In any case the orbits of comets are exposed to such tremendous perturbations from the planets that it is unsafe from the present orbit of a comet to conjecture what that orbit may have been in remote antiquity.
We must conceive a time when the sun was swollen to such an extent that it filled up the entire space girdled by the orbit of Mercury.
On the throne, in order that Poland, undivided and as strong as circumstances would permit, might be drawn wholly within the orbit of Russia.
The orbit is completely open behind.
But unless the orbit is an ellipse the body will never complete a revolution, but will recede indefinitely from the centre of motion.
To do this the actual speed in the orbit, and in a yet higher degree the angular speed around F, must be greatest at pericentre, and continually diminish till the apocentre is reached.
One of these is the position of the line MN through the sun at F in which the plane of the orbit cuts some fundamental plane of reference, commonly the ecliptic. This is called the line of nodes, and its position is specified by the angle which it makes with some fixed line FX in the fundamental plane.
The other element is the inclination of the plane of the orbit to the fundamental plane, called the inclination simply.
This, and the inclination of the orbit being given, we have all the geometrical data necessary to compute the coordinates of the planet itself.
When a new celestial body, say a planet or a comet is discovered, the astronomer meets with the problem of determining the orbit from several observed positions of the body.
To form a conception of this problem it is to be noted that since the position of the body in space can be computed from the six elements of the orbit at any time we may ideally conceive the coordinates of the body to be algebraically expressed as functions of the six elements and of the time.
The problem of determining an orbit may be regarded as coeval with Hipparchus, who, it is supposed, found the moving positions of the apogee and perigee of the moon's orbit.
Orbit open behind; and ridges of lower cheek-teeth generally terminating in small loops.
As the entire time required for light to pass over the radius of the earth's orbit is only about 500 seconds, this error is fatal to the method.
If S is the area of the orbit described in time T by an electron of charge e, the moment of the equivalent magnet is M = eST; and the change in the value of M due to an external field H is shown to be OM = - He'S/47rm, m being the mass of the electron.
This will be evident if we consider that, since radii vectores of the hodograph represent velocities in the orbit, the elementary arc between two consecutive radii vectores of the hodograph represents the velocity which must be compounded with the velocity of the moving point at the beginning of any short interval of time to get the velocity at the end of that interval, that is to say, represents the change of velocity for that interval.
Ordinary meteors, in the region of the earth's orbit, appear to be separated by intervals of about 250 m.
The explanation of these recurring phenomena is that a great cloud or distended stream of meteors revolves around the sun in a period of 331years, and that one portion of the elliptical orbit intersects that of the earth.
In 1867 the remarkable discovery was made that Tempel's comet (1866: I.) revolved in an orbit identical with that of the Leonids.
Biela's comet of 1826, which had a period of 6.7 years, presented a significant resemblance of orbit with that of the meteors, but the comet has not been seen since 1852 and has probably been resolved into the meteoric stream of Andromedids.
She contemplated an alliance with Spain, a state quite outside the orbit of Sweden's influence, the firstfruits of which were to have been an invasion of Portugal.
Deferens, bearing down), in ancient astronomy, the mean orbit of a planet, which carried the epicycle in which the planet revolved.
Tisserand in 1895.1 It involved the action of no third mass, but depended solely upon the progression of the line of apsides in a moderately elliptical orbit due to the spheroidal shape of the globes traversing it.
Having two components revolving about their common centre of gravity - and the first to have its orbit calculated.
Encke, the astronomer who first investigated its orbit and showed its periodicity.
I too would fain be a track-repairer somewhere in the orbit of the earth.