Time Travel Makes for Good Fiction, But is it Real?

[Chrissi]

Re: Time Travel Makes for Good Fiction, But is it Real?

Not the same. It takes potential energy in the fuel and turns it into kinetic energy. The energy changes forms, but doesn't get created or destroyed.

As for the fuel: it also changes forms. Cars might not have been the best example. Let's look at humans and eating. We eat food and digest it to take it's potential energy and turn it into energy we use to live. The food doesn't cease to exist however, it just changes forms. It goes from nice delicious food with potential energy to feces.

I'm still missing something here.

We all know that matter and energy cannot be created nor destroyed, but I was under the impression that matter can be converted to energy and vice versa.

I don't know if this is just me, but I don't feel like I excrete quite as much food as I take in..... is this an illusion? I would assume that some of it is being converted to energy, isn't it?

[RandomPscho]

Re: Time Travel Makes for Good Fiction, But is it Real?

We all know that matter and energy cannot be created nor destroyed, but I was under the impression that matter can be converted to energy and vice versa.

In very very small quantities.

Particle accelerators convert energy into subatomic particles, for example by colliding electrons and positrons. Some of the kinetic energy in the collision goes into creating new particles.

and...

I don't know if this is just me, but I don't feel like I excrete quite as much food as I take in..... is this an illusion? I would assume that some of it is being converted to energy, isn't it?

It has been a while since I last took biology, but I believe the energy is created by the breaking of the glucose through hydrolysis. I think it is just giving off its kinetic energy, though I'm not quite sure.

[Afrobean]

Re: Time Travel Makes for Good Fiction, But is it Real?

So wait.

They can create matter by colliding matter with antimatter?

How?

[RandomPscho]

Re: Time Travel Makes for Good Fiction, But is it Real?

It's not possible, however, to collect these newly created particles and assemble them into atoms, molecules and bigger (less microscopic) structures that we associate with 'matter' in our daily life. This is partly because in a technical sense, you cannot just create matter out of energy: there are various 'conservation laws' of electric charges, the number of leptons (electron-like particles) etc., which means that you can only create matter / anti-matter pairs out of energy. Anti-matter, however, has the unfortunate tendency to combine with matter and turn itself back into energy. Even though physicists have managed to safely trap a small amount of anti-matter using magnetic fields, this is not easy to do.

Also, Einstein's equation, Energy = Mass x the square of the velocity of light, tells you that it takes a huge amount of energy to create matter in this way. The big accelerator at Fermilab can be a significant drain on the electricity grid in and around the city of Chicago, and it has produced very little matter.

How? -- through a particle accelerator, when the particles collide.

[Afrobean]

Re: Time Travel Makes for Good Fiction, But is it Real?

I saw a special on Discovery or History channel or something like that, and unless I'm mistaken, they never mentioned CREATING matter OR energy.

Doesn't matter either way. Possible creation of matter through this means is irrelevant to the discussion at hand. It was only even brought up as an aside because someone erroniously said that black holes convert matter into energy. Black holes simply take in matter and combine it into it's singularity. If they converted matter to energy, they wouldn't have any mass... they'd be masses of energy. Also, I'm not COMPLETELY familiar with black holes, but I am quite sure that they DO have mass, as without it, they'd have no gravity.

[RandomPscho]

Re: Time Travel Makes for Good Fiction, But is it Real?

They are not creating matter and energy, they are changing forms of what is already existing. Is it better if I say that matter is the product of the collision?

[xinpig]

Re: Time Travel Makes for Good Fiction, But is it Real?

black holes are like garbage disposals they all lead somewhere but i cant find where it goes

[ninjja_]

Re: Time Travel Makes for Good Fiction, But is it Real?

black holes are like garbage disposals they all lead somewhere but i cant find where it goes

Black holes are areas in space with MASSIVE gravitational force, whatever, I don't know how to phrase things right now its like 11:16 in the morning and I just woke up. They are not like garbage disposals, more like landfills, you're dropped there and NEVER expected to be found again. Ight?

[Reach]

Re: Time Travel Makes for Good Fiction, But is it Real?

I saw a special on Discovery or History channel or something like that, and unless I'm mistaken, they never mentioned CREATING matter OR energy.

Doesn't matter either way. Possible creation of matter through this means is irrelevant to the discussion at hand. It was only even brought up as an aside because someone erroniously said that black holes convert matter into energy. Black holes simply take in matter and combine it into it's singularity. If they converted matter to energy, they wouldn't have any mass... they'd be masses of energy. Also, I'm not COMPLETELY familiar with black holes, but I am quite sure that they DO have mass, as without it, they'd have no gravity.

Black holes tend to take in matter and convert it to radiation, which is certainly energy, either in wave form or particle form.

Also, Black holes don't eat all of the matter to increase its size. As I said above, black holes give off a lot of radiation (about 50% is converted to radiation?).

Lastly, of course black holes have mass. The idea is that a singularity, given the solutions to GR, has an infinite density (but in reality, we arn't sure and it is probably just very large). Given D=m/v, where you have a lot of mass concentrated into an abnormally small volume.

[t0ni]

Re: Time Travel Makes for Good Fiction, But is it Real?

first, watch this, a clip from the discovery channel.
Pretty much I understand it, it's about the light!!!

http://youtube.com/watch?v=oRWwI61so5Q

[allflowerz]

Re: Time Travel Makes for Good Fiction, But is it Real?

Slautherhouse % made me believe it might be possible in a different way -the mind.

[lord_carbo]

Re: Time Travel Makes for Good Fiction, But is it Real?

Screw M-theory, let's go to Carbo-theory.

Time travel, ahahahahahaha.

That's to assume that time is actually a dimension and not just a way to measure and conceptualize duration, as Afro said.

And I'm very well aware of how Einstein's theories relate to spacetime, and I know a very brief overview of string theory from that Flash video. The 4th dimension is nothing to me; even if time shares a lot of properties with dimensions.

[monkeybomb45]

Re: Time Travel Makes for Good Fiction, But is it Real?

i figured out how to go back in time....sail west around the world (it would take like 3-4 months or something if you stop and look at all the tourist attractions around the globe) and when you got back to where you live, you would be one day behind!!....and you totally wouldnt know it! (international dateline) ^_^

[RandomPscho]

Re: Time Travel Makes for Good Fiction, But is it Real?

This is Critical Thinking.

And I'm very well aware of how Einstein's theories relate to spacetime, and I know a very brief overview of string theory from that Flash video. The 4th dimension is nothing to me; even if time shares a lot of properties with dimensions.

I need to check up on it, but most versions of the string theory contain 10 dimensions and time is considered the 4th. M-Theory is 11 dimensions.

[Afrobean]

Re: Time Travel Makes for Good Fiction, But is it Real?

first, watch this, a clip from the discovery channel.
Pretty much I understand it, it's about the light!!!

http://youtube.com/watch?v=oRWwI61so5Q

"You will disappear from sight as you travel into the past."

Since when was traveling faster than the speed of light a justifiable way to say that time would go backwards?

Also, according to that logic, hyper space is impossible, because as soon as you'd hit the speed of light, you'd go into the past. This is kind of stupid, because the concept he explains at the very beginning is pretty much exactly what hyper space is (or rather, how it works theoretically). Also: I'm not sure if hyper space is technically the right word for what I'm thinking of, or if that's just a term used in science fiction.

but most versions of the string theory contain 10 dimensions and time is considered the 4th.

Yeah. I don't really buy the whole lot of string theory. 4th dimension-- not time in my opinion, but rather a different thing. Time, as far as I'm concerned, is just something we decided on that allows us to keep appointments. Beyond that, I don't really get where the whole "strings vibrating in the 10th dimension MAKES THINGS HAPPEN". Where did they come up with that ****?