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# Is it possible to get an abosolute perfect sphere? watch

BTW science fact:

If the earth was shrunk down to the size of a snooker ball

It'd be the most spherical ball ever.
Not true. Firstly the earth isn't even an approximate sphere - it's an oblate spheroid (deviation from a perfect sphere is well over one part in one thousand). And things like mountains cause 'bumps' of order one part in ten thousand.

In contrast, state of the art manufacturing can create spheres accurate to about one part in one million.
2. (Original post by dbmag9)
If you don't want your sphere to be an object in the normal sense, you could regard the field around a particle as a sphere; seems to me that'd be a darn sight closer than anything you could get made of matter, at least.

I have a feeling that quantum physics probably prohibits that from functioning as a sphere, though.
Yes: what about the electron orbital around a hydrogen atom. That is perferctly spherical, isn't it?
And the "pressure" could be another hydrogen atom - thats why you can never get them to actually touch each other because the two spheres can withstand the pressure of the pushing the two particles together.

Maybe.... I'm only A2 level chemistry haah!
The most perfect sphere in existence.

"The roundness delta of the finished sphere (being held above) is about 50 nm on a 93.6 mm diameter. It is believed to be the roundest object in the world."
4. (Original post by jbottle1)
Yes: what about the electron orbital around a hydrogen atom. That is perferctly spherical, isn't it?
No.
Hydrogen orbitals:
5. (Original post by flugestuge)
No.
Hydrogen orbitals:
It should be noted the diagrams are representative of the probability density of an electron being there and in fact it is "space". The only thing stopping them "crashing" together is the mutual repulsion of the positive nuclei.
6. (Original post by jbottle1)
Yes: what about the electron orbital around a hydrogen atom. That is perferctly spherical, isn't it?
And the "pressure" could be another hydrogen atom - thats why you can never get them to actually touch each other because the two spheres can withstand the pressure of the pushing the two particles together.

Maybe.... I'm only A2 level chemistry haah!
Its not to do with pressure its to do with fundamental charges I thought o.O ?

Also as mentioned above hydrogen orbitals are not perfectly spherical, no shape is actually perfect to what we see it as (if that makes sense!).
7. (Original post by DFranklin)
Not true. Firstly the earth isn't even an approximate sphere - it's an oblate spheroid (deviation from a perfect sphere is well over one part in one thousand). And things like mountains cause 'bumps' of order one part in ten thousand.

In contrast, state of the art manufacturing can create spheres accurate to about one part in one million.

I heard it from Neil Degrasse Tyson

Are you going to argue physics with him?
I heard it from Neil Degrasse Tyson

Are you going to argue physics with him?
erm yeah if you accept googles results concerning the shape of the earth you can trivially conclude this is the case personally.

On an aside I have no idea who that person is.
9. (Original post by DeanK22)
erm yeah if you accept googles results concerning the shape of the earth you can trivially conclude this is the case personally.

On an aside I have no idea who that person is.
http://en.wikipedia.org/wiki/Neil_deGrasse_Tyson

he's a "famous" astrophysicist
http://en.wikipedia.org/wiki/Neil_deGrasse_Tyson

he's a "famous" astrophysicist
From a scan of that page (though I may regret saying this without looking at his personal page) he dosen't actually do anything or has done anything in his field (whatever that may be) - he literally is a face for science with respect to the public. Hell, half of his awards are non-scientific; wine collection, people magazine, etc.

I will retract this if someone does provide evidence otherwise (and a degree does not count as doing something.).
I heard it from Neil Degrasse Tyson
Cite?

Are you going to argue physics with him?
It's not a physics question, these are observed facts about the Earth (and state of the art manufacturing skills). Although I'm not convinced he actually said what you state, so I'm not sure I'm arguing with him anyhow.

Do the math: the Avogadro sphere mentioned earlier has a "out of roundness" of less than one part in a million. The earth has a diameter of about 13x10^6 meters. So for the earth to be as smooth as an Avogadro you'd have to have no 'bumps' more than 13 meters high. Mount Everest is (much) more than 100 times this, but more mundanely, so are a *lot* of buildings.
12. Circular reasoning?
Light is massless sweetie x

and is a particle-wave

maybe you should read less science and get a life.
14. Right... I wrote it wrong, [and was semi-trolling] {plus it wasn't intended as a serious comment}

in a lecture [i saw on google videos]

he was talking about asteroids the size of everest hitting the earth

then said if the earth was shrunk down to the size of a cueball, it'd be the smoothest cueball ever i.e. you wouldn't feel everest if you ran your fingers over it.

so he didn't say spherical, [and I realise the earth buldges even prior to the thread being made] just smooth. but then it wasn't intended to be a 100% fact which I kinda said it was

BUT relating to my other 'fact' which I believe is a fact;

How is light massless?

Are the following true;

Photons contain no mass
Light travels in straight lines
Light only appears to bend because space is bent [gravitational lensing]

& how is light 'not a particle wave' ? Muller [from berkley uni] in one of his lectures said "light is a particle wave" so I choose to believe him, unless you can give me a valid reason/instance where it is not a particle wave.
15. I don't see that discussions about whether light is a wave or particle belong in this forum, particularly given your tone and that you are "semi-trolling". Take it elsewhere.
Light is massless sweetie x

and is a particle-wave

can you explain this?
it is probably common knowledge, but i can't come to terms with even light photons being massless,

the term "particle-wave" increases my confusion
17. (Original post by JordanCarroll)
can you explain this?
it is probably common knowledge, but i can't come to terms with even light photons being massless,

the term "particle-wave" increases my confusion
think about it the other way around ...

can something with mass ever reach the speed of light? the answer is no.

it can get to something like 99.99999999999% the speed of light but never reach it

it takes more and more mass to get there that to reach the speed of light you would need infinite mass.

that's why light just travels at the speed of light and no slower/faster [it may appear slower going through glass but that's because it's travelling between the material]

As for particle wave ... light behaves both as a particle and a wave, so it's not one or the other it's both !!

I can't really explain it too well but there's a series of Actual Lectures taught at Berkeley Uni on youtube talking about such things
18. sub atomic particles are perfectly spherical on their own arent they?
19. The way mass 'works' [it's a theory, the LHC is about proving this]

is that particles interact with the higgs boson, and acquire their mass via that.

Light [photons] don't interact with this field, therefore have no mass, therefore travel at the speed of light.
think about it the other way around ...

can something with mass ever reach the speed of light? the answer is no.

it can get to something like 99.99999999999% the speed of light but never reach it

it takes more and more mass to get there that to reach the speed of light you would need infinite mass.

that's why light just travels at the speed of light and no slower/faster [it may appear slower going through glass but that's because it's travelling between the material]

As for particle wave ... light behaves both as a particle and a wave, so it's not one or the other it's both !!

I can't really explain it too well but there's a series of Actual Lectures taught at Berkeley Uni on youtube talking about such things
http://everything2.com/title/Why+mat...speed+of+light

just googled this, people explaining why no mass could reach speed of light through math.

haha i do like your explanation

EDIT: 2nd reply interesting also i should know this even as a fairly lay person when it comes to physics

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