Ask a physicist anything. (5)

[Michael]

LiveLeak.com - 12 Year old boy disproves Einstein's theory while eating a sandwich

Could you help Mrs. Barnett answer her 12 year old son's math question?

 

[Wiccan_Child]

3 dimensional math question here...

Okay, when I was much younger, I made a cute airplane dog fighting game on my Commodore 64.

Think super old school.

Now, in this game, obviously I was very limited in some of the physics involved.

Both planes could only fly in 8 directions. (Up, Down, Left, Right, Up Left, Up Right, Down Left, Down Right)

Instead of showing actual ammunition being fired between the two planes, which made the game run super chunky (I programmed it in BASIC), I opted to generate a simple formula.

I found that if you subtracted the two memory locations on the screen (1024 - 2048 I think) of both the planes and then divided it by the plane's direction (-39, -40, -41, -1, 1, 39, 40, 41).... If that number was even, this would be that the one plane had the other directly in it's site.

Obviously if the plane was going horizontal (-1 or 1), it would always produce an even number in my equation so I had to tweak my formula just a titch.

Sorry for the ramble.

Anyway. Nutshell time.

Take the two memory locations of both planes and subtract them, divide that by the direction of one of the planes, if the number is even (with a horizontal exception), you can calculate if the other plane is in direct fire with the first one.

With that being said, could such a formula be generated in 3 dimensional space?

So say you have an object somewhere.

You have another object someplace else pointing in a certain direction.

Can you create a formula to see if that second object's direction is in perfectly direct site to the other?

If so, what are all of the number's or variables required for this?

If possible, could you provide a simple math example?

Thanks!

I super wuvs this thread!

In my notation, bold means vector and italic means variable.

This boils down to determining whether a point e is on a line r. The point is given by the location of the 'enemy' plane, (x[sub]e[/sub], y[sub]e[/sub], z[sub]e[/sub]), or e. The line is defined by two points: the location of the 'friendly' plane, (x[sub]f[/sub], y[sub]f[/sub], z[sub]f[/sub]), or f, and the direction it's pointing, which we can define as a point one 'unit' away from the 'friendly' craft, i.e., (x[sub]d[/sub], y[sub]d[/sub], z[sub]d[/sub]), or d.

So, the line is given by the vector r = ax + by + cz for some constants a, b, and c. So what are a, b, and c? Well, a = x[sub]d[/sub] - x[sub]f[/sub], b = y[sub]d[/sub] - y[sub]f[/sub], and c = z[sub]d[/sub] - z[sub]f[/sub].

So the line is given by: r = (x[sub]d[/sub] - x[sub]f[/sub])x + (y[sub]d[/sub] - y[sub]f[/sub])y + (z[sub]d[/sub] - z[sub]f[/sub])z.

To see whether the point lies on the line, we can create another line R connecting both planes, and see if they're identical; that is, if there is some number n such that nr = R.

So, as before, R = (x[sub]e[/sub] - x[sub]f[/sub])x + (y[sub]e[/sub] - y[sub]f[/sub])y + (z[sub]e[/sub] - z[sub]f[/sub])z.

Since nr = R can be written n = R/r, we get

n = [(x[sub]e[/sub] - x[sub]f[/sub])/(x[sub]d[/sub] - x[sub]f[/sub])]x + [(y[sub]e[/sub] - y[sub]f[/sub])/y[sub]d[/sub] - y[sub]f[/sub])]y + [(z[sub]e[/sub] - z[sub]f[/sub])/(z[sub]d[/sub] - z[sub]f[/sub])]z.

In other words, since each coefficient in r should be a multiple of the corresponding coefficient in R, the ratios of each pair of corresponding coefficients should be the same number: n.

That is, (x[sub]e[/sub] - x[sub]f[/sub])/(x[sub]d[/sub] - x[sub]f[/sub]) = (y[sub]e[/sub] - y[sub]f[/sub])/y[sub]d[/sub] - y[sub]f[/sub]) = (z[sub]e[/sub] - z[sub]f[/sub])/(z[sub]d[/sub] - z[sub]f[/sub]).

If that equation is true, then our point is on the line.
If that equation is true and n turns out to be positive, then the friendly plane is indeed aiming at the enemy plane - if it's negative, then the enemy is exactly behind the friendly plane.

Hope that makes sense!

EDIT: Alternatively, work out the angle subtended at the friendly plane by the 'direction' point and the enemy plane, and if that angle is 0°, you're aiming true. This has the added bonus of telling you just how far off your sights are.

 

[Wiccan_Child]

LiveLeak.com - 12 Year old boy disproves Einstein's theory while eating a sandwich

Could you help Mrs. Barnett answer her 12 year old son's math question?

Kudos to the child prodigy, but I don't think he's blown Einstein's theory out of the water. All he's done is posit a larger value than c that should go in place of c in Einstein's field equations. What, exactly, is the question?

 

[Upisoft]

Could you help Mrs. Barnett answer her 12 year old son's math question?

Intelligent boy, no doubt. Anyway the error he makes is that the light never accelerates, even when it changes direction. Changing direction is interaction with matter via EM force. For example the reflection of a photon is absorption of it and then emitting another photon. Yes, there is impulse transfer leading to acceleration of the mirror, but the photons themselves are not accelerated.

 

[Michael]

Intelligent boy, no doubt. Anyway the error he makes is that the light never accelerates, even when it changes direction. Changing direction is interaction with matter via EM force.

Hmmm. As I understand it, spacetime is 'bent' near massive objects and the path of light is bent with it. The concept of acceleration of that light in such an environment is interesting. You're right it CAN be related to absorption, but the bending is a gravitational process as well.

 

[Maxwell511]

Riddle me this! If I have a standard plug and a four-plug-socket extender, if I plug four more extenders into the original one, I will have a total of 16 free plug sockets.

Since there's no such thing as a free lunch, what happens?

I would not advice this, however if you did do that and the transients or power requirements did not make stuff explode, what would happen is the the frequency of the voltage would change in the entire power system. This would cause automatic controls to change the power output of the generators and supply you the much demanded extra power.

What of the original plug socket is constant, and is divvied up between the 16 connected sockets?

Voltage and current at the lowest part of your socket tree are generally constant*. Not in a necessary physical manner, more as in it is designed that way. There are human designed automatic control systems to make sure that the currents and voltages are contained between certain values. There are also people monitoring the situation in order to make sure the automatic control systems are working.

As a first/last resort there are fuses and circuit breakers to prevent you doing something really stupid.

Is it constant voltage but exponentially small current, or vice versa?

Neither. You would think that, due to the necessity of the first law of thermodynamics. However how the electrical power transmission system is designed is to increase the energy output of generators as more energy is required. So the voltage and current or power (since P=VI, sort of) can remain constant while you plug more things to the socket.

We can do this by measuring frequency derivations of the voltage signal and having control systems to produce the appropriate response. This is largely due to the magic of synchronous machines. Induction machines don't fair that well in the system we currently have.

I've always wanted to know

And now you sort of do. The whole trick to design electrical power systems to try and keep voltages and currents constant at the "sockets" and this is achieved by changing the energy input into the system.

An incredibly bizarre thing about this is that the communication between the socket and the generators is pretty close to the speed of light. It is the only man made machine that I know of that can do this is sort of high speed communication. The more bizarre thing about this is that we are using mostly late "19th" century technology to do this. But then again Nikola Tesla was a bizarre alleged** man.

*Assuming we define constant as according to a certain amount of significant units.

** Sometimes I have my doubts on the generally accepted place and date of birth of Tesla. I am torn between the idea that he was born sometime in the 22th century on Earth and invented a time machine, which malfunctioned on its maiden voyage, leaving him stranded in the 19th century. There is also the possibility that was stranded on Earth without an ability to contact his "Home" planet. What do you think?

 

[Wiccan_Child]

I would not advice this, however if you did do that and the transients or power requirements did not make stuff explode, what would happen is the the frequency of the voltage would change in the entire power system. This would cause automatic controls to change the power output of the generators and supply you the much demanded extra power.

Voltage and current at the lowest part of your socket tree are generally constant*. Not in a necessary physical manner, more as in it is designed that way. There are human designed automatic control systems to make sure that the currents and voltages are contained between certain values. There are also people monitoring the situation in order to make sure the automatic control systems are working.

As a first/last resort there are fuses and circuit breakers to prevent you doing something really stupid.

So... there are controls to keep the bottommost sockets at a constant voltage and current by altering the current and/or voltage topmost socket, but there are limits to how much the topmost socket can be altered by. Is that it?

Neither. You would think that, due to the necessity of the first law of thermodynamics. However how the electrical power transmission system is designed is to increase the energy output of generators as more energy is required. So the voltage and current or power (since P=VI, sort of) can remain constant while you plug more things to the socket.

We can do this by measuring frequency derivations of the voltage signal and having control systems to produce the appropriate response. This is largely due to the magic of synchronous machines. Induction machines don't fair that well in the system we currently have.

And now you sort of do. The whole trick to design electrical power systems to try and keep voltages and currents constant at the "sockets" and this is achieved by changing the energy input into the system.[/quote]
What do you mean by energy input, exactly? I'm not being facetious, I do just want to know Is it P = IV? Or the amount of joules passing from behind the socket to the wire leading from the socket, per second?

You can probably guess electronics is not my forté

An incredibly bizarre thing about this is that the communication between the socket and the generators is pretty close to the speed of light. It is the only man made machine that I know of that can do this is sort of high speed communication. The more bizarre thing about this is that we are using mostly late "19th" century technology to do this. But then again Nikola Tesla was a bizarre alleged** man.

*Assuming we define constant as according to a certain amount of significant units.

** Sometimes I have my doubts on the generally accepted place and date of birth of Tesla. I am torn between the idea that he was born sometime in the 22th century on Earth and invented a time machine, which malfunctioned on its maiden voyage, leaving him stranded in the 19th century. There is also the possibility that was stranded on Earth without an ability to contact his "Home" planet. What do you think?

I think his ideas are too unimpressive to be either futuristic or alien. No mention of relativity, quantum mechanics, or more esoteric things? Pfft, he's just a dirty great experimentalist

 

[Maxwell511]

Here's a scenario. If you are in a dark room- pitch black, can't see anything and a person enters but the person is absolutely silent! So none of the 5 senses are telling you that someone has entered the room, but you know that someone has. I'm not talking psychic, I'm trying to think scientifically. You sense someone is there. I was wondering if what triggered the feeling could be a change in the EMF of the room by the person's presence. And if it was a change in the EMF, how could one tell?

The human body can be effected by changes in the local EMF however not at the power (or distance) that is released by other human bodies.

I could probably get you to "imagine" that people are in the room with EMF changes directed at your brain, however that would be by using electrodes on (or in) your scalp. The human body would not be able to produce the energy output, across a room, to do the same thing.

 

[Naraoia]

The human body can be effected by changes in the local EMF however not at the power (or distance) that is released by other human bodies.

I could probably get you to "imagine" that people are in the room with EMF changes directed at your brain, however that would be by using electrodes on (or in) your scalp. The human body would not be able to produce the energy output, across a room, to do the same thing.

Which makes me wonder... is that any different if we're both floating in the sea? (Ignoring water currents, of course ) I mean, water plus some dissolved ions conducts much better than air. I wonder if we need a specialised "electric sense", shark-style, or if we'd be able to sense someone just with what we have.

 

[Maxwell511]

Which makes me wonder... is that any different if we're both floating in the sea? (Ignoring water currents, of course ) I mean, water plus some dissolved ions conducts much better than air. I wonder if we need a specialised "electric sense", shark-style, or if we'd be able to sense someone just with what we have.

Not from the electric signals, we do not seem to be "designed" that way. Hammer head sharks and some sea creatures can do this, however this is because, as you said, water with ionic compounds can transmit electrical phenomenon further than air.

Through air we are dealing with an inverse square law like phenomenon that would require an insane amount of sensitivity to electric fields. So land creatures never seem to have that sense (or at least the ability to process those signals in appropriate ways). I could be wrong, if you did know of a species that evolved that type of sense on land, I would find that very interesting.

Humans can detect strong EMF signals, since they use electricity to transmit information to different parts of the brain or other body parts, however it just distorts their sense of reality and does add to it. Strong correctly directed EMFs just make us hallucinate.

We do have other senses over the five that Aristotle believed. I do think I would be able to sense you but it would be more due to this sense, or others, and the "noise" that you would create beyond the background signal of the sea.

 

[Steffenfield]

In my notation, bold means vector and italic means variable.

This boils down to determining whether a point e is on a line r. The point is given by the location of the 'enemy' plane, (x[sub]e[/sub], y[sub]e[/sub], z[sub]e[/sub]), or e. The line is defined by two points: the location of the 'friendly' plane, (x[sub]f[/sub], y[sub]f[/sub], z[sub]f[/sub]), or f, and the direction it's pointing, which we can define as a point one 'unit' away from the 'friendly' craft, i.e., (x[sub]d[/sub], y[sub]d[/sub], z[sub]d[/sub]), or d.

So, the line is given by the vector r = ax + by + cz for some constants a, b, and c. So what are a, b, and c? Well, a = x[sub]d[/sub] - x[sub]f[/sub], b = y[sub]d[/sub] - y[sub]f[/sub], and c = z[sub]d[/sub] - z[sub]f[/sub].

So the line is given by: r = (x[sub]d[/sub] - x[sub]f[/sub])x + (y[sub]d[/sub] - y[sub]f[/sub])y + (z[sub]d[/sub] - z[sub]f[/sub])z.

To see whether the point lies on the line, we can create another line R connecting both planes, and see if they're identical; that is, if there is some number n such that nr = R.

So, as before, R = (x[sub]e[/sub] - x[sub]f[/sub])x + (y[sub]e[/sub] - y[sub]f[/sub])y + (z[sub]e[/sub] - z[sub]f[/sub])z.

Since nr = R can be written n = R/r, we get

n = [(x[sub]e[/sub] - x[sub]f[/sub])/(x[sub]d[/sub] - x[sub]f[/sub])]x + [(y[sub]e[/sub] - y[sub]f[/sub])/y[sub]d[/sub] - y[sub]f[/sub])]y + [(z[sub]e[/sub] - z[sub]f[/sub])/(z[sub]d[/sub] - z[sub]f[/sub])]z.

In other words, since each coefficient in r should be a multiple of the corresponding coefficient in R, the ratios of each pair of corresponding coefficients should be the same number: n.

That is, (x[sub]e[/sub] - x[sub]f[/sub])/(x[sub]d[/sub] - x[sub]f[/sub]) = (y[sub]e[/sub] - y[sub]f[/sub])/y[sub]d[/sub] - y[sub]f[/sub]) = (z[sub]e[/sub] - z[sub]f[/sub])/(z[sub]d[/sub] - z[sub]f[/sub]).

If that equation is true, then our point is on the line.
If that equation is true and n turns out to be positive, then the friendly plane is indeed aiming at the enemy plane - if it's negative, then the enemy is exactly behind the friendly plane.

Hope that makes sense!

EDIT: Alternatively, work out the angle subtended at the friendly plane by the 'direction' point and the enemy plane, and if that angle is 0°, you're aiming true. This has the added bonus of telling you just how far off your sights are.

Awesome!

I actually understood that concept, believe it or not.

I'm still a little confused on direction but I'll keep rereading your post until I get it.

Thank you WC!

 

[Steffenfield]

I wrote a silly paper on Y2K back when everyone was all tragic about the possibilities.

I actually came up with, I don't know, perhaps a nifty solution at the time.

Basically, since our calendar, in it's most simplest of forms, is just a clock, I thought about using an alternative conversion system.

So, like how one could either say 90 seconds or a minute and a half.

Or how 13 months is the same as 1 year and 1 month.

The whole principle stood on such equivalents.

So instead of going from 2 digits for a year and reprogramming all the computers to then accept 4 digits, here was my alternative solution back then.

What I suggested was to stay within the same year but keep adding in more months beyond December.

It actually worked.

Here's a modern example that I used from this webpage.
Days Between Dates (Date Difference Calculator)

Basically, this would have extended the year 2000 to having an extra 87 months in it, or just a little over 7 years.

This is Christian forum, so yeah, 7 years of whatever, I thought, perhaps also matched up with the end times spoken about in Revelations.

Anyway, do you think that this could have worked? I never got any feedback because I didn't understand the internet back then so very few people even heard me talk about this.

Also, would there ever come a time in the distant future where this theory might be used?

I know I'm having such silly thoughts over this, believe me I'm not taking any of this seriously, but I don't know, I guess I was hoping to hear from some of you on it.

And yeah, this was completely my own unique idea after reading Daniel 7:25.

Any comments?

 

[Wiccan_Child]

Awesome!

I actually understood that concept, believe it or not.

I'm still a little confused on direction but I'll keep rereading your post until I get it.

Thank you WC!

I thought direction might be a bit confusing If you imagine a sphere around the plane, the direction the plane is facing can be thought of as a point on that sphere. There are more practical ways for real-life planes

I wrote a silly paper on Y2K back when everyone was all tragic about the possibilities.

I actually came up with, I don't know, perhaps a nifty solution at the time.

Basically, since our calendar, in it's most simplest of forms, is just a clock, I thought about using an alternative conversion system.

So, like how one could either say 90 seconds or a minute and a half.

Or how 13 months is the same as 1 year and 1 month.

The whole principle stood on such equivalents.

So instead of going from 2 digits for a year and reprogramming all the computers to then accept 4 digits, here was my alternative solution back then.

What I suggested was to stay within the same year but keep adding in more months beyond December.

It actually worked.

Here's a modern example that I used from this webpage.
Days Between Dates (Date Difference Calculator)

Basically, this would have extended the year 2000 to having an extra 87 months in it, or just a little over 7 years.

This is Christian forum, so yeah, 7 years of whatever, I thought, perhaps also matched up with the end times spoken about in Revelations.

Anyway, do you think that this could have worked? I never got any feedback because I didn't understand the internet back then so very few people even heard me talk about this.

Also, would there ever come a time in the distant future where this theory might be used?

I know I'm having such silly thoughts over this, believe me I'm not taking any of this seriously, but I don't know, I guess I was hoping to hear from some of you on it.

And yeah, this was completely my own unique idea after reading Daniel 7:25.

Any comments?

An interesting solution, but if you're reprogramming all the clocks to accept arbitrarily high numbers of months, why not reprogram them to accept 4-digit years while you're there? Or change the '19XX' moniker to '20XX', etc? There might also be problems with programs like Excel which call month numbers to do all sorts of calculations (I use it a lot in my homebrew calendar). Still, good idea

 

[mzungu]

Hmmm. As I understand it, spacetime is 'bent' near massive objects and the path of light is bent with it. The concept of acceleration of that light in such an environment is interesting. You're right it CAN be related to absorption, but the bending is a gravitational process as well.

YouTube - Gravity - From Newton to Einstein - The Elegant Universe

 

[Upisoft]

Hmmm. As I understand it, spacetime is 'bent' near massive objects and the path of light is bent with it. The concept of acceleration of that light in such an environment is interesting. You're right it CAN be related to absorption, but the bending is a gravitational process as well.

The path of the light is straight. It only appears to be bent, because you and the light are not in the same field. If you were there and checked it (locally), well it would look straight to you.

 

[mzungu]

The path of the light is straight. It only appears to be bent, because you and the light are not in the same field. If you were there and checked it (locally), well it would look straight to you.

Linearity is not possible where gravity exists; And gravity is everywhere in the universe.

 

[Naraoia]

Not from the electric signals, we do not seem to be "designed" that way. Hammer head sharks and some sea creatures can do this, however this is because, as you said, water with ionic compounds can transmit electrical phenomenon further than air.

Through air we are dealing with an inverse square law like phenomenon that would require an insane amount of sensitivity to electric fields. So land creatures never seem to have that sense (or at least the ability to process those signals in appropriate ways). I could be wrong, if you did know of a species that evolved that type of sense on land, I would find that very interesting.

No, I don't think I know of any. I'd be surprised, because of the insulation issue.

Awesome!

I actually understood that concept, believe it or not.

I was so delighted to see Wiccan's explanation. Vectors were my great love at school. Somehow they just make sense, don't they?

Linearity is not possible where gravity exists; And gravity is everywhere in the universe.

Let's start arguing about the definition of a "straight line"! My understanding was that "straight lines" exist in curved space (e.g. in gravitational fields), they just aren't, well, straight-straight if you look at them from the outside. So a photon in a gravitational field is still travelling along one of the "straight" lines of the local space, as in there isn't a shorter path between any two points along its trajectory.

Or whatever. Non-Euclidean space is weird.

 

[Wiccan_Child]

I was so delighted to see Wiccan's explanation. Vectors were my great love at school. Somehow they just make sense, don't they?

I was going to give the directional vector in spherical polar coordinates, but the conversion just got hideously messy

Let's start arguing about the definition of a "straight line"! My understanding was that "straight lines" exist in curved space (e.g. in gravitational fields), they just aren't, well, straight-straight if you look at them from the outside. So a photon in a gravitational field is still travelling along one of the "straight" lines of the local space, as in there isn't a shorter path between any two points along its trajectory.

Or whatever. Non-Euclidean space is weird.

It's like the metric expansion of space. Two points are 5m apart forever and ever, but it's the metre that expands. Crazy stuff.

 

[Jazer]

I wrote a silly paper on Y2K back when everyone was all tragic about the possibilities.

Y2K was basicly a scam by Bill Gates & his cronies to get everyone to go out and buy a new computer and upgrade all of their equipment. It put money in their pocket. As far as the Church, the Church Age did not begin until Pentacost around the year 30 AD. So this age will not end until at least April 13, 2029. That is when nasa says the 7 year apophis asteroid will be going by the earth. Actually in 2036 there is a slight chance it could hit the earth.

 

[Wiccan_Child]

Y2K was basicly a scam by Bill Gates & his cronies to get everyone to go out and buy a new computer and upgrade all of their equipment. It put money in their pocket.

And like all economic injections, it spurred the advance of computer technology. If people are stupid enough to think that buying a new computer will save the world, they're better off without their money.

As far as the Church, the Church Age did not begin until Pentacost around the year 30 AD. So this age will not end until at least April 13, 2029.

Why will this age end then? What's so special about 2000 years? What's so special about April 13th?

That is when nasa says the 7 year apophis asteroid will be going by the earth.

NASA predicts a 0.0004% chance of impact in 2036, and even if it hits, its impact will be on par with a particularly strong volcano. Not exactly end-of-the-world.

Actually in 2036 there is a slight chance it could hit the earth.

'Slight' being something of an understatement