Ask a physicist anything. (3)

[BrianOnEarth]

Also, how can time be a dimension?

Time - Wikipedia, the free encyclopedia

My view is this. Time is a concept that requires memory and repeatable change. Time is a count of changes. A clock is a device that shows us how many times an oscillator has oscillated. That's it.

So it is a relative thing. We can only observe changes. So general relativity concerns how many changes one observer sees versus another when they are moving at different speeds relative to the speed of light.

There is no such thing as the future or the past there is only now. It is erroneous to convolute a representation of a count of events into the existence of a past and a future.

 

[Wiccan_Child]

I'd suggest squirrels. That way after the first couple tests go all wahoonie shaped you can have a nice empirical data set to answer her earlier question.

I was on a date yesterday cool and we saw this squirrel come up to us and start digging in the ground. Turns out it had stored its acorns there and was having a munch! Never seen a squirrel actually do that before. Good times.

Momentum - Wikipedia, the free encyclopedia

Photon - Wikipedia, the free encyclopedia

Mass: zero
Momentum: h/λ, i.e., non-zero

 

[Wiccan_Child]

Time - Wikipedia, the free encyclopedia

My view is this. Time is a concept that requires memory and repeatable change. Time is a count of changes. A clock is a device that shows us how many times an oscillator has oscillated. That's it.

So it is a relative thing. We can only observe changes. So general relativity concerns how many changes one observer sees versus another when they are moving at different speeds relative to the speed of light.

There is no such thing as the future or the past there is only now. It is erroneous to convolute a representation of a count of events into the existence of a past and a future.

Relativity begs to differ. The past and the future, exist as much as an entire stretch of road exists, despite you being in only one place on that road. Classically, time is change, and the past doesn't exist. But we've moved on from classical mechanics.

 

[Wiccan_Child]

This device, and all devices like it, is a heater.

Weird world, huh.

 

[BrianOnEarth]

Relativity begs to differ. The past and the future, exist as much as an entire stretch of road exists, despite you being in only one place on that road. Classically, time is change, and the past doesn't exist. But we've moved on from classical mechanics.

Please elaborate.

 

[Wiccan_Child]

Please elaborate.

To which part?

 

[Frumious Bandersnatch]

Relativity begs to differ. The past and the future, exist as much as an entire stretch of road exists, despite you being in only one place on that road. Classically, time is change, and the past doesn't exist. But we've moved on from classical mechanics.

And how does one integrate the second law of thermodynamics into this view? Doesn't it provide a so-called "arrow of time"?

 

[Wiccan_Child]

And how does one integrate the second law of thermodynamics into this view? Doesn't it provide a so-called "arrow of time"?

Yes, inasmuch as the way a system develops isn't a mirror image of the reverse. The present obviously affects the future, in that the next moment is, well, the present in the future scratch. It's hard to reconcile our intuitive view of how the future is determined by the present, and the relativistic idea that time is a dimension with the past and future existing as much as the present.

 

[Frumious Bandersnatch]

Yes, inasmuch as the way a system develops isn't a mirror image of the reverse. The present obviously affects the future, in that the next moment is, well, the present in the future scratch. It's hard to reconcile our intuitive view of how the future is determined by the present, and the relativistic idea that time is a dimension with the past and future existing as much as the present.

I think it is pretty difficult to reconcile thermodynamics relativity in general especially general relativity. I was at a Gordon Conference on the epidermis in 1999 and a conference on thermo was going on at the same time at the same conference center. I saw some of their poster and they were really puzzling. By the way you might be interested to know that Murray Gell-Mann was at the thermo conference and I did get to talk to him briefly on an elevator ride. He is a really nice guy and everyone calls him Murray. He seems to have no ego to speak of. We talked about the birds in the area including the cuckos that woke everyone up in the morning.

 

[BrianOnEarth]

To which part?

All of it will do.
Specifically, please elaborate about why you think the theory of general relativity requires that a past and a future must co-exist with a now in reality.

 

[catzrfluffy]

What's the rarest element on earth?

And is it true that daddy-long-legs are really poisonous, they just can't bite you?

*shudder *shudder

 

[Chesterton]

By how many goals will America defeat England in the World Cup?

 

[catzrfluffy]

Waaaaaaaaaaaaaaaake up!

 

[Wiccan_Child]

All of it will do.
Specifically, please elaborate about why you think the theory of general relativity requires that a past and a future must co-exist with a now in reality.

Because general relativity implies (or posits, depending on how you look at it) a 4-dimensional spacetime continuum; space and time, in the general relativistic model, aren't distinct entities, but manifestations of the same entity. This allows for a proper treatment and understanding of Lorentz transformations. If nothing else, this model simplifies the mathematics.

Classically, time is a universal, invariant variable (invariant variable?!), independent to the petty goings on of common matter.

 

[Wiccan_Child]

What's the rarest element on earth?

All the unnatural elements (i.e., ones that only exist because we made it so) are obviously rare, but the rarest naturally occuring element on Earth is Astatine.

And is it true that daddy-long-legs are really poisonous, they just can't bite you?

*shudder *shudder

Horrible buggers, shoot on sight till squish.
I had to look this up, but it turns out 'daddy-long-legs' refers variously to crane flies (gross flies as seen in your picture), harvestmen (arachnids, but not spiders) and cellar spiders (actual spiders). The first two have no venom, while the third's venom is so weak as to be harmless to humans.

By how many goals will America defeat England in the World Cup?

I believe that'd be an imaginary number .

Waaaaaaaaaaaaaaaake up!

British people need their sleep, how else do we end up looking so fabulous .

 

[AV1611VET]

Is Titanium the hardest substance in the universe?

And what is Titanium Tetrachloride? is that what they call 'stainless steel'?

 

[lucaspa]

Is Titanium the hardest substance in the universe?

No. The hardest naturally occurring substance is diamond. BTW, "hardness" has a very specific definition when you are talking about material properties: Hardness - Wikipedia, the free encyclopedia

And what is Titanium Tetrachloride? is that what they call 'stainless steel'?[/quote]

TiCl4 is a mineral. It is not stainless steel. Stainless steel is a form of steel, which is mostly iron. Different types of stainless steel has varying amounts of Manganese, chromium, nickel, and molybdenum in addition to the iron. You can see a chart of the composition of stainless steels here:
http://www.engineersedge.com/stainless_steel.htm

Do you not know how to conduct a simple Google search?

 

[Hespera]

What's the rarest element on earth?

And is it true that daddy-long-legs are really poisonous, they just can't bite you?

*shudder *shudder

That looks like a crane fly to me.

 

[Wiccan_Child]

Do you not know how to conduct a simple Google search?

He either knows the answer and is participating in the thread, or prefers to get an answer from a human.

Or, indeed, perhaps he doesn't know how to use Google...

That looks like a crane fly to me.

No no no, it's clearly a daddy-long-legs.

 

[AV1611VET]

He either knows the answer and is participating in the thread, or prefers to get an answer from a human.

Or both --