It has also been found that certain comets have orbits which cannot be distinguished from that of an elongated ellipse, the sun occupying one of the Foci.
There are, however, some cometswhose orbits are perfectly elliptical, and whose return may be calculated with a fair amount of accuracy.
The number of the cometsthat exist in the solar system cannot be ascertained with any degree of accuracy, but the total probably extends into millions.
So that if this be true, then the earth and the planets, the sun and stars, comets and meteors, are moved through space solely because they are being pushed by some medium, or pulled to the centre by the motions of the same medium.
There is another important difference between the orbits of the comets and those of the planets.
This class of comets may be divided into two kinds, which are known as Short Period Comets and Long Period Comets respectively.
Then we have comets with single tails, or double, and in some cases even multiple tails.
As has already been pointed out, comets perform their journey round the sun, not only in the plane of the ecliptic, but also at all angles relatively to that plane.
There are about two dozen comets which revolve around the sun, and which return at intervals lying between three years and 76 years.
Of the Long Period Comets there are several known.
One of the more famous of the short period class of comets is that known as Halley's Comet, which has a period of about 76 years.
This is just what they would be if comets had the genesis above supposed.
How happens this close kinship--how happens there to be this family of comets so much like the planetoids and so much like one another, but so unlike comets at large?
There would result, too, comets unlike one another in constitution.
Footnote 15: It is true that since this essay was written reasons have been given for concluding that comets consist of swarms of meteors enveloped in aeriform matter.
Unlike planets, whose orbits approximate to one plane, comets have orbits that show no relation to one another; but cut the plane of the ecliptic at all angles, and have axes inclined to it at all angles.
We have already seen that this view of the origin of comets harmonizes with the characters of their orbits; but the evidence hence derived is much stronger than was indicated.
While all the planets go round the sun from west to east, comets as often go round the sun from east to west as from west to east.
But if extreme eccentricity of an orbit necessitates such inability, it seems quite possible that comets have no other orbits than elliptic ones.
Further significant evidence is furnished by the comets of short periods.
Then, in the fourth place, the physical constitution ofcomets accords with the hypothesis.
The comets knew just how the point of that stick felt, for they were prodded with it whenever they misbehaved themselves; accordingly, they all remained very quiet, while he gave his orders for the day.
She said she had lived through a score of such scares, and would snap her fingers at all the comets of the heavens at once.
Dost thou not behold in those eccentric comets with which thine eyes are sometimes astonished, that the planets themselves are subject to death?
The natural philosopher, himself, conjectures that in former ages, these comets have overthrown the surface of this mundane ball, and caused great revolutions on the earth.
The Times pointed out some time ago that the theory which now associates meteors and comets in the most unmistakable manner, was suggested by one accident, and confirmed by another.
The same holds good also with certain comets and with the sun himself.
The received system of the universe, founded upon these so called discoveries, is that each of the stars is a sun, having planets and comets revolving round it, as our sun has the earth and other planets revolving round him.
Modern discoveries make it probable that each of these stars is a sun, having planets and comets revolving round it, as our sun has the earth and other planets revolving round him.
Although there could be little doubt that thecomets were retained in their orbits by the same laws which regulated the motions of the planets, yet it was difficult to put this opinion to the test of observation.
The evidence which enabled astronomers to definitely associate comets with meteoric showers and falling stars leads one into a world of romance.
It is difficult to comprehend the vastness of these clusters of meteors which constitute the wreck of comets and the source of the principal bombardments.
But comets seem to be controlled by no known law, and you never can tell where you may encounter them.
Comets have well been called "the spectres of space.
Now comets sometimes move very rapidly (especially when they are near the Sun), and had it been possible to have warned some observer to the E.
Their observations of comets may be singled out as having been of inestimable value to various 19th-century computers, especially E.
The sound of these words may be large but facts do not bear out the theory, for eclipses do not appear to have captivated our great poets to anything like the extent that Moon, Stars, and Comets have done.
He created seven comets (in opposition to the seven planets), and they went on their destructive paths through the heavens, filling all things with danger, and all men with terror.
In like manner the periods of D'Arrest's and Biela's comets correspond to the hiatus at 3.
It does not secure the stability of all periodic comets nor of the meteor streams revolving about the sun.
With all due respect to the authority of great names, the present writer has not wholly abandoned the theory that some comets of short period are specially related to the minor planets.
Did comets originate within the solar system, or do they enter it from without?
In former epochs, when the dimensions of the sun were much greater than at present, this falling of comets into the central orb of the system must have been a comparatively frequent occurrence.
The Relation of Short-Period Cometsto the Zone of Asteroids.
I had not long to wait, for, as if ordered so for my special accommodation, the mighty downrush of comets with their whirling drapery swung westward and remained aslant for nearly half an hour.
At length, as if commanded to go on again, scores of arrowy comets shot forth from the bottom of the suspended mass as if escaping from separate outlets.
Seen from this point towards noon, in the spring, the rainbow on its brow seems to be broken up and mingled with the rushing comets until all the fall is stained with iris colors, leaving no white water visible.
To discover the true nature of comets has hitherto proved beyond the power of science.
The answer to this question would introduce comets into the category of ordinary planets or would exclude them for ever.
In the time of Alexander comets were supposed by the majority of the Greek philosophers to be merely meteors generated in our atmosphere.
This argument, offered by Herschel in favour of the system which transforms comets into self-luminous bodies, has not, as we may perceive, much force.
Pons, the director of the Observatory at Marseilles, and the most celebrated discoverer of comets of whom the annals of Astronomy have ever had to register the success.
Astronomy, moreover, has been directly enriched by several comets through this excellent and respectable lady.
Since comets are generally visible only during a few days or weeks at the utmost, the determination of their orbits is attended with peculiar difficulties.
As soon as it was established that the returns of comets might be calculated beforehand, those bodies lost for ever their ancient prestige.
It was necessary, then, to prove that the orbits of cometsare curves which return into themselves, or that the same comet has been seen on several distinct occasions.
The aphelia of the comets of short period ought therefore to be found, for the most part, in the vicinity of the orbits of the major planets.
As comets are subject to great changes of appearance, one can never be identified by any description of its magnitude, brilliancy, etc.
Few comets of small perihelion distance should have their perihelia in the vicinity of longitude 80 deg.
The cosmical masses from which comets are derived seem to traverse in great numbers the interstellar spaces.
Comets were portents to Increase Mather, President of Harvard College; "preachers of Divine wrath, heralds and messengers of evil tidings to the world.
I doubt, too, whether the Young Astronomer will pass the rest of his life in hunting for comets and planets.
The guessing the course of comets began then to be very much in vogue.
He proves that there is no such thing as a celestial matter which goes from west to east since the comets traverse those spaces, sometimes from east to west, and at other times from north to south.
The ancients were almost in the same way of thinking with Mr. Whiston, and fancied that comets were always the forerunners of some great calamity which was to befall mankind.
After having shown by his sublime theory the course and inequalities of the planets, he subjects comets to the same law.
The old idea that comets came from outer space and therefore travelled in hyperbolas can, he points out, be true of few, if any, of them.
Thus not only are comets a part of our system now recognized, but they act as finger-posts to planets not yet known.
Of this Percival was, of course, well aware, and in fact, in his study of the comets associated with Jupiter he had pointed out that there probably was a planet far beyond the one for which he was now in search.
Now if the comets are travelling in orbits around the Sun they must be throughout their course within its control, and not within that of some other star; and therefore he computes how far the Sun’s control extends.
Indeed seventy-six of these associations were then known, andcomets sometimes break up into such streams.
After calculating the possible conditions and analyzing the actual orbits of Jupiter’s family, he comes to the provisional conclusion that these comets have been drawn from the neighborhood.
Pierre Appian, who first ascertained the fact that the tails ofcomets are usually turned from the sun, examined this comet with a view to verify his statement, and to ascertain the true direction of its tail.
The majority of comets can be seen only by the aid of the telescope.
The distances to which different comets recede from the sun are equally various.
The quantity of matter in comets is exceedingly small.
Many cometshave no nucleus, but present only a nebulous mass, exceedingly attenuated on the confines, but gradually increasing in density towards the centre.
The periods of comets in their revolutions around the sun are equally various.
Such are some of the accounts of comets of past ages; but it is probable we must allow much for the exaggerations naturally accompanying the descriptions of objects in themselves so truly wonderful.
Of the physical nature of comets little is understood.
An intermediate number of bodies called comets and meteors, which revolve in very eccentric orbits.
They shine like suns, these two, amid multitudes of watery comets and tenebrific constellations, too sorrowful without such admixture on occasion!
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "comets" in a variety of sentences. We hope that you will now be able to make sentences using this word.
