Sciencemadness Discussion Board

Why does Fusion work?

jgourlay - 19-6-2009 at 11:46

My boss and I were in an alternative energy debate today, and a "fundamental" question came up that has me completely stymied.

Why is fusion, in this case fusion of hydrogen to helium, exothermic? Put another way: so gravity makes the pressure really high at the core of the sun, fine: why does that make it hot?

For that matter, it sounds like gravity is your perpetual motion something for nothing machine? Gravity has to do work to pull things together and cram them ever harder into each other....

12AX7 - 19-6-2009 at 13:40

So, you're asking something like this?

Let's say you have a big ball of gas out in space, initially fairly cool and at a low pressure. If there is enough mass present, the gas will draw together under gravity. The gas compresses and heats adiabatically. Simple gasses won't radiate heat (e.g., H2, He) until they get a lot hotter, while complex molecules and dust (which are probably present in small amounts) may radiate heat. As the gas ball draws together, it heats up; if it heats up slowly, and radiates slowly, pressure falls and it can collapse faster. If it doesn't radiate much, it may reach an equilibrium of some scale. Even so, it will eventually reach fairly high pressures in the middle, which will inevitably reach fairly high temperatures (especially if there's so much dust that, down to the center, it reflects as much as it radiates -- a greenhouse effect). If the temperature and pressure is high enough (around a solar mass of hydrogen), fusion can begin, creating additional heat. Soon, the gas ball comes to thermal and geometric equilibrium and a star is born.

Is that what you were thinking? The basic ideas are, in space, 1. everything is so huge that gravity does some serious amounts of work, 2. all that work goes into heat (due to compression), and 3. because the surface area to volume ratio is so low, the heat can't radiate away fast enough. So it gets really hot and dense.

The limiting case is where there's enough mass together (> 1.44 solar masses, no fusion) that it collapses into a neutron star or black hole.

Incidentially, black holes are the most efficient mass-to-energy converters, throwing off something like 20% RME (as radiation from the plasma, including black body radiation, bremsstrahlung and synchrotron radiation) when stuff falls in. The other 80% stays inside the black hole, unless it's small and hot, giving off Hawking radiation, in which case it would be 100% over the life of the singularity.

Tim

merrlin - 19-6-2009 at 16:40

Fusion between atoms is energetically favored when the average binding energy for the nucleons in the product atom is greater than the average binding energy in the reacting atoms. Search for "binding energy" on Wikipedia. Roughly speaking, elements above iron can release energy by fission and those below iron can release energy through fusion. However, as 12AX7 has pointed out, fusing atoms takes a lot of work, even for the "easy" ones.

JohnWW - 19-6-2009 at 19:28

That's right, because of the high coulombic energy barrier that has to be overcome in fusing nuclei due to the repulsive charges on the protons, even when attempting the fusion of the lowest-charged possible nuclei, two deuterons. But up to about iron, there is a net radiant energy release on fusion where it results in another stable nucleus. This accounts for why iron, and to a lesser extent neighboring elements such as manganese, chromium, vanadium, titanium, cobalt, nickel, and copper, are the most abundant metals in Earth's core. Because of their density they sink (along with most of the other heavy metals including gold and the platinum metals) into the core, and their abundance is depleted on the surface. The interiors of "white dwarf" stars, not massive enough to become neutron stars, are believed to also consist mostly of iron and neighboring elements.

Fe-56 is probably the nucleus in which binding energy is at a maximum, with no possible net energy release by fusion even with one additional proton or deuteron, and no energy gain on fission even if it were possible.

Pyrovus - 20-6-2009 at 01:20

Actually, nickel 62 is the nucleus with the greatest binding energy per nucleon:

http://en.wikipedia.org/wiki/Nickel-62

jgourlay - 22-6-2009 at 05:10

12ax7: gravity does work, understood. But what is gravity that it does not run out of the ability to do work?

Sauron - 22-6-2009 at 19:10

Fusion works because God is Hungarian and He did not want Edward Teller to look stupid.

12AX7 - 23-6-2009 at 03:10

Good answer.

Gravity does not run out of the ability to do work because the universe has not ran out of the work put into it by the Big Bang (indeed, it's projected that the universe will never shrink).

Tim

hissingnoise - 23-6-2009 at 04:55

I find the idea of an infinitely expanding universe curiously chilling. . .
And any way you look at it, the Big Bang Theory still remains a theory.

12AX7 - 24-6-2009 at 01:47

Yeah, it would be elegant if the universe collapsed again, in an infinite(?) series of bangs and crunches. Sadly, the estimated universe is larger than its Schwarzschild radius, precluding this. Indeed, evidence suggests some unknown expansive force, which so far has been fairly kind to us (if it were much larger, the universe could only be a few billion years old, and the diversity of structure we see could not have developed), may eventually rip apart the fabric of space (it seems to be increasing; if it increases without bound, eventually it will even dissociate atoms, nuclei, perhaps even quarks, until a low pressure mist of nothingness remains).

Tim

JohnWW - 24-6-2009 at 19:02

Quote: Originally posted by hissingnoise  
I find the idea of an infinitely expanding universe curiously chilling. . .
And any way you look at it, the Big Bang Theory still remains a theory.
and that is how it will remain, - just a theory, because it requires all matter in the universe to have been present in a "singularity", i.e. at a single point in space, which would also have had to have been a gigantic "black hole", about 13.7 billion years ago. NONE of the proponents of the theory have been able to point to the angular and distance coordinates of the specific location in space when the "big bang" occurred, or to explain where the energy came from to propel all the matter in the universe outward in all directions from such a single location with enough force to reach mutual escape velocity. And at the same time, thanks to academic hegemony and sloth in physics and astronomy, no salaried academic physicist or astronomer, of any influence, has dared to question the theory on account of these obvious unsuperable flaws, for fear of losing their fat-salaried jobs or research grants.

Of course, something must have happened to result in the creation of all the matter in the universe about or not long before 13.7 billion years ago, as free protons and electrons, because of the measurable rate of conversion by fusion of matter into increasingly heavy elements. The ages and compositions of the oldest stars are crucial evidence in this regard. But the matter must have filled space uniformly to begin with, until the propagation of an irregularity in distribution resulted in the coalescence under the influence of gravity and ongoing fusion processes. Although due to gravitational coalescence the distribution of matter in space has become quite uneven on scales of up to millions of light-years, there is NO evidence of any anisotropy in distribution on an infinite scale which points to the existence of any point at which a "big bang" may have occurred.

not_important - 24-6-2009 at 20:14

Quote: Originally posted by JohnWW  
... NONE of the proponents of the theory have been able to point to the angular and distance coordinates of the specific location in space when the "big bang" occurred...


This is because the proposed Big Bang is not only an explosion of matter/energy, but of space - the Monoblock was all of space, the Bang expanding space and reducing the density of matter as it proceeded.

And past the Big Bang itself is the phase change and resulting hyperinflationary period, which evens out fluctuations in space/energy-densities save for those resulting from quantum fluctuations at that time and results in a nearly homogeneous and isotropic universe. Again, it was space itself expanding, with matter-energy going along for the ride, not matter expanding out into pre-existing space.

There are and have been other variants of the Big Bang theory, indeed hyperinflation replaced several earlier models of the BB. Out and out alternatives to the BB include the Friedmann oscillatory universe, the Milne model (which similar to your concept of the BB does not include metric expansion of space but simply an explosion of matter), the Hoyle steady state model, and Zwicky's tired light theory. None of these could successfully explain observations and in general have been retired.

The steady state models for the most part fell when the comic microwave background was discovered, although there are still a few supporters; the remaining form of this group of theories require a universal 'fog' of iron needles to produce the CMB. Steady state theories also run afoul of nucleosynthesis and light element abundance issues.

The TeVeS gravity theory supports some alternative models, and removes the need for dark matter as well. However it has its own problems, such as the need for a fairly massive neutrino.

Alternative cosmological models continue to be discussed, but so far all are noticeably less successful at explaining observations than is the current set of Big Bang models.

chemrox - 24-6-2009 at 21:13

I think we're past the Big Bang and into the big bounces. It inflates . then it deflates to zero/pure energy but it does this over and over just as the Buddhist cosmologists were saying 1600 years ago. Big Bang vs Big Bounce may be semantics to most of us. The physicists tell me its in making the math work and bring quantum and relativity together. I don't think in equations so I have to stay at home and cook. Anyway, here's my simplistic lay view: if all the space time is converted to energy at the singularity, then there are as many or few singularities as you choose because at that moment there's no past no future. As far as ongoing and irreversible inflation goes recall that galaxies participate in that as accelerating units with black holes at the centers. We only just proved black holes exist so we don't know what sort of localized contraction they may provide. Quasars are throwing out huge amounts of energy that is conserved thus much matter and space time is consumed at the same time.

tom haggen - 11-7-2009 at 09:14

You've all got it wrong. The universe is less than 7,000 years old.

[Edited on 11-7-2009 by tom haggen]

hissingnoise - 11-7-2009 at 11:32

I know there are people who actually believe that tom, but I have to assume that you're joking. . .

not_important - 11-7-2009 at 21:48

Quote: Originally posted by chemrox  
I think we're past the Big Bang and into the big bounces. ...


Problem is that the boffins have done the maths, and entropy has an effect on 'bouncing' cyclic universes, each cycle expands longer and larger than its predecessor until finally there it resembles and open universe - heat death, matter spread thin or decayed, all that.

The other thing is that if we were in a contraction phase we should see the nearer galaxies slowing their flight 'from us', pausing, and starting towards us - the nearest ones being blueshifted, then a shell of them not really moving relative to use, the the standard increasing red shift as you look further out. The transition from red shift to blue shift would expand further and further out as time passes, the CMB would show a similar increasing blue shift as photons from further and further away from us reach us (provided that the shrinking is sufficiently slower than light - as it is the space-time metric that expands and contracts it can do so 'faster than light' without violating the rules.)

Membrane models can support oscillatory universes without running into the entropy boost problem, I believe, but it is rather different than the simple Big Bang+Crunch models.


tom haggen - 11-7-2009 at 21:54

Actually to be honest I dont believe there is 100% proof that the universe is older than 7,000 years. Even you guys say that the big bang theory is just a theory and not concrete evidence. Im not sure how old the universe is.

12AX7 - 11-7-2009 at 22:04

Do you have proof that it is 7000 years old? Is that a testable hypothesis?

Oddly, I can test that the universe is more than 0 seconds old, but how much older remains to be seen. I can at least tell with certainty that it is not -1 seconds old!

Tim

not_important - 11-7-2009 at 23:19

Quote: Originally posted by tom haggen  
Actually to be honest I dont believe there is 100% proof that the universe is older than 7,000 years. Even you guys say that the big bang theory is just a theory and not concrete evidence. Im not sure how old the universe is.


Every 'law' in science is a theory, granted a theory that has much evidence that it is true. Newtons laws were shown to be incorrect once you got moving fast enough, they exists as a close approximation at low speeds of their replacements, but still not correct as originally stated.

There is plenty of evidence that the Earth is much older than a few thousand years. Erosion, radioisotope dating, things like repeated beds of coal - marine sediments - shoreline soils - soils supporting heavy vegetation - coal for dozens of cycles, seafloor spreading, and so on. And there's much more astronomical/cosmological evidence that doesn't depend on the Big Bang. Recently genetic evidence has been added as well.

You can say the the universe was created that way, with the geological conditions in place, with stars just appearing to be thousands to millions of light years away but really aren't, or that they are that distant but light was created so as to appear to have left those stars in a distant non-existent past.

However that seems to add complexity, of an ever increasing nature. And would you want to live in a created universe were the creator went to the efforts of hiding the created nature of that universe, and then states you will be punished for believing those skillfully crafted lies? Wanting such a state of being goes way beyond masochism.



[Edited on 12-7-2009 by not_important]

497 - 11-7-2009 at 23:50

Quote:
Do you have proof that it is 7000 years old? Is that a testable hypothesis?


So true.. Seriously, can anyone show me ANY decent evidence that the earth isn't billions of years old?

hissingnoise - 12-7-2009 at 12:14

Quote: Originally posted by tom haggen  
Im not sure how old the universe is.

No one is, but current estimates put it at around 14 billion years, but it could conceivably be much older than that. . .
Time is only as old as the universe!

tom haggen - 13-7-2009 at 08:20

Radioisotope dating is completely flawed. The only way radioisotope dating would be accurate is if you assumed that the level of radio active isotopes that you are using to date things with have remained at a constant level in the earth's atmosphere indefinitely. To assume we know what the composition of the earth's atmosphere was even 50,000 years ago is complete rubish. I have no proof that the earth and the universe are less than 7,000 thousand years old, I'm simply saying that theres no proof that the universe and the earth are billions of years old. Using geometry and the physics of light to guess how far away stars are, to prove how old the universe is, cannot be trusted either. People can't prove how long stars have been in exsistence by measuring there distance from us. If you have no idea how something came into exsistance, there's no way you can prove how long it has exsisted for. For all you know a magical smurf who can fly on a surf board made it all appear. The dating of the universe and the earth is a complete pseudoscience and has no more scientific credibility than the nazi racial sciences.

[Edit Ramiel: Godwin's law just turned the argument over to the blue team! reductio ad Hitlerum, you just lost the game]

[Edited on 13-7-2009 by tom haggen]

[Edited on 14-7-2009 by Ramiel]

Lambda-Eyde - 13-7-2009 at 08:45

http://en.wikipedia.org/wiki/Ice_core

At first I was having a hard time determining whether you were trolling or not.
Now I see that you're actually serious about this complete bullshit, and I can't understand why you even bother - it's ScienceMadness!

It's people like you who obstruct the advancement of science, and we need some serious change in attitude if that's going to change.

hissingnoise - 13-7-2009 at 08:50

Quote: Originally posted by tom haggen  
Using geometry and the physics of light to guess how far away stars are, to prove how old the universe is, cannot be trusted either.

And star distances, tom, are calculated, not guessed at. . .

setback - 13-7-2009 at 09:17

Quote: Originally posted by 497  
Quote:
Do you have proof that it is 7000 years old? Is that a testable hypothesis?


So true.. Seriously, can anyone show me ANY decent evidence that the earth isn't billions of years old?


Some people are willing to blindly cling to ignorance in the face of overwhelming evidence.

setback - 13-7-2009 at 09:42
Quote:

The dating of the universe and the earth is a complete pseudoscience and has no more scienctific [sic] credibility than the nazi racial sciences.



I find it kind of ironic that you believe the dating of Earth to be pseudoscience, yet you entertain the notion that Earth could be 7000 years old.

Also, why do you feel the need to bring up the Nazis?

tom haggen - 13-7-2009 at 09:47

You know whats cool about ice cores?(no pun intended) They prove that planes exsisted over 200,000 years ago!

http://creation.com/the-lost-squadron

[Edited on 13-7-2009 by tom haggen]

setback - 13-7-2009 at 09:53

Wow, creation.com, huh? Sounds like a real credible source. I can show you links that support principles of alchemy and homeopathy but that doesn't mean there is any truth to them. This is a forum for the discussion of science, not pseudoscience, and certainly not for stories from the bible.

Stories from the bible are just that, told to keep people in line back in the day. Also told to try and explain things that they hadn't the first clue about. To take them seriously is laughable. What about the dinosaurs? Did the devil place fossils in the ground to try and hide the truth? Are shows like the Flintstones documentary?

[Edited on 13-7-2009 by setback]

Polverone - 13-7-2009 at 10:24

It is just inviting a flame war to bring Nazi comparisons into a science thread. It is also inviting more heat than illumination to use this thread as a jumping-off point for attacks on religious belief.

I ask that everyone confine their discussion to scientific and factual claims and interpretations.

I don't think tom haggen's misperception of the age of the earth should go unchallenged, but I don't think he should suffer a full-blown attack on religious belief in response. We have religious members here who are fine scientists and contributors. It is unnecessary to attack the entire edifice of religion to challenge the half-truths, untruths, and philosophical pretzels typically employed in defense of a young earth.

[Edited on 7-13-2009 by Polverone]

vulture - 13-7-2009 at 11:45

Quote:

You know whats cool about ice cores?(no pun intended) They prove that planes exsisted over 200,000 years ago!


Have you actually read that article? First of all, it does not mention that anyone claimed the ice the planes were found in was 200,000 years old. Secondly, they were buried on the Greenland ice shelf, which has comparatively fast moving glaciers and much more snowfall than Antartica, where most icecores used for these purposes come from.

They then dispute the claim of the planes sinking into the ice that the surrounding air wasn't room temperature. Ever thought about the fact that planes that just landed are hot?

The tactic used is classic. Find something extraordinary that illustrates your point and ignore all evidence that suggests otherwise. Be sure to be vague in any claims you make so it's harder to dispute them.


[Edited on 13-7-2009 by vulture]

NeutralIon - 13-7-2009 at 11:58

Quote: Originally posted by tom haggen  
The dating of the universe and the earth is a complete pseudoscience and has no more scientific credibility than the nazi racial sciences.




[Edited on 13-7-2009 by tom haggen]


Time to invoke Godwin's Law, declare this thread over and tom haggen has lost

not_important - 13-7-2009 at 19:26

Quote: Originally posted by tom haggen  
Radioisotope dating is completely flawed. The only way radioisotope dating would be accurate is if you assumed that the level of radio active isotopes that you are using to date things with have remained at a constant level in the earth's atmosphere indefinitely. To assume we know what the composition of the earth's atmosphere was even 50,000 years ago is complete rubish. I have no proof that the earth and the universe are less than 7,000 thousand years old, I'm simply saying that theres no proof that the universe and the earth are billions of years old. Using geometry and the physics of light to guess how far away stars are, to prove how old the universe is, cannot be trusted either. People can't prove how long stars have been in exsistence by measuring there distance from us. If you have no idea how something came into exsistance, there's no way you can prove how long it has exsisted for. For all you know a magical smurf who can fly on a surf board made it all appear. The dating of the universe and the earth is a complete pseudoscience and has no more scientific credibility than the nazi racial sciences.




[Edited on 13-7-2009 by tom haggen]


Carbon 14 is the common radioisotope used for dating that has a relationship to the atmosphere, and also to cosmic ray flux values which I'm surprised you failed to mention.

C14 dating is only good for a 50 kyear span, longer than that and too much of it has decayed away to remain detectable. Other isotopes, ones not formed by cosmic ray collisions with atmospheric atoms, are used for longer spans.

As for C14 - The concentration of nitrogen in the atmosphere is the important one, plus the cosmic ray flux. Reduce the amount of N2 in the atmosphere, or reduce the cosmic ray flux, and reduce the C14 production rate as a result.

Massive changes in the amount of N2 in the atmosphere over the last few thousand years are unlikely, based on our understanding of the nitrogen cycle; cosmic ray intensity is a more likely variable. But we don't have to guess at the historical values of these, as we can correlate tree rings in multiple samples of wood, count the rings, and calibrate C14 readings to dates from ring counting for 8 to 9 thousand years back.

And lake sediments give us another check on C14, allowing us to say that the rate of production of C14 has not changed more than 15% in the last 22 thousand years. But even the tree rings take us back further than 7 thousand years.

http://www.infidels.org/library/modern/dave_matson/young-ear...

But for dating rocks in terms of geological time spans, we don't use C14 produced in the atmosphere by cosmic rays, we use radioisotopes that to produce require conditions much more extreme than exist on Earth outside of nuclear reactors and particle accelerators. The dating process takes samples of minerals that exclude the decay child element in their formation, and look at the concentration of the parent isotope and element along with those of the child. In some cases several different parent-child pairs can be used for the same mineral sample, allowing a check for contamination and lose of a parent or child element.

Related to this method is the concentration of a child isotope in a mineral where the parent radioisotope is short lived and has totally decayed away. As a dating process all this can tell us is that the sample must be older than the extinction time of the parent, but as most of the isotopes used half a half live of between 10^5 and 10^7 years years, the samples must be at least ten times as old as that.

If you can't trust geometry and the physics of electromagnetic radiation, I assume that you never travel by airplane or use radio communications, as both depend on those untrustworthy things.

Again, as I noted in my earlier comment, there are a number of occurrences of sedimentary rocks where the same pattern repeats over and over. This may be alternation between deep and shallow water sediments, with the associated ripple patterns &ct. Or it may be dozens and dozens of layers of fossilised soil, topped by coal, then marine sediments, beach deposits, and once again soil. These repeating layers could not have been laid down in a short period of time, they show the grading of current sedimentary deposits, development of soil with roots or roots casts, and so on. In a few cases they include layers of volcanic materials, which can be dated and are found to agree with the sequence they hold in the layer cake of sediments; they also show weathering patterns as can be seen in current volcanic deposits - weather that is much too slow for the full structure to have laid down in even thousands of years.



JohnWW - 14-7-2009 at 00:52

Another evidence of the age of Earth's rocks and many of its ancient (millions of years old) fossils is potassium-argon dating, in which long-lived K-40 in hard rocks (particularly granite, diorite, granodiorite, and sedimentary rocks derived therefrom, and to lesser extents more basic igneous rocks) decays to Ar-40 by positron emission or K-electron capture and to Ca-40 by beta-emission with a half-life of 1.249 x 10^9 years. The extent to which the K-40 has decayed, as judged by the Ar-40 left trapped in the rocks (Ca-40 is too common to be used), and also by the remaining K-40- radioactivity compared to that in fresh samples of K from sources like sea-water, enables an estimate of the ages of the rocks to be made, based on the half-life of K-40; see http://en.wikipedia.org/wiki/Potassium-argon_dating . Rubidium-strontium dating works the same way, being also useful for dating even older specimens of the same rocks containing high levels of K, Rb, and Cs, being based on the decay of Rb-87 with a half-life of 4.88 x 10^10 years; see http://en.wikipedia.org/wiki/Rubidium-strontium_dating .

Another test of rock ages, applicable mostly to granitic rocks and sedimentary rocks derived from them, is the remaining U-235 and 233 (half-lives some 10^7 or 10^8 million years) and U-238 (half-life 4.5 x 10^9 years), Pu-244 (half-life 82 million years, the longest-lived plutonium isotope), and Th-232 (half-life 2 x 10^11 years) left in them, compared to their final decay products, mostly Pb-208, 207, 206, and a small amount of Bi-209. The latter metals do not occur normally in granitic rocks other than as radioactive decay products, and the intermediate decay products are very short-lived by comparison. Because of the mode of origin of such heavy radioactive elements in supernova explosions, they would have been originally present in roughly equal amounts. About half the original U-238 is found to be left, dating Earth as about 4.6 x 10^9 million years old, while nearly all the original Th-232 is still present undecayed; but only very small (but significant) amounts remain of U-235 (and 233) and Pu-244 (which has gone through about 55 half-lives). Granitic rocks also contain the rare-earth metals, several of which have long-lived alpha-emitting isotopes, and their remaining amounts and decay products tell the same story.

tom haggen - 14-7-2009 at 08:42

When you conduct a scientific experiment you must have a control in order to conduct the experiment properly. This means you have to recreate the same experiment in identical conditions accept the variable you are testing. The earth is ever changing and you have no control in your experiment. Ice sheets shift. Radio active element levels vary ect. ect. there is no way to recreate the atmosphere of the earth in the past it is completely impossible. The oldest way we have to accurately see the levels of radio active elements in the earths atmosphere is in trees since they are the oldest living organisms on the planet. Once something dies your scientific experiments become invalid. The only remote proof that the universe is very old is by measuring the distances of stars from our location using the physics of light, and I am skeptical on that as well. This topic is all about propaganda and certain groups of people try to use this topic to push their agenda. Whether you are religious or a secular humanist neither of them have 100% proof.




[Edited on 14-7-2009 by tom haggen]

vulture - 14-7-2009 at 09:16

Quote:

using the physics of light, and I am skeptical on that as well


You must be getting pretty desperate. You are skeptical on the physics of light? Better pray your eyesight doesn't deteriorate, or you might need glasses, which are, after all, based on the pseudoscience of light. You do realize that the very way by which you are posting your denial here depends on the physics of light? Fiber optics?

Let me ask you something: Assume you had cancer, would you undergo radiotherapy if it could cure you?

[Edited on 14-7-2009 by vulture]

[Edited on 14-7-2009 by vulture]

tom haggen - 14-7-2009 at 09:32

Well every one assumes that stars are really far away because of their distance of light years away from us. Claiming that this must mean the universe is billions of years old is false. Whose to say that the big bang didn't travel faster than the speed of light? Also im on wireless internet right now :P

[Edited on 14-7-2009 by tom haggen]

Polverone - 14-7-2009 at 09:53

Isochron dating neatly gets around the varying levels of radioactive elements problem. It uses multiple minerals in the same rock to calibrate the decay measurements. JohnWW earlier posted examples of the technique but the page I've linked explains it at greater length.

The only way to reconcile a young earth with isochron dating is to assume that elements had different chemical behaviors in the past, or that radioactive decay happened more rapidly in the past. There's no empirical evidence that chemical properties or radioactive half-lives change over time, so retreating to this position is no better than solipsism. There's no proof that God didn't create the universe a few thousand years ago and doctor all the physical evidence to make it look 6 orders of magnitude older, but only in the same way that there is no proof that your brain wasn't created by the robots of the Matrix an hour ago and implanted with a lifetime of false memories.

hissingnoise - 14-7-2009 at 09:57

Quote: Originally posted by tom haggen  
Well every one assumes that stars are really far away because of their distance of light years away from us. Claiming that this must mean the universe is billions of years old is false.

So you'll deny everything that appears to be at odds with creationism?
You're prepared to say that all modern physics and astronomy is a lie because it seems to deny the existence of a Super Being. . .
Seriously tom, you're close to "flat-earth territory" on this one.

AgentOrange - 14-7-2009 at 10:54

Quote: Originally posted by tom haggen  
Radioisotope dating is completely flawed. The only way radioisotope dating would be accurate is if you assumed that the level of radio active isotopes that you are using to date things with have remained at a constant level in the earth's atmosphere indefinitely. To assume we know what the composition of the earth's atmosphere was even 50,000 years ago is complete rubish. I have no proof that the earth and the universe are less than 7,000 thousand years old, I'm simply saying that theres no proof that the universe and the earth are billions of years old. Using geometry and the physics of light to guess how far away stars are, to prove how old the universe is, cannot be trusted either. People can't prove how long stars have been in exsistence by measuring there distance from us. If you have no idea how something came into exsistance, there's no way you can prove how long it has exsisted for. For all you know a magical smurf who can fly on a surf board made it all appear. The dating of the universe and the earth is a complete pseudoscience and has no more scientific credibility than the nazi racial sciences.

[Edit Ramiel: Godwin's law just turned the argument over to the blue team! reductio ad Hitlerum, you just lost the game]

[Edited on 13-7-2009 by tom haggen]

[Edited on 14-7-2009 by Ramiel]


For someone who is a member of a science forum, you sure don't seem to have much knowledge of (or faith in) the scientific process....

tom haggen - 14-7-2009 at 12:39

Im just saying something doesn't seem right about estimating the age of the universe because we can see stars from billions of light years away. as for using rocks to date things with. You may know how long it takes for those elements to decay but you dont know when it started decaying.

[Edited on 14-7-2009 by tom haggen]

AgentOrange - 14-7-2009 at 13:32

Quote: Originally posted by tom haggen  
You may know how long it takes for those elements to decay but you dont know when it started decaying.

[Edited on 14-7-2009 by tom haggen]


Hmmmmmmm :(

I have to say Tom, you don't really sound like you know what you're talking about.

[Edited on 14-7-2009 by AgentOrange]

not_important - 14-7-2009 at 14:14

Quote: Originally posted by tom haggen  
... You may know how long it takes for those elements to decay but you dont know when it started decaying.

[Edited on 14-7-2009 by tom haggen]


You still seem to be confusing C14 dating with other types or radiodating. C-14, Be-10, and H-3 (tritium) are produced in the atmosphere by cosmic rays, and dating techniques are based on direct measurements of the isotope's activity. C-14 is used with organic materials, H-3 with ground water as its short half life of 12&1/3 years allows determination of how long ago water was in the form of precipitation. Be-10 is used for some geological dating of surface soils.

But most radioisotope dating does measure how long ago the mineral containing the isotope was formed. For example, uranium is trapped in zircon during the mineral's formation, but lead does not fit into the crystal structure and is rejected. A newly formed zircon crystal will contain U-235 and U-238 in proportion to their concentrations in the surrounds, but only the tiniest traces of lead.

U-235 eventually decays to Pb-207, while U-238 decays to Pb-106. By measuring the amounts of all 4 isotopes the time elapsed since the formation of the zircon can be determined. When the uranium isotopes were formed doesn't matter, as the measurement is based on the time when they were trapped in the forming zircon crystal. The absolute amount of uranium is not used as the direct clock reading, but rather the U-235/Pb-207 and U-238/Pb-106 ratios. The two clocks also allow for a cross checking that compensates for any loss of decay-formed lead from the zircon.

Other pairs used are Sm-147/Nd-143, and Rb-87/Sr-87; the latter is not as precise with errors on the order of 1% to 2%.

Fission track dating can be used to determine the time since the mineral was last heated to a few hundred degrees C or higher. Similar to that is thermoluminescence dating, with a reset typically around 400 C. Errors from resets will result in lower (younger) readings than actual ages.

The Al-26/Mg-26 is normally used to date relative ages of mineral formation within a few million years of isotope formation. But it can also be used to set a minimum age of the Solar System: the ratio of Al and Mg isotopes in chondrules in meteorites tells us that the sample must be older than 10 half lifes of Al-26, because we can't detect any Al-26 but there was some there when the minerals were formed. As Al-26 has a half life of 720 thousand years, the chondrules must be more than 7 million years old.

Now if by "when it started decaying" you are implying that currently unstable isotopes were stable - not decaying - at one time, then you're challenging the same theories that also have to do with how the computer you use and the optoelectronic devices used in fiber optic networks operate. Say those theories are wrong, and you also are saying that those quantum devices work differently than the way we think they do, the theories that have been used to create new types of devices based on predictions of those theories.

To break radiodecay without also breaking quantum devices is no simple task, to claim the theories are wrong you must supply not only a new theory for radiodecay but also for all the other effects covered by the present theories.

Note that radioisotopes being more stable in the past would lead to materials dating younger than they are, not older. For them to appear older than they are radioactive decay would have to be faster in the past. Consider how for the oldest rocks dated - around 4,5 billion years, to actually be only say 10 thousand years old, a ratio of nearly 6 orders of magnitude, how much faster would the decay rates have to have been. Then consider how much faster the energy release would have been, and the amount of radioisotopes present in the Earth's crust and how much more would have been at the starting point in time of the rapid decay. Now think about the release of heat that means, and the much higher background radiation level that would result. And the same problems to quantum theories as above apply, breaking radiodecay also messes up a lot of other stuff.


497 - 14-7-2009 at 17:16

not_important, sadly, I think you're wasting your (virtual) breath with that. He has clearly demonstrated that he will not or cannot even consider what you're saying is possible.. Trying to reason further is useless in my opinion. Even the best of evidence will be do nothing to convince someone who won't even give it a chance...

Vogelzang - 14-7-2009 at 17:22

The Pope accepts the Big Bang theory, or was that the last Pope.

JohnWW - 14-7-2009 at 17:47

Quote: Originally posted by Vogelzang  
The Pope accepts the Big Bang theory, or was that the last Pope.

Since the Vatican Conference of 1870 (during which God expressed his displeasure with the Catholic Church by afflicting Rome with raging thunderstorms and lightning), Popes have claimed to be infallible, when speaking ex cathedra on matters of faith or morals, on the basis of the promises that Christ made to the infant Church. However, it is not clear whether this includes matters of science and technology, which are fields in which no Pope has ever had qualifications (or in commerce/business subjects or law, for that matter).

But in reality, who in his right mind takes seriously the Pope's ex cathedra pronouncements on matters like contraception, abortion, homosexuality, divorce, etc., which date only from around the 1960s? Especially after the Catholic Church persisted for so long, until the 17th century, with its doctrine that the Sun and stars and all the planets revolved around Earth, on pain of being burnt at the stake.

[Edited on 15-7-09 by JohnWW]

tom haggen - 15-7-2009 at 10:32

your explanation with the zircon crystal is still lacking a controll. You can't duplicate the earths atmosphere X amount of years ago to see how the mechanism for creating that crystal happened. The earth is not a laboratory figure it out.

[Edited on 15-7-2009 by tom haggen]

UnintentionalChaos - 15-7-2009 at 11:16

Quote: Originally posted by tom haggen  
your explanation with the zircon crystal is still lacking a controll. You can't duplicate the earths atmosphere X amount of years ago to see how the mechanism for creating that crystal happened. The earth is not a laboratory figure it out.

[Edited on 15-7-2009 by tom haggen]


I think you're confusing carbon dating with radioactive isotope dating. Nothing in a zircon crystal has anything to do with the atmosphere.

The idea is that zircon crystals are extremely resilient to being destroyed and often contain small amounts of uranium and thorium, which are radioactive and decay into lead at a known, fixed rate. This lead becomes trapped in the crystal. Zircon does not contain any appreciable amount of lead upon formation because the crystal structure excludes it due to ion size and charge. This fact cannot change. Therefore, lead found in zircon can be assumed to be entirely from the decay of uranium and thorium. By examining the ratios of specific isotopes of lead to specific isotopes of uranium, the amount of time the crystal has existed can be calculated.

As far as elements go, the earth is a more or less closed system (small contributions from meteors and such over time), so the technique is theoretically sound. There are natural processes that can decrease the lead content to some degree and throw the results off, but in the big scheme of things, nothing could possibly throw them off in ways that would validate a young earth.

Take 5 minutes ang google what you're talking about before you continue to make an ass out of yourself.

[Edited on 7-15-09 by UnintentionalChaos]

not_important - 15-7-2009 at 11:58

The atmosphere has nothing to do with it(*), zircon forms from a melt or under conditions of high pressure and temperature in near melt conditions; these have been duplicated today and continue to exist within the Earth.

Zircon is its own control, as it excludes Pb during crystal formation the only lead within it comes from the decay of uranium trapped within the zircon structure (which has a strong affinity for uranium). The differing decay rates of the 2 uranium isotopes means we are measuring two clock, which gives an internal check. The actual amount of uranium isn't critical, so long as it is within a range set by detectability on the low end and excessive modification of the zircon structure on the high end, this is a rather wide range.

The presence of external lead, not formed by radiodecay of uranium, can be tested for by measuring the amount of Pb-204. Using the lead isotope rations from lead in galen, which excludes uranium from its structure, allows you to find the background ratios of Pb-204/206/207. This lets you correct for lead contamination of the zicron, alternatively you can use micro analysis to locate and exclude the regions of contamination, or just select crack-free zircons as contaminants are generally found lining cracks in the crystals.

Note that zircon can also have fission track dating performed on it, giving a lower bound to the age - the time since the zircon was last heated hot enough to anneal existing fission track damage. The uranium/lead age should be no less than the fission track age.


(*)Unless you are suggesting that the Earth's atmosphere was hot and dense enough 7000 years ago to dissolve appreciable amounts of ZrSiO4. And even then it still works, it's just that little uranium would have decayed in that short of time. If you had bothered to look up the chemistry of ZrSiO4, you would have found that atmospheric conditions extreme enough to impact zircon formation would have been rather tough on most other minerals and rocks, and utterly destructive to life. We do not live in the atmosphere of a star, nor within a hot gas giant; suggesting that the Earth was such a short time ago is indicative of something regarding your reasoning.

tom haggen - 21-2-2010 at 22:13

alright turns out i was getting in over my head on this topic but im still not convinced and too lazy to do the research so i guess you guys win at this point. also i have to upload a picture so i can use the hyperlink to post it on my camaro website i belong to now so dont mind the pic



sciencemadness is not a general purpose image hosting site

[Edited on 2-22-2010 by Polverone]

cars.gif - 21kB

IrC - 21-2-2010 at 22:51

While unsure how this information aids in understanding fusion I can add if you read the bible in its ancient languages understanding colloquialisms and figures of speech as used at the time of writing you learn the earth is very old. So old in fact billions of years is not unthinkable. In point of fact there is no evidence in the writings giving a hint of an idea the earth is not as old as science today believes. Score one for science and zero for reading the book in English and taking thoughts out of context or completely wrong (or both). And then trying to use these fallacies not written in the Word to prove something every child who has ever explored in a rock quarry knows cannot possibly be true.

chief - 23-2-2010 at 01:55

Theres one interesting thing about the sun:
The total gravitational energy for disassembling the mass of the sun into infinity, i.e. the potential gravitational energy of it's mass
--> is said to be larger than the entire radiational energy which it emits during it's 10-15 billion estimated years of total lifetime ...

There are some MIT-physics-courses on youtube, and the Prof. calculated this in either this or one of the neighbouring videos:
http://www.youtube.com/watch?v=vqPsB6jb6ig

======================

bbartlog - 23-2-2010 at 10:29

Doesn't sound right to me...

Escape velocity for the sun = 6.3 x 10^5 m/s
Energy per kilo to remove is then ~ 2 x 10^11 Joules
Multiplying by the Sun's mass of 2x10^30 kg you then get 4 x 10^41 J to disassemble the sun
The actual figure is lower because you really want to integrate over the curve as removal gets easier (remember that the Sun's gravity grows less as you remove the mass piecewise)

Meanwhile the Sun emits 4 x 10^26 J/sec in energy, or about 1.25 * 10^34 J per year, so it would only take on the order of 10^7 or ten million years in order for the Sun to throw off enough energy to match the cost of its own disassembly.

I should probably actually look at the video. But there are two other factoids that make this idea seem implausible. One is that the radiation we see in the heavens is dominated by that generated by nuclear reactions. If the kind of gravitational or kinetic energy effects you describe were predominant we would expect more of the light we see to be generated by falling matter or the blackbody radiation from formation of new stars. Second, we already know that stars (even those much larger than Sol, with per-mass-unit energy costs for disassembly orders of magnitude larger) can blow themselves quite to pieces in a matter of hours from the energy of nuclear fusion.

IrC - 23-2-2010 at 22:13

Quote: Originally posted by 12AX7  
Do you have proof that it is 7000 years old? Is that a testable hypothesis?

Oddly, I can test that the universe is more than 0 seconds old, but how much older remains to be seen. I can at least tell with certainty that it is not -1 seconds old!

Tim


I have to add something not discussed here. In fact in these type discussions the points in my mind are never looked at.

Olbers paradox for one. Why are we not all melting? Even at night. The best answer is the universe is too young still, it will be hotter later when all that light reaches us. So we see a dark night sky. If from this fact we assume the universe is not infinite in age (and likely not static) but we can make measurements of what light there is and do many calculations which if correct should all come together and they do resulting in we have a good handle on factoids about the universe. From this and knowing by other means details of the universe like : ~14 billion years of age, approximate size, number of stars and average density and knowing other factors such as the total combined light from various sources we get a clear picture of the facts. In essence we may not know everything but these facts we are clear on, leave no room for consideration of ideas to quote Gump "as stupid as stupid gets".

Consideration of the brightness of the night sky includes red shifting from expansion, dust, apparent brightness of stars (remember the squares cancel meaning distant stars are very bright for the distance) and adding the afterglow, and so on. We can assume the expansion will always keep the night sky dark since as the light finally reaches us and adds together so much red shifting has occurred. Good then that as time goes by we can still use our telescopes at night.

The point I am making is this means the universe could be much older than we think yet from many measured parameters we can be sure it is not younger than around a billion years plus the age of the oldest globular cluster. Amazingly enough we arrive at ~ 14 billion years.

Another point: take the number of stars, surface brightness, angular area, and so on. Consider all stars as old as the sun. If the universe was 7000 years old and had no real expansion time all the light from all stars we see has had time to get here with little red shift loss. The light would vaporize titanium on the surface of the earth. Even at night. If we assume magically it is 7000 years old and the light just started from the known distances the sky would be very much darker and this also we can measure. Not to mention having to say the universe is younger than the things in it. To get the oil we burn and the fossils we see it takes little effort to show therefore the universe is also much younger that the earth if you can buy that one.

Without all the details as to why I might add if we are close on the Hubble constant then we know the maximum is around 20 billion years so again I believe we all have a good handle on the age.

From another view. Clearly the universe must be at least as old as the oldest object in it. We have such good data on the most distant globular clusters we know they are around 12 or 13 billion years old. This provides good evidence we are correct in our 14 billion year estimate. Now add this. We know enough about stars to know a lifetime is maybe 10 billion years maximum. Where did the matter we are made of come from. From supernovas. So at least one and a half stellar cycles must have occurred for us to be made of elements other than H and He and be living under a second generation (minimum) star already halfway through its life. Likely at least two supernovas are needed to account for all of the heavier elements in just our solar system. I believe all the facts we now know with great certainty gives us a good idea the universe is at least 10 billion years plus the suns age old at the very minimum.


[Edited on 2-24-2010 by IrC]

fdsa

tom haggen - 27-2-2010 at 15:51

fdsaf


[Edited on 27-2-2010 by tom haggen]



[Edited on 28-2-2010 by Ramiel]

Photo0166.jpg - 52kB

IrC - 28-2-2010 at 01:35

I was hoping someone would be interested in discussing my points on Olbers Paradox, yet all I see is Tom the jerkweed using the site for free image hosting. No actual post just some cryptic letters and really do we need to see the damn spark plugs. Here is an idea Tomweed, start your own thread titled "my image hosting ripoff". Better yet pay for your own hosting instead of ripping off the people who are paying for this site.

Or irritating the people like me who could give a rats ass about your spark plugs in a picture annoyingly large.

hissingnoise - 28-2-2010 at 04:37

I'm not irritated; I'm amused and perplexed - I like a bit of surrealism!
The reason it's here is kind of incidental?
But Olber's Paradox seems to point to The Big Bang and this reduces us and our universe to mere schrapnel.

[Edited on 28-2-2010 by hissingnoise]

hissingnoise - 28-2-2010 at 07:00

Wow! Perfection just got better?

(Oops! Not Whimsy!)

[Edited on 28-2-2010 by hissingnoise]

IrC - 28-2-2010 at 15:48

Quote: Originally posted by hissingnoise  
I'm not irritated; I'm amused and perplexed - I like a bit of surrealism!


You may be right.

As to shrapnel I can live with this so long as the universe outlives me. Never liked the cycling crunch thing, I hate small spaces.


[Edited on 2-28-2010 by IrC]

hissingnoise - 1-3-2010 at 15:51

I'd prefer the steady state myself; I find all change unsettling. . .

IrC - 1-3-2010 at 16:58

Quote: Originally posted by hissingnoise  
I'd prefer the steady state myself; I find all change unsettling. . .


I guess with nothing new or useful added by now no one is going to discuss Olbers on proving the age so I'll move on to more interesting things (or threads). Would not have bothered to make this post except I wanted to comment on your S.S. preference. That is, if it were static we would be flash frying now or soon since the red shift from expansion would not exist. So give me shrapnel for creation and moderate weather. After 25 years in the Arizona desert I have no further need for excess heat.


[Edited on 3-2-2010 by IrC]

Rosco Bodine - 1-3-2010 at 20:29

My theory is that everything we see and think we know and everything we experience is sort of like that movie the Matrix .....a contrived illusion which
operates according to what we estimate are the "laws of nature" .....but we only know a fractional part of all that is .....and by design or inherent limitiation of the form of being which we are....a fraction of the knowing it all is our operational ceiling.

IrC - 1-3-2010 at 21:31

I think the string and brane theories are getting close to what is real and dimensions likely do number up to 11 or so. From this and knowing we cannot perceive even a half dozen of these dimensions creation could be very different in whole than what we know. Yet you can carry this too far. If for example our belief of the universe consisted of only what is in our visual range in the sky above we might conclude it is all nothing more than an illusion created by some deity and has no solid reality. Later when a meteor comes through the roof and levels the house would we alter the belief system. Of course if none of it was really real we would wonder where the heat of the sun is coming from.

Or a 1930's physicist sees a positron and an electron (yes lets assume he can see it for now) coming from the collision of two photons of more than .511 Mev energy. He concludes there are two particles. A 21st century physicist looks at this and concludes there is only one particle the bulk of which exists in dimensions outside of our perception today and the particles seen in the 30's are merely extensions in our "lower" dimensions of this single entity and decides this is the source of quantum connectivity between the opposite particles. Who is right one wonders.

Better yet is anyone going to bring the cause of fusion back up or has the thread forever disintegrated into philosophy.

Rosco Bodine - 1-3-2010 at 22:20

Philosophy is but a shadow of the dimensions of the religion it once was,
and fusion is but entropy in retreat toward singularity, fleeing from an
"expanding universe" where its place was no longer found ....
but relatively speaking, while "travelling" towards its destination it goes
"away" from its previous "remainder universe"
still apparently expanding ......looking in the rear view mirror at a view which just became every other direction than straight ahead! What dimension is this
"straight ahead" when you can never go "back home" anymore ?

IrC - 1-3-2010 at 22:43

You win, you have me too confused to reply.

Edit to add: oddly there seems to be some logic in this.


[Edited on 3-2-2010 by IrC]

Rosco Bodine - 1-3-2010 at 22:47

I can't answer my own question really ....but visualizing it , it has a shape and it is spherical.