A starship is travelling at 0.9c and collides with a small rock. Will it leave a clean hole through, or will...
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A starship is travelling at 0.9c and collides with a small rock. Will it leave a clean hole through, or will more happen?
$begingroup$
Say there is a football sized rock in the path of the ship. Will it create a football sized hole through the ship in the blink of an eye, or will more happen? The ship would be filled with metal, water, some fuel and air for simplicity sake. Will there be a huge shockwave throughout the ship from the impact? Will it collide with enough energy to initiate fusion with the atoms of the hull?
impact relativistic-rocket
asked 5 hours ago
Nick van der KroonNick van der Kroon
863
$endgroup$
add a comment |
$begingroup$
Say there is a football sized rock in the path of the ship. Will it create a football sized hole through the ship in the blink of an eye, or will more happen? The ship would be filled with metal, water, some fuel and air for simplicity sake. Will there be a huge shockwave throughout the ship from the impact? Will it collide with enough energy to initiate fusion with the atoms of the hull?
impact relativistic-rocket
asked 5 hours ago
Nick van der KroonNick van der Kroon
863
$endgroup$
14
$begingroup$
what-if.xkcd.com/1
$endgroup$
– Hobbes
5 hours ago
3
$begingroup$
A simpler to visualize, but totally equivalent, question would be to consider the ship as stationary and ask what would happen if it were hit by a rock that is traveling at .9c.
$endgroup$
– Ray Butterworth
4 hours ago
$begingroup$
Do you have shields? (If you don't have shields don't even attempt to go that fast) Are your shields up? Using a warp bubble? (If thick enough the warp bubble might prevent it from hitting your ship.)
$endgroup$
– cybernard
1 hour ago
add a comment |
$begingroup$
Say there is a football sized rock in the path of the ship. Will it create a football sized hole through the ship in the blink of an eye, or will more happen? The ship would be filled with metal, water, some fuel and air for simplicity sake. Will there be a huge shockwave throughout the ship from the impact? Will it collide with enough energy to initiate fusion with the atoms of the hull?
impact relativistic-rocket
asked 5 hours ago
Nick van der KroonNick van der Kroon
863
$endgroup$
Say there is a football sized rock in the path of the ship. Will it create a football sized hole through the ship in the blink of an eye, or will more happen? The ship would be filled with metal, water, some fuel and air for simplicity sake. Will there be a huge shockwave throughout the ship from the impact? Will it collide with enough energy to initiate fusion with the atoms of the hull?
impact relativistic-rocket
impact relativistic-rocket
asked 5 hours ago
Nick van der KroonNick van der Kroon
863
asked 5 hours ago
Nick van der KroonNick van der Kroon
863
asked 5 hours ago
Nick van der KroonNick van der Kroon
863
asked 5 hours ago
Nick van der KroonNick van der Kroon
863
asked 5 hours ago
Nick van der KroonNick van der Kroon
863
863
14
$begingroup$
what-if.xkcd.com/1
$endgroup$
– Hobbes
5 hours ago
3
$begingroup$
A simpler to visualize, but totally equivalent, question would be to consider the ship as stationary and ask what would happen if it were hit by a rock that is traveling at .9c.
$endgroup$
– Ray Butterworth
4 hours ago
$begingroup$
Do you have shields? (If you don't have shields don't even attempt to go that fast) Are your shields up? Using a warp bubble? (If thick enough the warp bubble might prevent it from hitting your ship.)
$endgroup$
– cybernard
1 hour ago
add a comment |
14
$begingroup$
what-if.xkcd.com/1
$endgroup$
– Hobbes
5 hours ago
3
$begingroup$
A simpler to visualize, but totally equivalent, question would be to consider the ship as stationary and ask what would happen if it were hit by a rock that is traveling at .9c.
$endgroup$
– Ray Butterworth
4 hours ago
$begingroup$
Do you have shields? (If you don't have shields don't even attempt to go that fast) Are your shields up? Using a warp bubble? (If thick enough the warp bubble might prevent it from hitting your ship.)
$endgroup$
– cybernard
1 hour ago
14
14
$begingroup$
what-if.xkcd.com/1
$endgroup$
– Hobbes
5 hours ago
$begingroup$
what-if.xkcd.com/1
$endgroup$
– Hobbes
5 hours ago
3
3
$begingroup$
A simpler to visualize, but totally equivalent, question would be to consider the ship as stationary and ask what would happen if it were hit by a rock that is traveling at .9c.
$endgroup$
– Ray Butterworth
4 hours ago
$begingroup$
A simpler to visualize, but totally equivalent, question would be to consider the ship as stationary and ask what would happen if it were hit by a rock that is traveling at .9c.
$endgroup$
– Ray Butterworth
4 hours ago
$begingroup$
Do you have shields? (If you don't have shields don't even attempt to go that fast) Are your shields up? Using a warp bubble? (If thick enough the warp bubble might prevent it from hitting your ship.)
$endgroup$
– cybernard
1 hour ago
$begingroup$
Do you have shields? (If you don't have shields don't even attempt to go that fast) Are your shields up? Using a warp bubble? (If thick enough the warp bubble might prevent it from hitting your ship.)
$endgroup$
– cybernard
1 hour ago
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
@Hobbes answered this in a comment.
Your final guess
Will it collide with enough energy to initiate fusion with the atoms of the hull?
is correct.
See the first XKCD What-If comic, "Relativistic Baseball" for details.
The short answer is your entire spaceship is going to suffer a sudden and gratuitous existence failure due to the fusion reaction.
ps - as noted in the comments, the fusion reaction won't begin until shortly after the rock hits the ship. If the ship is bigger than the distance between the pitcher's mound and home plate then it won't really matter much - you'll have an unscheduled/uncontained fusion reaction somewhere in your ship, possibly not in the engine compartment.
If the ship is small enough, then I'd assume Everyday Astronaut's answer would apply.
edited 16 mins ago
Mason Wheeler
4701712
answered 5 hours ago
Dan PichelmanDan Pichelman
1,4272715
$endgroup$
14
$begingroup$
I love the line at the end of the XKCD, after explaining how the fusion fireball would destroy everything around that "A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base."
$endgroup$
– geoffc
4 hours ago
1
$begingroup$
Is that a Starship Titanic reference?
$endgroup$
– 0xDBFB7
4 hours ago
1
$begingroup$
Bit of a difference here is that the baseball in question is having a fusion reaction with the air around it. A starship in the near-vacuum of space isn't going to have that problem. (It would of course still be catastrophic, but maybe not the giant fusion explosion described.) I suspect the damage would be somewhat more localized, as it's only where matter collides with other matter that there's a problem.
$endgroup$
– Darrel Hoffman
2 hours ago
6
$begingroup$
@DarrelHoffman: The spaceship is presumably filled with air (and/or denser material as stated by the OP) and at least 19m long (approximate distance between the batter and the pitcher in baseball), so you would have a similar effect. Maybe the front (at least the part not hit by the rock) survives a bit longer, until the gamma-rays from the back of the ship reach it.
$endgroup$
– Graipher
2 hours ago
4
$begingroup$
"is your entire spaceship is going to suffer a sudden and gratuitous existence failure" I can't stop laughing. As for the crew, and quoting a other What-if: they "wouldn't die of anything", they would just "stop being biology and start being physics"
$endgroup$
– Barranka
2 hours ago
|
show 3 more comments
$begingroup$
I answer this question from a purely structural-mechanical point of view (i.e. not considering fusion as provided in @DanPichelman's answer).
Will it create a football sized hole through the ship in the blink of an eye [...]?
That's probably right. The rock hits the structure so fast that no inertial effects have a chance of taking place before the incident is already over. "Communication" of the subjected material with the surroundings would simply be too slow. So, any elasticity or plasticity of the structural material would be irrelevant to the impact. The rock would leave a hole the approximately shape of its silhouette. As it goes through the layers of the ship, that silhouette will of course change.
Will there be a huge shockwave throughout the ship from the impact?
I guess not as much as you'd expect, from a structural point of view. Except that the hull of the ship contains residual stresses beforehand. Those might relax after the structure has been weakened, causing waves propagating through the ship in the classical way. But that would not be of any significance since the ship would have major leakage of its inner atmosphere (if it was pressurized).
Think of a classical metal shear. There, the surrounding material is mounted somewhere, and only the local part of the material is affected by the "impact". In the case of our starship, the mounting force of the surrounding material is its inertia.
answered 3 hours ago
Everyday AstronautEveryday Astronaut
1,669729
$endgroup$
$begingroup$
It seems probable to me that any spaceship that accelerated to 0.9c would have encountered matter previously which would (assuming the ship still exists) accumulate as a wave front ahead of said ship. Making the presence of an object with -0.9c relative velocity surviving to make contact incredibly unlikely, especially if it was natural.
$endgroup$
– Giu Piete
2 hours ago
1
$begingroup$
The energy is carried sideways not by sound or mechanical forces but by gamma rays, X rays and other energetic particles.
$endgroup$
– Steve Linton
2 hours ago
$begingroup$
Wouldn't the fragments of the impacted materials in the ship spread to hit other things like when a bullet strikes a bone and the bone fragments then impact other organs and such? (excepting the whole fusion aspect.)
$endgroup$
– Tracy Cramer
43 mins ago
$begingroup$
As the mass starts interacting with the ship, conservation of momentum would dictate that the center of mass of (football plus affected parts of ship) will in the short term have a constant velocity, which will be somewhere between the velocities of the football and the ship. If the football is heavy relative to the stuff it passes through, all of that mass is going to be squished flat and won't re-expand until the ship is a long way away. If the football passes through enough denser material, however, it might be slowed enough that other effects take over.
$endgroup$
– supercat
2 mins ago
add a comment |
$begingroup$
On 0.9c, the kinetical energy of an 1g rock is $mc^2(frac{1}{sqrt{1-frac{v^2}{c^2}}}-1)$ (ref).
Substituting 0.9c and 0.001kg, we get 116 TJ.
As a comparison, the Little Boy nuclear bomb released 93 TJ energy.
Also the result would look similar. No known spaceship material could resist this.
answered 2 hours ago
peterhpeterh
1,93111531
$endgroup$
2
$begingroup$
Wouldn't we need to decelerate the rock to zero (resp. spaceship velocity) to release that kinetic energy?
$endgroup$
– Guntram Blohm
1 hour ago
$begingroup$
@GuntramBlohm Yes. It would decelerate to nearly-zero (in the frame of the spaceship) on collision. Its impulse would be quite small (compared to its kinetical energy), so the result would be probably a gas cloud, moving roughly on the original trajectory of the spaceship.
$endgroup$
– peterh
1 hour ago
$begingroup$
You might recalculate. The volume of a football is about 4.6 liters, and assume a specific gravity of rock as 2.5 (it can be much greater, but it's about right for stuff like limestone or granite), the mass of the rock will be 11.5 kg, more or less. So you're looking at more like 1.3 EJ.
$endgroup$
– WhatRoughBeast
1 hour ago
$begingroup$
@WhatRoughBeast The kinetical energy depends on the mass, volume doesn't matter. In this answer, I intentionally used a small mass to show that even a collision with a very little mass would be fatal. If you use $approx$ 10000 times bigger mass, also the kinetical energy would be 10000 times bigger. Note, space waste is a major problem even on Low Earth Orbit, despite that there we are talking about thousand times smaller masses and 30000x smalles velocities.
$endgroup$
– peterh
1 hour ago
2
$begingroup$
@WhatRoughBeast The essence of the answer is that a collision with practically any small object is unavoidably fatal with any currently known technology, and results a gas cloud. It is a proof. I could rewrite the question for a body mass of, f.e. 10kg, the result would be the same. The goal is to show, that not only a collision with a 10kg stone is fatal, already a collision with an 1g stone is fatal.
$endgroup$
– peterh
1 hour ago
|
show 1 more comment
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
@Hobbes answered this in a comment.
Your final guess
Will it collide with enough energy to initiate fusion with the atoms of the hull?
is correct.
See the first XKCD What-If comic, "Relativistic Baseball" for details.
The short answer is your entire spaceship is going to suffer a sudden and gratuitous existence failure due to the fusion reaction.
ps - as noted in the comments, the fusion reaction won't begin until shortly after the rock hits the ship. If the ship is bigger than the distance between the pitcher's mound and home plate then it won't really matter much - you'll have an unscheduled/uncontained fusion reaction somewhere in your ship, possibly not in the engine compartment.
If the ship is small enough, then I'd assume Everyday Astronaut's answer would apply.
edited 16 mins ago
Mason Wheeler
4701712
answered 5 hours ago
Dan PichelmanDan Pichelman
1,4272715
$endgroup$
14
$begingroup$
I love the line at the end of the XKCD, after explaining how the fusion fireball would destroy everything around that "A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base."
$endgroup$
– geoffc
4 hours ago
1
$begingroup$
Is that a Starship Titanic reference?
$endgroup$
– 0xDBFB7
4 hours ago
1
$begingroup$
Bit of a difference here is that the baseball in question is having a fusion reaction with the air around it. A starship in the near-vacuum of space isn't going to have that problem. (It would of course still be catastrophic, but maybe not the giant fusion explosion described.) I suspect the damage would be somewhat more localized, as it's only where matter collides with other matter that there's a problem.
$endgroup$
– Darrel Hoffman
2 hours ago
6
$begingroup$
@DarrelHoffman: The spaceship is presumably filled with air (and/or denser material as stated by the OP) and at least 19m long (approximate distance between the batter and the pitcher in baseball), so you would have a similar effect. Maybe the front (at least the part not hit by the rock) survives a bit longer, until the gamma-rays from the back of the ship reach it.
$endgroup$
– Graipher
2 hours ago
4
$begingroup$
"is your entire spaceship is going to suffer a sudden and gratuitous existence failure" I can't stop laughing. As for the crew, and quoting a other What-if: they "wouldn't die of anything", they would just "stop being biology and start being physics"
$endgroup$
– Barranka
2 hours ago
|
show 3 more comments
$begingroup$
@Hobbes answered this in a comment.
Your final guess
Will it collide with enough energy to initiate fusion with the atoms of the hull?
is correct.
See the first XKCD What-If comic, "Relativistic Baseball" for details.
The short answer is your entire spaceship is going to suffer a sudden and gratuitous existence failure due to the fusion reaction.
ps - as noted in the comments, the fusion reaction won't begin until shortly after the rock hits the ship. If the ship is bigger than the distance between the pitcher's mound and home plate then it won't really matter much - you'll have an unscheduled/uncontained fusion reaction somewhere in your ship, possibly not in the engine compartment.
If the ship is small enough, then I'd assume Everyday Astronaut's answer would apply.
edited 16 mins ago
Mason Wheeler
4701712
answered 5 hours ago
Dan PichelmanDan Pichelman
1,4272715
$endgroup$
14
$begingroup$
I love the line at the end of the XKCD, after explaining how the fusion fireball would destroy everything around that "A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base."
$endgroup$
– geoffc
4 hours ago
1
$begingroup$
Is that a Starship Titanic reference?
$endgroup$
– 0xDBFB7
4 hours ago
1
$begingroup$
Bit of a difference here is that the baseball in question is having a fusion reaction with the air around it. A starship in the near-vacuum of space isn't going to have that problem. (It would of course still be catastrophic, but maybe not the giant fusion explosion described.) I suspect the damage would be somewhat more localized, as it's only where matter collides with other matter that there's a problem.
$endgroup$
– Darrel Hoffman
2 hours ago
6
$begingroup$
@DarrelHoffman: The spaceship is presumably filled with air (and/or denser material as stated by the OP) and at least 19m long (approximate distance between the batter and the pitcher in baseball), so you would have a similar effect. Maybe the front (at least the part not hit by the rock) survives a bit longer, until the gamma-rays from the back of the ship reach it.
$endgroup$
– Graipher
2 hours ago
4
$begingroup$
"is your entire spaceship is going to suffer a sudden and gratuitous existence failure" I can't stop laughing. As for the crew, and quoting a other What-if: they "wouldn't die of anything", they would just "stop being biology and start being physics"
$endgroup$
– Barranka
2 hours ago
|
show 3 more comments
$begingroup$
@Hobbes answered this in a comment.
Your final guess
Will it collide with enough energy to initiate fusion with the atoms of the hull?
is correct.
See the first XKCD What-If comic, "Relativistic Baseball" for details.
The short answer is your entire spaceship is going to suffer a sudden and gratuitous existence failure due to the fusion reaction.
ps - as noted in the comments, the fusion reaction won't begin until shortly after the rock hits the ship. If the ship is bigger than the distance between the pitcher's mound and home plate then it won't really matter much - you'll have an unscheduled/uncontained fusion reaction somewhere in your ship, possibly not in the engine compartment.
If the ship is small enough, then I'd assume Everyday Astronaut's answer would apply.
edited 16 mins ago
Mason Wheeler
4701712
answered 5 hours ago
Dan PichelmanDan Pichelman
1,4272715
$endgroup$
@Hobbes answered this in a comment.
Your final guess
Will it collide with enough energy to initiate fusion with the atoms of the hull?
is correct.
See the first XKCD What-If comic, "Relativistic Baseball" for details.
The short answer is your entire spaceship is going to suffer a sudden and gratuitous existence failure due to the fusion reaction.
ps - as noted in the comments, the fusion reaction won't begin until shortly after the rock hits the ship. If the ship is bigger than the distance between the pitcher's mound and home plate then it won't really matter much - you'll have an unscheduled/uncontained fusion reaction somewhere in your ship, possibly not in the engine compartment.
If the ship is small enough, then I'd assume Everyday Astronaut's answer would apply.
edited 16 mins ago
Mason Wheeler
4701712
answered 5 hours ago
Dan PichelmanDan Pichelman
1,4272715
edited 16 mins ago
Mason Wheeler
4701712
edited 16 mins ago
Mason Wheeler
4701712
edited 16 mins ago
Mason Wheeler
4701712
4701712
answered 5 hours ago
Dan PichelmanDan Pichelman
1,4272715
answered 5 hours ago
Dan PichelmanDan Pichelman
1,4272715
answered 5 hours ago
Dan PichelmanDan Pichelman
1,4272715
1,4272715
14
$begingroup$
I love the line at the end of the XKCD, after explaining how the fusion fireball would destroy everything around that "A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base."
$endgroup$
– geoffc
4 hours ago
1
$begingroup$
Is that a Starship Titanic reference?
$endgroup$
– 0xDBFB7
4 hours ago
1
$begingroup$
Bit of a difference here is that the baseball in question is having a fusion reaction with the air around it. A starship in the near-vacuum of space isn't going to have that problem. (It would of course still be catastrophic, but maybe not the giant fusion explosion described.) I suspect the damage would be somewhat more localized, as it's only where matter collides with other matter that there's a problem.
$endgroup$
– Darrel Hoffman
2 hours ago
6
$begingroup$
@DarrelHoffman: The spaceship is presumably filled with air (and/or denser material as stated by the OP) and at least 19m long (approximate distance between the batter and the pitcher in baseball), so you would have a similar effect. Maybe the front (at least the part not hit by the rock) survives a bit longer, until the gamma-rays from the back of the ship reach it.
$endgroup$
– Graipher
2 hours ago
4
$begingroup$
"is your entire spaceship is going to suffer a sudden and gratuitous existence failure" I can't stop laughing. As for the crew, and quoting a other What-if: they "wouldn't die of anything", they would just "stop being biology and start being physics"
$endgroup$
– Barranka
2 hours ago
|
show 3 more comments
14
$begingroup$
I love the line at the end of the XKCD, after explaining how the fusion fireball would destroy everything around that "A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base."
$endgroup$
– geoffc
4 hours ago
1
$begingroup$
Is that a Starship Titanic reference?
$endgroup$
– 0xDBFB7
4 hours ago
1
$begingroup$
Bit of a difference here is that the baseball in question is having a fusion reaction with the air around it. A starship in the near-vacuum of space isn't going to have that problem. (It would of course still be catastrophic, but maybe not the giant fusion explosion described.) I suspect the damage would be somewhat more localized, as it's only where matter collides with other matter that there's a problem.
$endgroup$
– Darrel Hoffman
2 hours ago
6
$begingroup$
@DarrelHoffman: The spaceship is presumably filled with air (and/or denser material as stated by the OP) and at least 19m long (approximate distance between the batter and the pitcher in baseball), so you would have a similar effect. Maybe the front (at least the part not hit by the rock) survives a bit longer, until the gamma-rays from the back of the ship reach it.
$endgroup$
– Graipher
2 hours ago
4
$begingroup$
"is your entire spaceship is going to suffer a sudden and gratuitous existence failure" I can't stop laughing. As for the crew, and quoting a other What-if: they "wouldn't die of anything", they would just "stop being biology and start being physics"
$endgroup$
– Barranka
2 hours ago
14
14
$begingroup$
I love the line at the end of the XKCD, after explaining how the fusion fireball would destroy everything around that "A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base."
$endgroup$
– geoffc
4 hours ago
$begingroup$
I love the line at the end of the XKCD, after explaining how the fusion fireball would destroy everything around that "A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base."
$endgroup$
– geoffc
4 hours ago
1
1
$begingroup$
Is that a Starship Titanic reference?
$endgroup$
– 0xDBFB7
4 hours ago
$begingroup$
Is that a Starship Titanic reference?
$endgroup$
– 0xDBFB7
4 hours ago
1
1
$begingroup$
Bit of a difference here is that the baseball in question is having a fusion reaction with the air around it. A starship in the near-vacuum of space isn't going to have that problem. (It would of course still be catastrophic, but maybe not the giant fusion explosion described.) I suspect the damage would be somewhat more localized, as it's only where matter collides with other matter that there's a problem.
$endgroup$
– Darrel Hoffman
2 hours ago
$begingroup$
Bit of a difference here is that the baseball in question is having a fusion reaction with the air around it. A starship in the near-vacuum of space isn't going to have that problem. (It would of course still be catastrophic, but maybe not the giant fusion explosion described.) I suspect the damage would be somewhat more localized, as it's only where matter collides with other matter that there's a problem.
$endgroup$
– Darrel Hoffman
2 hours ago
6
6
$begingroup$
@DarrelHoffman: The spaceship is presumably filled with air (and/or denser material as stated by the OP) and at least 19m long (approximate distance between the batter and the pitcher in baseball), so you would have a similar effect. Maybe the front (at least the part not hit by the rock) survives a bit longer, until the gamma-rays from the back of the ship reach it.
$endgroup$
– Graipher
2 hours ago
$begingroup$
@DarrelHoffman: The spaceship is presumably filled with air (and/or denser material as stated by the OP) and at least 19m long (approximate distance between the batter and the pitcher in baseball), so you would have a similar effect. Maybe the front (at least the part not hit by the rock) survives a bit longer, until the gamma-rays from the back of the ship reach it.
$endgroup$
– Graipher
2 hours ago
4
4
$begingroup$
"is your entire spaceship is going to suffer a sudden and gratuitous existence failure" I can't stop laughing. As for the crew, and quoting a other What-if: they "wouldn't die of anything", they would just "stop being biology and start being physics"
$endgroup$
– Barranka
2 hours ago
$begingroup$
"is your entire spaceship is going to suffer a sudden and gratuitous existence failure" I can't stop laughing. As for the crew, and quoting a other What-if: they "wouldn't die of anything", they would just "stop being biology and start being physics"
$endgroup$
– Barranka
2 hours ago
|
show 3 more comments
$begingroup$
I answer this question from a purely structural-mechanical point of view (i.e. not considering fusion as provided in @DanPichelman's answer).
Will it create a football sized hole through the ship in the blink of an eye [...]?
That's probably right. The rock hits the structure so fast that no inertial effects have a chance of taking place before the incident is already over. "Communication" of the subjected material with the surroundings would simply be too slow. So, any elasticity or plasticity of the structural material would be irrelevant to the impact. The rock would leave a hole the approximately shape of its silhouette. As it goes through the layers of the ship, that silhouette will of course change.
Will there be a huge shockwave throughout the ship from the impact?
I guess not as much as you'd expect, from a structural point of view. Except that the hull of the ship contains residual stresses beforehand. Those might relax after the structure has been weakened, causing waves propagating through the ship in the classical way. But that would not be of any significance since the ship would have major leakage of its inner atmosphere (if it was pressurized).
Think of a classical metal shear. There, the surrounding material is mounted somewhere, and only the local part of the material is affected by the "impact". In the case of our starship, the mounting force of the surrounding material is its inertia.
answered 3 hours ago
Everyday AstronautEveryday Astronaut
1,669729
$endgroup$
$begingroup$
It seems probable to me that any spaceship that accelerated to 0.9c would have encountered matter previously which would (assuming the ship still exists) accumulate as a wave front ahead of said ship. Making the presence of an object with -0.9c relative velocity surviving to make contact incredibly unlikely, especially if it was natural.
$endgroup$
– Giu Piete
2 hours ago
1
$begingroup$
The energy is carried sideways not by sound or mechanical forces but by gamma rays, X rays and other energetic particles.
$endgroup$
– Steve Linton
2 hours ago
$begingroup$
Wouldn't the fragments of the impacted materials in the ship spread to hit other things like when a bullet strikes a bone and the bone fragments then impact other organs and such? (excepting the whole fusion aspect.)
$endgroup$
– Tracy Cramer
43 mins ago
$begingroup$
As the mass starts interacting with the ship, conservation of momentum would dictate that the center of mass of (football plus affected parts of ship) will in the short term have a constant velocity, which will be somewhere between the velocities of the football and the ship. If the football is heavy relative to the stuff it passes through, all of that mass is going to be squished flat and won't re-expand until the ship is a long way away. If the football passes through enough denser material, however, it might be slowed enough that other effects take over.
$endgroup$
– supercat
2 mins ago
add a comment |
$begingroup$
I answer this question from a purely structural-mechanical point of view (i.e. not considering fusion as provided in @DanPichelman's answer).
Will it create a football sized hole through the ship in the blink of an eye [...]?
That's probably right. The rock hits the structure so fast that no inertial effects have a chance of taking place before the incident is already over. "Communication" of the subjected material with the surroundings would simply be too slow. So, any elasticity or plasticity of the structural material would be irrelevant to the impact. The rock would leave a hole the approximately shape of its silhouette. As it goes through the layers of the ship, that silhouette will of course change.
Will there be a huge shockwave throughout the ship from the impact?
I guess not as much as you'd expect, from a structural point of view. Except that the hull of the ship contains residual stresses beforehand. Those might relax after the structure has been weakened, causing waves propagating through the ship in the classical way. But that would not be of any significance since the ship would have major leakage of its inner atmosphere (if it was pressurized).
Think of a classical metal shear. There, the surrounding material is mounted somewhere, and only the local part of the material is affected by the "impact". In the case of our starship, the mounting force of the surrounding material is its inertia.
answered 3 hours ago
Everyday AstronautEveryday Astronaut
1,669729
$endgroup$
$begingroup$
It seems probable to me that any spaceship that accelerated to 0.9c would have encountered matter previously which would (assuming the ship still exists) accumulate as a wave front ahead of said ship. Making the presence of an object with -0.9c relative velocity surviving to make contact incredibly unlikely, especially if it was natural.
$endgroup$
– Giu Piete
2 hours ago
1
$begingroup$
The energy is carried sideways not by sound or mechanical forces but by gamma rays, X rays and other energetic particles.
$endgroup$
– Steve Linton
2 hours ago
$begingroup$
Wouldn't the fragments of the impacted materials in the ship spread to hit other things like when a bullet strikes a bone and the bone fragments then impact other organs and such? (excepting the whole fusion aspect.)
$endgroup$
– Tracy Cramer
43 mins ago
$begingroup$
As the mass starts interacting with the ship, conservation of momentum would dictate that the center of mass of (football plus affected parts of ship) will in the short term have a constant velocity, which will be somewhere between the velocities of the football and the ship. If the football is heavy relative to the stuff it passes through, all of that mass is going to be squished flat and won't re-expand until the ship is a long way away. If the football passes through enough denser material, however, it might be slowed enough that other effects take over.
$endgroup$
– supercat
2 mins ago
add a comment |
$begingroup$
I answer this question from a purely structural-mechanical point of view (i.e. not considering fusion as provided in @DanPichelman's answer).
Will it create a football sized hole through the ship in the blink of an eye [...]?
That's probably right. The rock hits the structure so fast that no inertial effects have a chance of taking place before the incident is already over. "Communication" of the subjected material with the surroundings would simply be too slow. So, any elasticity or plasticity of the structural material would be irrelevant to the impact. The rock would leave a hole the approximately shape of its silhouette. As it goes through the layers of the ship, that silhouette will of course change.
Will there be a huge shockwave throughout the ship from the impact?
I guess not as much as you'd expect, from a structural point of view. Except that the hull of the ship contains residual stresses beforehand. Those might relax after the structure has been weakened, causing waves propagating through the ship in the classical way. But that would not be of any significance since the ship would have major leakage of its inner atmosphere (if it was pressurized).
Think of a classical metal shear. There, the surrounding material is mounted somewhere, and only the local part of the material is affected by the "impact". In the case of our starship, the mounting force of the surrounding material is its inertia.
answered 3 hours ago
Everyday AstronautEveryday Astronaut
1,669729
$endgroup$
I answer this question from a purely structural-mechanical point of view (i.e. not considering fusion as provided in @DanPichelman's answer).
Will it create a football sized hole through the ship in the blink of an eye [...]?
That's probably right. The rock hits the structure so fast that no inertial effects have a chance of taking place before the incident is already over. "Communication" of the subjected material with the surroundings would simply be too slow. So, any elasticity or plasticity of the structural material would be irrelevant to the impact. The rock would leave a hole the approximately shape of its silhouette. As it goes through the layers of the ship, that silhouette will of course change.
Will there be a huge shockwave throughout the ship from the impact?
I guess not as much as you'd expect, from a structural point of view. Except that the hull of the ship contains residual stresses beforehand. Those might relax after the structure has been weakened, causing waves propagating through the ship in the classical way. But that would not be of any significance since the ship would have major leakage of its inner atmosphere (if it was pressurized).
Think of a classical metal shear. There, the surrounding material is mounted somewhere, and only the local part of the material is affected by the "impact". In the case of our starship, the mounting force of the surrounding material is its inertia.
answered 3 hours ago
Everyday AstronautEveryday Astronaut
1,669729
answered 3 hours ago
Everyday AstronautEveryday Astronaut
1,669729
answered 3 hours ago
Everyday AstronautEveryday Astronaut
1,669729
answered 3 hours ago
Everyday AstronautEveryday Astronaut
1,669729
1,669729
$begingroup$
It seems probable to me that any spaceship that accelerated to 0.9c would have encountered matter previously which would (assuming the ship still exists) accumulate as a wave front ahead of said ship. Making the presence of an object with -0.9c relative velocity surviving to make contact incredibly unlikely, especially if it was natural.
$endgroup$
– Giu Piete
2 hours ago
1
$begingroup$
The energy is carried sideways not by sound or mechanical forces but by gamma rays, X rays and other energetic particles.
$endgroup$
– Steve Linton
2 hours ago
$begingroup$
Wouldn't the fragments of the impacted materials in the ship spread to hit other things like when a bullet strikes a bone and the bone fragments then impact other organs and such? (excepting the whole fusion aspect.)
$endgroup$
– Tracy Cramer
43 mins ago
$begingroup$
As the mass starts interacting with the ship, conservation of momentum would dictate that the center of mass of (football plus affected parts of ship) will in the short term have a constant velocity, which will be somewhere between the velocities of the football and the ship. If the football is heavy relative to the stuff it passes through, all of that mass is going to be squished flat and won't re-expand until the ship is a long way away. If the football passes through enough denser material, however, it might be slowed enough that other effects take over.
$endgroup$
– supercat
2 mins ago
add a comment |
$begingroup$
It seems probable to me that any spaceship that accelerated to 0.9c would have encountered matter previously which would (assuming the ship still exists) accumulate as a wave front ahead of said ship. Making the presence of an object with -0.9c relative velocity surviving to make contact incredibly unlikely, especially if it was natural.
$endgroup$
– Giu Piete
2 hours ago
1
$begingroup$
The energy is carried sideways not by sound or mechanical forces but by gamma rays, X rays and other energetic particles.
$endgroup$
– Steve Linton
2 hours ago
$begingroup$
Wouldn't the fragments of the impacted materials in the ship spread to hit other things like when a bullet strikes a bone and the bone fragments then impact other organs and such? (excepting the whole fusion aspect.)
$endgroup$
– Tracy Cramer
43 mins ago
$begingroup$
As the mass starts interacting with the ship, conservation of momentum would dictate that the center of mass of (football plus affected parts of ship) will in the short term have a constant velocity, which will be somewhere between the velocities of the football and the ship. If the football is heavy relative to the stuff it passes through, all of that mass is going to be squished flat and won't re-expand until the ship is a long way away. If the football passes through enough denser material, however, it might be slowed enough that other effects take over.
$endgroup$
– supercat
2 mins ago
$begingroup$
It seems probable to me that any spaceship that accelerated to 0.9c would have encountered matter previously which would (assuming the ship still exists) accumulate as a wave front ahead of said ship. Making the presence of an object with -0.9c relative velocity surviving to make contact incredibly unlikely, especially if it was natural.
$endgroup$
– Giu Piete
2 hours ago
$begingroup$
It seems probable to me that any spaceship that accelerated to 0.9c would have encountered matter previously which would (assuming the ship still exists) accumulate as a wave front ahead of said ship. Making the presence of an object with -0.9c relative velocity surviving to make contact incredibly unlikely, especially if it was natural.
$endgroup$
– Giu Piete
2 hours ago
1
1
$begingroup$
The energy is carried sideways not by sound or mechanical forces but by gamma rays, X rays and other energetic particles.
$endgroup$
– Steve Linton
2 hours ago
$begingroup$
The energy is carried sideways not by sound or mechanical forces but by gamma rays, X rays and other energetic particles.
$endgroup$
– Steve Linton
2 hours ago
$begingroup$
Wouldn't the fragments of the impacted materials in the ship spread to hit other things like when a bullet strikes a bone and the bone fragments then impact other organs and such? (excepting the whole fusion aspect.)
$endgroup$
– Tracy Cramer
43 mins ago
$begingroup$
Wouldn't the fragments of the impacted materials in the ship spread to hit other things like when a bullet strikes a bone and the bone fragments then impact other organs and such? (excepting the whole fusion aspect.)
$endgroup$
– Tracy Cramer
43 mins ago
$begingroup$
As the mass starts interacting with the ship, conservation of momentum would dictate that the center of mass of (football plus affected parts of ship) will in the short term have a constant velocity, which will be somewhere between the velocities of the football and the ship. If the football is heavy relative to the stuff it passes through, all of that mass is going to be squished flat and won't re-expand until the ship is a long way away. If the football passes through enough denser material, however, it might be slowed enough that other effects take over.
$endgroup$
– supercat
2 mins ago
$begingroup$
As the mass starts interacting with the ship, conservation of momentum would dictate that the center of mass of (football plus affected parts of ship) will in the short term have a constant velocity, which will be somewhere between the velocities of the football and the ship. If the football is heavy relative to the stuff it passes through, all of that mass is going to be squished flat and won't re-expand until the ship is a long way away. If the football passes through enough denser material, however, it might be slowed enough that other effects take over.
$endgroup$
– supercat
2 mins ago
add a comment |
$begingroup$
On 0.9c, the kinetical energy of an 1g rock is $mc^2(frac{1}{sqrt{1-frac{v^2}{c^2}}}-1)$ (ref).
Substituting 0.9c and 0.001kg, we get 116 TJ.
As a comparison, the Little Boy nuclear bomb released 93 TJ energy.
Also the result would look similar. No known spaceship material could resist this.
answered 2 hours ago
peterhpeterh
1,93111531
$endgroup$
2
$begingroup$
Wouldn't we need to decelerate the rock to zero (resp. spaceship velocity) to release that kinetic energy?
$endgroup$
– Guntram Blohm
1 hour ago
$begingroup$
@GuntramBlohm Yes. It would decelerate to nearly-zero (in the frame of the spaceship) on collision. Its impulse would be quite small (compared to its kinetical energy), so the result would be probably a gas cloud, moving roughly on the original trajectory of the spaceship.
$endgroup$
– peterh
1 hour ago
$begingroup$
You might recalculate. The volume of a football is about 4.6 liters, and assume a specific gravity of rock as 2.5 (it can be much greater, but it's about right for stuff like limestone or granite), the mass of the rock will be 11.5 kg, more or less. So you're looking at more like 1.3 EJ.
$endgroup$
– WhatRoughBeast
1 hour ago
$begingroup$
@WhatRoughBeast The kinetical energy depends on the mass, volume doesn't matter. In this answer, I intentionally used a small mass to show that even a collision with a very little mass would be fatal. If you use $approx$ 10000 times bigger mass, also the kinetical energy would be 10000 times bigger. Note, space waste is a major problem even on Low Earth Orbit, despite that there we are talking about thousand times smaller masses and 30000x smalles velocities.
$endgroup$
– peterh
1 hour ago
2
$begingroup$
@WhatRoughBeast The essence of the answer is that a collision with practically any small object is unavoidably fatal with any currently known technology, and results a gas cloud. It is a proof. I could rewrite the question for a body mass of, f.e. 10kg, the result would be the same. The goal is to show, that not only a collision with a 10kg stone is fatal, already a collision with an 1g stone is fatal.
$endgroup$
– peterh
1 hour ago
|
show 1 more comment
$begingroup$
On 0.9c, the kinetical energy of an 1g rock is $mc^2(frac{1}{sqrt{1-frac{v^2}{c^2}}}-1)$ (ref).
Substituting 0.9c and 0.001kg, we get 116 TJ.
As a comparison, the Little Boy nuclear bomb released 93 TJ energy.
Also the result would look similar. No known spaceship material could resist this.
answered 2 hours ago
peterhpeterh
1,93111531
$endgroup$
2
$begingroup$
Wouldn't we need to decelerate the rock to zero (resp. spaceship velocity) to release that kinetic energy?
$endgroup$
– Guntram Blohm
1 hour ago
$begingroup$
@GuntramBlohm Yes. It would decelerate to nearly-zero (in the frame of the spaceship) on collision. Its impulse would be quite small (compared to its kinetical energy), so the result would be probably a gas cloud, moving roughly on the original trajectory of the spaceship.
$endgroup$
– peterh
1 hour ago
$begingroup$
You might recalculate. The volume of a football is about 4.6 liters, and assume a specific gravity of rock as 2.5 (it can be much greater, but it's about right for stuff like limestone or granite), the mass of the rock will be 11.5 kg, more or less. So you're looking at more like 1.3 EJ.
$endgroup$
– WhatRoughBeast
1 hour ago
$begingroup$
@WhatRoughBeast The kinetical energy depends on the mass, volume doesn't matter. In this answer, I intentionally used a small mass to show that even a collision with a very little mass would be fatal. If you use $approx$ 10000 times bigger mass, also the kinetical energy would be 10000 times bigger. Note, space waste is a major problem even on Low Earth Orbit, despite that there we are talking about thousand times smaller masses and 30000x smalles velocities.
$endgroup$
– peterh
1 hour ago
2
$begingroup$
@WhatRoughBeast The essence of the answer is that a collision with practically any small object is unavoidably fatal with any currently known technology, and results a gas cloud. It is a proof. I could rewrite the question for a body mass of, f.e. 10kg, the result would be the same. The goal is to show, that not only a collision with a 10kg stone is fatal, already a collision with an 1g stone is fatal.
$endgroup$
– peterh
1 hour ago
|
show 1 more comment
$begingroup$
On 0.9c, the kinetical energy of an 1g rock is $mc^2(frac{1}{sqrt{1-frac{v^2}{c^2}}}-1)$ (ref).
Substituting 0.9c and 0.001kg, we get 116 TJ.
As a comparison, the Little Boy nuclear bomb released 93 TJ energy.
Also the result would look similar. No known spaceship material could resist this.
answered 2 hours ago
peterhpeterh
1,93111531
$endgroup$
On 0.9c, the kinetical energy of an 1g rock is $mc^2(frac{1}{sqrt{1-frac{v^2}{c^2}}}-1)$ (ref).
Substituting 0.9c and 0.001kg, we get 116 TJ.
As a comparison, the Little Boy nuclear bomb released 93 TJ energy.
Also the result would look similar. No known spaceship material could resist this.
answered 2 hours ago
peterhpeterh
1,93111531
answered 2 hours ago
peterhpeterh
1,93111531
answered 2 hours ago
peterhpeterh
1,93111531
answered 2 hours ago
peterhpeterh
1,93111531
1,93111531
2
$begingroup$
Wouldn't we need to decelerate the rock to zero (resp. spaceship velocity) to release that kinetic energy?
$endgroup$
– Guntram Blohm
1 hour ago
$begingroup$
@GuntramBlohm Yes. It would decelerate to nearly-zero (in the frame of the spaceship) on collision. Its impulse would be quite small (compared to its kinetical energy), so the result would be probably a gas cloud, moving roughly on the original trajectory of the spaceship.
$endgroup$
– peterh
1 hour ago
$begingroup$
You might recalculate. The volume of a football is about 4.6 liters, and assume a specific gravity of rock as 2.5 (it can be much greater, but it's about right for stuff like limestone or granite), the mass of the rock will be 11.5 kg, more or less. So you're looking at more like 1.3 EJ.
$endgroup$
– WhatRoughBeast
1 hour ago
$begingroup$
@WhatRoughBeast The kinetical energy depends on the mass, volume doesn't matter. In this answer, I intentionally used a small mass to show that even a collision with a very little mass would be fatal. If you use $approx$ 10000 times bigger mass, also the kinetical energy would be 10000 times bigger. Note, space waste is a major problem even on Low Earth Orbit, despite that there we are talking about thousand times smaller masses and 30000x smalles velocities.
$endgroup$
– peterh
1 hour ago
2
$begingroup$
@WhatRoughBeast The essence of the answer is that a collision with practically any small object is unavoidably fatal with any currently known technology, and results a gas cloud. It is a proof. I could rewrite the question for a body mass of, f.e. 10kg, the result would be the same. The goal is to show, that not only a collision with a 10kg stone is fatal, already a collision with an 1g stone is fatal.
$endgroup$
– peterh
1 hour ago
|
show 1 more comment
2
$begingroup$
Wouldn't we need to decelerate the rock to zero (resp. spaceship velocity) to release that kinetic energy?
$endgroup$
– Guntram Blohm
1 hour ago
$begingroup$
@GuntramBlohm Yes. It would decelerate to nearly-zero (in the frame of the spaceship) on collision. Its impulse would be quite small (compared to its kinetical energy), so the result would be probably a gas cloud, moving roughly on the original trajectory of the spaceship.
$endgroup$
– peterh
1 hour ago
$begingroup$
You might recalculate. The volume of a football is about 4.6 liters, and assume a specific gravity of rock as 2.5 (it can be much greater, but it's about right for stuff like limestone or granite), the mass of the rock will be 11.5 kg, more or less. So you're looking at more like 1.3 EJ.
$endgroup$
– WhatRoughBeast
1 hour ago
$begingroup$
@WhatRoughBeast The kinetical energy depends on the mass, volume doesn't matter. In this answer, I intentionally used a small mass to show that even a collision with a very little mass would be fatal. If you use $approx$ 10000 times bigger mass, also the kinetical energy would be 10000 times bigger. Note, space waste is a major problem even on Low Earth Orbit, despite that there we are talking about thousand times smaller masses and 30000x smalles velocities.
$endgroup$
– peterh
1 hour ago
2
$begingroup$
@WhatRoughBeast The essence of the answer is that a collision with practically any small object is unavoidably fatal with any currently known technology, and results a gas cloud. It is a proof. I could rewrite the question for a body mass of, f.e. 10kg, the result would be the same. The goal is to show, that not only a collision with a 10kg stone is fatal, already a collision with an 1g stone is fatal.
$endgroup$
– peterh
1 hour ago
2
2
$begingroup$
Wouldn't we need to decelerate the rock to zero (resp. spaceship velocity) to release that kinetic energy?
$endgroup$
– Guntram Blohm
1 hour ago
$begingroup$
Wouldn't we need to decelerate the rock to zero (resp. spaceship velocity) to release that kinetic energy?
$endgroup$
– Guntram Blohm
1 hour ago
$begingroup$
@GuntramBlohm Yes. It would decelerate to nearly-zero (in the frame of the spaceship) on collision. Its impulse would be quite small (compared to its kinetical energy), so the result would be probably a gas cloud, moving roughly on the original trajectory of the spaceship.
$endgroup$
– peterh
1 hour ago
$begingroup$
@GuntramBlohm Yes. It would decelerate to nearly-zero (in the frame of the spaceship) on collision. Its impulse would be quite small (compared to its kinetical energy), so the result would be probably a gas cloud, moving roughly on the original trajectory of the spaceship.
$endgroup$
– peterh
1 hour ago
$begingroup$
You might recalculate. The volume of a football is about 4.6 liters, and assume a specific gravity of rock as 2.5 (it can be much greater, but it's about right for stuff like limestone or granite), the mass of the rock will be 11.5 kg, more or less. So you're looking at more like 1.3 EJ.
$endgroup$
– WhatRoughBeast
1 hour ago
$begingroup$
You might recalculate. The volume of a football is about 4.6 liters, and assume a specific gravity of rock as 2.5 (it can be much greater, but it's about right for stuff like limestone or granite), the mass of the rock will be 11.5 kg, more or less. So you're looking at more like 1.3 EJ.
$endgroup$
– WhatRoughBeast
1 hour ago
$begingroup$
@WhatRoughBeast The kinetical energy depends on the mass, volume doesn't matter. In this answer, I intentionally used a small mass to show that even a collision with a very little mass would be fatal. If you use $approx$ 10000 times bigger mass, also the kinetical energy would be 10000 times bigger. Note, space waste is a major problem even on Low Earth Orbit, despite that there we are talking about thousand times smaller masses and 30000x smalles velocities.
$endgroup$
– peterh
1 hour ago
$begingroup$
@WhatRoughBeast The kinetical energy depends on the mass, volume doesn't matter. In this answer, I intentionally used a small mass to show that even a collision with a very little mass would be fatal. If you use $approx$ 10000 times bigger mass, also the kinetical energy would be 10000 times bigger. Note, space waste is a major problem even on Low Earth Orbit, despite that there we are talking about thousand times smaller masses and 30000x smalles velocities.
$endgroup$
– peterh
1 hour ago
2
2
$begingroup$
@WhatRoughBeast The essence of the answer is that a collision with practically any small object is unavoidably fatal with any currently known technology, and results a gas cloud. It is a proof. I could rewrite the question for a body mass of, f.e. 10kg, the result would be the same. The goal is to show, that not only a collision with a 10kg stone is fatal, already a collision with an 1g stone is fatal.
$endgroup$
– peterh
1 hour ago
$begingroup$
@WhatRoughBeast The essence of the answer is that a collision with practically any small object is unavoidably fatal with any currently known technology, and results a gas cloud. It is a proof. I could rewrite the question for a body mass of, f.e. 10kg, the result would be the same. The goal is to show, that not only a collision with a 10kg stone is fatal, already a collision with an 1g stone is fatal.
$endgroup$
– peterh
1 hour ago
|
show 1 more comment
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14
$begingroup$
what-if.xkcd.com/1
$endgroup$
– Hobbes
5 hours ago
3
$begingroup$
A simpler to visualize, but totally equivalent, question would be to consider the ship as stationary and ask what would happen if it were hit by a rock that is traveling at .9c.
$endgroup$
– Ray Butterworth
4 hours ago
$begingroup$
Do you have shields? (If you don't have shields don't even attempt to go that fast) Are your shields up? Using a warp bubble? (If thick enough the warp bubble might prevent it from hitting your ship.)
$endgroup$
– cybernard
1 hour ago