From a score of well-observed original orbits it is shown that the "new" long-period comets generally come from regions between about 50000 and 150000 A. U. distance. The sun must be surrounded by a general cloud of comets with a radius of this order, containing about 1011 comets of observable size; the total mass of the cloud is estimated to be of the order of 1/10 to 1/100 of that of the earth. Through the action of the stars fresh comets are continually being carried from this cloud into the vicinity of the sun.
Jan OortRelated topics
action carry cloud containing distance earth fresh general mass observable order radius score show size sun vicinity 100 starsRelated quotes
We must, with God's help, eradicate the deadly poison of the demon of anger from the depths of our souls. So long as he dwells in our hearts and blinds the eyes of the heart with his somber disorders, we can neither discriminate what is for our good, nor achieve spiritual knowledge, nor fulfill our good intentions, nor participate in true life; and our intellect will remain impervious to the contemplation of the true, divine light; for it is written, 'Man's anger does not bring about the righteousness of God' (Jms. 1:20).
John Cassian
Any region of space-time that has no gravitating mass in its vicinity is uncurved, so that the geodesics here are straight lines, which means that particles move in straight courses at uniform speeds (Newton's first law). But the world-lines of planets, comets and terrestrial projectiles are geodesics in a region of space-time which is curved by the proximity of the sun or earth... No force of gravitation is... needed to impress curvature on world-lines; the curvature is inherent in the space...
James Jeans
A point which I want very much to establish is that the choice of these 'Readymade' was never dictated by aesthetic delectation. This choice was based on a reaction of visual indifference with at the same time a total absence of good or bad taste.... in fact a complete anesthesia. One important characteristic was the short sentence which I occasionally inscribed on the 'readymade'. That sentence instead of describing the object like a title was meant to carry the mind of the spectator towards other regions more verbal.
Marcel Duchamp
I always saw a close kinship between the needs of "pure" mathematics and a certain hero of Greek mythology, Antaeus. The son of Earth, he had to touch the ground every so often in order to reestablish contact with his Mother; otherwise his strength waned. To strangle him, Hercules simply held him off the ground. Back to mathematics. Separation from any down-to-earth input could safely be complete for long periods - but not forever. In particular, the mathematical study of Brownian motion deserved a fresh contact with reality.
Benoît Mandelbrot
The subject of this book is the structure of space-time on length-scales from 10-13cm, the radius of an elementary particle, up to 1028cm, the radius of the universe. ...we base our treatment on Einstein's General Theory of Relativity. This theory leads to two remarkable predictions about the universe: first, that the final fate of massive stars is to collapse behind an event horizon to form a 'black hole' which will contain a singularity; and secondly, that there is a singularity in our past which constitutes, in some sense, a beginning to the universe.
Stephen Hawking