 |
 |
Planck Length and Electron Size
Name: Kevin
Status: student
Age: N/A
Location: N/A
Country: N/A
Date: N/A
Question:
According to some sources I have seen the smallest unit of
length is defined as a Planck length, 1e-35m. A proton as designated is
classical physics has a dimension of 1e-15m, and an electron has a "size" of
1e-22m. With this said, the smallest unit of measure I can think of is the
subatomic distance between adjacent particles. However due to the force
between 2 adjacent atoms, I believe it is called the strong force, 2 things
never actually come into contact with each other. Since I feel that this is
the smallest unit of measure, I do not understand how a length of 1e-35m to
exist. An electron is 1e13 times larger than this predetermined length, so
even if there is something that forms electrons, that is a significant
difference is size.
Replies:
Hi Kevin, there are a lot of unresolved questions in this field, so
it's easy to become confused. In fact, I am quite confused by your
question. It sounds like you are questioning the existence of the
Planck length -- is this what you are asking? The Planck length is
simply a unit (like a meter or a mile). However, if you are questioning
the practical definition you provided (that it is the "smallest
possible length"), then I would agree with you. I am not sure that
calling it "the smallest possible length" is quite right -- perhaps a
better way of phrasing it might be that classical theory becomes
meaningless at lengths smaller than the Planck length. So it would not
be useful to envision two protons as two hard spheres that approaching
each other to a "Planck length" distance because quantum effects at
that size scale would dominate this classical view. I am not sure if
I have answered your question, so please respond back to clarify.
Hope this helps,
Burr Zimmerman
Kevin,
First, protons and electrons are not the only particles. A particle
that interacts much less that a proton or electron, and can therefore
get much closer to other particles, is the neutrino. Electrons and
protons are "fermions": two of the same particle cannot exist in the
same place at the same time. A neutrino has no electric charge and is a
"boson": the number of neutrinos that can exist on top of each other,
that can even pass through each other, is unlimited.
The Plank length is the smallest distance that can be measured. This
does not mean that the distance between two objects cannot be less, but
that any distance you measure will be so uncertain that nobody will know
for certain that the distance is less. Many of the limits within
quantum physics apply more to measurement than to existence. If no
distance measurement less than 1e-35m can ever be measured, then there
is no way to verify whether or not such a distance can exist. You could
say it is more a limit to what we can know rather than what can be.
Dr. Ken Mellendorf
Physics Instructor
Illinois Central College
Click here to return to the Physics Archives
| |
Update: June 2012
|
|
