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  #281  
Old 13.12.2007, 11:49
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Re: Ask a Scientist

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That's a parabolic mirror. I'm asking about a spherical mirror. even if I wasn't moving and the light source was static.

The reflection of colour would be everywhere as would the reflection of light.

Perhaps I am lacking in the understanding of the properties of light, but what would the behaviour or the (various) wavelengths of light be in the sphere?
There's a spherical mirror on that page too, as you can see reflected light is focused in the centre so if you stand there, you would see your reflection all over the inside of the sphere, but I doubt it would be a reflection you would recognize. I do not think the wavelengths would be affected, whatever is emmited is bounced back.
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Old 13.12.2007, 12:51
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Re: Ask a Scientist

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Even if I wasn't moving. Wouldn't everything, in terms of light and reflection be everywhere in the sphere, no one point or area in the sphere would show a reflection of me because every other point in the sphere would be reflecting another point.

Kind of like a cartesian product of light.
I think you are forgetting that you are not symmetrical, so there won't be all sorts of symmetric light waves floating around--it would definitely be very bright but you would still see a distorted picture of yourself.

I think you are thinking of light as a particle, in that each photon/particle of light can be reflected an infinite number of times in your sphere. But this is not true--Every material is going to adsorb some of the light and allow a certain amount of light to pass through--in other words, it's impossible that every photon of light would be reflected. There is also refraction to consider--unless the surface is entirely smooth (and of course, nothing is, because it's made up of atoms or molecules).

It's also important to consider that light is also a wave, and these waves interfere with each other. You know how noise-canceling headphones work? They create sounds which interfere with the outside sounds, so you end up hearing nothing. A super nerdy explanation is that mathematically, the sum of two waves will be zero. Some of the light will interfere with itself as well, but of course, not all.

What you see with your eyes is not all the light, of course--only the light that's reflected/refracted into your eye, which depends on your angle. All the light reflecting from the sphere will not reach your eye at the same time.

In short, you have reflection, refraction, adsorption, interference, an asymmetrical being in the sphere, and he'll be able to see a distorted self in very bright light.

Hey, I'm so excited that 10 years of scientific education is finally being put to good use!!! :-)
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  #283  
Old 13.12.2007, 13:40
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Re: Ask a Scientist

Thanks, that's what I wanted to say but was way too lazy that type all that out.

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I think you are forgetting that you are not symmetrical, so there won't be all sorts of symmetric light waves floating around--it would definitely be very bright but you would still see a distorted picture of yourself.

I think you are thinking of light as a particle, in that each photon/particle of light can be reflected an infinite number of times in your sphere. But this is not true--Every material is going to adsorb some of the light and allow a certain amount of light to pass through--in other words, it's impossible that every photon of light would be reflected. There is also refraction to consider--unless the surface is entirely smooth (and of course, nothing is, because it's made up of atoms or molecules).

It's also important to consider that light is also a wave, and these waves interfere with each other. You know how noise-canceling headphones work? They create sounds which interfere with the outside sounds, so you end up hearing nothing. A super nerdy explanation is that mathematically, the sum of two waves will be zero. Some of the light will interfere with itself as well, but of course, not all.

What you see with your eyes is not all the light, of course--only the light that's reflected/refracted into your eye, which depends on your angle. All the light reflecting from the sphere will not reach your eye at the same time.

In short, you have reflection, refraction, adsorption, interference, an asymmetrical being in the sphere, and he'll be able to see a distorted self in very bright light.

Hey, I'm so excited that 10 years of scientific education is finally being put to good use!!! :-)
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  #284  
Old 13.12.2007, 13:46
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Re: Ask a Scientist

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.....There is also refraction to consider--unless the surface is entirely smooth (and of course, nothing is, because it's made up of atoms or molecules).....
The surface would only have to be smooth enough to reflect the light.. so if the lightwave has a certain amplitude and wavelength it would have to be smooth enough to bounce it back as opposed to absorbing it. At least that's what I would assume, but I could be wrong on this one. It most definitely would not be dark.
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  #285  
Old 13.12.2007, 14:23
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Re: Challenging "science" question !!

[quote=Terry;141780
Is there a scientist out there that can propose a method of converting "sh*t into ice cream" -- then I can try and convince my doctor that anything is possible. [/quote]

I'm not a doctor, I'm an engineer working on my Ph.D. (although I have watched tons of Grey's Anatomy). I do know, however, a little bit about how joints work--it's related to my current work. There is incredibly low friction in your joints, and it depends on how much lubricating fluid you have, how well your cartilage makes this lubricating fluid, if you have enough cartilage, if it's damaged (tears, holes), if it's too hard or soft, how well it's connected to your bones and muscles, how well your muscles work. How healthy joints work is also not so well understood since, well, there aren't so many volunteers who let surgeons cut their legs apart for no reason. But if all the right conditions are not met, you can experience a lot of pain and problems with movement.

Injured joints don't make the right fluid, and damaged and scarred cartilage probably doesn't fit together so well as it did before it was injured. Also, an ankle is a very complicated joint--much more complicated than a knee or hip. I don't know the specifics, but I can imagine that after the healing of your injury, the surgeon is not left with a lot of healthy, non-scarred tissue to work with. And after it heals, even more scar tissue will grow, which might not be in an ideal shape or condition--it's all very complicated.

However, this is not to say that by visiting another doctor/surgeon (maybe even a sports medicine doctor? a friend of mine did that once)? All different doctors have different skills/confidence/optimism. (That I learned from Grey's Anatomy :-)) You wouldn't want to ask a doctor to do something he doesn't feel good about.

But in short, unfortunately, not everything is possible, but that doesn't mean you shouldn't get a second opinion.
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  #286  
Old 13.12.2007, 14:47
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Re: Ask a Scientist

here's one....

now, I know this is impossible...but what would happen if:

A large hole was drilled right through the earth, completely, straight through the center...and we jumped in? Would we fall at the same rate the whole way down?

...and once we passed the center, we would then fall "up" for a bit on the other side, then back down...then eventually settle in the center...but could you hold yourself steady or would you rotate and spin around at the center? (no up, no down...just a single point)
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Old 13.12.2007, 14:52
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Re: Ask a Scientist

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here's one....

now, I know this is impossible...but what would happen if:

A large hole was drilled right through the earth, completely, straight through the center...and we jumped in? Would we fall at the same rate the whole way down?

...and once we passed the center, we would then fall "up" for a bit on the other side, then back down...then eventually settle in the center...but could you hold yourself steady or would you rotate and spin around at the center? (no up, no down...just a single point)
You would burn before you would reach the center. What you do then does not depend on any physics

If you survive the heat, you may actually end up in a zero gravity zone once at the center (equal pull in all directions). In reference with the earth's radius you are approximately a point. If you can manage to stay in the middle you should be able to turn.

Would this hole have air in it?
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  #288  
Old 13.12.2007, 14:58
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Re: Ask a Scientist

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You would burn before you would reach the center. What you do then does not depend on any physics
...oh ya, i forgot to mention I'll have my "burn" suit on...

...Mmmm, air in the hole....I'll have my "air assisted burn suit on"...complete with mp3 capabilities for the way down
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  #289  
Old 13.12.2007, 15:11
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Re: Ask a Scientist

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here's one....

now, I know this is impossible...but what would happen if:

A large hole was drilled right through the earth, completely, straight through the center...and we jumped in? Would we fall at the same rate the whole way down?

...and once we passed the center, we would then fall "up" for a bit on the other side, then back down...then eventually settle in the center...but could you hold yourself steady or would you rotate and spin around at the center? (no up, no down...just a single point)
Oh, I'm totally depressed, I lost all my data for today!!
So, I'll answer your question--we discussed it in high school physics:

The force of gravity acts depends on the mass of the two objects--in this case, the earth, and the man. It is a directional force between two objects, and depends on the distance--(for you nerds, you can say there's a force vector between the two objects). This means that if the earth is below our feet, it will pull us down. Things change in the middle of the earth--there is an approximately equal amount of earth on both sides of us. In the very center of a big spherical hole in the middle of the earth, you'd experience no gravity, but if you managed to get to one side of the hole, you'd be pulled to that side slightly, because the effect of gravity increases with a shorter distance.

Now, to the scenario of a big tunnel directly through the middle of the earth. So, if you jump into the middle of the earth, and the hole went directly all the way through the earth--you would probably pass the center of the earth, slow and stop, be pulled back, slow down and stop--you would oscillate until you stopped at the middle and floated around a bit. You wouldn't spin because you wouldn't experience any force to make you spin--no gravity. But like the case above, if you managed to be closer to one side of the tunnel than the other, you also might be pulled to the side.
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  #290  
Old 13.12.2007, 15:17
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Re: Ask a Scientist

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You would burn before you would reach the center. What you do then does not depend on any physics

If you survive the heat, you may actually end up in a zero gravity zone once at the center (equal pull in all directions). In reference with the earth's radius you are approximately a point. If you can manage to stay in the middle you should be able to turn.

Would this hole have air in it?
It also depends on whether there is air in the hole and the diameter of the hole. If you jump in the hole you will speed up quite a bit before you reach the center, so depending on that speed, the gravitational force will stop you sooner or later past the center and pull you back towards the center. With air you also have wind resistance slowing your fall.
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  #291  
Old 13.12.2007, 15:22
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Re: Challenging "science" question !!

[quote=wah;145414]I'm not a doctor, I'm an engineer working on my Ph.D. etc. etc.

Thanks for the very informative reply. I have subsequently seen my specialist, again, who after viewing the latest results from MRi scans basically said everything that you covered i.e. messed up cartilage, lots of scar tissue, distorted bone -- you name it I seem to have it.

As a result he has decided that the risk of further damage from yet another operation is greater than chance of improvement - his opinion based on his ability.

He has sent all my x-rays, CT scans, MRi scans etc. to a colleague at the Schultess (?spelling) to seek their opinion.

In the meantime I wait and limp (in some discomfort but not actually "real" pain).

The saga continues.
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  #292  
Old 13.12.2007, 15:50
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Re: Challenging "science" question !!

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Thanks for the very informative reply. I have subsequently seen my specialist, again, who after viewing the latest results from MRi scans basically said everything that you covered i.e. messed up cartilage, lots of scar tissue, distorted bone -- you name it I seem to have it.

As a result he has decided that the risk of further damage from yet another operation is greater than chance of improvement - his opinion based on his ability.

He has sent all my x-rays, CT scans, MRi scans etc. to a colleague at the Schultess (?spelling) to seek their opinion.

In the meantime I wait and limp (in some discomfort but not actually "real" pain).

The saga continues.
Best of luck with that Terry,

I am working in the Schulthess and the lower extremity team here are really good. Most of the Professional Ice Hockey and Football players from the region are treated here. My girlfriend went under the knife for a foot problem here last year too and she is happy with the results.
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  #293  
Old 13.12.2007, 16:26
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Re: Ask a Scientist

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Depends on the set-up. Some urinals are all linked together and have one master flush that is timed.

The second type of automatic flushing urinal has an infrared sensor that detects movement and hence flushes when the person leaves.
Not just urinals. In Munich airport I found a WC which automatically flushed when you stood up.

And a bar here used to have a system where not only did the washbasin tap automatically switch on when you put your hands underneath it, but the towel dispenser dished out clean dry towel when you put your hands up to it.
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  #294  
Old 13.12.2007, 16:29
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Re: Ask a Scientist

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Not just urinals. In Munich airport I found a WC which automatically flushed when you stood up.

And a bar here used to have a system where not only did the washbasin tap automatically switch on when you put your hands underneath it, but the towel dispenser dished out clean dry towel when you put your hands up to it.
Most likely IR motion sensor or similar.
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Old 13.12.2007, 16:59
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Re: Ask a Scientist

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Now, to the scenario of a big tunnel directly through the middle of the earth. So, if you jump into the middle of the earth, and the hole went directly all the way through the earth--you would probably pass the center of the earth, slow and stop, be pulled back, slow down and stop--you would oscillate until you stopped at the middle and floated around a bit. You wouldn't spin because you wouldn't experience any force to make you spin--no gravity. But like the case above, if you managed to be closer to one side of the tunnel than the other, you also might be pulled to the side.
Is the tunnel through the rotational axis of the earth or not? If it goes from equator to equator on the other side, you will be travelling at the surface rotation speed and somehow need to decelerate to zero relative to the earth's core. You might need a trolley on rails to stop friction burns against the tunnel wall.

On the other hand, if the tunnel goes through the rotational axis (north pole to south pole), you would be spinning at the rate of 1 revolution per 24 hours.
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  #296  
Old 13.12.2007, 17:17
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Re: Ask a Scientist

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Will my iron-free shirt NEVER rust?
Umm if this is a real question, I have to imagine that you're reading the label wrong...An iron-free shirt has to do with ironing out the wrinkles being unnecessary, not with iron, the metal, rusting.

By the way, if any of your clothes ever appear to "rust" (reddish brown staining after washing), the problem is with the water you're using, not with the clothes themselves. Either your water source has high levels of iron and should be treated, or part of your washing machine is rusting and delivering iron to the water...
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Old 13.12.2007, 17:21
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Re: Ask a Scientist

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Not just urinals. In Munich airport I found a WC which automatically flushed when you stood up.
Ladies' WCs like this are really common, especially in the U.S. I guess there are enough people out there not flushing to make this worthwhile!
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  #298  
Old 13.12.2007, 17:23
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Re: Ask a Scientist

Or you can just add EDTA to all of your laundry loads.

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By the way, if any of your clothes ever appear to "rust" (reddish brown staining after washing), the problem is with the water you're using, not with the clothes themselves. Either your water source has high levels of iron and should be treated, or part of your washing machine is rusting and delivering iron to the water...
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Old 13.12.2007, 17:33
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Re: Ask a Scientist

This is one for the mathemagicians. I am not one.

I see mathemtics as a language, a naturally occurring language through which we understand concepts our spoken language does not accommodate.

Crude example, Big bang vs. genesis. They go on to say the same thing really, the only difference being the language they were written in. One was written in a modern empirical and scientific language and the other one was written in a figurative language.

If whoever wrote Genesis 4-5000 years ago spoke mathematics, he would have written te same story, but somewhat differently.

My question is this.

Has mathematics reached the end of its life? How much more is there to discover using it? How many major break-throughs have there been since say quantum mechanics and how old is that?

I have been told that there is a lot that remains unanswered, or shall we say there are open issues. But my nderstanding of this is that there are revisions that need to me made, not cracking open doors to new territories.

Is another vehicle or language going to come along and take us to levels of understanding that mathematics is not capable of? If mathematics is based on constants and naturally occurring numbers, is there anything else?
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Old 13.12.2007, 17:33
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Re: Ask a Scientist

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Umm if this is a real question, I have to imagine that you're reading the label wrong...An iron-free shirt has to do with ironing out the wrinkles being unnecessary, not with iron, the metal, rusting.
I think you missed the joke there

|quote]By the way, if any of your clothes ever appear to "rust" (reddish brown staining after washing), the problem is with the water you're using, not with the clothes themselves. Either your water source has high levels of iron and should be treated, or part of your washing machine is rusting and delivering iron to the water...[/QUOTE]

This might be relevant for Switzerland. In the UK, all modern water pipes are copper, but the ones in my first office here were iron. You didn't normally see it, but if you were the first one to arrive at work in the morning and fill the coffee machine, you needed to run the tap for several minutes until the water became clear.
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