6 ms·

At first I thought he would be a quack, but his technical credential look legit. http://www.icarusinterstellar.org/team/harold-white/ http://www.icarusinterste

At first I thought he would be a quack, but his technical credential look legit. http://www.icarusinterstellar.org/team/harold-white/ http://www.icarusinterstellar.org/team/harold-white/ I just wish he would explain a little better why this was an allowable violation of relativity.

Tloewald 13y ago
I think the problem with the warp drive is topological. His drive relies on expanding space behind you and contracting it in front. OK. But what happens when you turn the drive off? Assuming all this squashing and stretching doesn't involve discontinuities, at best you're back where you're started from. At worst, you're in some kind of weird messed up crappy nook in spacetime where you're a long way from your starting point and your destination.
- zeckalpha 13y ago
  So it's more of an improbability drive?
  - themstheones 13y ago
    Yes, of the infinite variety.
    - Tloewald 13y ago
      Or infinitely ;-) But, hey, I'd love to be wrong.
- mistermcgruff 13y ago
  My understanding is that using a substance called "spice gas" you're able to enable this drive through a process called "folding."
  - textminer 13y ago
    HN-as-a-hivemind really should approve of this sort of snark. It's nerd-snark!
- mattstocum 13y ago
  I think that's why you still move the ship forward within the warp bubble (to borrow a Star Trek term). So you're compressing space in front of you, while moving forward into the compressed space.
  - Goosey 13y ago
    Right. In a sense it operates on the same principle as why the known universe is larger than it is old (as space-time continues to expand and light has further to go)
    - Tloewald 13y ago
      Except the universe hasn't shrunk.
- snowwrestler 13y ago
  > Assuming all this squashing and stretching doesn't involve discontinuities, at best you're back where you're started from. Are we sure space is perfectly elastic? What if space is infinitely plastic? Then when you turn the drive off, for all observable data you would be sitting in normal space just short of your destination.
- rdmcfee 13y ago
  Not so much. It's more analogous to surfing on a wave. Any object with mass warps spacetime towards itself. This doesn't cause an infinite buildup of 'spacetime' on the object's surface. There are concerns with built up energy in front of the spaceship but not being sent back to your origin.
DennisP 13y ago
It's the Alcubierre drive. First paper on the idea was published in 1994, and everybody seems to think it's legit according to relativity, though with large practical difficulties. http://en.wikipedia.org/wiki/Alcubierre_drive http://en.wikipedia.org/wiki/Alcubierre_drive
- Steuard 13y ago
  Large theoretical difficulties, too! To the best of my knowledge, nobody has ever been able to write down a complete mathematical description where an Alcubierre bubble "turns on" or "turns off": instead, the math always seems to describe a scenario where the warp bubble exists (and is inaccessible from the outside) into the infinite past and infinite future. Also, all versions of Alcubierre's model that I am familiar with require forms of matter and energy with properties completely different from anything ever observed (and different from most mainstream ideas for possible new types of matter and energy as well): namely, they require violations of various "energy conditions". http://en.wikipedia.org/wiki/Energy_condition http://en.wikipedia.org/wiki/Energy_condition The vast practical difficulties are in addition to the enormous theoretical challenges. I would absolutely love it if something like the Alcubierre drive could be made real, but there are multiple steps between here and there that would each deserve a Nobel prize. If I were White, I'd be talking about how I'd solved all of those problems (or any of them!) before jumping straight to trying to generate a warp bubble in the lab.
  - EthanHeilman 13y ago
    >If I were White, I'd be talking about how I'd solved all of those problems (or any of them!) before jumping straight to trying to generate a warp bubble in the lab. Why not try to generate a bubble, if it works great, otherwise try formalize it in greater detail. If warp bubbles are possible than it may be that they are already being created through random chance at the micro-level in the natural world.
    - VLM 13y ago
      "Why not try to generate a bubble," Missing the part from the paragraph about having no idea how to generate that condition, although if it existed in the past it would presumably be "sorta stable" in fact it would never be able to shut off as presently understood. A good analogy would be trying to talk to the original Lada Ada about silicon based computers without the folks of that era knowing enough solid state physics to contemplate whats going on in a simple transistor. "So if you could magically understand how to create a transistor, which won't happen for a century, then logically it follows that such and such array of those magic devices would make a great full adder circuit to add binary numbers"

Tloewald 13y ago

I think the problem with the warp drive is topological. His drive relies on expanding space behind you and contracting it in front. OK. But what happens when you turn the drive off? Assuming all this squashing and stretching doesn't involve discontinuities, at best you're back where you're started from. At worst, you're in some kind of weird messed up crappy nook in spacetime where you're a long way from your starting point and your destination.

zeckalpha 13y ago
So it's more of an improbability drive?
- themstheones 13y ago
  Yes, of the infinite variety.
  - Tloewald 13y ago
    Or infinitely ;-) But, hey, I'd love to be wrong.
mistermcgruff 13y ago
My understanding is that using a substance called "spice gas" you're able to enable this drive through a process called "folding."
- textminer 13y ago
  HN-as-a-hivemind really should approve of this sort of snark. It's nerd-snark!
mattstocum 13y ago
I think that's why you still move the ship forward within the warp bubble (to borrow a Star Trek term). So you're compressing space in front of you, while moving forward into the compressed space.
- Goosey 13y ago
  Right. In a sense it operates on the same principle as why the known universe is larger than it is old (as space-time continues to expand and light has further to go)
  - Tloewald 13y ago
    Except the universe hasn't shrunk.
snowwrestler 13y ago
> Assuming all this squashing and stretching doesn't involve discontinuities, at best you're back where you're started from. Are we sure space is perfectly elastic? What if space is infinitely plastic? Then when you turn the drive off, for all observable data you would be sitting in normal space just short of your destination.
rdmcfee 13y ago
Not so much. It's more analogous to surfing on a wave. Any object with mass warps spacetime towards itself. This doesn't cause an infinite buildup of 'spacetime' on the object's surface. There are concerns with built up energy in front of the spaceship but not being sent back to your origin.

DennisP 13y ago

It's the Alcubierre drive. First paper on the idea was published in 1994, and everybody seems to think it's legit according to relativity, though with large practical difficulties. http://en.wikipedia.org/wiki/Alcubierre_drive http://en.wikipedia.org/wiki/Alcubierre_drive

Steuard 13y ago
Large theoretical difficulties, too! To the best of my knowledge, nobody has ever been able to write down a complete mathematical description where an Alcubierre bubble "turns on" or "turns off": instead, the math always seems to describe a scenario where the warp bubble exists (and is inaccessible from the outside) into the infinite past and infinite future. Also, all versions of Alcubierre's model that I am familiar with require forms of matter and energy with properties completely different from anything ever observed (and different from most mainstream ideas for possible new types of matter and energy as well): namely, they require violations of various "energy conditions". http://en.wikipedia.org/wiki/Energy_condition http://en.wikipedia.org/wiki/Energy_condition The vast practical difficulties are in addition to the enormous theoretical challenges. I would absolutely love it if something like the Alcubierre drive could be made real, but there are multiple steps between here and there that would each deserve a Nobel prize. If I were White, I'd be talking about how I'd solved all of those problems (or any of them!) before jumping straight to trying to generate a warp bubble in the lab.
- EthanHeilman 13y ago
  >If I were White, I'd be talking about how I'd solved all of those problems (or any of them!) before jumping straight to trying to generate a warp bubble in the lab. Why not try to generate a bubble, if it works great, otherwise try formalize it in greater detail. If warp bubbles are possible than it may be that they are already being created through random chance at the micro-level in the natural world.
  - VLM 13y ago
    "Why not try to generate a bubble," Missing the part from the paragraph about having no idea how to generate that condition, although if it existed in the past it would presumably be "sorta stable" in fact it would never be able to shut off as presently understood. A good analogy would be trying to talk to the original Lada Ada about silicon based computers without the folks of that era knowing enough solid state physics to contemplate whats going on in a simple transistor. "So if you could magically understand how to create a transistor, which won't happen for a century, then logically it follows that such and such array of those magic devices would make a great full adder circuit to add binary numbers"