GAS VS GRAVITY - IS STAR FORMATION POSSIBLE? Herman Adams and others have reasoned like this: 1 - the first stars, according to mainstream science, formed from hydrogen gas, undergoing gravitational collapse. 2 - hydrogen (the lightest element) is so light that even the earths gravity cannot hold it, and it rises up from the ground. 3 - EVEN IF the tiny gravity of a hydrogen cloud could pull it inward, that would produce higher pressure in the middle, and gases flow from high pressure to low pressure, i.e. back outward again 4 - therefore, because of 2 and 3 above, 1 could not have happened. Since the mathematical derivation of the Jeans Mass (the threshold of gravitational collapse) did not convince our creationist friends, here is an equation-less response: 1: yes, that is indeed the current theory. 2: It is true that hydrogen rises when released at ground level because of Archimedes Principle. Hydrogen has lower density than the air it displaces, and therefore has *buoyancy* at ground level, like a helium balloon. It rises up until it reaches the height where the atmospheric density equals its own. This happens in the outermost layer of earths atmosphere, called the exosphere, which is composed of hydrogen and helium (precisely because they are the least dense, or lightest, gases). Note that hydrogen STOPS in the exosphere. It does not escape earths gravity. The earths gravity IS strong enough to hold it. 3: This is almost, but not quite, accurate. The accurate statement is that there is a pressure-gradient force that acts on gases, pushing them in the direction of lower pressure. Whether the force produces MOVEMENT in that direction, depends on whether it is strong enough to overcome OTHER forces, in this instance gravity. 4: The real question here is, just how strong would the gravity of a hydrogen gas cloud be? The way this is worked out is by considering the sum total of the forces acting on a hydrogen molecule due to the tiny gravity of each of the other hydrogen molecules in the cloud, as vectors. Ill spare you the calculus, but for the outermost molecules, the result is the same as if the entire rest of the clouds mass was concentrated in its centre. These clouds can have truly huge total masses (think of the total mass of the solar system). The pull on the molecules is enough to pull them inwards, and does indeed overcome the outward pressure from the rising density and temperature. Once the temperature reaches a critical level, nuclear fusion starts, and the star ignites. This is a REALLY SLOW process. It can take HUNDREDS OF MILLIONS of years to go from a fairly even, thinly spread hydrogen cloud to a stars ignition, and then another ten thousand years before the fusion reaction heats up the outer layers to the familar fireball of a sun. So, then next standard creo question is, How do you know, were you there? And Ill freely admit that I was not. This is an extrapolation from the mathematically-formulated laws of physics. I dont ask that you believe this if it conflicts with your holy book. But I DO ask that you appreciate that it is logical - if you wish, think of this as how it WOULD have happened if God had not simply created everything in six days, 6,000 years ago.
Posted on: Tue, 29 Jul 2014 13:36:32 +0000
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