Ask a physicist anything. (5)

[Gracchus]

God must have been pretty intelligent to come up with evolution

So I guess a zygote must have been pretty intelligent to come up with embryology?

 

[SAMMISPARROW]

He who is faithful cannot be convinced otherwise. ...........man

 

[mzungu]

What causes sonoluminescence?

There are several theories involved in explaining this.
Below is an excerpt from wiki:

The dynamics of the motion of the bubble is characterized to a first approximation by the Rayleigh-Plesset equation (named after Lord Rayleigh and Milton Plesset):

This is an approximate equation that is derived from the incompressible Navier-Stokes equations (written in spherical coordinate system) and describes the motion of the radius of the bubble R as a function of time t. Here,

is the viscosity, p the pressure, and

the surface tension. The over-dots represent time derivatives. This equation, though approximate, has been shown to give good estimates on the motion of the bubble under the acoustically driven field except during the final stages of collapse. Both simulation and experimental measurement show that during the critical final stages of collapse, the bubble wall velocity exceeds the speed of sound of the gas inside the bubble[4]. Thus a more detailed analysis of the bubble's motion is needed beyond Rayleigh-Plesset to explore the additional energy focussing that an internally formed shock wave might produce.

 

[Assyrian]

So I guess a zygote must have been pretty intelligent to come up with embryology?

That's the God you posit one that is the product of human evolution and imagination. I am talking about an eternal God who is responsible for the evolution that produced us. Of course it doesn't prove there is such a God, that is after all why it is called faith, but it does show there a Christians with a higher view of God than the impression you seem to get from Creationists.

 

[Wiccan_Child]

A fifth grader could answer this simple question

Could you provide a quote by Einstein? The only thing it proves is that a physicist is not smarter than a fifth grader either.

You attempted to use Einstein's belief in God as proof that God exists - yet when it was shown that Einstein didn't believe in God, you turned round and used that as proof that God exists.

i could easily demonstrate how a murderer is changed by God word, there are many who been changed by it.

By all means, demonstrate this.

Can you demonstrate how a black hole works or time space just as easily? Like i said, I'm done i only wanted to answer that question.

I still don't know what question you're asking. Are you saying its easier to show God's ability to change people, than it is to talk about physical phenomena?

 

[SAMMISPARROW]

You attempted to use Einstein's belief in God as proof that God exists - yet when it was shown that Einstein didn't believe in God, you turned round and used that as proof that God exists.


By all means, demonstrate this.


I still don't know what question you're asking. Are you saying its easier to show God's ability to change people, than it is to talk about physical phenomena?

May I ask, what causes the earth to go round its axis, and at a perfect speed and non stop.

 

[Wiccan_Child]

May I ask, what causes the earth to go round its axis, and at a perfect speed and non stop.

The Earth is constantly 'falling' towards the Sun, due to gravity, but because the Earth is also constantly moving 'sideways', it 'overshoots', like an imaginary cannon shooting something around the Earth:

The mechanics of this system are such that the Earth continues to orbit the Sun.

The Earth itself is also rotating, and continues to do so because there's nothing to stop it: Newton's Laws tell us that an object will continue moving (and, indeed, rotating) indefinitely until acted upon by another force. Since there's nothing to stop the Earth moving or rotating, it continues to do so.

The reason it moves and rotates at all are a result of how the Earth formed. Simply put, a massive object that hits the Earth is unlikely to hit it at exactly 0°, thus, this will cause the Earth to spin (imagine one billiard ball hitting another at an angle - the latter will spin).

I'm not sure what you mean by 'perfect speed', though.

 

[AV1611VET]

There are several theories involved in explaining this.
Below is an excerpt from wiki:

The dynamics of the motion of the bubble is characterized to a first approximation by the Rayleigh-Plesset equation (named after Lord Rayleigh and Milton Plesset):

This is an approximate equation that is derived from the incompressible Navier-Stokes equations (written in spherical coordinate system) and describes the motion of the radius of the bubble R as a function of time t. Here,

is the viscosity, p the pressure, and

the surface tension. The over-dots represent time derivatives. This equation, though approximate, has been shown to give good estimates on the motion of the bubble under the acoustically driven field except during the final stages of collapse. Both simulation and experimental measurement show that during the critical final stages of collapse, the bubble wall velocity exceeds the speed of sound of the gas inside the bubble[4]. Thus a more detailed analysis of the bubble's motion is needed beyond Rayleigh-Plesset to explore the additional energy focussing that an internally formed shock wave might produce.

WOW!

-- I asked all that!?

 

[Wiccan_Child]

WOW!

-- I asked all that!?

Short answer: sound waves cause bubbles to form which collapse quickly, releasing light.

 

[AV1611VET]

Short answer: sound waves cause bubbles to form which collapse quickly, releasing light.

Is that like taking a sheet of paper and wadding it up until it changes into pure energy?

 

[mzungu]

May I ask, what causes the earth to go round its axis, and at a perfect speed and non stop.

First of all the earth does not spin at a perfect speed. Tidal forces between the earth and moon and the fact that the moon is moving away from the earth (approximately 4 cm per year.) has resulted in the earth loosing rotational speed by 1.4 milliseconds per solar day per century.

The Earth's orbit is also not uniform. It cycles from almost a perfect circular orbit to an elliptical orbit every 100,000 years.

 

[mzungu]

Is that like taking a sheet of paper and wadding it up until it changes into pure energy?

No but if you want an analogy albeit the opposite to sonoluminescence and does not release light is "Cavitation".

 

[Wiccan_Child]

Is that like taking a sheet of paper and wadding it up until it changes into pure energy?

Not quite. The sound creates the bubble, but the bubble is unstable, and it collapses.
Think of it like stretching an elastic band: you pull and pull and pull slowly, it doesn't make a sound. But when you let go, it snaps back with a loud bang. That's what's happening with sonoluminescence: the sound creates the bubble, pushing the water aside, but that's unstable, so the water crashes back together rapidly - creating a flash of light.

 

[AV1611VET]

No but if you want an analogy albeit the opposite to sonoluminescence and does not release light is "Cavitation".

Thank you, sir!

 

[AV1611VET]

Not quite. The sound creates the bubble, but the bubble is unstable, and it collapses.
Think of it like stretching an elastic band: you pull and pull and pull slowly, it doesn't make a sound. But when you let go, it snaps back with a loud bang. That's what's happening with sonoluminescence: the sound creates the bubble, pushing the water aside, but that's unstable, so the water crashes back together rapidly - creating a flash of light.

Ah -- got it.

Thank you!

 

[SAMMISPARROW]

First of all the earth does not spin at a perfect speed. Tidal forces between the earth and moon and the fact that the moon is moving away from the earth (approximately 4 cm per year.) has resulted in the earth loosing rotational speed by 1.4 milliseconds per solar day per century.

The Earth's orbit is also not uniform. It cycles from almost a perfect circular orbit to an elliptical orbit every 100,000 years.

Ok OK and thanks for your observations but you still have not answered my question as to what is the initial cause of these movements.

 

[SAMMISPARROW]

The Earth is constantly 'falling' towards the Sun, due to gravity, but because the Earth is also constantly moving 'sideways', it 'overshoots', like an imaginary cannon shooting something around /IMG]

The mechanics of this system are such that the Earth continues to orbit the Sun.

The Earth itself is also rotating, and continues to do so because there's nothing to stop it: Newton's Laws tell us that an object will continue moving (and, indeed, rotating) indefinitely until acted upon by another force. Since there's nothing to stop the Earth moving or rotating, it continues to do so.

The reason it moves and rotates at all are a result of how the Earth formed. Simply put, a massive object that hits the Earth is unlikely to hit it at exactly 0°, thus, this will cause the Earth to spin (imagine one billiard ball hitting another at an angle - the latter will spin).

I'm not sure what you mean by 'perfect speed', though.

How was the earth formed and where do these massive objects come from?

 

[mzungu]

How was the earth formed and where do these massive objects come from?

http://www.youtube.com/watch?v=DpWE7VQGPtshttp://www.youtube.com/watch?v=qq7-CVX7HKk&feature=related

 

[Wiccan_Child]

How was the earth formed and where do these massive objects come from?

A good question. Solar systems begin as massive clouds of dust and gas, typically the remnant of a supernova (i.e., a star that died and exploded, spraying the surrounding area with all the elements). This dust cloud eventually collapses under its own gravity, with small bits of dust sticking to others, creating larger clumps that can attract more and more clumps. This process is how stars and planets form: stars at the centre, where gravity is strongest, and attract the vast majority of material.

This large proto-star resembles a gas giant, like an enormous Jupiter: it's very large, but not quite large enough to undergo nuclear fusion. But it can still cause the proto-planets (large clumps of rock that have formed outside the centre) to begin orbiting it.

Obviously, if you have lots and lots of lumps of rock floating about, some are going to collide - that is, after all, how such lumps grow in size. Sometime, there are just glancing blows, or a gravitational torque. These will cause the lumps to spin (imagine kicking the edge of a spinny-chair - it will begin to spin, no?).

So, that's the basic principle behind the formation of the Earth (the initial dust cloud collapsing under its own gravity into a few discrete points, which ultimately become the Sun and the planets), and the spin of the Earth (interactions with other large bodies cause the Earth to rotate on an axis). There are other details, like how the Moon and asteriod field formed, how the Sun operates, etc, but that's that for now.

 

[Wiccan_Child]

YouTube - The Birth of Stars & Planets

Grr, curse your ninja-posting