Why do planets form?

[swansont]

a new theory called 'intelligent design' would have an easy answer to this' date=' which would be: an intelligence made the particles move together, because it has a certain purpose in the universe (kind of like 'divine-plan' theory)

[/quote']

 

ID is not a theory.

[syntax252]

ID is not a theory.

 

 

It ain't?

 

Why not?

[swansont]

ID makes no predictions and is not falsifiable.

[ydoaPs]

and it is by no means "new" even if it was a theory.

[syntax252]

ID makes no predictions and is not falsifiable.

 

I would have thought that it predicted a God, Heaven, judgement day etc.

 

I don't see why it is not falsifiable.

[swansont]

I would have thought that it predicted a God' date=' Heaven, judgement day etc.

 

I don't see why it is not falsifiable. [/quote']

 

Does it predict just one God? Why? Does God have to be omnipotent? What about the other attributes? Predict, specifically, when judgement day will occur.

 

Falsifiablity: Demonstrate a way to prove God doesn't exist. Demonstrate that heaven does exist.

[syntax252]

Does it predict just one God? Why? Does God have to be omnipotent? What about the other attributes? Predict' date=' specifically, when judgement day will occur.

 

Falsifiablity: Demonstrate a way to prove God doesn't exist. Demonstrate that heaven does exist.[/quote']

 

Aren't the same problems present in other theories?

 

Can one demonstrate that the big bang theory is true or false?

[[Tycho?]]

Aren't the same problems present in other theories?

 

Can one demonstrate that the big bang theory is true or false?

 

If it can't be falsified, it isn't a proper theory. Sting "theory" falls into this catagory, since right now it can't be proven or disproven.

 

Yes, big bang theory can be proven to be false, if some new peice of evidence came up that totally contradicted it. You can't really definitively prove a theory, since there is always something else that you could find that disagrees with it. But some theories, like special relativity, can be pretty much proven to be correct.

[syntax252]

']If it can't be falsified' date=' it isn't a proper theory. Sting "theory" falls into this catagory, since right now it can't be proven or disproven.

 

Yes, big bang theory can be proven to be false, if some new peice of evidence came up that totally contradicted it. You can't really definitively prove a theory, since there is always something else that you could find that disagrees with it. But some theories, like special relativity, can be pretty much proven to be correct.[/quote']

 

Well by those rules, then ID could be proven to be true if the intelligent designer showed up to testify.

[Sayonara]

Well by those rules, then ID could be proven to be true if the intelligent designer showed up to testify.

Since ID makes no predictions, that would simply shift the burden of proof to the question of whether or not it was "the" intelligent designer.

[star dust]

isn't a planet made because it didn't have enough energy to carry out Nuclear Fusion, like a star does?

[us.2u]

NEBULAE.... Nebulae are clouds of dust within galaxies. Bright diffuse nebualae are areas of hydrogen gas where new stars are being formed. Two types of nebulae are linked with the late stages of star development planetary nebulae are shells of gas thrown off by red giant stars. while supernova remants are the twisted wreckage of exploded massive stars. Some nebulae are dark because they contain no stars to illuminate them,& are visible only when silhouted against a brighter background......us.2u

[Ophiolite]

There appear to be some misconceptions concerning planetary formation. Here are some points that address some of them.

1. The trigger to collapse a gas cloud gravitationally into a stellar system may be provided by the shock wave of a nearby (in astronomical terms) supernova, or by collision with other interstellar gas clouds.

2. This intitiates a period of gravitational collapse within a gas cloud that will, by chance, have some rotational motion.

3. It will also be quite chaotic, so that this collapse may have more than one centre. This is how multiple star systems originate.

4. As the nebula collapses two important things happen: it heats up; it collapses into a disc (since this is a lower energy state.)

5. At this point magnetic interaction between the disc and the forming proto-star transfer angular momentum to the disc. This accounts for the otherwise bizarre fact that while 99% of the mass of the solar system resides in the sun, 99% of the angular momentum it to be found in the planets.

6. A temperature gradient exists between the star and the outer reaches of the nebula. Close to the proto-star iron, nickel and related elements can condense, but nothing else, at first. (This is part of the reason Mercury has such a large iron core.) Further out silicate minerals can condense.

These form small particles that then begin to accumulate due to impact with other particles (because of their geometric cross section) and attraction to other particles (because of their gravitational cross section).

At around 1000km diameter these planetesmals are large enough to remelt internally and differentiate into an iron-nickel core and a stony exterior. When some of these are disrupted by later collisions they produce the debris we know today as stony and iron meteorites. (There is another category, the chondrites, that are residual from the formation of the solar system.)

Further out it is cool enough for ices and gases to condense. Here is where Jupiter forms. The planetesmals in the inner system, of iron and 'stone', collide and amalgamate until we have Mercury, Venus, Earth and Mars. Those between MArs and Jupiter are disrupted by Jupiters powerful gravity field and never make it together as a planet.

Jupiter and Saturn and to a lesser extent Uranus and Neptune, throw many of the icy bodies formed in that region further out of the system, into the Oort cloud where they provide the reservoir of comets that periodically venture into the inner system.

 

That may not be it in a nutshell, perhaps a coconut gourd. Hope it clarifies.

[coquina]

"That may not be it in a nutshell, perhaps a coconut gourd. Hope it clarifies.

"

Thanks - I for one, understand the process more clearly.

[ensonik]

Orphiolite, great answer. Very in depth and satisying. Can you elaborate on the variance in size and density of planetery bodies in relation to the sun? I understand why the gaseous planets are further away, etc, but am unclear on that lack of linearity in terms of size and gravitational pull of planets as they get further from the sun.