suprabeast

the thing about travelling through the universe is that if you apply a force, a ship can travel at a great speed due to the lack of any resistances pulling it back , therefore you can greatly increase a ships speed by applying an impulse..... so once that impulse has been applied, the ship will move at a constant velocoty due to the fact that there is nothing more accelerating it and nothing decelerating it.

So now someone comes along and pushes it a bit more, so it will accelerate faster with still nothing to slow it down. so eventually you could approach light speed then a finger push on the back of the ship could just push it over that level

OllyK

When you've finsihed reading up about it on wikipedia

Iain Young

Very true. That's how the recent lunar orbiter was launched. It's actually powered by an ion drive. Very little in the way of thrust, but it's cumulative and so although it took a long time to get there, it managed to escape the earths gravity / orbit with very little fuel etc.

So, we wouldn't need an huge ship to put my plan into action, just a very long time

OllyK

That makes the assumption that "space" is empty - it isn't. There have been proposals to make ships with big sails that catch the particles that are whizzing about out there - ride on "the solar wind" of photons from the sun as it were

Iain Young

The fact is that nobody knows exactly what dark matter (or energy) actually is. It's just that the behaviour of the various objects in the universe cannot be explained using the current laws of physics unless there is a large amount of mass / energy present which we currently cannot see and know nothing about...

It's all theoretical at this point...

OllyK

I ought to start every post with "I know nothing but..."

The way I understood was that dark matter can't be detected by usual means, i.e. directly, but its existence can be inferred by gravitational effects on things that can be observed. I.e. something is causing an anomolous observation and whatever it is that's causing it has been labelled dark matter. Or have I got it AAF?

suprabeast

maybe its just a following from the point that you cant create something from nothing, therefore if you create matter and and equal amount of antimatter then effectively you still have nothing because when you put the 2 together , you are back to zero.

suprabeast

maybe not around here, but if you got the edges of the universe it would be pretty damn empty i would have thought?

Iain Young

You shouldn't mix matter and anti-matter though. Might make a rather large bang (have you never watched star trek? )

You've got it about right Olly. Dark matter / energy cannot be detected directly using convention means, but instead its presence is inferred by observing its effect on other things.

Much in the same way as they are discovering planets around other stars. They are not seeing them directly, but are determining their presence by watching the wobble of the parent star!!

Jap2Scrap

There are edges?

suprabeast

well there must be a point like a wave where the universe moves outwards.

OllyK

OK, so you have to get to the edge of the universe, that is moving away from you at near light speed, to test if you can make your new ship travel at better than light speed. I think you are going to be rather old by the time you get to your test zone!!

AFAIK, radiation and other particles are coming back towards us from the edge of space which is, in part, how we know how old the universe is. So I don't think that theory floats either.

Again I may be wrong here, but if you apply a force to something that causes it to accelerate and there is nothing to impede it, it should continue to increase in velocity (at the rate of acceleration applied) without the need for any further input of energy.

OllyK

Do we know that? Or is that just comfort thinking trying to make the universe behave in terms we understand (the balloon in a room analogy). I don't know either way.

suprabeast

well if it is expanding then there must be space here now that wasnt here yesterday and more space here tomorrow that aint here today.... somewhere there must be a line where new space appears

suprabeast

the force needs to be constant for the object to continue accelerating hence why i used the word impulse.

ok so there maybe a small restrictive force like radiation pushing back the object, so you just need a force large enough to over come that.

Iain Young

Unless it is exapanding into a space that is already there. If that space is infinite, then the universe can continue to expand infinitely. No edges needed...

Edcase

Perhaps that is just radiating into our universe from other universes?

suprabeast

but then if the space is already there, the universe is still at a position that it wasnt yesterday therefore there must be a line to join the points ... your theory is the same as a balloon.... it gets bigger into space that is already there, but it still has an edge

OllyK

I have no idea, it sounds plausible, but I don't know how the expansion of the universe works. I do know that so many of the general rules and concepts fall apart at the extremes which is why I was questioning it.

Iain Young

The universe (or the balloon) has an edge, but the area it is expanding into is infinitely large and so doesn't have an edge.

suprabeast

oh i see your point, my point was concerned with getting to the edge of our universe as we know it, ie the balloon, not the edge of the infinitely large area outside of which there are no edges!

OllyK

Ahhh, damn my physics is getting rusty.

And I think under newtonian physics you'd be fine, the problems come at speeds close to the speed of light (as I understand it) when it all falls apart, relativistic physics comes in to play and you need to have 0 mass to get to light speed. I need to do some more reading!

OllyK

That's going to cause some real headaches in the physics labs if that is found to be the case

Iain Young

Mine too

If I remember correctly, in theory you also need an infinite amount of energy to get to the speed of light as well, (might be thinking of something else though)....

suprabeast

well its all theoretical but for the equation to work, you need an approaching zero mass and infinite energy for the equation to give a finite answer

Edcase

Perhaps its from the lamp lighting the petri dish?????

GRANT

A couple of point.
Dark matter has another name that is Higgs Field which is modern explanation for
what used to be called Ether.
This was use to describe the emptyness of space.In recent years there has been a lot of reseach into the TOE ( Thoery of everything) which tries to match the laws of Thermodynamics (2nd Law) and Quantum mechanics and General Relativity
That is the realtionship between the very small and the very large.
This led to a new chain of thought called String Theory and later Superstring Theory.
The BB itself raises a few problems in relation to the speed of light and dispersment of heat.Scientist have found that the temperature through the Universe is very evenly spread.But how can this be so if the BB started from one point.
If the dispersing universe moved at the speed of light then the temparature would reduce the further away you moved from the point of origin.

I can recommend a series of books by Michael Green and Richard Feynman

TonyG

Only if you have mass - Relativistic mechanics shows that the faster you go, the more massive you get. THe bigger the mass, the larger the force needed to push it along at a constant acceleration.

MattPiece

The balloon theory is used to describe how galaxies, etc. are spreading away from each other within the Universe, not actually how the Universe is expanding itself into space.

TonyG

Oh, the other thing - the three spacecraft all travelling at the speed of light inside each other? From which point are you observing them? I know it sounds paradoxical, but they would all be travelling at SOL. Relativity again. It's to do with length contraction and time dilation. I'm desperately trying to remember the details here...