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Profile Allie in Vancouver
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Message 1299898 - Posted: 28 Oct 2012, 19:12:50 UTC - in response to Message 1299801.
Last modified: 28 Oct 2012, 19:13:19 UTC

I think I have a very good question, they claim the universe is 13.7 billion years old. But surly we aren't sitting right smack in the middle so how do they derive 13.7 vs maybe 27.4 or something older.

There's a few indicators that have made them come up with the 13-14 billion year old number.

Observation indicates that the universe is expanding. (Cue JG and his 'there ain't no such thing as red-shift' rant! ;0) ) If things are expanding then it follows that things were closer together in the past. Calculate backward in time and somewhere between 10 and 15 billion years ago everything would have been condensed to a point.

Assuming that science's best guess on stellar evolution is accurate (and I tend to think it is) then red dwarf stars can have very long lives. Some could last for hundreds of billions of years. Yet, we see no stars of any sort that are more than 10 – 12 billion years old.

There are some other reasons for the 13.4 billion year estimate but the reasoning is heavily mathematical, somewhat arcane and I'll let someone who is a better author that I am to explain.
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Message 1299991 - Posted: 28 Oct 2012, 23:06:41 UTC

Maybe the ultimate question is "Why is the speed of light fixed?" and then "What makes 186,000mps special?" Why not 200,000 mps?
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Message 1300177 - Posted: 29 Oct 2012, 11:12:22 UTC

Time has been shown to speed up within certain areas or spots where extraterrestrial crafts have been thought to have landed here on earth.

Evidence?

What is the definition of the length of a second?

As if you didn't know ....

Since 1967, the international second has been defined to be:

The duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

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Message 1300256 - Posted: 29 Oct 2012, 16:22:35 UTC

here's my problem with anything traveling close to the speed of light. weight or mass for a better term. Any object with any mass traveling at, near, or beyond light speed would have a distinct gravitational pull on objects it passes. More mass equals greater pull at light speed I see this as being dangerous. Since it potentially could pull asteroids, meteors, comets, and other space objects into different orbits. Or worse pull these objects in behind the light speed object. When the lightspeed object(assuming spaceship) slows it could have dozens if not hundreds of objects coming at it from thje rear
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Message 1300360 - Posted: 29 Oct 2012, 21:09:15 UTC

Time can be distorted as speed increases, as predicted by Einstein's theories. I can't recall the exact logic, because I never had to consider that particular corner of his work while doing my work at very low temperatures (77K = too hot, sub 4K = normal, even a few trips to sub 1K...) - you can have real fun with liquid helium and tomatoes, but that's a different story....
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Message 1300378 - Posted: 29 Oct 2012, 22:12:14 UTC

It is easier of you consider "time" as an n-dimensional plane than a linear object. By doing so you can have the time-plane distort without disturbing our geometric planes, or you can distort our geometric planes without affecting the time-plane. Once you've done this transformation you can start to think about exceeding the speed of light in our set of geometric planes, but without exceeding it in the time-plane. The maths is in the "quite exciting" club until you give up trying to work everything back to our view of geometry....


This reminds me of an old sci-fi book that started with the phrase "Time was proceeding at it usual rate of one second per second", and ended, two hundred odd (very odd) pages later with the phrase "Time was one more proceeding at its usual rate of one second per second".
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Message 1300467 - Posted: 30 Oct 2012, 6:44:26 UTC

but in the emptiness of space.. there is no 'mass' :P
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Message 1300490 - Posted: 30 Oct 2012, 10:19:50 UTC - in response to Message 1300467.

but in the emptiness of space.. there is no 'mass' :P

Even in empty space, there is about one hydrogen atom per size of a grape fruit, so not even space is completely void of mass. Years ago, I read of a possible earth based space craft that could theoretically obtain about 86% of the speed of light that would shaped like a huge scoop close to the size of the moon, that would scoop up those hydrogen atoms, and fuse them as a propulsion source that is self fueling. Of course that is not practicle, but theoretically possible.

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Message 1300527 - Posted: 30 Oct 2012, 13:26:38 UTC

There are various theories about "sling shots" around the sun to launch vehicles into interstellar sapce at near light speeds.

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Message 1300550 - Posted: 30 Oct 2012, 20:06:11 UTC

Mass is a "funny", it is the result of an interaction between gravity and particles, or an interaction between gravity and a wave. Now in which set of dimensions does this interaction occur? That entirely depends on the model you are using.




Can I take another aspirin now please - I'm getting a headache thinking about the prospects of distorting our geometric set of planes in the time domain in such a way that it becomes possible to move faster than light, but without increasing the mass of the object you are trying to move within the geometric/time set of planes....
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Message 1300568 - Posted: 30 Oct 2012, 20:52:42 UTC

If only we could trick physics into thinking that an object didn't have any mass, then faster than light speed would be possible.

wibble wibble

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Message 1300573 - Posted: 30 Oct 2012, 21:08:22 UTC

The problem isn't so much fooling physics as being able to manipulate the correct set of dimensions without upsetting our normal set of dimensions.
Our normal set of dimensions, the "geometric", "temporal time" and "gravity" relate to each other in a predicable manner, however there is a lot of theory around that indicates that this relationship is actually controlled by another set of dimensions, which, if we could manipulate them would allow us to change the relationship between say non-temporal-time and temporal-time in such a a way that we could proceed through temporal-time at say 0.001ts per nts, thus be able to approach light speed in our time domain...
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Message 1300606 - Posted: 31 Oct 2012, 0:15:00 UTC - in response to Message 1300490.

but in the emptiness of space.. there is no 'mass' :P

Even in empty space, there is about one hydrogen atom per size of a grape fruit, so not even space is completely void of mass. Years ago, I read of a possible earth based space craft that could theoretically obtain about 86% of the speed of light that would shaped like a huge scoop close to the size of the moon, that would scoop up those hydrogen atoms, and fuse them as a propulsion source that is self fueling. Of course that is not practicle, but theoretically possible.

Steve


You're the last person I'd ever want to argue physics with, Steve, but the Ram Scoop engine you are talking about wouldn't work at higher speeds. Scooping up those atoms robs momentum from the spaceship which is, presumably, gained back when you launch it out the back end. The faster your exhaust, the better, of course but it is hard to imagine a jet velocity of even half of the speed of light. (Just a few percent is more likely.) and attempting to go faster than the jet speed means that it costs more energy to scoop them up than you get out of them.

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Message 1300802 - Posted: 31 Oct 2012, 21:00:58 UTC - in response to Message 1300606.

but in the emptiness of space.. there is no 'mass' :P

Even in empty space, there is about one hydrogen atom per size of a grape fruit, so not even space is completely void of mass. Years ago, I read of a possible earth based space craft that could theoretically obtain about 86% of the speed of light that would shaped like a huge scoop close to the size of the moon, that would scoop up those hydrogen atoms, and fuse them as a propulsion source that is self fueling. Of course that is not practicle, but theoretically possible.

Steve


You're the last person I'd ever want to argue physics with, Steve, but the Ram Scoop engine you are talking about wouldn't work at higher speeds. Scooping up those atoms robs momentum from the spaceship which is, presumably, gained back when you launch it out the back end. The faster your exhaust, the better, of course but it is hard to imagine a jet velocity of even half of the speed of light. (Just a few percent is more likely.) and attempting to go faster than the jet speed means that it costs more energy to scoop them up than you get out of them.

Fair enough. It was based on a fusion reaction, and I just remembered reading about it many years ago, and haven't seen anything about it since. I am pleased you are familiar with it also. The other point is that there are free floating hydrogen atoms in "empty" space.

Steve
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Message 1300824 - Posted: 31 Oct 2012, 23:35:45 UTC
Last modified: 31 Oct 2012, 23:36:27 UTC

You could accelerate at one g for six months or so and achieve a fair percentage of the speed of light. The problem as I see it is to find an engine that can carry this much fuel especially since relativistic effects must be considered as to increased mass. I suspect that the only solution might be anti-matter annilation which would yield a near 100% mass conversion to energy.

I also suspect that this may be way off in the far far future if ever. If we found a habitable planet in the Proxima Centauri system than maybe we could go there some day.

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Message 1301012 - Posted: 1 Nov 2012, 16:45:57 UTC - in response to Message 1300802.
Last modified: 1 Nov 2012, 16:48:12 UTC


but in the emptiness of space.. there is no 'mass' :P

Even in empty space, there is about one hydrogen atom per size of a grape fruit


1 atom per grape fruit isnt a mass lol

if you point my belly and say 'thats a mass!!' that i understand ! and you're right!

but 1 atom per inch3 ?? we didnt even succeeded to invent a microscope to see that atom !
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