Warp drives are exotic solutions of general relativity that offer novel means of transportation. In this study, we present a solution for a constant-velocity subluminal warp drive that satisfies all of the energy conditions. The solution involves combining a stable matter shell with a shift vector distribution that closely matches well-known warp drive solutions such as the Alcubierre metric. We generate the spacetime metric numerically, evaluate the energy conditions, and confirm that the shift vector distribution cannot be reduced to a coordinate transformation. This study demonstrates that classic warp drive spacetimes can be made to satisfy the energy conditions by adding a regular matter shell with a positive ADM mass.
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The universe is 13.8 billion years old. The JWST has found galaxies formed just 400 million years after the Big Bang. It took the earth 4.6 billion years to form, and 1 billion years to create life.
Our best theory of the universe, General Relativity, has solutions that allow for faster-than-light travel via some Alcubierre type drive (some [without negative mass](https://arxiv.org/abs/2405.02709)), and even wormholes.
Even with newtonian mechanic style solutions, it's estimated that it would only take Von Neumann self-replicating probes about 100k years to traverse our own galaxy.
Is it really that unlikely that some non-human intelligence potentially *billions* of years…
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more advanced than us found our planet and uses it to study us or for whatever other purposes to them? IMO no.
And if you would do any research beyond just the headlines, you might come to the realization that our probably has government has recovered crashed/landed NHI craft.
I'm happy to point you to some not-so-light reading if you want to have a real conversation about this.
https://arxiv.org/pdf/2405.02709
https://github.com/NerdsWithAttitudes/WarpFactory
I'm impressed that they've removed the requirement for negative energy, but it's not quite ready to hand the drawings to your local machine shop to build one. It requires matter packed to an energy density on the order of 10^39 joules per cubic meter.
According to [1], oil has a (chemical) energy density of 4.5x10^10 joules per cubic meter, purified uranium produces 1.5x10^15 J/m^3 in a fission reactor, and that same uranium in pure mass-to-energy conversion produces on the order of 10^21 J/m^3. Uranium has a density of 19x10^3 kg/m^3, and the nucleus of an atom or neutron star has a…
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density on the order of 4x10^17...if you can build the entire ship out of pure neutrons, you're still coming up short by a factor of ~100.
All that does suggest that it seems reasonable we'd be able to observe gravity waves from a long distance if a machine like that ever experienced a loss of compression.
[1]: https://drexel.edu/~/media/Files/greatworks/pdf_sum10/WK8_La...
> not moving fast: so where does the time dilation come from?!
I think it’s from shifting momentum?? The paper is far beyond me [1]. But as I understood it, you’re directly modifying space-time with energy instead of using acceleration as a go-between.
[1] https://arxiv.org/html/2405.02709v1
In honor of Alan Turing's hundredth birthday, I unwisely set out some thoughts about one of Turing's obsessions throughout his life, the question of physics and free will.