If you were shot by a grain of sand(at lightspeed)

[Train]

Originally posted by: Arkaign

Originally posted by: JTsyo

Originally posted by: mugs
Hmmmm... well, we take out tanks by hitting them with oversized lawn darts at about 3000 mph. I figure a grain of sand moving at the speed of light would have quite a lot of kinetic energy.

well that only works because the tanks have multiple inches of armor. If you were to fire the same round through a regular car it would cause almost no damage other than putting 2 holes in it. Spalling of the armor is what gets the crew.

EDIT: I mean through the car door or roof, not through the engine block or some heavy area.

The army was running into the same problem using armor-piercing rounds on unarmored targets. The shots would pass right through the targets and they would still be able to fight. Of course those guys were probably doped up.
Based on these examples, I think the grain would just pass through as long as it didn't hit anything hard and imparted some of its energy. As long as it was occurring in vacuum, I don't think there's enough time for any secondary thermal effects either.

I'm not a physicist but my understanding of the subject is that the object nearing lightspeed doesn't actually increase in mass but just acts like it does. For mass to increase either volume or density would have to increase both would take more matter to increase. Not sure what that would mean at the atomic level though.

This is essentially correct.

Either by impact or hydrostatic shock, at the speeds we are talking about, there's simply no way the density of a human target would be enough to transfer a meaningful amount of energy, and thus, damage would be almost insignificant.

Fire the ~light speed sand grain at a 10-foot-diameter ball of lead, and you'd see a tremendously different reaction.

Nope.

At that speed, water = led.

Ever see high speed boat races? Water is essentially concrete when those things crash. A human body for the sake of this experiment is a bag of water.

The molecules of your body will be literally exploding under the impact, creating a massive energy wave that rips you to shreads.

 

[HardcoreRobot]

Originally posted by: hiromizu
Yea but a space shuttle is flying at a few hundred miles per hour in space. In this case you're not moving and there's air n stuff to cause resistance. It's all relative.

ROFL... seriously why are you even trying? the space shuttle moves quite a bit faster than that, 17-18,000 mph if what Im reading is correct.

 

[JJ650]

Bah.
I'll find some way to perform this experiment but I will skew the results via observation.
Take that sand!

 

[Arkaign]

Train, that's completely different. Human tissue is not dense enough to effectively slow down (and thereby transfer much of) high-speed / low-size projectiles.

This has already become a problem with conventional weapon ballistics, and why rounds designed to transfer more kinetic energy to the target in the form of damage has been an ongoing effort.

If your simplistic ideas of impact were realistic, then we should all be dead from the ~lightspeed neutrinos that pass through all of us constantly.

There isn't a way for a human to absorb anywhere remotely the type of potential energy in a lightspeed grain of sand.

 

[hiromizu]

Originally posted by: HardcoreRobot

Originally posted by: hiromizu
Yea but a space shuttle is flying at a few hundred miles per hour in space. In this case you're not moving and there's air n stuff to cause resistance. It's all relative.

ROFL... seriously why are you even trying? the space shuttle moves quite a bit faster than that, 17-18,000 mph if what Im reading is correct.

you've been punked by bruno

 

[JJ650]

Originally posted by: TruePaige
The grain of sand would generate enough heat energy through its air resistance to rip itself apart.

Surprised no one said it, but unless I'm mistaken it should be right.


Also, perhaps you inherently negate this in the root of the hypothetical question but my first thought on reading the thread title was Terminal Velocity.

So, we get to be cooked "well done" instead of death by hydrostatic shock???

Which is worse? Poll needed.

 

[PlasmaBomb]

Originally posted by: dainthomas

Originally posted by: Arkaign
A similar concept is the interaction between us and neutrinos. These are exceptionally tiny particles that travel at incredibly high velocities, and they pass through us constantly without any discernible damage whatsoever. They do have mass as well, albeit they are still relatively tiny in scale :

http://en.wikipedia.org/wiki/Fileroton_proton_cycle.png

A neutrino has a mass of around .0713 x 10^-33g.

A grain of sand has a mass of around 12 x 10^-2g.

So a difference of 31 orders of magnitude. I'd say it would do slightly more damage.

Neutrinos are also "odd", and small, very very small. They can pass through the "empty space" in an atom. A grain of sand can't, an analogy would be expecting a sledgehammer to pass through an ant without interacting.

 

[spidey07]

Originally posted by: Arkaign
Train, that's completely different. Human tissue is not dense enough to effectively slow down (and thereby transfer much of) high-speed / low-size projectiles.

This has already become a problem with conventional weapon ballistics, and why rounds designed to transfer more kinetic energy to the target in the form of damage has been an ongoing effort.

If your simplistic ideas of impact were realistic, then we should all be dead from the ~lightspeed neutrinos that pass through all of us constantly.

There isn't a way for a human to absorb anywhere remotely the type of potential energy in a lightspeed grain of sand.

Absolutely there is. And you keep bringing up neutrinos when it has no bearing at all. Grain of sand is bigger than atoms/particles.

The moment the sand hit you there would be a massive amount of energy transfered to your body and you'd just go POOF and the sand would carry on losing very little energy. But it lost enough to vaporize you.

 

[Train]

Originally posted by: Arkaign
Train, that's completely different. Human tissue is not dense enough to effectively slow down (and thereby transfer much of) high-speed / low-size projectiles.

This has already become a problem with conventional weapon ballistics, and why rounds designed to transfer more kinetic energy to the target in the form of damage has been an ongoing effort.

If your simplistic ideas of impact were realistic, then we should all be dead from the ~lightspeed neutrinos that pass through all of us constantly.

There isn't a way for a human to absorb anywhere remotely the type of potential energy in a lightspeed grain of sand.

Your not thinking of the magnitude of light speed. As soon as the grain hit the surface, even if only haf a square milimeter in surface area, those skin molecules will be exploding in all directions. Shockwave from the surface alone would kill you. now repeat every few microns on a straight line through your body. The shock would be insane.

EDIT: and Nuetrons are subatomic particles... they essentially dont even touch us. Horrible analogy.

 

[PlasmaBomb]

Originally posted by: RESmonkey

Originally posted by: RESmonkey
I'm going to work this out using mechanics for an inelastic and elastic collision. BUT it's probably not going to be accurate since things moving at such speeds are not in the realm of Newtonian mechanics, but left for QFT, which I don't know, yet.

Ok this is probably wrong because I didn't take in account the make up of the human body, it's compression properties, etc. Just a simple physics thing:

Inelastic:

Mass of grain of sand -> 6.3E-7kg
mass of random human -> 75kg
speed -> (.999999999)(3E8 m/s)
(6.3E-7kg)(.999999999)(3E8) = ( 75kg + 6.3E-7kg)(vfinal)

vfinal -> 2.52 m/s

Elastic:

Dunno, depends?







The sand has a kinetic energy of about 94 Joules.



Can someone help me out here?

I can help you out... you are waaaaaaaaaaaaaaaaaaaaaaaaaaaaay out.

Doh... I was out too. So hands up to that one

 

[zinfamous]

Of course you all realize that this won't be decided until Rubycon weighs in .

 

[darkxshade]

I respectfully bow out of this discussion as I have no effin idea what I'm talking about since it's getting way too technical. My original curiosity is if the grain of sand sized hole on your body would kill you. I didn't think about or consider the result other external influences as far as physics is concerned so you've taken the discussion to a whole new level.

 

[edro]

There is an asteroid show on the Discovery Channel where they shoot a BB at a pool of sand at high velocities to estimate asteroid impacts.
I think they shot the BB around 5000 ft/sec, and it left an impact cone the size of a dinner plate and about 10" deep.

Multiply that velocity by about 200,000 and you get the speed of light.

I am on the "You'd be vaporized" bandwagon.

Found this on Wikipedia:
Relativistic Kill Vehicle

 

[JJ650]

LOL @ The sand will not react with you group.

Even though small, it's gonna react. If they didn't react, sand blasters would be useless. Let me tell ya. Get a hand close to sand blaster nozzle and you will see what I mean.

 

[HardcoreRobot]

Originally posted by: hiromizu

Originally posted by: HardcoreRobot

Originally posted by: hiromizu
Yea but a space shuttle is flying at a few hundred miles per hour in space. In this case you're not moving and there's air n stuff to cause resistance. It's all relative.

ROFL... seriously why are you even trying? the space shuttle moves quite a bit faster than that, 17-18,000 mph if what Im reading is correct.

you've been punked by bruno

sure
better than repeatedly punking myself in front of the whole world posting nonsense about things i dont understand

 

[darkxshade]

What if in this hypothetical situation the grain of sand is a constant(at the speed of light) e.g it does not slow down even on impact? Would it still impart any energy into the body? I'm thinking juggernaught.

 

[Crusty]

Originally posted by: HardcoreRobot

Originally posted by: hiromizu

Originally posted by: HardcoreRobot

Originally posted by: hiromizu
Yea but a space shuttle is flying at a few hundred miles per hour in space. In this case you're not moving and there's air n stuff to cause resistance. It's all relative.

ROFL... seriously why are you even trying? the space shuttle moves quite a bit faster than that, 17-18,000 mph if what Im reading is correct.

you've been punked by bruno

sure
better than repeatedly punking myself in front of the whole world posting nonsense about things i dont understand

Yeah, if anyone got 'punked' in this thread.... it'd be hiromizu for posting like a flaming idiot.

 

[mryellow2]

E = (1/2) X .05 g X (299 792 458 m / s)(299 792 458 m / s)

:

2,246,887,946,842,044.1 joules

~ to 570,000 tons of exploding TNT =o

 

[hiromizu]

Originally posted by: Crusty

Originally posted by: HardcoreRobot

Originally posted by: hiromizu

Originally posted by: HardcoreRobot

Originally posted by: hiromizu
Yea but a space shuttle is flying at a few hundred miles per hour in space. In this case you're not moving and there's air n stuff to cause resistance. It's all relative.

ROFL... seriously why are you even trying? the space shuttle moves quite a bit faster than that, 17-18,000 mph if what Im reading is correct.

you've been punked by bruno

sure
better than repeatedly punking myself in front of the whole world posting nonsense about things i dont understand

Yeah, if anyone got 'punked' in this thread.... it'd be hiromizu for posting like a flaming idiot.

tru dat. ima go make a ham sandwich

 

[her209]

Doesn't the grain of sand gain mass as its speed increases?

http://www.newton.dep.anl.gov/...sci/phy99/phy99186.htm

 

[RESmonkey]

Originally posted by: PlasmaBomb

Originally posted by: RESmonkey

Originally posted by: RESmonkey
I'm going to work this out using mechanics for an inelastic and elastic collision. BUT it's probably not going to be accurate since things moving at such speeds are not in the realm of Newtonian mechanics, but left for QFT, which I don't know, yet.

Ok this is probably wrong because I didn't take in account the make up of the human body, it's compression properties, etc. Just a simple physics thing:

Inelastic:

Mass of grain of sand -> 6.3E-7kg
mass of random human -> 75kg
speed -> (.999999999)(3E8 m/s)
(6.3E-7kg)(.999999999)(3E8) = ( 75kg + 6.3E-7kg)(vfinal)

vfinal -> 2.52 m/s

Elastic:

Dunno, depends?







The sand has a kinetic energy of about 94 Joules.



Can someone help me out here?

I can help you out... you are waaaaaaaaaaaaaaaaaaaaaaaaaaaaay out.

Doh... I was out too. So hands up to that one

My bad, forgot to square the speed. It's 28350000000 joules now.



Question: How do we know it won't just pass right through us, cutting a small hole in our body (not hitting any vital organs)?

 

[SphinxnihpS]

My guess is that this would be enough mass to vaporize the entire planet.

 

[Train]

Originally posted by: RESmonkey
Question: How do we know it won't just pass right through us, cutting a small hole in our body (not hitting any vital organs)?

essentially it does.. BUT even at .5 mm sq, and through 150 mm of body... thats 75 cubic mm of body mass that has gone where? Well it was just smashed into by a grain of sand with what is essentially infinite energy. It explodes at an atomic level, taking everything with it.

 

[RESmonkey]

Originally posted by: Train

Originally posted by: RESmonkey
Question: How do we know it won't just pass right through us, cutting a small hole in our body (not hitting any vital organs)?

essentially it does.. BUT even at .5 mm sq, and through 150 mm of body... thats 75 cubic mm of body mass that has gone where? Well it was just smashed into by a grain of sand with what is essentially infinite energy. It explodes at an atomic level, taking everything with it.

?

 

[Train]

Originally posted by: RESmonkey

Originally posted by: Train

Originally posted by: RESmonkey
Question: How do we know it won't just pass right through us, cutting a small hole in our body (not hitting any vital organs)?

essentially it does.. BUT even at .5 mm sq, and through 150 mm of body... thats 75 cubic mm of body mass that has gone where? Well it was just smashed into by a grain of sand with what is essentially infinite energy. It explodes at an atomic level, taking everything with it.

?

so much force that the hydorgen and oxygen atoms that make up the water that make up most of your body would separate.. and head in all directions in an explosion like fashion.