Are warp drives science now?

Today we'll talk about one of my favorite topics, warp drives. I am fascinated by warp drives because they are future technology straight out of science fiction and yet they are not for any obvious reason impossible. After all, Einstein taught us that space can indeed deform and that distances can indeed shrink and that time can indeed dilate. So why not bend and deform space-time to get us faster from one place to another?

Well, the devil is in the details. While warp drives have been studied in Einstein's theory of general relativity, they require unphysical stuff: negative energies, repulsive gravity, or things that move faster than light already. In this video, I summarize what new scientific literature has been published on this in the past year, and what progress has been made.

The Alcubierre drive paper is here:

And that about the Natario class here:

The paper from White et al is here:

Kudos to Gianni Martire and Matt Visser for helping with this video.

0:00 Intro
0:42 What's a warp drive?
2:15 Weird stuff that warp drives need
4:14 The new warp drive solutions
6:00 Criticism on the new solutions
8:40 Did someone actually build a warp drive?
9:34 What does this all mean?
10:41 Sponsor message

#physics #space #science

[JamesSmith-uiiu]

I hope people watching Dr. Hossenfelder's video realize how much work is going into these. She is literally posting every week a scientific review video about a different topic. Reading, understanding all these papers is one thing but condensing and summarizing them all into junks "regular" people can comprehend is a totally different animal. Plus making a video of it and presenting it. I believe this is equally impressive as a working warp drive!.

[wardsr]

Being a "public" physicist requires a thick skin. Physicists can be a cantankerous bunch. I am very grateful for Sabine's courage being out here explaining current work so that I can get a true picture of what's what. Thank you Sabine! I hope that this is lucrative enough to keep you on this path.

[billwesley]

what I love about these talks is she times everything just perfectly, no down time at all, not a sense of hurry ether, but it is dense with information, you have to pay unbroken attention or you'll fall off the train of thought. She does not dumb it down, she smartens presentations up.

[oneworldonehome]

"Do not look to the stars as an escape from life. Do not look at the prospect of space travel as a wonderful adventure into uncharted and uninhabited regions. Do not think that you can go anywhere you want and that you will develop over time a technology for traveling quickly through all the dimensions of life, zipping around the universe as if it were your own neighborhood. Do not think your conveyances will take you anywhere you want in the blink of an eye. Such notions are to be expected from young races full of imagination and hopeful expectation. But they do not fit into the reality of life as it has evolved over a much longer period of time."

A quote from *Life in the Universe* - Chapter 3: The Limits of Space Travel, by Marshall Vian Summers.
I warmly recommend checking out this great book, it's not only awesome but also free online.

[En_theo]

"on short distances, the Casimir effect (...) has energy densities that are effectively negative". I would definitely appreciate a video on that particular point, since I have always been told that negative energy does not exist.

[jeffburrell]

I always smile when you say "Yes, that guy again."
On a serious note, a decade or so ago I got fed up with announcements of "discoveries" of things that were predicated on computer simulations rather than actually building something. I have nothing against computer simulations, but simulations are only as good as our ability to accurately model something and on the inputs given the simulation. I will continue to yawn a bit and say "that's nice" until something actually appears in matter and energy that does what a given simulation predicts.

[theraven]

Even a sub-luminal warp drive would still be revolutionary as it might effectively bring the entire solar system within relatively easy reach of humans. Perhaps it could shorten the travel time to Mars from six months to, say, two weeks and Neptune to a few months instead of years. Opening the solar system to exploration would be truly a new epoch for humanity. Forget Star Trek, give me The Expanse.

[CAThompson]

Hah, I was literally waiting for Sabine to say or write something about the baby warp bubble since it popped up in the media.
This video is more than I expected and has made me rather happy, thanks to Sabine and her team. :D

[joshieecs]

even having a "slow" reactionless drive would be revolutionary for space travel.

[andytroo]

re: warp drives ; are not these solutions static? - there is another 2 aspects to their physicality - how do you actually create them, and 2, if the matter to make them is outside the central field, how do you move them around?
the v<c solutions give you a chance for this, but to me it seems that in all of these solutions you need hugely more mass than the ship, surrounding and moving with the ship. This doesn't help with the 'how do you make it go fast' problem, unless the time dilation effect on the center becomes relevant.

[autolyticus]

You know it's going to be a good one when it mentions Albert "That guy again" Einstein within the first 30 seconds

[JackAdrianZappa]

I'm curious. Why is there the need for expanding the space behind? If you are capable of compressing the space in front using some mechanism other than having a physical mass in front (which I'm assuming would be needed for any type of warp drive anyway), why not just make a gravity engine which would pull the ship forward? What's the purpose of expanding the space behind? Symmetry? Energy transposition? What?

I'm assuming that a gravity drive would be a v<c warp drive, but if manipulation of the space time fabric is possible, this would be a significant achievement as stuff wouldn't have to be thrown out the back all the time to provide acceleration.

[Shamazya]

I appreciate how even though faster than light travel might not be possible Sabine points out that approaching light speed is still a game changer.

[DisFuntastic]

I really love your video's Sabine! The quality of the content, the dry witty humor you sprinkle over your video's! Thank you for your work teaching your viewers while at the same time entertaining them in such a great way.

[samuelfisher]

8:35 "If we could at least travel with nearly the speed of light, that would already be great progress."
Understatement of the century.

[martiningram]

Thank you Sabine, I'm very grateful for these videos. I'm so happy you cut through the hype, especially because this stuff is (in my opinion) exciting enough without exaggerations. This video was entertaining and clear, and I'm looking forward to watching more.

[enriquegarciacota]

Hi Sabine! Thanks for this one, I hope your back pain got better

[AnMuiren]

Great job making this speculative science more accessible. Thank you.

[Lucien]

I've been fascinated by this stuff for years.. My tip for FTL travel is that the whole solution lies in the FTL region - Special Relativity and maybe General Relativity fail at the speed of light - and a completely different model is needed. (Something like an absolute frame maybe.)

Another tip is that the best route to the FTL is the speed of light. - Light as having zero net mass can be seen as interacting with things at both FTL and STL velocities. A bit deeper allows the description that wave like behavior is FTL like and particle like behaviour is STL like.

A third tip is about basic mathematical inequalities. The speed of light is measured from STL space and looks like a constant fixed velocity. My hypothesis is that from the FTL perspective the speed of light has multiple values at least one of which approximates to zero. This unifies FTL mechanics with quantum mechanics.

A fourth tip is that negative mass can be made to fit very nicely in a symmetry with positive mass.. This solves the problem of the origin of mass in the universe. Negative mass would have negative time and would probably be mostly non-interacting. A good possible candidate is obviously dark matter..

[mayhem]

With time dilation meaning time slows down as you approach LS any theoretical journey exceeding LS would mean the traveller arriving before he actually left and so if he returned home to check he'd turn off the gas, he might have not caught his flight but already be at his destination simultaneously. Therefore I think we can rule out exceeding lightspeed as a physical thing in any universe.