# How would a time-oven work? [closed]

I was thinking about a sci-fi microwave-like device to make a banana ripen more quickly. Assuming that the various technical hurdles had been solved, how might this, in simple terms, operate?

edit: I guess this question is asking what mechanism, given our current understanding of how time works, could warp it in such a way time passes more quickly inside a microwave sized object. Maybe by somehow manipulating the rate at which entropy takes place, if that makes sense.

• Here's why we can't answer this: Figuring out how this would operate is one of the various technical hurdles that you waved your hand over. It might be possible to make a banana ripen faster using some biological or chemical process, but I know of no physical process that advances time at a faster rate in a small, isolated environment – Jim Aug 23 '17 at 13:14
• Unless there's a Nobel Prize as the bounty, I don't think you're gonna get a satisfactory answer – user95137 Aug 23 '17 at 14:21

Leave your banana on Earth. You get into your device. Launch into space at very close to the speed of light and then come back after whatever period you are prepared to wait.

Very roughly speaking, the rate at which time is "speeded up" for the earthbound banana is the Lorentz factor $\gamma = (1-v^2/c^2)^{-1/2}$ (for constant velocities in flight and instantaneous accelerations; for more realistic scenarios the calculations are more complex but no more illuminating - see Twin Paradox, calculating spacetime intervals from both perspectives ).

Thus if you wanted to eat a banana in 24 hours that would have ripened in 10 days then you would need to travel into space (and come back again) over the course of a day at roughly $$\frac{1}{\sqrt{1 - v^2/c^2}} \simeq 10$$ i.e. at $v \simeq 0.995c$.

Of course everything else on Earth would have moved on by 10 days too, so that milk you left in the refrigerator has gone off.

• your milk goes bad in less than 10 days? You need to buy a better brand, or at least check the expiry date at the store before you pick it up – Jim Aug 23 '17 at 13:25
• No, you're using the wrong kind of milk – Selene Routley Aug 23 '17 at 13:32
• @Jim Maybe they don't have fresh milk. They might have had to pick some up the next day; but that day got skipped because they couldn't wait for a banana to ripen naturally. – JMac Aug 23 '17 at 16:49
• Could you launch earth and everything except the oven somehow? – mcintyre321 Aug 23 '17 at 21:02
• @mcintyre321 The "twins paradox" (actually not a paradox) is asymmetric. You have to do the accelerating, the banana has to be unaccelerated. – ProfRob Aug 24 '17 at 11:46

you could experimentally determine whether bananas ripen more in a microwave rich environment or not. It has been done:

peel and slice banana or bananas in a microwave safe bowl. Cover with waxed paper. Microwave for one minute.

• It is ironic that a suggestion to experiment with the idea is downvoted, on a site for physics ! If the idea works in reality, then is the time to see the physics explanations. Of course special relativity plays a large role in microwaves at the micro level. After all classical EM follows lorenz transformations. If one wants a yogi (catch left ear by right hand behind head) position to explain why it works is a matter of taste. – anna v Aug 25 '17 at 3:19
• I have voted down because this answer appears to have misread the question. The question has nothing to do with the electromagnetic waves we call microwaves; it asks whether something could achieve the same outcome as a microwave oven (namely cooking something within a box) by speeding up the rate of time within the box, rather than heating it directly. – gj255 Aug 31 '17 at 13:34