Whats the power required to get something the size of a bb to the speed of light?

[Pudgygiant]

E=M(~34596000000)

 

[sandorski]

This is all over my head, but you never know when something will be discovered that throws things on their ear. A component of light, some previously unnoticed energy or radiation, or some other thing that changes our perceptions and/or possibilities. The Atom was once thought to be the smallest thing in the Universe, but that changed and opened a whole new realm of possibilities. I'm not suggesting we will find anything, just that the possibility certainly exists, we don't understand everything yet.

 

[Kntx]

Since no one else has mentioned it yet I thought I would...

Why would you ever want to go faster than the speed of light???

If you were able to travel at the speed of light, or at some speed very close to it; from your point of view the travel time would be instantanious.

 

[RossGr]

Here is a thread at another forum which has some interesting numbers.

To reach .6c you would need a mass ratio of 2 (1 gram of fuel for every gram of payload.)

for .9c, a mass ratio of 4.259
.99c ---------------------- 14.1
.999c--------------------- 44.7
.9999c------------------- 141.4

In the next post, is the fuel requierments for a 3yr trip to Adronameda Galaxy

Thus you would need 1.6*1013 g of fuel per gram of payload to complete the trip, or just about the mass of Deimos for every 100 kg of payload ( including the empty mass of the ship itself).

I have not copied the math behind the numbers. Take a look at the thread to get that.

 

[Skyclad1uhm1]

Btw, you also have to accelerate all that fuel, so the requirements will grow fast.

 

[RossGr]

Originally posted by: Skyclad1uhm1
Btw, you also have to accelerate all that fuel, so the requirements will grow fast.

If you were to read the thread associated with those number you would know what has been considered.

 

[grant2]

Originally posted by: zhena
The speed of light in a (vacuum) is a constant in our universe. It doesn't matter what angle you view it from and it's not relative to anything.
Now what does that mean? Well take my car example. (Ignoring the obvious) if I say the cars were both traveling at say .75c you would say that the speed of one car relative to the other is 1.5c or faster than the speed of light. That?s not so, you can't use standard Newtonian Physics when it comes to this.

One object can?t go faster than the speed of light, even relatively compared to another object.

So let's say we have a car .75 light years north of the earth, and another .75 light years south of the earth. let's say for our example, the earth is stationary.

So both cars drive towards the earth @ .75c, so they arrive in 1 year. But you're saying that's impossible, because it would mean their relative speed to each other was 1.5c??

 

[RossGr]

Originally posted by: grant2

Originally posted by: zhena
The speed of light in a (vacuum) is a constant in our universe. It doesn't matter what angle you view it from and it's not relative to anything.
Now what does that mean? Well take my car example. (Ignoring the obvious) if I say the cars were both traveling at say .75c you would say that the speed of one car relative to the other is 1.5c or faster than the speed of light. That?s not so, you can't use standard Newtonian Physics when it comes to this.

One object can?t go faster than the speed of light, even relatively compared to another object.

So let's say we have a car .75 light years north of the earth, and another .75 light years south of the earth. let's say for our example, the earth is stationary.

So both cars drive towards the earth @ .75c, so they arrive in 1 year. But you're saying that's impossible, because it would mean their relative speed to each other was 1.5c??

No, that is not correct. You are in the postion of a third opserver measureing two independent velocitys. Speical Relativity places no restriction on that. If an observer in one car were to measure the velocity of 2nd car the result would be less then c.

 

[zhena]

So let's say we have a car .75 light years north of the earth, and another .75 light years south of the earth. let's say for our example, the earth is stationary.

So both cars drive towards the earth @ .75c, so they arrive in 1 year. But you're saying that's impossible, because it would mean their relative speed to each other was 1.5c??

grant2 the problem is you can't ask a question like that, because it doesn't make sense (once again with regard to high speeds)

from whos point of view are you talking about? There is no such thing as traveling with speed in an empty space. motion is relative to something. if an object travels with some speed it means its traveling with speed X per some unit of time T relative to something. T changed depending on your point of view.
so if you we're to assume a closed system of 3 things, earth being the center of the universe--a stationary object.

if you were in either one of those cars, to you it would seem maybe like a minute till you reached EARTH.

if you were on EARTH then I suppose it would seem like the two cars would arrived at the same time, and if we were to say that EARTH is the absolute center, thus its an actual stationary object I suppose you could say that it would take a year from your point of view for the cars to arrive.

This means that the cars with respect to you are traveling at .75c but does NOT imply that they are traveling at 1.5c with respect to each other.

---------
i just came back from hanging out at a bar with a group of friends... and as i just read everything i typed seems like i am totally wrong somewhere..
somebody feel free to correct me

 

[f95toli]

The threory behind all of this is actully quite easy, no complex math at all. The trick is to realize that you can not really understand it because the consquences of the theory is so "strange" that we cannot use our "everyday-intuition".
The only thing you can do is to accept the theory and try to learn how to use it.
I should also mention that the teory of relativity is pretty "normal" compared to some things of quantum mechanics, I was close to a mental breakdown a few times when I tried to "understand" things like the Schrödingers cat, after a while you simply get used to the thing.

.

 

[User1001]

Now I have tons of things to look forward to once I take Physics.

 

[yhelothar]

who said fuel would always be the way used to accelerate?
there are tons of ways to accelerate than fuel.
One interesting way I've seen was from howstuffworks.com, scientists have used light to propel a small object. It beams several lasers onto a parabolic mirror, and all the lasers focus at one point, causing the air to heat up so much that it explodes, propelling an object.
Working prototypes have already been made, so this is no theory.

There was a good article on interstellar space travel on the 2/03 issue of Sky & Telescope magazine. They proposed that if we can accelerate at 1g(9.8m/s which will give us the same gravity as earth), we would be able to reach 0.8c within a year. This would allow enough time dialation for us to easily reach an 8 lightyears star in 4years, or a 6000 lightyears nebula in 17 years.

 

[AbsolutDealage]

Originally posted by: virtualgames0
who said fuel would always be the way used to accelerate?
there are tons of ways to accelerate than fuel.
One interesting way I've seen was from howstuffworks.com, scientists have used light to propel a small object. It beams several lasers onto a parabolic mirror, and all the lasers focus at one point, causing the air to heat up so much that it explodes, propelling an object.
Working prototypes have already been made, so this is no theory.

There was a good article on interstellar space travel on the 2/03 issue of Sky & Telescope magazine. They proposed that if we can accelerate at 1g(9.8m/s which will give us the same gravity as earth), we would be able to reach 0.8c within a year. This would allow enough time dialation for us to easily reach an 8 lightyears star in 4years, or a 6000 lightyears nebula in 17 years.

Wow, nice to know that space is now filled with air. That should make things much easier.

The point is that you will always have to expel something in order for there to be thrust. Expulsion of matter = loss of mass... that spent mass is your fuel regardless of what it is. (And I know that space is not in fact a vacuum, but any mass that exists is negligable from a propulsion standpoint).

 

[silverpig]

Originally posted by: AbsolutDealage

Originally posted by: virtualgames0
who said fuel would always be the way used to accelerate?
there are tons of ways to accelerate than fuel.
One interesting way I've seen was from howstuffworks.com, scientists have used light to propel a small object. It beams several lasers onto a parabolic mirror, and all the lasers focus at one point, causing the air to heat up so much that it explodes, propelling an object.
Working prototypes have already been made, so this is no theory.

There was a good article on interstellar space travel on the 2/03 issue of Sky & Telescope magazine. They proposed that if we can accelerate at 1g(9.8m/s which will give us the same gravity as earth), we would be able to reach 0.8c within a year. This would allow enough time dialation for us to easily reach an 8 lightyears star in 4years, or a 6000 lightyears nebula in 17 years.

Wow, nice to know that space is now filled with air. That should make things much easier.

The point is that you will always have to expel something in order for there to be thrust. Expulsion of matter = loss of mass... that spent mass is your fuel regardless of what it is. (And I know that space is not in fact a vacuum, but any mass that exists is negligable from a propulsion standpoint).

Uh, no you don't. Do sailboats expel anything?

Work is being done on building a solar sail spacecraft which will use photon pressure from the sun for propulsion.

 

[PolymerTim]

I've heard lots of good things about the solar sail research, but I do wonder about its limitations. I think current research would just be happy to use it in our solar system, but outside of the solar system, I don't think there would be enough light to provide the kind of acceleration need to get to another solar system. It's sounds like a great way to get to Neptune, though.

 

[RossGr]

It does not matter how you accelerate your ship, wether it be with a laser pointingout the back of your ship. Or a laser pointing at a sail, the energy requirement will be unchanged. The only question is in how effeciently can you convert your fuel to motion. The laser will require energy (fuel) to power it wether it be space based or land based.

I once attended a lecture were the prof (Dr. Larry Schecter) derive all the critical rocket equations and planed a reasonable trip with a reasonable payload to nearby star. Even assuming perfect mass to energy of motion conversion the mass of fuel required was approximatly that of the solar system. In other words one would need to convert the entire solar system to pure energy in order to complete the trip.

The numbers I linked to seem to bear this out. If 100kgs payload requiers the mass of a small moon it would not be hard to imagaine a ship that required a solar system mass equivelent fuel.

 

[PolymerTim]

Those numbers kind of confirm my thoughts on the use of solar sails. The nice thing about use of solar sails is that you don't have to carry the fuel with you, but even with this great reduction in total payload weight, I think you'd realistically be limited to the solar system. But that's great news if we want to visit the moons of Jupiter in the next 100 years. Maybe someone could do the calculations on the energy required to move a 100kg ship from earth to Jupiter in a reasonable amount of time. Of course as someone pointed out I think you'd still have to have your own fuel to stop and then forget about a return trip. Unless solar sails can work in reverse or be used to turn in a reasonable radius (I don't think they can). So OK, how about a 100kg unmanned probe + fuel to stop. How much energy would that take, and how does that compare to the typical concentrations of energy from the sun between earth and Jupiter. IT seems to me that you could figure out how big the sails would have to be (assuming 100% conversion into kinetic energy) to accomplish the trip in a reasonable amount of time.

 

[capybara]

Originally posted by: virtualgames0

There was a good article on interstellar space travel on the 2/03 issue of Sky & Telescope magazine. They proposed that if we can accelerate at 1g(9.8m/s which will give us the same gravity as earth), we would be able to reach 0.8c within a year. This would allow enough time dialation for us to easily reach an 8 lightyears star in 4years, or a 6000 lightyears nebula in 17 years.

no, this assumes constant acceleration at speeds above c, and its NOT a fact that you can exceed c

 

[f95toli]

Capybara: I think he meant that you can travel 6000 lightyears in 17 years relativte to the time on the ship, it would still take more than 6000 years relative to the people left on earth.

 

[sillymofo]

Actually, as I read on, I think we all figured out something. Even if you can achieve light speed traveling, it still won't get you any where, as far as the universe is concerned. We have already possess something that can travel faster than any physical means out there, the only problem is if we'd ever figure out how to use them properly.... our thoughts! We can pretty much get our thoughts to any destination in nano seconds, as long as we know the destination, just figure out a way to get our body follow... hmmm... tough. Since we're on the subject of possibilities, why not forget physics altogether and explore other means?

 

[moomoo40moo]

I read somewhere (I think Popular Mechanics) that earlier this century, some guy had plans to build a space ship that would travel the speed of light. I think it said that the space ship would like shrink the space in front of the ship, and expand it in the rear of the ship, propelling it to the speed of light. Only problem they had was that the ship's fuel had to consist of like 1 gram (i think) of negative energy, for this to happen. But I guess there is not enough of this "negative" energy in the universe. So, idk. Just my 2 pennies.