Basic concepts[ edit ] A spin interacts with a magnetic or an electric field. In general, these interactions are orientation dependent.
Not bad, for kitty litter. But a civilization that does gain the ability to create relativistic kinetic-kill weapons becomes a deadly threat to any and all alien civilizations in range.
I had this image of putting a relatively small payload on top of a bloody massive conventional booster and firing it of -- the poor mans R-bomb i guess -- but after looking at some calculations this doesn't look likely. From the kinetic energy equation and Tsiolkovsky's equation you get: Canceling terms gives that: After reaching this velocity any additional acceleration REDUCES the energy impacted on the target so you might as well shut off the engines and let it coast.
The final case is for relativistic velocities although being fired from ships that are stationary with respect to each other otherwise the maths is really nasty! So is it just me or does this completely defy the concept of the poor-mans R-bomb so that instead it requires some sort of some handwavium total-conversion drive?
Also this shows that to be effective a kinetic-missile must have a high exhaust velocity, not just a lot of fuel. While I suppose in order to evade point defense they need to be going faster but every extra second of thrust would reduce the damage inflicted to the target.
Paterson is optimizing a more plausible scenario. His "poor man's R-bomb" is constrained by a particular exhaust velocity, and the question is how to squeeze the maximum kinetic energy into the payload.
I'm not sure whether his analysis is correct, but it seems plausible. The optimum energy efficiency would actually be reached at an terminal velocity equal to the exhaust velocity.
But that doesn't seem to be the objective of the poor man's R-bomb. The poor man's R-bomb seems to be limited by loaded mass rather than energy budget. You don't use any sacrificial propellant at all, you just use pure fuel at the maximum exhaust velocity you can manage all the way.
His conclusion is essentially correct, if we assume the poor man's R-bomb must be internally powered. Still, this is nothing new to those of us who have seriously considered the problem of fast interstellar propulsion.
We gave up on the idea of internal power for fast interstellar propulsion years ago, on the pretty obvious grounds that no fuel has a sufficient usable energy density. If you want to reach high relativistic speeds, you should use external power--either in the form of a laser beam or particle beam or "runway" track or relativistic kinetic impactors.
All the energy put into achieving that velocity had transformed the Intruder into a kinetic storage device of nightmarish design. If it struck a world, every gram of the vessel's substance would be received by that world as the target in a linear accelerator receives a spray of relativistic buckshot.
Someone, somewhere, had built and was putting to use a relativistic bomb -- a giant, roving atom smasher aimed at worlds The gamma-ray shine of the decelerating half was also detectable, but it made no difference.
One of the iron rules of relativistic bombardment was that if you could see something approaching at 92 percent of light speed, it was never where you saw it when you saw it, but was practically upon you In the forests below, lakes caught the first rays of the rising Sun and threw them back into space.
Abandoning the two-dimensional sprawl of twentieth-century cities, Sri Lanka Tower, and others like it, had been erected in the world's rain forests and farmlands, leaving the countryside virtually uninhabited.
Even in Africa, where more than a hundred city arcologies had risen, nature was beginning to renew itself. It was a good day to be alive, she told herself, taking in the peace of the garden.
Then, looking east, she saw it coming -- at least her eyes began to register it -- but her optic nerves did not last long enough to transmit what the eyes had seen. It was quite small for what it could do -- small enough to fit into an average-sized living room -- but it was moving at 92 percent of light speed when it touched Earth's atmosphere.
A spear point of light appeared, so intense that the air below snapped away from it, creating a low-density tunnel through which the object descended. The walls of the tunnel were a plasma boundary layer, six and a half kilometers wide and more than deep -- the flaming spear that Virginia's eyes began to register -- with every square foot of its surface radiating a trillion watts, and still its destructive potential was but fractionally spent.
Thirty-three kilometers above the Indian Ocean, the point began to encounter too much air. It tunneled down only eight kilometers more, then stalled and detonated, less than two-thousandths of a second after crossing the orbits of Earth's nearest artificial satellites.
Virginia was more than three hundred kilometers away when the light burst toward her. Every nerve ending in her body began to record a strange, prickling sensation -- the sheer pressure of photons trying to push her backward.
No shadows were cast anywhere in the tower, so bright was the glare. It pierced walls, ceramic beams, notepads, and people -- four hundred thousand people. The maglev terminal connecting Sri Lanka Tower to London and Sydney, the waste treatment centers that sustained the lakes and farms, all the shops, theaters, and apartments liquefied instantly.Consider: a single light-year is an inconceivable abyss.
Denumerable but inconceivable. At an ordinary speed — say, a reasonable pace for a car in a megalopolitan traffic, two kilometers per minute — you would consume almost nine million years in crossing it.
Port Manteaux churns out silly new words when you feed it an idea or two. Enter a word (or two) above and you'll get back a bunch of portmanteaux created by jamming together words that are conceptually related to your inputs..
For example, enter "giraffe" and you'll get .
Port Manteaux churns out silly new words when you feed it an idea or two. Enter a word (or two) above and you'll get back a bunch of portmanteaux created by jamming together words that are conceptually related to your inputs.. For example, enter "giraffe" and you'll get .
The President of the European Academy of Sciences, Alain Tressaud and its Presidium invite you to the reception, organized on April 13th, , at a.m, to be held at the Fondation Universitaire in Brussels, for the occasion of the taking office of the new President Rodrigo Martins and the new Heads of Divisions and Officers.
absolute magnitude: the magnitude an object would have at the standard distance of 10 parsecs. absorption line: a more or less narrow range of wavelengths in a spectrum that is darker than neighboring wavelengths.
Absorption lines are seen in stars. angles: are measured in degrees or arcminutes. The photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles).The photon has zero rest mass and always moves at the speed of light within a vacuum..
Like all elementary particles, photons are currently best explained by quantum.