebula of Orion, are as a rule not comparable with each other.
The distances of the spiral nebulae are exceedingly great.
Of all celestial objects the nebulae fill the greatest angles, so that we are forced to conclude, with regard to the actual size of the greater nebulae as they exist in space, that they far surpass all other objects in bulk.
The marvels of the spiral nebulae are unfolded, their multitudinous forms portrayed and deciphered.
Hamilton he was able in the course of only two years to organize thoroughly the work of the Observatory, and to adapt the Crossley reflector for his purpose, taking photographs of the nebulae that have never been equalled.
His discovery that mostnebulae have a spiral structure is of fundamental importance.
The Astronomical Society of London, very much to its honour, voted her a gold medal for her reduction of thenebulae discovered by her renowned brother.
There was no moonlight; but the great masses of nebulae that spot the southern sky enlighten, as they set, a part of the terrestrial horizon.
When, declining toward the horizon, they traversed the great nebulae of Sagittarius and the Ship, they appeared of a dark blue.
Their scintillation was scarcely sensible at the horizon, which seemed illumined by the great nebulae of the southern hemisphere.
The light of the nebulae is never more splendid than when they are in part covered by sweeping clouds.
We have seen that the stronger our telescopes the more stars, star-clusters, and nebulae we see, and we cannot doubt that there are still countless heavenly bodies quite unknown to us.
After a few years, however, when powerful telescopes showed that many of the nebulae were only clusters of very minute stars, astronomers thought that Laplace's teaching had been wrong.
It would take a lifetime and he didn't even know which of the four or five spiral nebulae in the skies of the human worlds was the Lhari Galaxy.
The stars are with us, the nebulae and the central fires are their throne and altar.
Nature was Nature everywhere, in the nebulae as in the stifled plane tree of a city court.
It seems to be pretty certain that all true nebulae are gaseous, and show almost exactly the same spectrum.
When Sir John Herschel had extended his father's researches into the Southern Hemisphere he was also led to the belief that some nebulae were a phosphorescent material spread through space like fog or mist.
You have been thus led to the outer rim of speculative science, for beyond the nebulae scientific thought has never hitherto ventured.
As regards inorganic nature, then, we may traverse, without let or hindrance, the whole distance which separates the nebulae from the worlds of to-day.
Behind the orbs, we now discern the nebulae from which they have been condensed.
Bearing this in mind, and referring to some of the figures of the marvellous spiral nebulae which Lord Rosse's telescope has revealed to us, I shall now bring these suggestions to a conclusion.
The stars and the nebulae we have always with us, but where are the myriad earlier forms that were the antecedents of the present animal life of the globe?
In the next four nebulae of the table--including the one we introduced to represent the Asteroids--we see that their regions of greatest density are respectively 19.
If there be nebulae at the temperature of incandescence, they must be possessed of densities, or pressures, corresponding to that temperature.
Regions of greatest density in the 9 nebulae dealt with; compared with the orbits of the planets made from them.
And we have still to add that the extreme diameters of the 9 nebulae are the same as those we used for the analysis; as also, that we make use of only the first of the proportions just cited, viz.
Some people evidently seem to think that nebulae can be incandescent and give the spectrum of incandescent gas, without their density or pressure being increased to the corresponding degree.
Later observations with the Crossley reflector, with longer exposure-times and more sensitive plates, render it probable that the number ofnebulae discoverable with this powerful instrument is of the order of half a million.
New Nebulae discovered photographically with the Crossley Reflector of the Lick Observatory," Mon.
Many thousands of unrecorded nebulae exist in the sky.
The main purpose of this volume is to reproduce and make available for study, the larger and more interesting nebulae and clusters on the programme, sixty-eight in number.
Incidentally, in making these photographs, great numbers of new nebulae have been discovered.
The existence of ring-nebulae may be held to render such a form probable.
All these kinds of nebulae have stars involved in them, and apparently forming part of their structure, while others which do not differ in appearance from ordinary stars are believed by Dr.
Many of these clusters which are not very crowded and of irregular forms, strongly suggest an origin from the equally irregular and fantastic forms of nebulae by a process of aggregation like that which Dr.
But the first person to point out the real teaching of the facts as to the distribution of the nebulae was not an astronomer, but our greatest philosophical student of science in general, Herbert Spencer.
The regions beyond our cluster and above or below the plane of the Milky Way are those where the small irresolvable nebulae abound, and these may indicate that sun-formation is not yet active in those regions.
We thus see that the two phenomena may be complementary to each other, the condensation of nebulae having gone on most rapidly where material was most abundant, resulting in numerous star-clusters where there are now few nebulae.
A careful examination of them will give a clearer idea of the very remarkable facts of distribution of star-clusters and nebulae than can be afforded by any amount of description or of numerical statements.
As undoubted changes have occurred in many of the larger nebulae during the last fifty years, we may anticipate that analogous changes will soon be noted in the stars and the nebulous masses of the Milky Way.
The gaps that exist in nebulae are millions of miles across, and the earth would require days and weeks to go such distances, granting that it were traveling in the proper direction.
I know it because I have demonstrated with my new spectroscope, which analyzes extra-visual rays, that all those dark nebulae that were photographed in the Milky Way years ago are composed of watery vapor.
If suns and planets were derived by a process of condensation from such nebulae as exist to-day, perhaps the process of evolution was attended by an evolution of the chemical elements themselves.
When the gigantic telescope of Lord Rosse had resolved some nebulae into clusters of stars, it was thought that all other nebulae might be of the same character; the visible basis of the hypothesis was gone.
Before the day of the spectroscope all speculation upon the chemistry of the stars was in vain; with its advent the material unity of planets, suns, and nebulae was made clear.
The nebulae are simple; in the hotter stars a few more elements appear; more still can be detected in colored stars and the sun; but the planets, represented by our earth, are most complex of all.
Another, and a more valuable work, was The Reduction and Arrangement in the Form of Catalogue, in Zones, of All the Star-Clusters and Nebulae Observed by Sir W.
To her nephew, Sir John Herschel, it proved invaluable, as it supplied the needful data "when he undertook the review of the nebulae of the northern hemisphere.
Reduction and Arrangement in the Form of Catalogue, in Zones, of All the Star-clusters and Nebulae Observed by Sir W.
Besides the eight comets by her discovered, she detected several remarkable nebulae and clusters of stars, previously unnoticed, especially the superb nebulae known as No.
From this point of view the radio-active atoms represent an intermediate stage between nebulae and chemical atoms, the process of contraction giving rise to the heat emissions.
The essence of the meteoritic theory, it will be recalled, is that all stars have their origin in nebulae which consist essentially of clouds of relatively small meteorites.
And many types of nebulaeand stars are now studied which were never so much as imagined until they revealed themselves upon the photographic plate.
In particular, a closer acquaintance with comets, meteorites, star-clusters, and nebulaehas helped us to realize the great significance of the smaller bodies which are found in millions in the space between the stars.
According to the fabulous stories of the natives, the islets of mica-slate, situate in lake Amucu, augment by their reflection the lustre of the nebulae of the southern sky.
As yet we know nothing with certainty, but it is thought that by means of the spectroscope some stages of the operation may be seen in progress in the nebulae and stars.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "nebulae" in a variety of sentences. We hope that you will now be able to make sentences using this word.
