Not if that is all you have to start with there aren’t! Are you familiar with the word fusion?
Momentum, mv, is not G (6.674×10−11 m3⋅kg−1⋅s−2). And how many other gravitational forces are there? The Milky Way galaxy is expanding at 500 m.s-1 What has that got to do with the eventual gravitational collapse of all nebulae? Molecular clouds have a density of between a hundred (10-12 g) and a million particles cm-3 (10-16 g). Their gravitational attraction to each other is not affected by the meaninglessly small galactic expansion within that cc. 500 m.s-1 / (10^33 km x 10^5 ly r = 10^38 km = ) 10^43 cm (OOM) = 10^5 cm.s-1 / 10^43 cm = 10-38 cm.s-1 (OOM) ten to the minus thirty eight cm per second per cubic centimetre. For that cc to expand by a cm omnidirectionally due to galactic expansion (increasing its volume by 10 OOM) would take 10^38 s = 3x10^30 years. 3x10^20 x older than the universe. The first stars formed by 10^8 The sun half that from its parent nebula a grandchild of those first stars. How many numbers would you like? There are infinite infinities of them.
And of course complementing internal gravitation is radiation pressure from outside.
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And fusion just happens? Funny how it’s taken science so long to perfect it after discovering fission.
If, by collapse, you mean dissipation, then nothing. It’s a fact.
How about EMF? Hydrogen ions are all positive. Which is stronger, EMF or gravity?
No I don’t mean black is white, although etymologically it is of course, although white is not black.
How about it? As stars take OOM 100,000,000 years to form, how much star formation will have occurred in the 25 years we’ve been able to see in ‘close-up’ (as if from about 10^14 km) ? Can you do the ‘math’ from that? A 2.5x10-7th. And in your omniscience, what proportion of the particles is hydrogen ions? I mean, you must know all things as you know that astrophysics is fundamentally (I do love that word, there are so many others in it; fun, mental, fundament) wrong?
So is there anyone else apart from your self exalted, peerless self, a genius above all others, who says that four centuries of physics is wrong? Including the physicist who created the greatest single output of the human mind? Who are your awesome peers, also greater than Newton?
PS Try looking in Orion. Over just four years.
This has already been explained to you before; and you’ve shown no signs of reading or understanding why your arguments haven’t worked.
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Science perfected fusion starting with Eddington’s realisation in 1920, Gamow’s contribution of quantum tunnelling 8 years later, applied by Atkinson and Houtermans the following year. Just three years later Oliphant demonstrated fusion. The story didn’t stop in 1932 of course! What you mean is technology. Fusion cannot be commercially harnessed. Ever. Apart from by solar heating and the photoelectric effect. How do you think stars work?
Here’s how they start to. How it just happens.
'I have mulled over this a couple of times (it’s a really interesting question!), and hopefully come up with a somewhat enlightening answer. I haven’t been able to find a good, modern reference for these details (perhaps I just suck at literature searches…) so there’s a little mucking around in the history books
The total timescale of evolution onto the main sequence for a protostar in the T Tauri mass range ( < 3 solar masses) is on the order (of magnitude) of several tens of millions of years. The ignition of fusion is not precisely a “runaway” reaction: however it occurs relatively quickly and once it starts, gravitational contraction quickly ceases.
The evolution of a 1 solar mass protostar follows these basic steps. Things are a little different for different masses - too complicated to explain here but the references should provide ample further reading!
- A Jeans-unstable cloud of gas and dust begins to contract, exchanging gravitational potential energy for kinetic energy, and thus heat. The luminosity of the protostellar cloud increases as it collapses. It takes around 100,000 years for the initial period of rapid collapse to finish, at this point the cloud is very luminous (perhaps 20 solar luminosities and 8000K).
- Over the next 1 million years, the protostellar cloud slowly contracts and cools to around 4500K. The protostar then travels down the Hayashi track, contracting further but changing little in temperature - its luminosity continues to fall. This is the stage where T Tauri stars are at. Most T Tauri stars are younger than 3 million years old.
- The star then follows the Henyey track, where the luminosity begins to slowly increase again as a radiative zone develops in the star’s core and it continues to slowly contract. This can take some tens of millions of years.
- Finally, the conditions in the core are extreme enough for fusion to begin. The timescale from all the energy being provided by gravitational contraction to all the energy being provided by fusion, is on the order of 1 million years. The star’s luminosity (counter-intuitively) decreases again when this happens, as the energy from fusion doesn’t quite offset that from gravitational contraction, which ceases when fusion begins.
Figure: the The Lg/L curve describes the amount of energy gained from gravitational contraction over the total luminosity of the star. The logarithmic time axis is in seconds (reproduced from Iben (1965), Figure 3).
References:
- I. Iben (1965), Stellar Evolution. I. The Approach to the Main Sequence
- R. Larson (1972), The evolution of spherical protostars with masses 0.25 M_solar to 10 M_solar
- L. Henyey et al (1955), The Early Phases of Stellar Evolution
Interesting reading I came across for somewhat higher mass protostellar formation:
They’re all wrong of course.
Where? Exact post, please. If you’re going to play teacher, then be helpful.
Well you’ve had the maths explained to you here for starters. Yet your only response to it was to nitpick at a side detail while completely ignoring the central point altogether. This is another tactic that I see time and time again with you YECs, and I’m sorry, but it’s dishonest.
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I’ve been told I should be answering everyone, so pick which arguments are most important, because I can’t keep up with multiple arguments at once sometimes.
The maths. OK.
First, are you sure that you have the correct equation? G=gM/r^2
I don’t think so, as there is no single gravitational center to a nebula. You would have to use the force equation for each molecule in the cloud in relation to all others.
Now, everyone tell me why I’m wrong.
The major problem for evolution is the formation of the first stars. Evolutionary astronomers believe that the first stars formed from a collapsing cloud of gas. But such clouds today are too hot and diffuse to collapse. Current theories involve compression by supernovae or cooling by heat radiation from dust granules, but this would require pre-existing stars.
Is this quote out of context?
Neil deGrasse Tyson
“Not all gas clouds in the Milky Way can form stars at all times. More often than not, the cloud is confused about what to do next. Actually, astrophysicists are the confused ones here. We know [believe - PS] the cloud wants to collapse under its own weight to make one or more stars. But rotation as well as turbulent motion within the cloud work against that fate. So, too, does the ordinary gas pressure you learned about in high-school chemistry class. Galactic magnetic fields also fight collapse: they penetrate the cloud and latch onto any free-roaming charged particles contained therein, restricting the ways in which the cloud will respond to its self-gravity. The scary part is that if none of us knew in advance that stars exist, front line research would offer plenty of convincing reasons for why stars could never form.”
Even he admits that Boyle’s law applies here.
Yes, but note that he rightly notes it is only a part of a complex combination of forces, not the only or even the primary driving force.
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Why is there not a net center of mass?
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He affirms that stars are formed from gravitational collapse of gas clouds, just as science has understood for many decades. What is it with the YEC love of quote mining prominent exponents of science to support their cheap rhetoric?
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I’m sorry, Patrick, but that is just patent nonsense. Of course a gas cloud has a centre of gravity. For it to not have a centre of gravity, it would have to be infinite in extent and of uniform density.
But there’s an equation that does precisely that! It’s called Gauss’s Law and it looks like this:
\nabla \cdot\mathbf g = -4 \pi G \rho
Or in integral form:
\oint_{\partial V} \mathbf g \cdot d \mathbf A = -4 \pi G M
That is the equation from which the Jeans instability is ultimately derived. But of course, I very much suspect that partial differential equations such as that are waaaaaaaaaaaaaaaaaaaaaay out of your league.
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It’s enough force that he concludes that the current research is against star formation by any known means.
Because if there were, it would be a solid object, not a cloud. Even water doesn’t react to gravity as a solid object does. Works for us because it gives us tides.
Sounds to me like he says our ignorance would have led us to the wrong conclusions had we not known better…
Give it time.
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