Hi !
You might laugh abit from reading the topic title and semi-title, but as physicists, where can you see negative numbers ?
Length is more or equal to zero.
Mass is more or equal to zero.
Even speed can be described as direction (degrees) and length - vector with no negative sign.
I want to point out that I read a book about math history and it says
ages ago people thought that
negative numbers are like imaginary numbers - not exist.
I want to know what changed their mind ??
Can anyone show me negative number in nature ?
Thanks
Niv
QUOTE (Niv+Jun 24 2009, 09:12 PM)
Hi !
You might laugh abit from reading the topic title and semi-title, but as physicists, where can you see negative numbers ?
Length is more or equal to zero.
Mass is more or equal to zero.
Even speed can be described as direction (degrees) and length - vector with no negative sign.
Can anyone show me negative number in nature ?
Plenty in Physics..
- dv / dt means negative acceleration; meaning slowing down.
- 32 degrees fahrenheit means frozen water.
- v means negative velocity; meaning going in the opposite direction
JW
You might laugh abit from reading the topic title and semi-title, but as physicists, where can you see negative numbers ?
Length is more or equal to zero.
Mass is more or equal to zero.
Even speed can be described as direction (degrees) and length - vector with no negative sign.
Can anyone show me negative number in nature ?
Plenty in Physics..
- dv / dt means negative acceleration; meaning slowing down.
- 32 degrees fahrenheit means frozen water.
- v means negative velocity; meaning going in the opposite direction
JW
In addition to that, everything that nature shows us is that there are deep symmetries to the universe. The language of symmetries are group operations, and part of the definition of a group is for every element there is an inverse. If there is addition +5 then there is also addition −5.
The pluses and minuses of electric charge work exactly this way.
The pluses and minuses of electric charge work exactly this way.
QUOTE (Lunarlanding+Jun 25 2009, 02:47 AM)
Plenty in Physics..
- dv / dt means negative acceleration; meaning slowing down.
- 32 degrees fahrenheit means frozen water.
- v means negative velocity; meaning going in the opposite direction
JW
about acceleration and velocity, I gave example that negative is one way to see it but "angle" is the other, like with polar coordinate system:
http://en.wikipedia.org/wiki/Polar_coordinate_system
And degrees can always be represented non-negatively.
@rpenner
First about the elctric charge - this is acctualy why I opened this thread, I thought about this example as well but what guarantee that they are acctualy "negative charges" ? Maybe mathematically its negative but in nature it can be described in another way like I did with velocity. (I hope that I clarify my meaning)
And about the symmetries is a big vague to me since when you say +5 you can't not think about the existance of (-5), but that's what im trying to understand - does physic really need negative numbers or are they simply mathematical tool that help us reach answers ?
Thanks you both for the replies !
- dv / dt means negative acceleration; meaning slowing down.
- 32 degrees fahrenheit means frozen water.
- v means negative velocity; meaning going in the opposite direction
JW
about acceleration and velocity, I gave example that negative is one way to see it but "angle" is the other, like with polar coordinate system:
http://en.wikipedia.org/wiki/Polar_coordinate_system
And degrees can always be represented non-negatively.
@rpenner
First about the elctric charge - this is acctualy why I opened this thread, I thought about this example as well but what guarantee that they are acctualy "negative charges" ? Maybe mathematically its negative but in nature it can be described in another way like I did with velocity. (I hope that I clarify my meaning)
And about the symmetries is a big vague to me since when you say +5 you can't not think about the existance of (-5), but that's what im trying to understand - does physic really need negative numbers or are they simply mathematical tool that help us reach answers ?
Thanks you both for the replies !
If you take that view then in nature you can say no negative numbers exist, you're just removing positive numbers, but this is more a matter of semantics and just complicated your thinkings, ie is -1 minus one or removing +1?
First off, don't think I'm getting cranky here, but I'm thinking the OPer is getting a bit of a bad rap... This user seems ignorant of physics, and so long as he or she acknowledges that, I don't have any problems with him/her.
Actually, I can see where he/she's coming from....
(Lunarlanding, I'm not dismissing your examples, they are valid (except for the temperature one, AFAIK), I'm just setting myself up for another point, later, so please bear with me...)
Actually, I can see where he/she's coming from....
(Lunarlanding, I'm not dismissing your examples, they are valid (except for the temperature one, AFAIK), I'm just setting myself up for another point, later, so please bear with me...)
QUOTE (Lunarlanding+)
- dv / dt means negative acceleration; meaning slowing down.
According to the GR, slowing down can be expressed in the same manner as speeding up. You merely do so in an opposite direction and from a frame of reference whose trajectory is parallel with that of the object in question before the deceleration.
QUOTE
- 32 degrees fahrenheit means frozen water.
-32 degrees Fahrenheit is the same temperature as 237.5944444 kelvin, a positive number, and no temperature can exist below 0 kelvin.QUOTE (->
| QUOTE |
| - 32 degrees fahrenheit means frozen water. |
-32 degrees Fahrenheit is the same temperature as 237.5944444 kelvin, a positive number, and no temperature can exist below 0 kelvin.
- v means negative velocity; meaning going in the opposite direction
- v means negative velocity; meaning going in the opposite direction
Again, according to GR, velocity has no preferred direction. -v can be equally validly expressed as +v.
QUOTE (rpenner+)
The pluses and minuses of electric charge work exactly this way.
This is the best example of a real negative number shown in this thread, IMHO. It would be possible to express negative charges using positive numbers (or letters, or symbols) but such expressions would bear much less resemblance to reality than our current method of expressing them. This is especially true when you consider (to my knowledge) that the electric charges might well have absolute minimum values, such as -1/3 or +2/3 for quarks.
Except for the universe itself. Antimatter and matter combine to annihilate each other releasing energy. If the known universe came to be through the reverse process then where is all the antimatter? For a symmetry to all the matter in the universe to exist then there needs to be an equal amount of antimatter.
Unless....
http://focus.aps.org/story/v17/st21
Except for the universe itself. Antimatter and matter combine to annihilate each other releasing energy. If the known universe came to be through the reverse process then where is all the antimatter? For a symmetry to all the matter in the universe to exist then there needs to be an equal amount of antimatter.
Unless....
http://focus.aps.org/story/v17/st21
Start with a collection of interacting particles, then create a mirror-image version (parity reversal, P), change the signs on all electrical charges ( C), and let time run backward ( T).
Although this is not the main point of the article it did spark a thought that there may be a negative timeline that mirrors our own. That if the big bang was the reverse reaction the reason we don't have antimatter throughout our universe is because the antimatter is being sent backwards (relative to us) through time. With the big bang being the point of origin for not only the universe but also for time then the antimatter being sent back through time is being sent through a negative timeline.
However this would also mean another universe besides our own exists but instead of distance separating these two universes, time separates them instead.
Although this is not the main point of the article it did spark a thought that there may be a negative timeline that mirrors our own. That if the big bang was the reverse reaction the reason we don't have antimatter throughout our universe is because the antimatter is being sent backwards (relative to us) through time. With the big bang being the point of origin for not only the universe but also for time then the antimatter being sent back through time is being sent through a negative timeline.
However this would also mean another universe besides our own exists but instead of distance separating these two universes, time separates them instead.
This reminds me of an old Star Trek episode from the animated series called "The Counterclock Incident."
http://www.startrek.com/startrek/view/libr...tail/22023.html
They go into a universe where all goes backwards. It is funny to think about....
Negative number? As soon as you owe money, that makes sense. The amount you owe could be called a negative number.
I guess we call all sorts of opposites negatives, like a positron; although I'd bet that those from the universe where there are positrons call our electrons negative. It is a point of view.
If the known universe came to be through the reverse process then where is all the antimatter?
If alert If alert and "if" has been spotted.
Who says that the known Universe came to be through the reverse process?
QUOTE
In addition to that, everything that nature shows us is that there are deep symmetries to the universe. The language of symmetries are group operations, and part of the definition of a group is for every element there is an inverse. If there is addition +5 then there is also addition −5.
This is the best explanation of the usage of negative numbers in physics so far in this thread, especially when taken with AN's post.QUOTE (->
| QUOTE |
| In addition to that, everything that nature shows us is that there are deep symmetries to the universe. The language of symmetries are group operations, and part of the definition of a group is for every element there is an inverse. If there is addition +5 then there is also addition −5. |
This is the best explanation of the usage of negative numbers in physics so far in this thread, especially when taken with AN's post.If you take that view then in nature you can say no negative numbers exist, you're just removing positive numbers, but this is more a matter of semantics and just complicated your thinkings, ie is -1 minus one or removing +1?
Niv,
The combination of those last two quotes was what sprung to my mind when I read the OP. The use of negative numbers can be ignored in much (but certainly not all) of physics, but this makes matters more difficult. For instance, the most basic arithmetic is addition, so it makes more sense to add negative numbers than to subtract positive numbers. (There is a similar symmetry between multiplication and division, however division allows more values to be expressed easily, such as 1/3 rather than 1*0.333... This holds so true that the very concept of fractions evinces it, fractions are merely a division problem. 1/3 is 1 divided by 3.)
But getting rid of negative numbers introduces a whole host of problems. Velocities (as in Lunarlanding's example) can always be expressed as positive numbers, but when you have two objects moving in opposite directions, you can use negative numbers to massively reduce the amount of mathematical work you need to do to model those two. Similarly, you can reduce the amount of work you need to do to model a decelerating object by using negative numbers.
But that's not all, those negative numbers I just mentioned are real negatives when observed from the right frame of reference. A FoR which is stationary wrt an inertial object will perceive it's slowing down as slowing down wrt an object which is moving in the direction of deceleration wrt the original object, or an FoR whose trajectory matches the pre-deceleration trajectory of an object will perceive that object's deceleration to be a negative number. A FoR which is 'stationary' at the point of impact of two approaching objects (stationary wrt both objects, not one or the other) will percieve the velocity of one object as a negative one wrt the other object, and vice versa.
To conclude my rantings, yes negative numbers can be said to exist in GR, but only in certain frames of reference. And the example rpenner gave is better than any other I could think up. It makes the most sense to express negative charge as a negative number. And only rpenner has even touched on Quantum Mechanics yet... (negative wavefunction levels, negative values in a scalar, negative entropy in closed systems, energy values below the minimum total potential energy of a system... The negatives simply abound in QM.)
So don't cast out negative numbers just because you can't hold -2 apples in your hand.
Niv,
The combination of those last two quotes was what sprung to my mind when I read the OP. The use of negative numbers can be ignored in much (but certainly not all) of physics, but this makes matters more difficult. For instance, the most basic arithmetic is addition, so it makes more sense to add negative numbers than to subtract positive numbers. (There is a similar symmetry between multiplication and division, however division allows more values to be expressed easily, such as 1/3 rather than 1*0.333... This holds so true that the very concept of fractions evinces it, fractions are merely a division problem. 1/3 is 1 divided by 3.)
But getting rid of negative numbers introduces a whole host of problems. Velocities (as in Lunarlanding's example) can always be expressed as positive numbers, but when you have two objects moving in opposite directions, you can use negative numbers to massively reduce the amount of mathematical work you need to do to model those two. Similarly, you can reduce the amount of work you need to do to model a decelerating object by using negative numbers.
But that's not all, those negative numbers I just mentioned are real negatives when observed from the right frame of reference. A FoR which is stationary wrt an inertial object will perceive it's slowing down as slowing down wrt an object which is moving in the direction of deceleration wrt the original object, or an FoR whose trajectory matches the pre-deceleration trajectory of an object will perceive that object's deceleration to be a negative number. A FoR which is 'stationary' at the point of impact of two approaching objects (stationary wrt both objects, not one or the other) will percieve the velocity of one object as a negative one wrt the other object, and vice versa.
To conclude my rantings, yes negative numbers can be said to exist in GR, but only in certain frames of reference. And the example rpenner gave is better than any other I could think up. It makes the most sense to express negative charge as a negative number. And only rpenner has even touched on Quantum Mechanics yet... (negative wavefunction levels, negative values in a scalar, negative entropy in closed systems, energy values below the minimum total potential energy of a system... The negatives simply abound in QM.)
So don't cast out negative numbers just because you can't hold -2 apples in your hand.
QUOTE
shows us is that there are deep symmetries to the universe
Except for the universe itself. Antimatter and matter combine to annihilate each other releasing energy. If the known universe came to be through the reverse process then where is all the antimatter? For a symmetry to all the matter in the universe to exist then there needs to be an equal amount of antimatter.
Unless....
http://focus.aps.org/story/v17/st21
QUOTE (->
| QUOTE |
| shows us is that there are deep symmetries to the universe |
Except for the universe itself. Antimatter and matter combine to annihilate each other releasing energy. If the known universe came to be through the reverse process then where is all the antimatter? For a symmetry to all the matter in the universe to exist then there needs to be an equal amount of antimatter.
Unless....
http://focus.aps.org/story/v17/st21
Start with a collection of interacting particles, then create a mirror-image version (parity reversal, P), change the signs on all electrical charges ( C), and let time run backward ( T).
Although this is not the main point of the article it did spark a thought that there may be a negative timeline that mirrors our own. That if the big bang was the reverse reaction the reason we don't have antimatter throughout our universe is because the antimatter is being sent backwards (relative to us) through time. With the big bang being the point of origin for not only the universe but also for time then the antimatter being sent back through time is being sent through a negative timeline.
However this would also mean another universe besides our own exists but instead of distance separating these two universes, time separates them instead.
QUOTE (H2O+Jun 30 2009, 12:44 PM)
Except for the universe itself. Antimatter and matter combine to annihilate each other releasing energy. If the known universe came to be through the reverse process then where is all the antimatter? For a symmetry to all the matter in the universe to exist then there needs to be an equal amount of antimatter.
Not everything has to be symmetric, dumbass...
Not everything has to be symmetric, dumbass...
You just keep believing that the Earths magnetic field would be depleted with that energy thought experiment.
QUOTE (H2O+Jun 30 2009, 01:44 PM)
Although this is not the main point of the article it did spark a thought that there may be a negative timeline that mirrors our own. That if the big bang was the reverse reaction the reason we don't have antimatter throughout our universe is because the antimatter is being sent backwards (relative to us) through time. With the big bang being the point of origin for not only the universe but also for time then the antimatter being sent back through time is being sent through a negative timeline.
However this would also mean another universe besides our own exists but instead of distance separating these two universes, time separates them instead.
This reminds me of an old Star Trek episode from the animated series called "The Counterclock Incident."
http://www.startrek.com/startrek/view/libr...tail/22023.html
They go into a universe where all goes backwards. It is funny to think about....
Negative number? As soon as you owe money, that makes sense. The amount you owe could be called a negative number.
I guess we call all sorts of opposites negatives, like a positron; although I'd bet that those from the universe where there are positrons call our electrons negative. It is a point of view.
QUOTE (H2O+Jun 30 2009, 05:44 PM)
If the known universe came to be through the reverse process then where is all the antimatter?
If alert If alert and "if" has been spotted.
Who says that the known Universe came to be through the reverse process?
Well, that leads to the question "By what other process was the big bang?"
Since matter and antimatter come together to completely annihilate each and the big bang was the beginning where there didn't exist any matter before it, then the big bang could have been the reverse.
Since matter and antimatter come together to completely annihilate each and the big bang was the beginning where there didn't exist any matter before it, then the big bang could have been the reverse.
If the gravitation of black holes is strong enough to capture light, then the speed of light coming out a black hole would have to be -C wouldn't it?
Couldn't you describe gravity generally as negative energy? Black holes capturing light is an extreme example of a universal phenomenon where escape velocity of one object to the gravitational pull of another is reduced as negative acceleration, no?
Couldn't you describe gravity generally as negative energy? Black holes capturing light is an extreme example of a universal phenomenon where escape velocity of one object to the gravitational pull of another is reduced as negative acceleration, no?
QUOTE (Lunarlanding+Jun 24 2009, 09:47 PM)
Plenty in Physics..
- dv / dt means negative acceleration; meaning slowing down.
- 32 degrees fahrenheit means frozen water.
- v means negative velocity; meaning going in the opposite direction
JW
See, I hope you are being silly, as all of those are caused by an artifact of the language.
There is no "negative acceleration". There is only positive acceleration along a vector in the opposite direction.
There is no negative temperature in the Kelvin scale. The Fahrenheit scale only gives negative because of the arbitrary numbers employed.
Again, negative velocity is a misnomer for the same reason negative acceleration is a misnomer.
=====
As for those who responded on this matter, while it is true that the notion of a "negative number" can make the math easier in many situations, this artifact of mathematical express COULD be misleading in the formulae for certain physical properties.
Even the notion of "positive" and "negative" charge are actually quite arbitrary. Just as "strange" "charm", etc, for the designation of quarks.
Perhaps an electron does not have a negative charge at all, but rather subtracts a positive.
While this distinction seems trivial, when dealing with certain functions and formulae it can potentially matter.
I don't think "real" negative numbers exist, after all, we don't have negative matter with negative mass and negative gravity. note that even "anti-matter" does not have negative mass or negative gravity.
- dv / dt means negative acceleration; meaning slowing down.
- 32 degrees fahrenheit means frozen water.
- v means negative velocity; meaning going in the opposite direction
JW
See, I hope you are being silly, as all of those are caused by an artifact of the language.
There is no "negative acceleration". There is only positive acceleration along a vector in the opposite direction.
There is no negative temperature in the Kelvin scale. The Fahrenheit scale only gives negative because of the arbitrary numbers employed.
Again, negative velocity is a misnomer for the same reason negative acceleration is a misnomer.
=====
As for those who responded on this matter, while it is true that the notion of a "negative number" can make the math easier in many situations, this artifact of mathematical express COULD be misleading in the formulae for certain physical properties.
Even the notion of "positive" and "negative" charge are actually quite arbitrary. Just as "strange" "charm", etc, for the designation of quarks.
Perhaps an electron does not have a negative charge at all, but rather subtracts a positive.
While this distinction seems trivial, when dealing with certain functions and formulae it can potentially matter.
I don't think "real" negative numbers exist, after all, we don't have negative matter with negative mass and negative gravity. note that even "anti-matter" does not have negative mass or negative gravity.
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