Where does the universe end?

[|Thomas|]

All i am saying is particles or energy didnt just decided to show up one day causing the birth of space, something cannot just appear. jesus thinking about space and its origins is scary.

Actually stuff just 'appears' all the time. There is a fundamental principle in physics known as the uncertainty principle, roughly speaking this is where the more we know about a certain property of a particle, the less we can know about another related property. For example, if you measure the position of a particle to a high degree of accuracy then you cannot make an accurate measurement of its momentum, it is physically impossible. This isn't a failure in measuring equipment, it is simply a property of the universe.

Now, as well as position and momentum related in this way so are energy and time. This means that particles of certain energies can appear out of the vacuum of space and then disappear again within an amount of time that the uncertainty principle allows. The larger the energy of particle, the less time it can exist for. This process has been measured countless times and it shows that the vacuum of space is filled with these virtual particles appearing and disappearing constantly.

Whether that or something similar caused the big bang I can't possibly say, nor can anyone else.

As for the whole 0.9r<1 business first year analysis modules will show that an infinitesimally small difference is no difference at all, no approximations necessary. It is similar to integrating certain decreasing functions where one limit is infinite and it can still result in a perfectly good whole number.

For the record I've just finished my first year of a physics degree so do take everything I say with a pinch of salt .

 

[edscdk]

Actually stuff just 'appears' all the time. There is a fundamental principle in physics known as the uncertainty principle, roughly speaking this is where the more we know about a certain property of a particle, the less we can know about another related property. For example, if you measure the position of a particle to a high degree of accuracy then you cannot make an accurate measurement of its momentum, it is physically impossible. This isn't a failure in measuring equipment, it is simply a property of the universe.

Now, as well as position and momentum related in this way so are energy and time. This means that particles of certain energies can appear out of the vacuum of space and then disappear again within an amount of time that the uncertainty principle allows. The larger the energy of particle, the less time it can exist for. This process has been measured countless times and it shows that the vacuum of space is filled with these virtual particles appearing and disappearing constantly.

Whether that or something similar caused the big bang I can't possibly say, nor can anyone else.

As for the whole 0.9r<1 business first year analysis modules will show that an infinitesimally small difference is no difference at all, no approximations necessary. It is similar to integrating certain decreasing functions where one limit is infinite and it can still result in a perfectly good whole number.

For the record I've just finished my first year of a physics degree so do take everything I say with a pinch of salt .

Are these particles the cause of hawkins radiation? (I wish I could stop work and study physics)

Was there an experiment that proved they existed? or was it jsut a conceptual experiment... something to do with putting two plates very close together so that the number of particles appearing on one side was greater that the other causing a a force to be applied on one side or the other..

 

[|Thomas|]

Are these particles the cause of hawkins radiation? (I wish I could stop work and study physics)

Was there an experiment that proved they existed? or was it jsut a conceptual experiment... something to do with putting two plates very close together so that the number of particles appearing on one side was greater that the other causing a a force to be applied on one side or the other..

I believe so, but it is well beyond me I'm afraid. The jist I believe is that on the event horizon (the region beyond which it is physically impossible for matter to escape from) virtual particles are formed in pairs, one matter and one antimatter. The matter particles have enough momentum to escape whereas the antimatter particles do not (don't ask me why, ask a proper physicist ). The antimatter particle then collides with a matter particle on the event horizon of the black hole, leading to a process called annihilation. Annihilation results in both particles being destroyed and replaced by photons of equivalent energies of the two particles, or better known as hawking radiation .

Unfortunately I don't know the nature of said experiments, other than extremely sensitive equipment can detect the fluctuations in net force a vacuum applies due to the formation of virtual particles.

In relation to hawking radiation though I don't believe it's ever been detected.

 

[SlyReaper]

I believe so, but it is well beyond me I'm afraid. The jist I believe is that on the event horizon (the region beyond which it is physically impossible for matter to escape from) virtual particles are formed in pairs, one matter and one antimatter. The matter particles have enough momentum to escape whereas the antimatter particles do not (don't ask me why, ask a proper physicist ). The antimatter particle then collides with a matter particle on the event horizon of the black hole, leading to a process called annihilation. Annihilation results in both particles being destroyed and replaced by photons of equivalent energies of the two particles, or better known as hawking radiation .

Unfortunately I don't know the nature of said experiments, other than extremely sensitive equipment can detect the fluctuations in net force a vacuum applies due to the formation of virtual particles.

In relation to hawking radiation though I don't believe it's ever been detected.

Hawking radiation has never been detected or produced experimentally. In order to produce it experimentally, you'd need a black hole. It's simply a prediction based on our current understanding of physics.

 

[Gilly]

I don't know you, so I wouldn't like to comment on your general level of competency. However, evidence in this thread suggests you are mathematically incompetent. This is nothing to be ashamed of - plenty of people can't do maths.

The article relates to people such as yourself, in as much as you seem to be mathematically incompetent, yet believe your judgement on a mathematical result is likely to be better than all the worlds mathematicians. Thereby vastly overestimating your own ability, whilst underestimating the ability of others.

Little to do with maths and lots to do with logic.

I freely admit I'm rubbish at everything but the most simple maths. It's never interested me enough to learn. It doesn't mean I cannot apply logic to a situation.

 

[SlyReaper]

Little to do with maths and lots to do with logic.

I freely admit I'm rubbish at everything but the most simple maths. It's never interested me enough to learn. It doesn't mean I cannot apply logic to a situation.

Logic is a large part of maths. And I can tell you right away that your insistence that 0.9r is not equal to 1 is most illogical. Especially since you have been presented with at least one water-tight proof.

 

[w11tho]

Little to do with maths and lots to do with logic.

I freely admit I'm rubbish at everything but the most simple maths. It's never interested me enough to learn. It doesn't mean I cannot apply logic to a situation.

Like I said, the most incompetent people aren't privy to their own downfalls.

In addition, you might like to know that mathematics is, quite literally, the study of consequences that logically follow from a set of axioms. The case in point: we have the axiomatic definition of the real numbers, and we have a sequence of logical steps which go from these axioms to the (trivial) result that "1" and "0.9r" are the same real number.

But then, you seem to think you know better. Armed with your formidable skills in logic, and a pocket full of dreams, you've come to the conclusion that you know better than a collective body of people who have spent their lives studying the subject at hand.

You are, quite literally, a prime example of the type of person the article was talking about.

 

[dangerstat]

Like I said, the most incompetent people aren't privy to their own downfalls.

In addition, you might like to know that mathematics is, quite literally, the study of consequences that logically follow from a set of axioms. The case in point: we have the axiomatic definition of the real numbers, and we have a sequence of logical steps which go from these axioms to the (trivial) result that "1" and "0.9r" are the same real number.

But then, you seem to think you know better. Armed with your formidable skills in logic, and a pocket full of dreams, you've come to the conclusion that you know better than a collective body of people who have spent their lives studying the subject at hand.

You are, quite literally, a prime example of the type of person the article was talking about.

The pure arrogance of your posts is disgusting - probably your a PhD student in something like pure or applied? You really really have no idea what your talking about.

 

[SlyReaper]

The pure arrogance of your posts is disgusting - probably your a PhD student in something like pure or applied? You really really have no idea what your talking about.

Arrogant or not, he's still correct.

 

[w11tho]

The pure arrogance of your posts is disgusting - probably your a PhD student in something like pure or applied? You really really have no idea what your talking about.

Calm yourself. If you'd like to point out the mistakes, that would be super.

 

[.walls]

Wow - only read the first page, so apologise if someone's already posted this. Does it not end at that restaurant?

 

[Hitman_Leon]

Little to do with maths and lots to do with logic.

I freely admit I'm rubbish at everything but the most simple maths. It's never interested me enough to learn. It doesn't mean I cannot apply logic to a situation.

Like I said, the most incompetent people aren't privy to their own downfalls.

In addition, you might like to know that mathematics is, quite literally, the study of consequences that logically follow from a set of axioms. The case in point: we have the axiomatic definition of the real numbers, and we have a sequence of logical steps which go from these axioms to the (trivial) result that "1" and "0.9r" are the same real number.

But then, you seem to think you know better. Armed with your formidable skills in logic, and a pocket full of dreams, you've come to the conclusion that you know better than a collective body of people who have spent their lives studying the subject at hand.

You are, quite literally, a prime example of the type of person the article was talking about.

Arrogant or not, he's still correct.

Being correct dose not give the writer the license to employ arrogance, w11tho, You sir may be a scholar but you will never be a gentleman.

Laura Teresa Marquez:

Arrogance and rudeness are training wheels on the bicycle of life -- for weak people who cannot keep their balance without them.

 

[wannabedamned]

haha, Love it.

Can I ask a question?

If 0.9r is 1, why do we bother to have 0.9r as a figure?

Surely LOGIC dictates they are different entities. Even if Mathematics has taught you otherwise.

 

[sid]

A few questions that pop up all the time answered here better than I can put it

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

 

[sid]

haha, Love it.

Can I ask a question?

If 0.9r is 1, why do we bother to have 0.9r as a figure?

Surely LOGIC dictates they are different entities. Even if Mathematics has taught you otherwise.

What logic is this? I haven't heard of it.

 

[SlyReaper]

haha, Love it.

Can I ask a question?

If 0.9r is 1, why do we bother to have 0.9r as a figure?

Surely LOGIC dictates they are different entities. Even if Mathematics has taught you otherwise.

Because it's an interesting thing to think about, and it demonstrates the concept of sequential convergence brilliantly. When you get to the core of mathematics, you never worry about the decimal representation of numbers anyway. It's simply a feature of the decimal number system (and in fact, any arbitrarily based number system) that it's possible to represent any rational number in more than one way.

You might as well ask, why do we even consider an irrational number such as e or pi a number. It's impossible to create a "perfect" circle in a universe where everything is made of discreet atoms or molecules, so why do we bother with the concept of pi?

 

[w11tho]

Being correct dose not give the writer the license to employ arrogance, w11tho, You sir may be a scholar but you will never be a gentleman.

I can live with that. Although, I do find it ironic that the arrogance finger is being pointed at me for picking up on the following situation:

Someone who, by their own admission, doesn't know much maths, believes himself to know better than all the mathematicians on the planet when it comes to judging the veracity of a mathematical statement.

 

[SlyReaper]

Don't you know? It's all a conspiracy by us mathematicians, to trick everyone else into believing wrong things.

 

[wannabedamned]

You might as well ask, why do we even consider an irrational number such as e or pi a number. It's impossible to create a "perfect" circle in a universe where everything is made of discreet atoms or molecules, so why do we bother with the concept of pi?

Heh, I like that actually. I never thought of that, Pi has no pattern, As a perfect circle really doesnt exist?

 

[Rameses]

The Matrix has you!