The physics of stopping a meteor with one punch (Synopsis)

“Human beings are strong because we have the ability to change ourselves.” Saitama, One Punch Man

The idea of stopping a meteor headed towards our planet with nothing but a superpowered human being sounds like a physical impossibility. But if you had a powerful enough, strong enough, fast enough human, it could be done, so long as you obeyed the laws of physics and conserved energy and momentum.

The speed your human would need to hit the meteor with would be tremendous; there would need to be something special about this human’s atoms to keep them from flying apart; the energy released by the in-air explosion would be catastrophically huge. But it could, in fact, save the city — or the entire planet — that it would have completely annihilated otherwise.

16 thoughts on “The physics of stopping a meteor with one punch (Synopsis)”

1. Ethan,
Do you have any articles in the works on Superman, or on each of the Marvel superheroes?

Or should I just get some comic books, or catch one of those flicks?

2. If you can create a (mostly) inelastic collision…

This seems to me a bigger problem in principle than getting up to speed. Getting up to relativistic speeds so you have the right kinetic energy is an engineering problem, however, you-the-puncher don’t get to decide whether your collision is elastic or inelastic.

Energy transfer in general is going to be a problem; as per the cited comic picture, what would really happen is you’d go straight though the meteor with some very large portion of your energy not transferred to it (and not going to friction, breakup, etc…).

A knife used edge-on will never squash a butter pat flat; for that you need a “turner” (the big flat thing you use to flip pancakes or squash burgers). Its the same problem here; a human being is the wrong shape and size object to be transferring all its energy and momentum to chemical bond breaking in a comet or meteor. You-the-superhero are a knife, not a turner.

On the plus side, being a knife means the meteor is also unlikely to have much effect on you. If you can survive the relativistic flight through air molecules (you can’t), you can survive going through the meteor, because it’s probably about the same resistance to something doing that fast (think of the old adage about falling into the ocean: “at that speed, hitting the water is like hitting concrete” – at relativistic speeds, the same is true of hitting air).

3. “Let’s call this meeting to order. General Abrams, can you give us an update?”

“Thank you Mr. President” replied Abrams. “The extent of the damage is still being evaluated but satellite imagery shows continental scale destruction”.

“Why were the damage estimates so wrong?” demanded the President.

“Well, Mr. President” replied Abrams. “The damage estimates were for a meteor strike, but that is not what happened. A vigilante who calls himself ‘One Punch Man’ leapt from Earth’s surface with enough force to annihilate the incoming meteor.”

“So this destruction isn’t from the meteor?”

“No sir” came the quick reply. “The damage is from the force of One Punch Man’s foot pushing against the Earth with enough force to instantly propel him to 99.99999997% the speed of light”.

“It has been a long time since I took a Physics Class” said the President “but, isn’t there something about equal and opposite reaction? Why isn’t the damage of One Punch Man’s leap just equal to the estimated damage of letting the meteor fall?”

“This isn’t really my department sir, but it has something to do with the surface area of a human foot versus the surface area of the meteor and the additional force needed to overcome extra drag to get to the meteor”.

The room fell silent for a moment as all eyes held on the President as he began to speak. “What do we do now?”

“Well sir, as you know we have a transporter device recovered from an alien spacecraft at Area 51. It is more of a ‘assemble a clone at a distance as the host is killed’ machine than an actual transporter, but we have a test subject code named @eric who has been using it. To overcome our shortage in manpower we disabled the killing part of the machine and are just beaming new @eric clones to the areas of devastation to help. So far we’ve got 2 million @erics in position and more are made every few seconds.”

The President considered for a moment before concluding “Thank you everyone. Is Twitter up and running? We have to get word out. I know how people think and the hunger for information in times of crisis is YUUUUUUGE.”

4. It is more of a ‘assemble a clone at a distance as the host is killed’ machine than an actual transporter

Okay denier, how do you ‘transport’ (a la Star Trek) a human being in a way that isn’t kill-and-clone then? Give me a notion of what would fit your bill. Because it seems to me that there can be no distinction between ‘transporter’ and ‘kill and clone’ unless you invoke dualism and claim there’s a unique and uncopyable spirit/soul that passes between the transmitter and receiver. Even if you ship all the atoms in the “transmit” box and reassemble them in the exact same configuration as they started, you’ve still been killed and recopied in the process. And atoms are atoms, they aren’t unique in any way – the info used to do the reassembly could use any old atoms to do it, with the same result. Right?

5. @eric #4

If I had to write a story that required a non-clone and kill transporter, I’d start in a universe where Digital Physics Cosmology (also called ‘It from Bit’) was validated. Three dimensional space is an illusion, and all of the particles in our universe encode not only vector information but also location. The transporter would work by being able to carry out bulk edits of particle location information so that the target object appeared to move in the illusion of our universe even though it was in fact the exact same matter as before just with different location information. To us caught up in the illusion it would appear that what was once here is now there.

Although it isn’t exactly the same, it does have loose parallels to the possible premise hinted at in the conclusion of Star Trek: The Next Generation S06E12 titled “Ship in a Bottle”.

6. What is the functional difference in (a) changing the position bit information, and (b) storing the bit data in some system, destroying the original, and then reproducing the same bit vector data with different location information?

You still need a concept of a soul to say there’s a difference. If you have an It from Bit world but all we are is bits, the results of those two processes are exactly the same.

7. Imagine traveling at warp 6, then having to transport to another ship due to some emergency; what would end up at the other ship? Might give a new meaning to ‘ Star trekking, across the universe’.

8. @ Denier
‘Amazing’ how quickly you managed to change the topic to your interest in teleportation techniques.
🙂

9. @PJ #8

Granted that I do more than my fair share of hijacking around here, but this one isn’t entirely my fault.

The sudden change of direction here was helped greatly by….

10. @eric

Take the analog of moving a file from one directory to another in a computer. If both directories are on the same physical disc then the file is not moved. The pointers are updated and what once appeared in one directory now appears in the other. In reality the file is still the exact same unmoved magnetic encoding in the exact location on the exact same platter. There are no copies being made and the movement is illusory.

Your alternative is more like moving the file from one disc to another. The file is copied to RAM before being written to the new location. While the write validation is being done there are 3 copies of the file: One resides at the original location with another in RAM and the third at the new location. Only after validation are the first two copies removed.

The process is the difference with the former satisfying non-Clone-and-Kill movement while the latter is Clone-and-Kill. If it is just the ones and zeros that have your focus then they are the same and I admitted as much previously, but if you are also including the disc, platter, and sector information in the comprehensive whole then they are different.

11. @eric

If you don’t like Digital Physics, you could do something similar with Star Trek Warp technology.

Take a target portion of the universe containing a person and pinch it off so that he or she now exists in their own personal ‘Warp Bubble’ universe. You can then reinsert the bubble universe someplace else.

At no point were there ever multiple copies of the person. The person who was at one place in the universe is now at another place in the universe. It even solves @Ethan’s problem of not being able to simultaneously know the position and motion by making it irrelevant. Just move the space like you’re repotting a plant.

12. “Take the analog of moving a file from one directory to another in a computer.”

OK.

“If both directories are on the same physical disc then the file is not moved. ”

Not necessarily.

Dang.

PS what was the purpose of that? Copying via sneakernet would be closer to the situation, but even then not really.

13. Take the analog of moving a file from one directory to another in a computer…
…Your alternative is more like moving the file from one disc to another

I understand there are differences in the two processes. I’m asking you the difference in the end state. What is it? And if the answer is “none”, how can you claim one you is really you and the other isn’t?

14. @eric #13

You’re moving the goal posts. The process difference was the purpose as in post #4 you asked the following:

Okay denier, how do you ‘transport’ (a la Star Trek) a human being in a way that isn’t kill-and-clone then? Give me a notion of what would fit your bill.