Posted on 01/17/2014 7:17:49 AM PST by 12th_Monkey
Interstellar flight certainly ranks among the most daunting challenges ever postulated by human civilization. The distances to even the closest stars are so stupendous that constructing even a scale model of interstellar distance is impractical. For instance, if on such a model the separation of the Earth and sun is 1 inch (2.5 centimeters), the nearest star to our solar system (Proxima Centauri) would be 4.3 miles (6.9 kilometers) away!
The fastest object ever built by the human species is the Voyager 1 space probe, moving at a speed of 18 miles per second. If it were heading toward Proxima Centauri (which it’s not), Voyager 1 would reach our nearest stellar neighbor in about 80,000 years.
Clearly, if interstellar travel is to be accomplished on human timescales, much greater speeds are required. At 10 percent of the speed of light (a thousand times faster than Voyager 1, but a conceivable speed for likely soon-to-be-realized fusion engines), Proxima Centuri could be reached in approximately 45 years — less than a human lifetime.
However, the necessary energies to achieve substantial fractions of the speed of light, thus cutting the travel time to the stars to less than a human lifetime, are equally mind-boggling.
Every pound of starship moving at 99.9 percent the speed of light will have a kinetic energy more than three times greater than the energy of the largest nuclear weapon ever detonated. Nevertheless, there may be a way of supplying an engine with such prodigious energies.
In his 1955 paper Geons, John Wheeler, one of the pioneers of the theory of black holes, coined the term "Kugelblitz" — which translates literally to "ball lightning." He suggested that if enough pure energy could be focused into a region of space, that energy would form a microscopic black hole,
(Excerpt) Read more at space.com ...
No observer could ever watch because the light illuminating the event would be trapped by the black hole.
Yes.
2) If the tube were not oriented vertically, but rather parallel to (i.e., in line with) the direction of motion of OA, thus undergoing apparent shortening in length (as per the Lorentz Transformation) as viewed by OB, then they couldn't agree on the length of the tube either, could they?
I believe that's correct. But consider this: if the light tube/clock were positioned horizontally, and the platform it was on was moving at precisely light speed (c), the light pulse would NEVER arrive at the other end of the tube. A "second" would drag out to infinity, as seen from the outside observer's point of view. Time would have come to a halt from that outside perspective. Of course, in theory at least, nothing can ever be accelerated to light speed, as it would require an infinite amount of energy to do it, but the effect does become more and more apparent at speeds approaching light.
[I’ve not heard that before. Interesting. How does a micro black hole evaporate? I thought once a black hole formed, matter falling into ti would sustain it and perhaps cause it to grow?]
That only works in large black holes that have enough gravitational attraction to bring things to the core of it.
You have remember the event horizon of the black is the “effective size” of it where the singularity is where all the matter that falls into it must end up.
For a microscopic black hole the event horizon is actually about the size of a single atom...
remember matter is porous ...
trying to hit one atom with another it really hard and you have to feed the micro black hole matter constantly otherwise it will evaporate.
A micro black would have to be literally shot into a place with extremely high matter density to be able to absorb enough matter to sustain itself... perhaps the inside of a star where matter density is very high...
A micro black hole in space passing through earth would simply pass through it, the only affect would be the radiation output around it as it slowly evaporates...
My high school physics teacher used the train example to explain relativistic time dilation back in the 1970s. 40 years later relativity still gives me a headache.
Let’s use the old twins example. One twin stays home in mission control and the other twin leaves on a rocket going at close to the speed of light. The twin on the rocket ages at a slower rate. When he arrives at Alpha Centauri he will be younger than his twin back on Earth.
Here is where I get lost. Speed and motion are entirely relative and not absolute. To the twin on the rocket, the twin on Earth is moving at close to the speed of light and the twin on the rocket is stationary. Why doesn’t the twin on Earth age at a slower rate relative to the twin on the rocket?
To really complicate things, use triplets with two going off in rockets in opposite directions from Earth each moving at just under the speed of light. To the brother on Earth, each of his brothers is moving away at the speed of light. To the brothers in the rockets, the brother on earth is moving away at the speed of light. What about the brother in the other rocket? He cannot move away at a relative speed of greater than the speed of light. So what speed are the brothers in the rockets moving relative to each other?
Like I said, relativity gives me a headache.
If I may ask, is this a particular field of study for you?
Doesn’t matter what it wants to be called,
the new name will become offensive
because it will come to mean “black hole” anyway.
Yes, that is true. You can even say that it hadn't even moved, since its travel distance would have contracted to zero by virtue of its traveling at light speed. Weird stuff, and just the tip of the cosmological iceberg.
in front of the said object traveling near light????
Yes. Think of the distance yet to travel as a unit of distance approaching the high-speed spaceship. The theory says that moving clocks tick out time more slowly and that moving units of distance are contracted.
Whatever you do, don't call it "black" in Spanish.
Breaking that name down in German, we have
Black Child Ball of Candy Attack
The "relative" nature of it collapses when the traveling twin returns to the same reference frame of the earth bound one. And to change ones inertia state of motion (constant speed, constant direction), an outside force must be applied. In other words, for these effects to become permanent energy must be applied. A lot of it. In order for the traveling twin to have stopped, he had to have applied a force, exerted energy. Once acceleration (or deceleration) enter into it, the relative aspects of it go away.
Bump for later comments. Some sci-fi authors have already used this but I can’t remember if it was Larry Niven, Greg Bear or Gregory Benford. Possibly somebody else.
A popular picture for understanding this idea is provided by a thought experiment consisting of one observer midway inside a speeding traincar and another observer standing on a platform as the train moves past. It is similar to thought experiments suggested by Daniel Frost Comstock in 1910[1] and Einstein in 1917.[2][3]
A flash of light is given off at the center of the traincar just as the two observers pass each other. The observer on board the train sees the front and back of the traincar at fixed distances from the source of light and as such, according to this observer, the light will reach the front and back of the traincar at the same time.
The observer standing on the platform, on the other hand, sees the rear of the traincar moving (catching up) toward the point at which the flash was given off and the front of the traincar moving away from it. As the speed of light is finite and the same in all directions for all observers, the light headed for the back of the train will have less distance to cover than the light headed for the front. Thus, the flashes of light will strike the ends of the traincar at different times.
The train-and-platform experiment from the reference frame of an observer on board the train
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Sorry, that previous one came from here:
http://en.wikipedia.org/wiki/Relativity_of_simultaneity#The_train-and-platform_thought_experiment
—translates literally to “ball lightning.” —
There are reports of Tesla “playing” with ball lightning which he created in his lab. I believe unduplicated to this day.
That’s an effect due to extreme differences in gravity, between the head of the object and the tail of the object. It’s a different phenomenon from length contraction, which is simply a consequence of any motion.
Yes, that is correct. If a photon had consciousness, it would perceive the travel to occur instantaneously. We, as outside observers, would still see that it took a fixed amount of time to travel the distance, though.
Suppose you build one of these things. After you get some Unobtanium to build the Dyson Cap, of course. You accelerate to 72% of the speed of light in five years. And, then the power source thingy, having used up all it’s energy, ‘evaporates’. Then a few years later, you get where you want to be. How do you stop?
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