As a result we have globular, spheroidal, and cometic nebulæ.
The rays of the sun in passing through or near the nucleus are so modified as to become visible in their further progress through the cometic atmosphere, while all the rest remain invisible.
The sword shaped tails, at variance with the common theory, can be accounted for by supposing a slight difference in density or material in the cometic atmosphere, which will deflect the light as seen.
The sphere at the perihelion would envelop the sun, and as a noticeable reduction is sometimes found in its so-called tail, the cometic atmosphere may impart to the sun at that time whatever is necessary to its use.
What we call the tail is merely a radius of the cometic atmosphere made visible, and as the comet moves through space, only different portions of the atmosphere come in sight, in obedience to the ordinary laws of light.
From what we observe in regard to the larger bodies of the universe--a clustering tendency being everywhere apparent,--it seems highly improbable that cometic matter should be uniformly distributed in the sidereal spaces.
If, therefore, the comet had been at that time directly between the sun and the earth, the latter must have been enveloped for a number of hours in the cometic matter.
It is evident also that the passage of the solar system through a region of space comparatively destitute of cometic clusters would be indicated by a corresponding paucity of comets.
And if several such cometic masses thus travelled towards the centre, they would exhibit the wheel-like figure with bent spokes, which is seen in the spiral nebulae.
Others have also remarked the same, and if we couple this fact with the suggestion just made, we are justified in suspecting that a greater quantity of cometic dust comes down the northern pole of the vortex than down the southern.
Some have theorized that the sun is maintained by the fall of cometic matter into it.
Simply this: that it is now conceded that meteoric showers are shreds and patches of cometic matter, dropped from the tail; and meteoric showers are stones.
The sunbeams pass as readily through the entire thickness of the cometic substance as they do through our own highly permeable atmosphere.
The comet's tail seems, in reality, to be a thin oblong case of vapour, formed out of the cometic substance by the increasing intensity of the sunshine, and enclosing the denser portion of that substance at one end.
Most probably, much of the matter that is thus thrown off from the cometic nucleus is never collected again, but is dissipated into space, and lost for ever to the comet.
If we could now discern the separate fragments of the comet, we should doubtless recognize a process in progress by which, in the course of many centuries, the separate cometic bodies will be disseminated all round the common orbit.
It was not till the time of Halley's comet, 1682, that modern astronomy began to consider the question of the possibly periodic character of cometic motions with attention.
Indeed, thus far, although the circumstances were striking, there was nothing to prevent astronomers from interpreting them as other cases of coincident, or nearly coincident, cometic paths had been interpreted.
This," said Ben, pointing to one of the dark lines in the cometic spectrum, "this is produced by the vapor of carbon in the nucleus of the heavenly visitant.
I was now scrutinizing the cometic spectrum very closely, being particularly attracted by a thin, faint line, which I thought Ben had overlooked.
The curvature of all the cometic tails when not seen from a point in or near the place of their motion.
The rapidity with which light travels would of course make this explanation absolutely perfect in explaining cometic tails lying always exactly in a straight line directed from the sun, or with their axis so situated.
How far electricity may be looked to for an explanation of cometic phenomena, is a doubtful point among astronomers and physicists.
We can understand that, while several have been found who have applauded the sea-bird paradox for what it might do in explaining comets' tails, its advocates have as yet not done much to reconcile it with cometic observation.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "cometic" in a variety of sentences. We hope that you will now be able to make sentences using this word.
