Vaccum

[Ashish]

Is universe really vaccum or any portion of it?

[Klaynos]

Nothing is perfect vacuum, when you start getting close you get things called vacuum fluctuations, which is a quantum effect.

 

But even in space there is allot of gas/dust just floating about...

[ecoli]

no.. there's a lot of stuff in the universe. planets, people, dust, random particles.

[Ashish]

Nothing is perfect vacuum, when you start getting close you get things called vacuum fluctuations, which is a quantum effect.

 

But even in space there is allot of gas/dust just floating about...

Thanks for your reply

Can explain the term vacuum fluctuations, which is a quantum effect.

[Klaynos]

Well a nice little qualitative explanations is, that because there is a finite uncertainty between energy and time, and energy is related to mass, if you consider some empty space for a short enough time, it contains an enormous amount of energy. This energy forms matter-antimatter pairs, which annihilate during the very short time which you are observing them in.

 

So this means that particles are being created and destroyed all the time, and exist for very very very very short time scales...

[Ashish]

As to your reference that [energy forms matter-antimatter pairs, which annihilate during the very short time which you are observing them in.

So this means that particles are being created and destroyed all the time, and exist for very very very very short time scales...]

 

Is that possible that there may not be particle but energy forms wave.

[Klaynos]

That was something I was wondering, I assume that you can get photon-antiphoton pairs created...

[Ashish]

That was something I was wondering, I assume that you can get photon-antiphoton pairs created...

but can you tell me that will that be a particle or wave

[Klaynos]

but can you tell me that will that be a particle or wave

 

When talking about things on such a small scale the words particle and wave get a bit mixed up, it depends on how you observe them, if you try and observe wave properties you will get them, if your try and observe particle properties you will get them as well :|

[Ashish]

When talking about things on such a small scale the words particle and wave get a bit mixed up, it depends on how you observe them, if you try and observe wave properties you will get them, if your try and observe particle properties you will get them as well :|

I think that everything in this universe is made up of particle (matter and antimatter) then how there can be a misconception of wave.

[Klaynos]

Well if for example you fire individual electrons at two slits, you get an interference patter on a detector on the other side of the slits, which is clearly a property of waves as it means the electrons travelled through both slits.

[swansont]

Is universe really vaccum or any portion of it?

 

Which definition of vacuum are you using?

 

If it's the complete absence of matter and energy, then no, as several posts have explained.

 

If it's a relative lack of matter, i.e. a significantly lower pressure than atmosphere, then yes, most of the universe is a vacuum.

[Ashish]

Well if for example you fire individual electrons at two slits, you get an interference patter on a detector on the other side of the slits, which is clearly a property of waves as it means the electrons travelled through both slits.

Yes but not on only one electron but it takes huge numbers of electron to come upto results of old ones.

But I think that from this (double-slit experiment with photons or other microscopic particles) that there is nothing like waves.

 

Which definition of vacuum are you using?

 

If it's the complete absence of matter and energy, then no, as several posts have explained.

 

If it's a relative lack of matter, i.e. a significantly lower pressure than atmosphere, then yes, most of the universe is a vacuum.

Can you explain me clearly

[iNow]

Can you explain me clearly

 

It depends on your definition.

 

If you define a "vacuum" as the complete absence of anything (matter and energy), then space is not that.

 

If you define a "vacuum" as an ALMOST complete absence of matter and energy, then yes... space is that.

 

Where are you struggling? What definition are you using?

[Ashish]

It depends on your definition.

 

If you define a "vacuum" as the complete absence of anything (matter and energy), then space is not that.

 

If you define a "vacuum" as an ALMOST complete absence of matter and energy, then yes... space is that.

 

Where are you struggling? What definition are you using?

OK then when we create a vaccum in a Lab then in which category will u place it

[ydoaPs]

OK then when we create a vaccum in a Lab then in which category will u place it

Which lab? In most cases, when we create a "vacuum" we mean "relatively low pressure area".

[iNow]

OK then when we create a vaccum in a Lab then in which category will u place it

 

 

That would be a partial vacuum. A perfect vacuum is an ideal state that you cannot get in a lab. Look at the following and slow down. Try to digest what it says before moving on:

 

http://en.wikipedia.org/wiki/Vacuum

 

[Norman Albers]

The vacuum is not at all nothing. You are asking a very good question at the edge of our understanding, Ashish. I think here Klaynos gets us into the ballpark (yeah, right).

[Ashish]

That was something I was wondering, I assume that you can get photon-antiphoton pairs created...

Please tell me about antiphotons or it is just lik ean antiparticle of it.

[Klaynos]

Yes but not on only one electron but it takes huge numbers of electron to come upto results of old ones.

But I think that from this (double-slit experiment with photons or other microscopic particles) that there is nothing like waves.

 

You do need many particles to form the interferance pattern, but if you fire them one at a time you get the same result as if you use a continuouse stream of them (it just takes more time) this means that the individual particle has traveled through both slits. This experiment has been preformed with things as large as buckminster fullerenes...

 

Please tell me about antiphotons or it is just lik ean antiparticle of it.

 

Yes, but it is indistinguishable from a normal photon.

[swansont]

That would be a partial vacuum. A perfect vacuum is an ideal state that you cannot get in a lab. Look at the following and slow down. Try to digest what it says before moving on:

 

http://en.wikipedia.org/wiki/Vacuum

 

 

In practice, though, very few use this terminology. If it's considerably lower pressure, you call it a vacuum. You then quantify how good of a vacuum it is, as shown in your link. Low, medium, high or ultra-high vacuum, as far as most lab applications go.

[doG]

OK then when we create a vaccum in a Lab then in which category will u place it

 

The absence of atmospheric pressure....

[iNow]

In practice, though, very few use this terminology. If it's considerably lower pressure, you call it a vacuum. You then quantify how good of a vacuum it is, as shown in your link. Low, medium, high or ultra-high vacuum, as far as most lab applications go.

 

If I interpret you correctly, vacuums must be seen along a continuum, not in a binary (yes/no) state? That seems quite logical. Thanks.

[Ashish]

Unable to interpret it.

[swansont]

If I interpret you correctly, vacuums must be seen along a continuum, not in a binary (yes/no) state? That seems quite logical. Thanks.

 

It's binary as far as having a vacuum or not, (much like pregnancy is a binary state, and then you ask how many months pregnant) but it's not a binary of having a perfect vacuum or not — since there is no such thing, there's no point in making that distinction.