Airbrush

You can approach the black hole if you are going very, very fast, orbiting a safe distance outside the event horizon, and your clock will slow down. You cannot go inside the event horizon and then return to Earth.

The probability of death by gamma ray burst is very, very small. Smaller than asteroid hits, supervolcanos, and almost any other disaster you can think of. But, over the lifespan of Earth, there is a possibility that one deadly GRB hit the Earth sometime during the past 4.5 Billion years. But for most of that time, nobody would have noticed, except perhaps for some bacteria. "....Now it seems that gamma ray bursts may not pose as much a danger to Earth or any other potential life in the universe, either, since they are unlikely to occur where life would develop...." Thanks for the link Swansont. Interesting article. We are safer than I thought.

Exactly, it would seem to be nearly a point source, but how can they speak with confidence of the entire universe being smaller than an atom (or smaller than a proton) when we have no idea how large of an area of contact there was between the membranes? Beside that, the word "nothing" is useless in this context. How can anyone know anything about "nothing"? Nothing has never existed, nor will it ever exist.

Just this morning on the Science Channel (my favorite) a reputable scientist spoke of the universe coming from "nothing" and that the entire universe was smaller than an atom at the moment of the Big Bang. Considering membranes of higher dimensions coming into contact and causing a Big Bang, the idea of "nothing" seems absurd, and that the entire universe was originally smaller than an atom also seems absurd. If 2 membranes come together they probably do NOT make contact at only one point, but a region of indefinite size, perhaps a region larger than the observable universe.

Well then, that is how I mean it "in the most abstract sense". I appreciate your knowledge on this, which exceeds mine, but you cannot say galaxies in a cluster are not moving relative to each other. They move and yet they are bound by gravity. They are bound forever by gravity, unless they can throw a galaxy out. They "orbit" or jostle past each other, or tear each other apart, and collide, but they are always moving through a changing center of mass, otherwise they would fly apart.

Now it works, thanks. But I don't understand how that supports your theory. If you would care to explain?

Does anyone know why the US does not reprocess fuel?

Your theory sounds very absurd. Your link to where you found out about tiny black holes zipping thru the Earth doesn't work. Try it out.

Please explain how the massive amounts of long-lived radioactive waste can be recycled and used for power production. If that was possible, don't you think they would be doing it?

The "speed of gravity" equals the speed of light. From Wiki: "In the context of classical theories of gravitation, the speed of gravity is the speed at which changes in a gravitational field propagate. This is the speed at which a change in the distribution of energy and momentum of matter results in subsequent alteration, at a distance, of the gravitational field which it produces. In a more physically correct sense, the "speed of gravity" refers to the speed of a gravitational wave. "The speed of gravitational waves in the general theory of relativity is equal to the speed of light in vacuum, c.[1] Within the theory of special relativity, the constant c is not exclusively about light; instead it is the highest possible speed for any physical interaction in nature. Formally, c is a conversion factor for changing the unit of time to the unit of space.[2] This makes it the only speed which does not depend either on the motion of an observer or a source of light and/or gravity. Thus, the speed of "light" is also the speed of gravitational waves and any massless particle....." http://en.wikipedia.org/wiki/Speed_of_gravity

Galaxies are not too far apart to influence each other. You should take a look at what wiki says about "galaxy clusters". "....When observed visually, clusters appear to be collections of galaxies held together by mutual gravitational attraction. However, their velocities are too large for them to remain gravitationally bound by their mutual attractions, implying the presence of either an additional invisible mass component, or an additional attractive force besides gravity. X-ray studies have revealed the presence of large amounts of intergalactic gas known as the intracluster medium. This gas is very hot, between 107K and 108K, and hence emits X-rays in the form of bremsstrahlung and atomic line emission. The total mass of the gas is greater than that of the galaxies by roughly a factor of two. However this is still not enough mass to keep the galaxies in the cluster. Since this gas is in approximate hydrostatic equilibrium with the overall cluster gravitational field, the total mass distribution can be determined. It turns out the total mass deduced from this measurement is approximately six times larger than the mass of the galaxies or the hot gas. The missing component is known as dark matter and its nature is unknown." http://en.wikipedia.org/wiki/Galaxy_clusters

If a comet travels by Jupiter, it may get "speeded up" and sling-shot away at a tangent (the way Voyager did), but that does not heat up the molecules inside the comet. It may accelerate to a much higher speed, but it only gets more kinetic energy. It does not heat up at all.

So you suggest that because we cannot accurately predict the motion of several dozen galaxies in a cluster, they are not orbiting their ever-changing center of gravity? Does anybody here agree with Dr Rocket on this? It seems obvious that a cluster of galaxies remain bound by gravity. So they have to move relative to the cluster, and what other motion is possible, except for irregular orbits around their common center of mass.

All speed does is slow down the passage of time, not make someone go back in time. So time travel is not a matter of speed. It is a matter of manipulating space-time to either teleport to a distance beyond light speed, or time travel. I don't buy the grandfather paradox, because if somebody could go back in time, they would be in a parallel universe. He might encounter his grandfather at a young age, but killing his grandfather would not affect him at all, since he is from a parallel universe.

Wow JohnStu, you have 62 posts in about 2 days! How is that possible? "Force cannot be created out of nowhere." Maybe so, but "nowhere" does not exist, neither does "nothing" exist. There is something everywhere.

Yes, it is all just fantasy, but you still have not answered my question. How is time travel definitely not possible? Your explanation was because not everybody in the world is time traveling. How does that matter?

Very nicely illustrated D H. I wonder why there are exactly 4 images of the distant quasar? Are there always 4?

The clouds of dust in our galaxy conceal a narrow band of the universe from us, not "half of the universe". What makes you think galaxies are not orbiting the center of mass of the cluster in which they are located? Everything gravitationally bound is orbiting a center of mass. The only exception to this rule is on the scale of superclusters. Superclusters do not seem to be orbiting other superclusters, but rather flying apart at an accelerating rate.

So how does one person going back in time, and not the whole world, have anything to do with time travel? That is the whole idea, which is somebody (or a select few) going back in time, and hopefully returning to our time to tell about it. If it was possible it would remain on the "above-top-secret" list, and we would probably never know about it.

If they are here in hiding, then they have probably been here hundreds or thousands of years. It was a lot easier to establish bases and spy on humans thousands of years ago. They would have been studying our progress and had plenty of time to conceal themselves from our technology. If humans can spy on other humans successfully, then ETs would have much more technological advantage, and easly evade our best detection devices.

I like the idea above that in the distant future these waste may become useful or even valuable. There are many good caverns or mines that are geologically stable, and a safe place for long-term storage. It is just a matter of time before one is chosen, out of necessity.

Bury it in a subduction zone. Then it will eventually get returned to the mantle and destroyed.

Mr. Jiggerj, you should be more respectful of the moderators and experts who take their time to try to answer your questions. Swansont is right, and you are being more difficult than you can imagine. I am amazed at his patience. I am not an expert, only a novice enthusiast. Nobody here has ever suggested that empty space is "nothing". You even suppose scientists believe in an "Absolute Nothing". "Nothing" is a useless, undefined concept in science discussions. Empty space is seething with virtual particles popping in and out of existence, and that ain't nothin'. The big bang popped out of what? Absolute Nothing? Nobody has ever suggested that. Empty space may be full of dark energy, and dark whatever, and that is all we can say about it until something new can be detected. Until then your argument is philosophical speculation.

The early gasses had enough pull to form stars because it was dense enough in the early universe to clump in huge clouds. Within these huge-mega clumps, smaller even more dense regions clumped even more rotating about itself, and the more massive they became, and denser until the stars ignited. The remaining hydrogen scattered between galaxies is too rarified, only a few atoms per cubic meter, to come together. Solid matter is created when a massive star forms an iron core and goes supernova creating even heavier, solid elements.

Even earlier than the furthest galaxies we can see, before there were any galaxies, all the way out to the Cosmic Microwave Background, and beyond.