Orbital velocity

“ Thus, if a space ship takes off from Earth, with its orbital velocity of about eighteen and one half miles per second relative to the Sun, goes free, dashes to Mars, lands free, and then goes inert, its original velocity, both in speed and in direction, is instantly restored, with consequences better imagined than described. ”

“ Hot Rod's pull on a taut cable would be to the south.
No. Lab One could be re-oriented to trail the thrusting balloon. But the lab's servos should have prevented that re-orientation unless the thrust were really heavy.
"What is our velocity?" he asked. Temporarily he was baffled by the placid Cow's literal translation of his request as one for any actual velocity, since she had replied with a figure very close to their original orbital speed. "What is our velocity at right angles to original course?" ”

“ You are now rising at near-maximum speed, and not much more forward velocity can be anticipated. You have an air-speed relative to surface of six-nine-two miles per hour. The rotational speed of Earth at this latitude is seven-seven-eight. You have, then, a total orbital speed of one-four-seven-oh miles per hour, or nearly twelve per cent of your needed final velocity. Since you will take off laterally and practically without air resistance, a margin of safety remains. ”

“ It may also seem incredible that any orbital movements could be permanent enough to sustain oscillatory vibrations of such inconceivable frequency as those which luminous rays are known to execute; but I have computed, from the probable dimensions of the hydrogen molecule as assigned by the molecular physicists, and an orbital velocity due to an ethereal origin for the components, that many hundreds of revolutions must occur for each transverse oscillation or elliptical deformation. ”

“ A spacecraft hits it up in the hundreds of miles per second. Say two hundred and seventy miles per second, which is about ten times the orbital velocity of Venus Equilateral. Then with a given dispersion of meteors throughout space, any spacecraft has ten times the possible chances of encounter because the ship covers ten times the volume in the same time. ”

“ It is probable that there are more systems with variations of speed under six kilometers than there are with larger ones; and all such are awaiting discovery. The velocity of our sun through space varies slightly, because it is attended by companions—very minute ones compared with the invisible bodies discovered in spectroscopic binaries. It is revolving around the center of mass of itself and its planets and their moons. Its orbit around this center is small, and the orbital speed very slight. The total range of speed is but three one hundredths of a kilometer per second. ”

“ A mass moving in free space in any direction excepting directly toward a similar mass, must receive a more active shower of corpuscles in its front than in its rear, and must thus be retarded by a differential of energy directly proportioned to its velocity. Every planet must accordingly encounter a tangential resistance to its orbital motion, proportional to its own gravitation and to its velocity. ”

“ The speed with which it travels is twenty-five miles a second, (for its orbit extends as far as Uranus, although by no means parabolic) , and yet it takes more than a year to pass. Imagine a procession 200,000 miles broad, every individual rushing along at the rate of twenty-five miles every second, and the whole procession so long that it takes more than a year to pass. It is like a gigantic shoal of herrings swimming round and round the sun every thirty-three years, and travelling past the earth with that tremendous velocity of twenty-five miles a second. ”

“ If instead of being at rest initially they had had a transverse relative velocity of 1⋅42 kilometres per second, they would just escape collision, and would revolve in equal ellipses in a period of one year round the center of inertia, just grazing one another's surfaces every time they come round to the nearest points of their orbits. ”

“ A comet, for example, having an orbit extending to the path of the planet Neptune, approaching so near the sun as to almost graze his surface in passing, would have a velocity within 86 miles of what we have assumed. Twice this assumed velocity would give 200,000,000 years’ heat; four times the velocity would give 800,000,000 years’ heat; and so on.
We are at perfect liberty to begin by assuming the existence of stellar masses in motion; for we are not called upon to explain how the masses obtained their motion, any more than we have to explain how they came to have their existence. ”

“ Since the sum total of rotary motion now seen in the planetary system must have been there from the beginning, he conceives the immense vaporous mass forming the sun and his atmosphere to have had a slow rotation on its axis. As the intensely hot mass gradually cooled, it would contract towards the centre. As it contracted, its velocity of rotation would, by the laws of mechanics, constantly increase; so that a time would arrive, when, at the outer boundary of the mass, the centrifugal force due to the rotation would counterbalance the attractive force of the central mass. ”

“ But this circumstance must greatly affect the rotation of 269 the resulting planet. In a decidedly hoop-shaped nebulous ring, the differences of velocity between the inner and outer surfaces will be very small; and such a ring, aggregating into a mass whose greatest diameter is at right angles to the plane of the orbit, will almost certainly give to this mass a predominant tendency to rotate in a direction at right angles to the plane of the orbit. ”

“ In the case of a propelling force, unless it is in a directly opposite direction, it will simply result in the body going off at a tangent, still maintaining its original rate of velocity in the original direction in conjunction with its new direction. For example: Mars and the Earth moving in virtually parallel directions in their respective orbits at present, it was a comparatively simple matter to lay a straight course for Mars, as the Earth’s orbit velocity was imparted to the Sphere when we left it. ”