Meet the NASA scientist devising a starship warp drive
newscientist.com
newscientist.com
With that in mind, I continue to be puzzled by the amount of press that this story seems to receive.
Kind of like you can compress ammonia (a bit) and nothing terribly interesting happens, and you can cool ammonia gas (a bit) and nothing terribly interesting happens, but do both at the same time and you've invented liquid ammonia and refrigeration and all kinds of nifty stuff.
On the other hand energy/mass seems rather fundamental. There are no multiple "easily" negatable components you can play with mixing together. There's no "add a to b to get the mass" going on. So you can't get sneaky with combinations and initial conditions to magically make negative mass/energy. It's really a different kind of problem.
The whole topic is pretty interesting to me because the first metamaterial stuff was constructed out of printed circuit boards with weird etchings right around the ham radio microwave 6cm and 9cm bands, which is right up my alley (doing weird ham radio things involving PCBs and such around those frequencies) Unfortunately I have been unable to figure out any practical engineering demo (like, an antenna or a waveguide or some such) that would be ham radio applicable in a real world demonstration. I guess I could make a really weird lens and place it in front of a 6cm horn waveguide antenna, but I can make a much simpler microwave lens antenna using about 1940s tech. Lens antennas using plates of styrofoam and aluminum foil work pretty well at 10 GHz ham radio band for example, but I digress.
Metamaterials are kind of a solution in search of a problem right now, like lasers in 1960s or home computers in the 80s or whatever. Most likely, much like the examples, it would be pretty hard to predict today just how important they might be in the future. Or maybe we're seeing the next "magnetic bubble memory" or magnetic amplifier technology or fluidic analog computing or whatever. Hard to predict.
These conditions are widely believed to apply to all realistic matter configurations (to the extent that the less-restrictive ones get used as postulates in some theorems in relativity), though there are some exceptions due to quantum effects (which I believe are usually short-lived). Just for example, a cosmological constant or other dark energy source does not violate the null energy condition.
It would be really cool to see any of the energy conditions violated for an extended time in a lab! I'm pretty sure, though, that it has not yet been done.
That's getting near the boundaries of my technical knowledge of the subject, though, so I won't argue further. It would be awesome if this could work out, but as I've said elsewhere there are multiple Nobel-worthy steps between what we know today and actually creating any sort of warp bubble in the lab. If I were White, I'd be publishing my solutions to those first!
It's a term used to describe the "this doesn't make sense" part of the world. No one knows what it is, does, or if it exists.
Dark matter at least has some described properties (and no one knows if it exists either).
Let's make the supposition that a science idea has to meet some standard of plausibility in order to be publishable. The standard being applied to this is that it hasn't (yet) been categorically denied by any incontrovertible law of nature. Not much fails this test. If you postulate access to a source of negative energy or to the inside of a black hole, nothing is technically impossible.
The path is there, the end discoveries (relative to many other fields) relatively certain, we just don't like to make the effort in any concerted way, and our government is broken; Congress would prefer it if they could just run NASA on a soundstage.
This is why SpaceX's plans for substantially reusable launch vehicles is so exciting. They have a credible roadmap towards cutting launch costs by a factor of ten or more. We're in one of those situations where yes, we could spend more billions on space exploration right now, but there's a very real chance that if we maintain current space spending for just a few years those extra billions could buy us a huge amount more. I bet projects like the planned asteroid mining venture are watching SpaceX's technology development program with bated breath.
I just wish he would explain a little better why this was an allowable violation of relativity.
But, hey, I'd love to be wrong.
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.
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.
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.
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.
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"
Your link mentions that negative energy density has been observed at very small scale as a result of the Casimir effect. It's difficult to see how that could be scaled up, but I suspect that's what White is using here.
(wikipedia)
The thought experiment: imagine a billiard table with a wormhole which curves around and goes three seconds into the past. Roll a billiard ball into the wormhole such that it will emerge three seconds earlier and knock itself off the path, so it doesn't enter the wormhole.
Instead, the ball emerges along a slightly different path, striking itself merely a glancing blow that allows it to enter the wormhole.
And why did it emerge with an altered path? Because it was struck a glancing blow.
I can only imagine this kind of thing happening in a reversible, constant entropy system and a system without intentional processes.
For example, imagine a programmable drone. It is programmed to enter the singularity if and only if nothing seems to emerge and to then avoid collision with anything once it emerges - and transmit a signal announcing it's emergence to boot. Maybe you could do setup a fancy scenario for not winding up with two (or no) drones at the "end". But things not longer seem very plausible.
And you could probably arrange for a thing to carry entropy backwards if you had a varying entropy a system. But that's left as an "exercise for the reader".
Why does it do that? I get why the principle demands that it does and I get why it's a stable solution once it's been made to happen, but how did it actually make the jump from "straight on" to "at an angle"? Presumably not every self-consistent causal loop materializes itself out of thin air just because it would work if it did.
Edit: possibly lame example, but in Terminator 2, we find out that terminators were a secret government project that went awry. Where did they get the technology? Well, a terminator from the future came back and died in Terminator 1 and the parts it left behind allowed engineers to get a head start on building one. So there's a similarly self-consistent causal loop. But it doesn't really answer the question of how there came to be terminators.
The wiki entry I linked is intriguing. It says in some cases there are an infinite number of consistent solutions. They found they could analyze those cases with quantum mechanics, doing a sum-over-histories that only includes the consistent solutions. That gave a probability for each particular outcome.
So maybe that's fundamentally how causation actually works in the universe, and in the absence of time loops it reduces to normal causality. Now I can't help speculate whether actual quantum mechanics involves time loops somehow. (And in fact, Cramer's transactional interpretation does involve waves travelling backwards in time.)
Another way to look at it, maybe, and take with a grain of salt because I came up with it myself: Imagine there isn't just one timeline. In the paradox the universe runs an infinite loop, the ball first going into the wormhole, then not, then it does, then it doesn't. But given quantum mechanics, the position and momentum of the ball is uncertain. Given a very large number of trials, it's eventually going to shift significantly. At some point, it hits on a consistent solution, and the looping finally stops.
As I said, I suspect this is not how it would end up happening, as I remember reading somewhere some weird stuff about how the speed of photons hitting you was always the same regardless of your speed.. But that gets too weird for me to comprehend.
But you need a more complex setup. If the two stars are static (or the relative velocity is 0) then in both trips you arrive later than the departure time, so there is no easy to spot paradox.
But let's suppose that the Sun is static and the other star is moving very fast (with a speed <c). In the first part of the travel, form the Sun point of view you are traveling forward in time with a speed than is greater than c (in spite allegedly you are in a "bubble" so you locally are traveling wit a speed smaller than c. The bubble and everything that is in it is traveling with speed >c.). From the other moving star point of view you (or the bubble) are traveling backwards in time. You reach there and then they see you approaching there.
We can compare this to sound of a supersonic plane, where the plane arrives first and then the sound arrives, but if you do the calculations the sound was emitted before the plane arrival time. But if you travel fast enough and the star is moving fast enough then the effect is different, with the correct standard calculations the light arrives later than the space ship, but the light "was" emitted after the ship arrival time. From their point of view the space ship was traveling backwards in time.
Once you are there, you only have to recalibrate all the systems to use the other star reference frame. All the inertial reference frames are equivalent, so this is easy.
And now you start the engines and travel forward in time with a speed > c in the other star reference frame. They don't see anything too special, only that you go too fast but they are unable to tell you that. But form the Sun's point of view you are now traveling backwards in time, so you arrive before you departure the other star!
So, let's peek the Sun's reference frame. You travel first forward in time and then backwards in time. Is the sum positive? If the other star is static then the sum is always positive an there are no surprises. But if the other star moves fast enough then the sum is negative and you arrive before you departure.
If you don't find a fast enough star then you can use a fast space station or a fast space ship as the other extreme in your journey. Or even use an abstract point traveling fast enough in the middle of the space.
You leave for alpha centauri and arrive in .437 years, you immediately return and arrive back on earth in another .437 years.
A radio broadcast in that time has traveled .837 light years.
That's hot enough to fuse boron-11 with hydrogen. You end up with three helium nuclei and some x-rays.
There are several attempts underway, though the one I linked above is the cheapest and apparently the furthest along. I wrote up some descriptions with references here: http://www.climatecolab.org/web/guest/plans/-/plans/contestI...
After all, film and video games (and, of course, the TV series that came before) were the inspiration for this as well, no?
And with regard to film, alcohol, and drugs specifically - these can all be tools to gain a different perspective on reality, they're not necessarily mindless escapism.
Aside from the third case, I'd argue against drugs being a waste of time. Unless you abuse them, they can actually increase your quality of life.
http://www.ted.com/talks/jane_mcgonigal_the_game_that_can_gi...
The entire idea of a warp-drive comes from science fiction and people daydreaming/trying to escape their current reality. The Hyperloop is directly out of Heinlein. Subterranean cannons on the moon as a public transport device... Without escapism we lose the essence of human creativity, imagining a future that is different from the present. Do you think we would have bothered to build rockets and go to space/the moon if science fiction hadn't whetted the public's curiosity?
If anything, the problem is that current escapism kind of sucks and we need to do it better.
edit:lose/loose
...TV, YouTube, Hacker News, works of fiction...
HN is a good bit better for that than reality TV, but not all resource consumption is bad. This endeavor in particular smells of a fairly cheesy "waste of time" low-budget, low-brow television show.
If he's right, it would be at least, a step in the right direction....
"and in particular a ring around it that is key to its propulsion system — in a way that he believes will greatly reduce the energy requirements" http://www.nytimes.com/2013/07/23/science/faster-than-the-sp...
| In 2012, physicist Harold White and collaborators announced that modifying the geometry of exotic matter could reduce the mass–energy requirements for a macroscopic space ship from the equivalent of the planet Jupiter to that of the Voyager 1 spacecraft (~700 kg)[5] or less,[19] and stated their intent to perform small-scale experiments in constructing warp fields.[5] White proposed changing the shape of the warp bubble from a sphere to a doughnut shape.[20][21] Furthermore, if the intensity of the space warp can be oscillated over time, the energy required is reduced even more.[5] According to White, a modified Michelson-Morley interferometer could test the idea: one of the legs of the interferometer would appear to be a slightly different length when the test devices were energised.[19]
http://en.wikipedia.org/wiki/White%E2%80%93Juday_warp-field_...
[1] http://www.quora.com/Physics/Can-a-large-energy-field-other-...
[2] http://www.quora.com/Physics/Can-a-large-energy-field-other-...
The second seems to suggest that energy fields, in general, do warp space.
But all energy warps space, and has a gravitational field.