Ask a physicist anything. (4)

[Steffenfield]

What ever happened to super conductivity?

You know, that junk which could float in the air.

I thought that was going to completely change our world.

 

[bigbadwilf]

What ever happened to super conductivity

They're still developing them, getting them to work at higher and higher temperatures, they've got one mixed metal oxide (Mercury, Barium, Calcium and Copper) to superconduct at a mere minus 140 degrees celcius...

 

[Wiccan_Child]

Thanks! Now my next question: Does gravity have mass and volume?

Nope. Mass and volume are properties of 'stuff', matter, antimatter, dark matter, etc.

 

[Wiccan_Child]

What ever happened to super conductivity?

You know, that junk which could float in the air.

I thought that was going to completely change our world.

The problem with super-conductivity is that it only really occurs near absolute zero. So it can only really be used in massive pieces of equipment - but it is being used. The newest supercomputers use superconducting processors and exploit the queer quantum-ness of the super-cold, and the LHC supercools its magnets to bend super-fast particles round in a circle.

 

[hisgrace26]

Nope. Mass and volume are properties of 'stuff', matter, antimatter, dark matter, etc.

I see. But gravity does exists right? But then it has no properties? How do you explain this? Thanks.

 

[Wiccan_Child]

I see. But gravity does exists right? But then it has no properties? How do you explain this? Thanks.

Gravity is the name given to a phenomenon. It 'exists' as a warping of spacetime by massive objects (i.e., objects with mass) that causes other objects to have their paths altered accordingly. It's not an extant thing unto itself, but the name given to a specific interaction of things (much as a 'chair' isn't a discrete object, but the name given to a specific arrangement of other objects).

In the usual sense of the term, gravity exists.

 

[Deleteriousnonsense]

Gravity is the name given to a phenomenon. It 'exists' as a warping of spacetime by massive objects (i.e., objects with mass) that causes other objects to have their paths altered accordingly. It's not an extant thing unto itself, but the name given to a specific interaction of things (much as a 'chair' isn't a discrete object, but the name given to a specific arrangement of other objects).

In the usual sense of the term, gravity exists.

That's an interesting take on gravity. So a massive object attracts other massive objects, but the force of this attraction is not a "thing" in and of itself, but simply a "what" that happens when massive objects are in proximity. Do I have you on record?

 

[Steffenfield]

Hey boys.

Here's something for you, and I'm really hoping for a response within the next few hours.

I would like all of the possible, different permutations on a 10 digit number that only has the numbers 3, 4, and 5 in them.

I need it in a way so that I can copy and paste each of them into my web browser one at a time.

A little help on this please?

 

[Steffenfield]

Well, I know there's 720 possibilities but I can't find a program or something to generate such numbers.

If any of you have access to something like this, perhaps you could post the results over at

Pastebin.com - #1 paste tool since 2002!

Thank you!

 

[hisgrace26]

Gravity is the name given to a phenomenon. It 'exists' as a warping of spacetime by massive objects (i.e., objects with mass) that causes other objects to have their paths altered accordingly. It's not an extant thing unto itself, but the name given to a specific interaction of things (much as a 'chair' isn't a discrete object, but the name given to a specific arrangement of other objects).

In the usual sense of the term, gravity exists.

So gravity has no mass and volume etc, but when you said "by massive objects" you are not referring to gravity itself, but rather some other objects correct?

Suppose if physicists know how "something came from non-existence", would this be more satisfactory and convincing then knowing how "something came from nothing"? How does "non-existence" different from "nothing"? Are they the same?

Hypothetically, say if we have a scale that goes something like this:

1.existence....2.nothing....3.non-existence

Can we say that nothing is the closes to non-existence? Non-existence cannot be defined, so perhaps there must always be something. Or is nothing stops there? Don't know if that make sense. You get the idea right?

 

[ug333]

Allow a non-physicist to take a crack at this: gravity is a force. Forces don't have weight or volume, but they can be measured. For example, momentum doesn't have weight or volume, but the momentum of an object can be measured. Heat doesn't have weight or volume ......

 

[Wiccan_Child]

That's an interesting take on gravity. So a massive object attracts other massive objects, but the force of this attraction is not a "thing" in and of itself, but simply a "what" that happens when massive objects are in proximity. Do I have you on record?

You should Einstein the credit, not me, but yea, that's the standard Relativistic explanation for gravity: massive objects twisting spacetime towards them, causing other massive objects to 'fall'.

 

[Wiccan_Child]

Hey boys.

Here's something for you, and I'm really hoping for a response within the next few hours.

I would like all of the possible, different permutations on a 10 digit number that only has the numbers 3, 4, and 5 in them.

I need it in a way so that I can copy and paste each of them into my web browser one at a time.

A little help on this please?

You could generate all numbers in base 4 from 1111111111 to 3333333333, then convert 1 to 3, 2 to 4, and 3 to 5?

 

[Wiccan_Child]

So gravity has no mass and volume etc, but when you said "by massive objects" you are not referring to gravity itself, but rather some other objects correct?

Correct.

Suppose if physicists know how "something came from non-existence", would this be more satisfactory and convincing then knowing how "something came from nothing"? How does "non-existence" different from "nothing"? Are they the same?

They're both colloquialisms by which we answer the old adage that "Ex nihilo, nihilo est".

Hypothetically, say if we have a scale that goes something like this:

1.existence....2.nothing....3.non-existence

Can we say that nothing is the closes to non-existence? Non-existence cannot be defined, so perhaps there must always be something. Or is nothing stops there? Don't know if that make sense. You get the idea right?

Existence is boolean; you either exist, or you don't. The English language demands we treat non-existence as a 'state', when it's really not. It's not a thing whence comes others, like a train station, and 'nothingness' is what we call the 'state' when nothing exists.

 

[Tinker Grey]

Well, I know there's 720 possibilities but I can't find a program or something to generate such numbers.

If any of you have access to something like this, perhaps you could post the results over at

Pastebin.com - #1 paste tool since 2002!

Thank you!

Well essentially you have a number in base 3 where you are using the digits 3, 4, and 5 rather than the digits 0, 1, and 2. Also you are analogously allowing leading 0's.

The question then is how many number are there from 3333333333[sub]3[/sub] to 5555555555[sub]3[/sub].

In base 10, we'd say we are counting from 0 to 10[sup]11[/sup]-1. So the answer for a base 10 number is 10[sup]11[/sup]-1.

So, I hope it is clear why I say the answer is 3[sup]11[/sup]-1 = 177146.

ETA: A much larger number than 720.

 

[Delphiki]

I just did this in Excel and I have 59049 rows. ??

I think if' it's 10 digits it's actually just 3^10

 

[Tinker Grey]

I just did this in Excel and I have 59049 rows. ??

I think if' it's 10 digits it's actually just 3^10

You are correct. I was wrong.

ETA: I was also unclear on this -- the number of values is 3[sup]10[/sup] (59049). The range of values (in base 10) is from 0 - 3[sup]10[/sup]-1 (using the different digits).

 

[Steffenfield]

Are you sure that number is correct guys?

I just want a 10 digit number with only 3s, 4s, and 5s in it.

And yeah, I'm trying to find myself a new phone number.

I did score one that is really close to what I wanted.

So right now, if a girl ever asks what my phone number would be, I can say in my best hillbilly voice impression that it's

"fo fee fo fi fee fi too fee fo too!" *lol*

It's got two 2s in it though, I was hoping for something with only 3s, 4s, and 5s.

And yeah, I found someone asking the same question and the answer was only 720 possible combinations.

Anyway, it's easier for me to copy and paste each number to see if it's already been taken than rifling through the entire list that's available.

Hope that makes some sense.

 

[catzrfluffy]

How much would you like to do this?

 

[Tinker Grey]

Well, look at it this way. Consider a 2 digit number. Consider also that you are allowing digits 0 thru 9. The number of possibilities are 100. 10[sup]2[/sup]. The 2 goes with the number of slots. If you have 3 slots, you have the 10[sup]3[/sup], 000 thru 999.

If you have 3 slots and only two things to put in them, you have the following combinations: 000, 001, 010, 011, 100, 101, 110, and 111. That's 8 or 2 (the number of items) raised to the 3 (the number of slots) or 2[sup]3[/sup].

If you have 2 slots and 3 items: You get 00, 01, 02, 10, 11, 12, 20, 21, and 22. That's 9 or 3[sup]2[/sup]. In the case of 3, 4, 5: 33, 34, 35, 43, 44, 45, 53, 54, 55. I'll leave it as an exercise () to find the 27 values for 3, 4, and 5 in three slots.

But, yeah, 10 slots with 3 items ... 3[sup]10[/sup].