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Sunspace
11-02-2009, 10:03 PM
On page two of Neal Stephenson's Snow Crash, the mighty car of the Deliverator is described as having "enough potential energy packed into its batteries to fire a pound of bacon into the Asteroid Belt." How much energy is this? (I assume we start on Earth. Neal did.)

Silophant
11-02-2009, 10:40 PM
Well, assuming it's aimed right, once it hits escape velocity, it'll get to the asteroid belt eventually. Escape Velocity is 25,000 mph, and according to this site (http://home.earthlink.net/~jedcline/ets.html), it takes 7.89 KwHr to accelerate 1 pound to escape velocity. According to this (http://mb-soft.com/public2/storing.html), a typical car battery stores about 1 KwHr. So, we're looking at a little less than eight car batteries worth of power.

Chronos
11-02-2009, 11:13 PM
I don't have time to do the calculations right now, but don't forget about the Sun's gravitational potential, too. Still, that'll be in the same ballpark, so it's a plausible amount of energy for a near-future vehicle's batteries.

matt_mcl
11-02-2009, 11:13 PM
It's a trick question. It's impossible to do, because it won't happen until pigs fly.

Der Trihs
11-03-2009, 12:03 AM
It's a trick question. It's impossible to do, because it won't happen until pigs fly.:D

Gorsnak
11-03-2009, 07:27 AM
Puts a new perspective on the "How long does bacon stay good?" thread, though.

pan1
11-03-2009, 08:39 AM
8 batteries(given the above numbers) would provide enough power to reach escape velocity but would not be enough to maintain it long enough to escape the atmosphere.

You need a rocket scientist to give a more accurate answer.

But things you need to know:
What propulsion system? I'm not aware of a battery powered propulsion system that can focus enough power in a portable space to break atmo. Once you're in space. An Ion drive is easily battery powered, but that's useless in atmo. Don't forget to account for the weight of the batteries. And AFAIK there does not exist a battery capable of lifting it's own weight to space.

tullsterx
11-03-2009, 08:54 AM
Pan, I don't think I understand you comment about maintaining escape velocity. I thought escape velocity was the speed needed to "break free" from a gravitational field without any additional impulse. Why would you need to "maintain" escape velocity?

pan1
11-03-2009, 09:43 AM
Pan, I don't think I understand you comment about maintaining escape velocity. I thought escape velocity was the speed needed to "break free" from a gravitational field without any additional impulse. Why would you need to "maintain" escape velocity?

Ok, so your bacon is launched immediately to escape velocity at the surface of Earth. It's been propulsed by a battery powered catapult. All the energy to set it going has been used and the bacon itself no longer has a propulsion generator, but it's going escape velocity.

...At the surface.

By the time it reaches 100 miles up, it's not going escape velocity anymore. It will still break atmo but it will settle into orbit or fall back down to earth without something to accelerate it back to escape velocity.

The calculations provided in the first few posts are valid from orbit, where things like wind resistance are not a factor, but not from the earths surface.

Attaining escape velocity is not enough to break orbit, you have to maintain it until you do. From orbit, theres not much to slow you down, but from the surface of the earth theres a hundred or so miles of atmosphere to get through.

unclelem
11-03-2009, 09:43 AM
Pan, I don't think I understand you comment about maintaining escape velocity. I thought escape velocity was the speed needed to "break free" from a gravitational field without any additional impulse. Why would you need to "maintain" escape velocity?

Atmospheric drag

ivn1188
11-03-2009, 10:03 AM
Ok, so your bacon is launched immediately to escape velocity at the surface of Earth. It's been propulsed by a battery powered catapult. All the energy to set it going has been used and the bacon itself no longer has a propulsion generator, but it's going escape velocity.

...At the surface.

By the time it reaches 100 miles up, it's not going escape velocity anymore. It will still break atmo but it will settle into orbit or fall back down to earth without something to accelerate it back to escape velocity.

The calculations provided in the first few posts are valid from orbit, where things like wind resistance are not a factor, but not from the earths surface.

Attaining escape velocity is not enough to break orbit, you have to maintain it until you do. From orbit, theres not much to slow you down, but from the surface of the earth theres a hundred or so miles of atmosphere to get through.

This is a completely incorrect understanding of escape velocity. Ignoring, for the moment, drag caused by the air, if an object is moving at escape velocity for it's given point in a gravitational field, it will never come back. Period. You don't need to keep your speed up unless you have drag acting to slow down your object. You are correct in that the escape velocity is not the whole story, but it's possible to figure out how much drag you need to overcome, and add that energy into your calculation so you get an escape speed adjusted for atmospheric drag. It is certainly possible to launch a ballistic object and escape the Earth's gravity well. (Ballistic meaning it is not powered, obviously.)

Furthermore, there is fundamentally no difference between an object falling back to Earth and settling into orbit. If you drop, throw, or shoot an object it is in orbit, albeit an orbit that intersects with the planet itself. If you think back to the experiment of drilling a hole through the Earth, you would oscillate between the entrance and exit of the shaft -- that's an orbit too.

Escape velocity is apparently a completely misunderstood idea on this board. It is nothing more than the speed at which you need to be moving at that point in a gravitational field to never come back. Or more simply, how fast you need to throw your baseball so it never comes back (in a vaccuum).

Irishman
11-03-2009, 10:13 AM
When I hear "enough potential energy packed into its batteries to fire a pound of bacon into the Asteroid Belt", I don't think "powering an electrically driven propulsion system like an ion drive". I think "that if set off in an explosion would make the pound of bacon fly through the air and space until it reached the Asteroid belt". YMMV.

I think Stephenson's intent was to emphasize a "boom" rather than suggest a practical means for delivering breakfast foods to space explorers. Not having read Snow Crash, however, I'm just guessing.

Obviously escape velocity is just a starting point. Since it neglects atmospheric friction, someone is going to have to estimate that. And someone is going to have to figure out blast efficiency - how much of that energy went into moving bacon upward vs how much went sideways away from the bacon, and how much was heat, and how much moved dirt out from under the bacon.

But at least there's one advantage to this approach - the bacon arrives cooked and ready to eat. ;)

pan1
11-03-2009, 10:21 AM
This is a completely incorrect understanding of escape velocity. Ignoring, for the moment, drag caused by the air, if an object is moving at escape velocity for it's given point in a gravitational field, it will never come back. Period. You don't need to keep your speed up unless you have drag acting to slow down your object. You are correct in that the escape velocity is not the whole story, but it's possible to figure out how much drag you need to overcome, and add that energy into your calculation so you get an escape speed adjusted for atmospheric drag. It is certainly possible to launch a ballistic object and escape the Earth's gravity well. (Ballistic meaning it is not powered, obviously.)

Furthermore, there is fundamentally no difference between an object falling back to Earth and settling into orbit. If you drop, throw, or shoot an object it is in orbit, albeit an orbit that intersects with the planet itself. If you think back to the experiment of drilling a hole through the Earth, you would oscillate between the entrance and exit of the shaft -- that's an orbit too.

Escape velocity is apparently a completely misunderstood idea on this board. It is nothing more than the speed at which you need to be moving at that point in a gravitational field to never come back. Or more simply, how fast you need to throw your baseball so it never comes back (in a vaccuum).

Of course I'm incorrect if you ignore the drag caused by air. My whole point is that the earlier calculation didn't account for drag caused by air.

And yes, an object must maintain escape velocity until its out of the gravity well. Just because it reaches escape velocity doesn't free it from the effects of gravity forever. If it slows back down for some reason before exiting the gravity well, its going to get caught again.

Achieving escape velocity at 100 ft off the ground is not a free ticket to deep space. It still has to be travelling at escape velocity when it reaches space. Which it won't be doing unless it was shot at a much greater speed than escape velocity. Since the whole point of my original argument was that the 8 car batteries math didn't take that into account...providing just enough energy to reach escape velocity is simply just not enough energy - from the Earth surface. From Orbit, as I've said before, it is enough energy.

ivn1188
11-03-2009, 10:25 AM
It's fairly clear that he means the amount of energy you would have to impart to the bacon in order to launch it to the asteroid belt. The method of imparting that quantum of energy doesn't matter, nor does its efficiency.

pan1
11-03-2009, 10:30 AM
It's fairly clear that he means the amount of energy you would have to impart to the bacon in order to launch it to the asteroid belt. The method of imparting that quantum of energy doesn't matter, nor does its efficiency.

I guess if you're just asking theoretically...but I was thinking too practically, I guess.

So if you can get all the energy out of 8 car batteries at once, you have the energy you need to launch bacon from earths orbit to the asteroid field (and beyond)

ivn1188
11-03-2009, 10:32 AM
Achieving escape velocity at 100 ft off the ground is not a free ticket to deep space. It still has to be travelling at escape velocity when it reaches space. Which it won't be doing unless it was shot at a much greater speed than escape velocity. Since the whole point of my original argument was that the 8 car batteries math didn't take that into account...providing just enough energy to reach escape velocity is simply just not enough energy - from the Earth surface. From Orbit, as I've said before, it is enough energy.

I didn't say you were incorrect. I did say that, based on your post, you made it sound like you don't understand escape velocity. It would have been much simpler to just say to you need to add the energy required to fight atmospheric drag.

Xema
11-03-2009, 11:10 AM
Atmospheric drag causes various problems for the "bacon-on-a-railgun" scheme. When that bacon emerges at 11,000m/s or so, it rapidly heats and vaporizes. I say slow it down some - it won't reach anywhere near the asteroid belt, but at least we might get some cooked bacon bits out of the deal.

Xema
11-03-2009, 11:13 AM
I didn't say you were incorrect. I did say that, based on your post, you made it sound like you don't understand escape velocity. It would have been much simpler to just say to you need to add the energy required to fight atmospheric drag.
Well, he/she did say "From orbit, theres not much to slow you down, but from the surface of the earth theres a hundred or so miles of atmosphere to get through.".

CalMeacham
11-03-2009, 11:17 AM
You need more than Escape Velocity from Earth to reach the asteroid belt -- you still have to overcome the gravitational potential due to the Sun between Earth's Orbit and the Asteroid Belt (as Chronos has already pointed out). It's a shallower curve, but by no means inconsequential. And if you don't overcome it you will not get to the asteroid belt, no matter how long you wait.

Duckster
11-03-2009, 11:49 AM
It's a trick question. It's impossible to do, because it won't happen until pigs fly.

I take it you haven't been reading the news of late. Quite a few news stories about how the swine flu ...

Sunspace
11-03-2009, 12:27 PM
Okay... we have an elecrically-powered pork-product projector on the earth's surface, which fires indestructible (i.e. perfect) pound-sized pork pieces into orbit. We have to supply energy to reach earth escape velocity, plus additional energy to compensate for the drag of the atmosphere, plus some additional amount to take us from earth orbit to the asteroid belt. I had an image of the pork piece coasting upwards, away from the earth and sun through the solar system, and moving slower and slower until at the centre of the asteroid belt, it comes to a halt for an instant, then slowly starts to fall backwards. It would probably fall back to land in the sun and lend a hint of pork flavour to the solar wind for a moment.

Is it possible to do this with one well-aimed shot? What if we wanted the pork to take up orbit in the belt, rather than just pausing there?

ivn1188
11-03-2009, 12:35 PM
No, the bacon will likely end up in orbit around Jupiter or Mars or one of the bigger asteroids. Each body has a region of space where it is the dominant gravitational well, called the Hill Sphere. I suppose it might be possible to time your shot so that you can slingshot around but if it stops in the asteroid belt, it's going to stay near there.

pan1
11-03-2009, 12:35 PM
Is it possible to do this with one well-aimed shot? What if we wanted the pork to take up orbit in the belt, rather than just pausing there?

Yes it's possible. Do I know the precise mathematical numbers involved, no. But, keep in mind that its probably just launched into orbit around the sun, so actually hitting the sun on the return trip is a bit tricky. You'd have to aim it close enough to another object, like Ceres, that the interaction would slow the bacon down and alter the trajectory to hit the sun.

Ditto, for settling into orbit in the asteroid belt.

Possible, yes. Easy, even to a rocket scientist, no. I don't know any nasa engineers that would want to try it without the possibility of correction thrusters.

CalMeacham
11-03-2009, 12:50 PM
Actually, after you get to the asteroid belt you'll have put the bacon into an elliptical orbit. It'll come back, cross the earth's orbit, and drop down to a minimum somewhere (I'd have to figure it out, and I ain't got the time right now -- probably still further out than Venus' orbit) before going back up towards the asteroid belt. It's not going to end up around Jupiter or Mars anytime soon.

Incidentally, there are ways to shoot a small package up into space without benefit of a rocket. The Laser Propulsion project I worked on for a few years was meant to do precisely that -- getting small packages into orbit, with only an outer shell and a block of Reaction Mass. Leik Myrabo's Apollo Lightship was supposed to do the same thing, but without the reaction mass -- he concentrated the light on the surrounding atmosphere.

Quercus
11-03-2009, 01:41 PM
Incidentally, there are ways to shoot a small package up into space without benefit of a rocket. The Laser Propulsion project I worked on for a few years was meant to do precisely that -- getting small packages into orbit, with only an outer shell and a block of Reaction Mass. Leik Myrabo's Apollo Lightship was supposed to do the same thing, but without the reaction mass -- he concentrated the light on the surrounding atmosphere.If technology has progressed enough that we have batteries nearly an order of magnitude better (actually, not nearly as technologically crazy as the auto-adjusting wheels on the skateboard), then we can just put the bacon on the Space Elevator, then catapult/railgun it out to the asteroids. Avoids atmosphere issues, and requires only the energy to counteract the gravity well (although the pre-cooking no longer happens)

Machine Elf
11-03-2009, 02:02 PM
And yes, an object must maintain escape velocity until its out of the gravity well.

Not true.

Just because it reaches escape velocity doesn't free it from the effects of gravity forever.

Actually, it does. That's the whole definition of escape velocity.

Steps:

1. Derive the equation for gravitational force on 1 lbm of bacon as a function of distance from earth's center.

2. Integrate from the earth's surface to a distance of infinity; this gives the total gravitational potential energy of the bacon after it has been moved infinitely far from the earth's surface. This is the amount of kinetic energy that must be imparted to the bacon, at the earth's surface, for it to keep moving away from the earth forever.

No matter what your object - porcine or otherwise - if you neglect atmospheric effects, escape velocity from the earth's surface is in the neighborhood of 25,000 MPH. Bacon launched with this initial velocity will continuously decelerate as it moves away from the earth, but barring interference from other celestial objects, it will indeed continue moving away from the earth forever.

Stathol
11-03-2009, 02:16 PM
Atmospheric drag causes various problems for the "bacon-on-a-railgun" scheme.

My mission for this week is to find a way to plausibly work the phrase "like bacon on a railgun" into a serious conversation.

Amusingly enough, this is not the first time that an attempt has been made to answer this exact question:

Bacon in the Asteroid Belt (http://scienceblogs.com/builtonfacts/2009/06/bacon_in_the_asteroid_belt.php)

It looks like they ignore the atmospheric effects, though.

Sunspace
11-03-2009, 02:22 PM
So, as you move farther and farther from the centre of the earth, the escape velocity at that point gets less and less? I'm imagining the bacon coasting slower and slower, but never quite stopping and falling back. This is in a universe where the bacon and the earth are the only two objects.

For going from the earth to the asteroid belt, would there also be calcualtion for the escape velocity from the sun, starting at the distance of the earth's orbit? And if we don't actually want to escape, but just go to the asteroid belt, we don't need to supply as much velocity?

Sunspace
11-03-2009, 02:26 PM
My mission for this week is to find a way to plausibly work the phrase "like bacon on a railgun" into a serious conversation.

Amusingly enough, this is not the first time that an attempt has been made to answer this exact question:

Bacon in the Asteroid Belt (http://scienceblogs.com/builtonfacts/2009/06/bacon_in_the_asteroid_belt.php)

It looks like they ignore the atmospheric effects, though.Cool! It turns out that you need much more energy to go from earth's oerbit to the asteroid belt than you need to only escape from the earth. Interesting.

pan1
11-03-2009, 02:26 PM
And yes, an object must maintain escape velocity until its out of the gravity well.

Not true.

Just because it reaches escape velocity doesn't free it from the effects of gravity forever.

Actually, it does. That's the whole definition of escape velocity.

So you're saying that if I manage to shoot a bb at 25,000 mph (defined as escape velocity earlier in the thread) from my back yard - it will leave earths gravity well. Even, when atmopheric drag reduces its speed to 24,999 after a small distance?

Think about what you're saying when you say what I said wasn't true.

You're saying that a satellite orbiting at orbital speed, that accidentally hits the wrong thruster and accelerates to 25000, then corrects itself back to orbital speed is screwed and cannot possibly return to orbit - no matter what amount of thrusting manuvers it undertakes.

Machine Elf
11-03-2009, 02:32 PM
So, as you move farther and farther from the centre of the earth, the escape velocity at that point gets less and less? I'm imagining the bacon coasting slower and slower, but never quite stopping and falling back.

Ayup, that's pretty much it. Like rolling up a hill whose slope gets more and more gentle as you approach the summit.

This is in a universe where the bacon and the earth are the only two objects.

A lonely, but oh-so-delicious universe.

For going from the earth to the asteroid belt, would there also be calcualtion for the escape velocity from the sun, starting at the distance of the earth's orbit? And if we don't actually want to escape, but just go to the asteroid belt, we don't need to supply as much velocity?

The sun would affect things. How much is hard to say without doing the math. I looked up the earth's orbital velocity around the sun, and figured out that the centripetal acceleration (and therefore the sun's gravitational acceleration at the earth's orbital radius) is about 0.006 meters per second, just a tiny fraction of earth's surface gravity. I'm too lazy to calculate solar escape velocity from the earth's orbital distance, but I'll WAG it doesn't add much to the 25K MPH we're already imparting to the bacon.

Boyo Jim
11-03-2009, 02:45 PM
You are all missing important factors

1. the bacon will probably fry on the way up. Atmospheric drag will heat the bacon, and the fat/grease will bubble up and be blown away in the wind.

So, in order to get a pound of bacon to the asteroid belt, you will need to start with quite a bit more bacon. How much? I dunno, but the fat content will be a variable in determining what the initial pile of bacon must weigh.

2. And, it might be what starts as bacon on the ground, won't be bacon by the time it gets into space. Can you call a hunk of charred carbon bacon?

So, I contend you need some kind of shell to protect the bacon from thermal destruction during the first few minutes of launch. Possibly, with the right material, the shell might weight less than the initial bacon mass that would be needed for an unshielded launch.

3. And then, once it gets into space and is subjected to near absolute zero temperature and possibly cosmic ray bombardment, can it survive as bacon the remainder of the journey? I don't know this either, but I am shocked that all you big brains haven't considered this. So I contend it will need some kind of environmental support system to maintain its essential baconness. All of which will add a great deal of weight to the initial launch.

I also contend that the point of the whole exercise is to deliver edible bacon to the asteroid belt. Otherwise, you might as well ask what it takes to deliver a pound of mass to the asteroind belt.

Fortunately we have the technology. It's called the Saturn V rocket. :p

Chronos
11-03-2009, 02:45 PM
Actually, after you get to the asteroid belt you'll have put the bacon into an elliptical orbit. It'll come back, cross the earth's orbit, and drop down to a minimum somewhere (I'd have to figure it out, and I ain't got the time right now -- probably still further out than Venus' orbit) before going back up towards the asteroid belt. It's not going to end up around Jupiter or Mars anytime soon.Assuming you're doing this the most efficient way, with a Hohmann transfer orbit, then the perihelion of the elliptical orbit will be exactly as far from the Sun as the Earth's orbit.

And since the original quote said nothing about efficiency, and since there are ways to make energy loss from atmospheric drag arbitrarily small, I think we're justified in ignoring the atmosphere.

CalMeacham
11-03-2009, 03:28 PM
Assuming you're doing this the most efficient way

Well, I didn't -- I figured they're just tossing it up there. The perihelion will be different.

Stathol
11-03-2009, 03:42 PM
And since the original quote said nothing about efficiency, and since there are ways to make energy loss from atmospheric drag arbitrarily small, I think we're justified in ignoring the atmosphere.
As a mental exercise, I agree. However, I don't think we're quite justified in ignoring it with respect to the OP's question:

enough potential energy packed into its batteries to fire a pound of bacon into the Asteroid Belt.
This definitely implies some sort of ballistic bacon and rules out more efficient, but exotic solutions like a space bacon elevator.

Silophant
11-03-2009, 03:48 PM
space bacon elevator.

Band Name!

Chronos
11-03-2009, 06:21 PM
Sure, but you still can't really take air resistance into account without more information than we have. What shape is the bacon? If it's a long, thin strand of bacon, then the air resistance might be very low (though it'd make it harder to fire it, but that's an engineering problem). If it's a roughly-spherical lump, or even something like a parachute shape, air resistance would be much greater.

Spatial Rift 47
11-03-2009, 06:57 PM
So you're saying that if I manage to shoot a bb at 25,000 mph (defined as escape velocity earlier in the thread) from my back yard - it will leave earths gravity well. Even, when atmopheric drag reduces its speed to 24,999 after a small distance?

Think about what you're saying when you say what I said wasn't true.

You're saying that a satellite orbiting at orbital speed, that accidentally hits the wrong thruster and accelerates to 25000, then corrects itself back to orbital speed is screwed and cannot possibly return to orbit - no matter what amount of thrusting manuvers it undertakes.

Hi, physics grad student at your service. There are a lot of hidden assumptions going on here that are complicating the issue. I'm going to deal with the three different scenarios that have been intermixing themselves in this escape velocity side discussion.

1) An inert mass (such as bacon) is launched ballistically from Earth's surface with an instantaneous initial velocity of 25,000 mph. There is no atmosphere.

In this simple scenario, the only relevant numbers are the bacon's kinetic energy and its gravitational potential energy. Joe Frickin Friday's post above explains why the bacon, assuming nothing else interferes, will never return to Earth.

2) An inert mass of bacon is launched ballistically from Earth's surface with an instantaneous initial velocity of 25,000 mph. The Earth has its usual atmosphere.

Here, the atmosphere gives us velocity-dependent drag, which will reduce the bacon's KE as it rises. This is not a problem, since the required KE for escape also reduces as the bacon rises. Offsetting it is a matter of using a higher initial velocity. This is your bb scenario, and 25k mph would be slightly insufficient to prevent it from falling back down.

3) An electronic satellite already in Low Earth Orbit misfires a thruster and reaches a speed of 25,000 mph.

This is a totally different scenario. As I pointed out above, escape velocity is not equal for all positions near Earth. An LEO satellite is already traveling at about 17k mph, so first of all it would have to be an accident exceeding the design specs of the satellite to bring it to 25k mph. Second, escape velocity for an LEO satellite is lower than 25k mph. Assuming an orbital altitude of 1,000 km, escape velocity is now about 23k mph.

Finally, and most importantly, a satellite with thrusters is not a ballistic object like the bacon was. If it does accidentally thrust itself into an escape trajectory, it can thrust itself back into orbit at the price of burning fuel. The word "ballistic" I keep using means that the object gets one impulse and then moves only under the influence of gravity. Any statement to the effect of "an object which reaches escape velocity never comes back" should be understood to apply only to ballistic objects.

Ok. I hope that clears things up.

Machine Elf
11-03-2009, 08:02 PM
Sure, but you still can't really take air resistance into account without more information than we have. What shape is the bacon? If it's a long, thin strand of bacon, then the air resistance might be very low

If it's long and thin enough, you could use it like a cape to slow your descent.

Heller Highwater
11-03-2009, 09:12 PM
To expand on what Spatial Rift 47 said, the whole idea of escape velocity is that it's the initial velocity needed by an object to escape the gravitational well, without further impulse. Because it's still affected by gravity, the object will obviously slow down as it escapes, but the point is that it won't slow down enough to return to Earth (neglecting air resistance, of course).

In contrast, if we had a magic rocket that was able to provide a constant acceleration to exactly counter the gravitation of earth at any particular height above the surface, if I were to give it an upwards push of 1 m/s it would (again neglicting air resistance) eventually escape, even though it never reaches escape velocity, since there's a constant thrust being provided. (Okay, eventually it'll get far enough away to reach a point where the escape velocity is reduced to 1 m/s, but you get the picture.)

To go back to the original point of the thread, there's a few things I'm wondering about. First, how much initial velocity could a car battery impart to a one-pound object, assuming all its potential energy were magically converted to kinetic energy of the bacon? How does this speed compare to escape velocity at the surface? Second, how much initial speed can be saved due to the fact that we only need to reach the asteroid belt before allowing the bacon to cease its outward journey? I mean, if we consider an isolated system with just the earth and a pound of bacon, shooting it at escape velocity will get it to an infinite distance from the earth eventually. However, we just need to get it to a distance of the astroid belt. This will take a smaller initial velocity, although I suspect it'll turn out to be a miniscule difference. I would suppose the same holds true for moving the bacon within the sun's potential well. Again, we don't have to have it escape entirely, just get far enough to reach the asteroid belt. These savings might (and I emphasize "might") be more substantial.

Superhal
11-03-2009, 09:43 PM
He's obviously insane to send bacon away from himself.

ivn1188
11-03-2009, 11:28 PM
Okay, eventually it'll get far enough away to reach a point where the escape velocity is reduced to 1 m/s, but you get the picture.

Just FYI that would be somewhere in the middle of the Oort cloud, about 10,000 AU out.

Xema
11-04-2009, 09:20 AM
2) An inert mass of bacon is launched ballistically from Earth's surface with an instantaneous initial velocity of 25,000 mph. The Earth has its usual atmosphere.
Here, the atmosphere gives us velocity-dependent drag, which will reduce the bacon's KE as it rises. This is not a problem, since the required KE for escape also reduces as the bacon rises. Offsetting it is a matter of using a higher initial velocity.
I don't think this works with any practical projectile (and certainly not for one consisting of bacon). Even at 25k mph, the energy lost to drag, and the destructive effects of the heating, would be enormous. At higher velocities, these problems are worse.

It's certainly not impossible - meteors (often with velocities greater than 25k mph) occasionally survive a plunge through the atmosphere). But a great many of them don't, and those that do expend serious energy heating themselves and the atmosphere. It takes some significant initial mass for a meteor to have a good chance of reaching the ground at high velocity.

Meteorite Impact Velocities
The average velocity of meteoroids entering our atmosphere is 10-70 km/second. The smaller ones that survive the trip to the Earth's surface are quickly slowed by atmospheric friction to speeds of a few hundred kilometers per hour, and so hit the Earth with no more speed than if they had been dropped from a tall building. For meteorites larger than a few hundred tons (which fortunately are quite rare), atmospheric friction has little effect on the velocity and they hit the Earth with the enormous speeds characteristic of their entry into our atmosphere. Thus, for example, it is estimated that the meteorite that produced the Barringer Crater was still travelling at 11 km/second when it struck what is now the Arizona desert 49,000 years ago.

Heller Highwater
11-04-2009, 09:33 AM
Just FYI that would be somewhere in the middle of the Oort cloud, about 10,000 AU out.
Wow, that's closer than I realized. Neat!

Sunspace
11-04-2009, 09:45 AM
You are all missing important factors

1. the bacon will probably fry on the way up...But I already postulated indestructible bacon. :) You post dioes lead to a good question, thoiugh; what is the most efficient shape for bacon passing through the atmosphere, especially at 25000 mph?

Boyo Jim
11-04-2009, 09:56 AM
But I already postulated indestructible bacon. :) You post dioes lead to a good question, thoiugh; what is the most efficient shape for bacon passing through the atmosphere, especially at 25000 mph?

I see you got to the indestructible thing in a later post.

But if it's indestructible, it's not edible! Bacon is the most delicate flower of meats. Do you really want to go to all this effort and trouble to deliver a lump of "thing that looks like bacon" to the starving natives of the asteroid belt? Won't someone think of the alien children?

LiveOnAPlane
11-04-2009, 11:37 AM
This has been quite interesting, but I would like to point out another thing that the OP missed.

The character in the book is talking about his car. I was deeply involved in hot rodding back int he sixties and seventies, and stay a little in it even today. And if there's one thing that is true about guys and their cars, it is that everybody lies about their car!

People used to ask me why my 1966 Mustang would only go 125 mph while everyone else's would go 145 mph. I told them it was because I was telling the truth.*

So, I have to say that while we've got answers on how much energy the Deliverator's car would need, we need to be very :dubious: about it actually having that much.

* And the true top speed of that car was actually 120 mph...see what I mean?

Stathol
11-04-2009, 11:45 AM
what is the most efficient shape for bacon passing through the atmosphere, especially at 25000 mph?

If my calculations are correct, when this bacon hits 25000 mph, you're going to see some serious shit!

I'm sorry, but someone had to say it.

lieu
11-04-2009, 12:24 PM
I'm thinkin' once it arrives we'll have to let the ol' Asteroid Belt out a notch.

Stagger415
11-04-2009, 01:05 PM
When the bacon heats up and begins too cook, perhaps we could get some small boost by using the burning grease as a propellant. That way the projectile is not simply ballistic in nature. In a very inefficient sense, the bacon is itself, a fuel.

Boyo Jim
11-04-2009, 01:08 PM
Also, if it boils off the top, it may reduce the friction, acting as a lubricant for the whole system.

Spatial Rift 47
11-04-2009, 01:10 PM
Xema, you are correct that there would be immense amounts of heat released as a slab of bacon moves through the atmosphere at speeds upwards of 20 kmph, likely sufficient to completely vaporize bacon. However, assuming (as has been stipulated above) indestructible bacon, you could indeed launch it from the surface with an escape velocity corrected to account for atmospheric drag.

In a more realistic scenario, if you wanted edible bacon to survive the trip, you'd have to either move it to the asteroid belt in a non-ballistic fashion (i.e. space bacon elevator) or encase it in something that would withstand the energies of launch (a big metal rocketship would do just fine).

Stathol: :D

Corner Case
11-04-2009, 01:39 PM
what is the most efficient shape for bacon passing through the atmosphere, especially at 25000 mph?It doesn't matter. The FAA and NORAD will monitor the Domestic Events Network and determine that no one knows what this object, launched from the surface, is, nor where it is headed. NORAD will dispatch two F-16 fighters. It's quality will be severely strained. It will droppeth as the gentile bits from heaven upon the place beneath.

Chronos
11-04-2009, 01:47 PM
How about this: We get, not one, but a billion Deliveratormobiles, and form a projectile out of a billion pounds of bacon. All the cars pool their available energy, and all work together to power a launcher to propel this mother of all meats. Due to square-cube scaling, atmospheric drag really will be negligible in this case, and the gravitationally-calculated escape speed will be correct. We have, then, a billion cars containing enough energy to launch a billion pounds of bacon. Is it not reasonable, then, to say that a single car has enough energy to launch a single pound?

Satchmo
11-04-2009, 07:34 PM
If my calculations are correct, when this bacon hits 25000 mph, you're going to see some serious shit!

I'm sorry, but someone had to say it.

Ah, my hat's off to you sir. Or Madam. That's the funniest thing I've seen in a month!
Well played.

We're also neglecting what effect the Bacon Salt would have on escape velocity.

foolscap
11-04-2009, 09:57 PM
When the bacon heats up and begins too cook, perhaps we could get some small boost by using the burning grease as a propellant. That way the projectile is not simply ballistic in nature. In a very inefficient sense, the bacon is itself, a fuel.

A ramjet augmented flight through the atmosphere neatly countering
air drag.:)
Perhaps a "bone in" ham hock to serve as an engine, burning the morrow.
But, this would be ham not bacon:smack:

Jake
11-06-2009, 12:03 PM
It's a trick question. It's impossible to do, because it won't happen until pigs fly.

Ah Matt, Matt Matt. I thought we'd broken you of this habit. Sigh. :)

11-06-2009, 03:38 PM
If the bacon is already in orbit around the Earth, and assuming the delicious-but-lonely universe, wouldn't any force applied in a direction away from the Earth (and adding to the velocity) deliver the bacon to any distance given enough time? (If you'll pardon my physics 101 level question.)

Chronos
11-06-2009, 04:09 PM
Any force will work if in the right direction and sustained long enough, but we're not asking about "enough force", we're asking about "enough energy".

Leo Bloom
11-06-2009, 04:33 PM
What about converting the bacon itself into a propulsive system? Not necessarily hidden in a nuclear mass (or vice versa)? Changed--how--into a nuclear system?

How big would the bacon have to be to at least get a slice or two out there?

I guess you'd have to start with the simple caloric expenditure per unit bacon, which I'm too lazy to look up now.

Boyo Jim
11-06-2009, 04:55 PM
Since we're talking about E=m(c squared), in theory the bacon's mass would be interchangeable with the mass of anything else. I'm doubtful that calories are relevant to niclear fission or fusion, though I could certainly be wrong.

But there must be some kind of efficiency factor based on the methodology of conversion and the material being fissioned or fused.

Irishman
11-14-2009, 03:15 AM
Corner Case said:
It doesn't matter. The FAA and NORAD will monitor the Domestic Events Network and determine that no one knows what this object, launched from the surface, is, nor where it is headed. NORAD will dispatch two F-16 fighters.

I think fighters might be slow getting there, depending upon the launch point. They'd likely hit it with an anti-ballistic missile missile.

Chronos
11-14-2009, 01:33 PM
Correction: They'd likely fire at it with an anti-ballistic missile missile. But since the bacon doesn't have any transponders for them to home in on, they'd probably miss.

Sunspace
11-14-2009, 05:25 PM
Correction: They'd likely fire at it with an anti-ballistic missile missile. But since the bacon doesn't have any transponders for them to home in on, they'd probably miss.Of course they'd miss. You need an anti-bacon missile for that job.

Chronos
11-14-2009, 11:53 PM
But who would want to build an anti-bacon missile?

Boyo Jim
11-15-2009, 01:01 AM
The turkey sausage industry.