What's the third most common element?(medium.com) |
What's the third most common element?(medium.com) |
It would be nice if someone could explain any of the exceptions to the Oddo-Harkins rule, such as the dip at atomic number 44, Ruthenium.
(Might also be confusing that Sn (Z=50) is labelled at the wrong place (Z=48)).
edit: here's a modified version,
There's a radius for color-charge interaction. This radius is thought to be one cause for larger elements being less likely to be stable; when protons are too far apart to exchange color-charge carriers, their magnetic repulsion can disrupt nucleic stability.
And different quarks have different energies. Every neutron has 2 Down quarks and 1 Up quark (UDD); every proton has 1 Down quark and 2 Up quarks (UUD). Down quarks are more energetic (massive) than Up quarks. After about 5 minutes, a neutron (UUD) decays into a proton (UDD), an electron, and an electron neutrino. This would seem to imply that an electron and a neutrino would equal the difference between an Up and Down quark.
All protons and neutrons have 3 quarks. There are other particles with 2, but they're much more rare. Nuclei with an odd number of nucleons (protons and neutrons) would have to have an even number of quarks. There may be something to the number of quarks, research into that is difficult because the act of pulling quarks apart requires so much energy that it just creates new quarks.
i imagine the same principle holds. if an odd (Hydrogen) forms with another odd, you get even. Hydrogen+helium=odd, but helium + helium = even. as the evens outnumber the odds, even more evens are forming with evens.
(1/36 probability of a sum of 2, 3/36 of a sum of 4, etc)
odd + odd = even (odd reduced by 2, evens increased by 1)
odd + even = odd (evens reduced by 1)
even + odd = odd (evens reduced by 1)
even + even = even (evens reduced by 1!)
When the evens outnumber the odds, odd+odd will be rare, so the percentage of evens will tend to decrease until it reaches 50%.
No matter many of each type you start with, the equilibrium position is 50-50% odd and even.
However: there may be an exception to this. If all the odds are in one place, then odd-odd may be more likely than random. If you have all evens in one place, you can't get back to having odds again - you can't (ever) increase the number of odds that already exist to balance things out, you can only decrease the evens. 0-100% odd and even could also be an equilibrium position.
H, He, C, N, O, Ne
What are the four most common elements in living cells?
H, C, N, O
(We invited the noble gasses to play, too, but they said something along the lines of, "Go away you peasants you'll mess up our perfect orbitals.")
tl;dr: Oxygen
But it's worth reading the article to learn why.
Link: http://commons.wikimedia.org/wiki/File:Nucleosynthesis_perio...
(Of course, most likely not in liquid form)
"People used to think gold was worth fightin' over, and that shit gets made by every supernova, which means pretty much every planet around a G2 star will have some. Stars burn through lithium as fast as they make it. All the available ore got made at the big bang, and we're not doin' another one of those. Now that's scarcity, friend."
PS: People might also like "Atomic Physics and Human Knowledge"[0] by Niels Bohr. It's a quick read (less than 60 pages).
[0]: https://archive.org/details/AtomicPhysicsHumanKnowledge
> Basically, the hydrogen-helium abundance helps us to model the expansion rate of the early universe. If it had been faster, there would be more neutrons and more helium. If it had been slower, more of the free neutrons would have decayed before the deuterium stability point and there would be less helium.
Isn't the inflation conceived to be as fast and long as necessary so that inputs to baryogenesis give result with hydrogen to helium ratios that are in line with experimental data?
So, by the time that the heavier elements are forming, the big bang has been done with and forgotten about for at least, like a microsecond. ;-)
Thinking about what you said I think necessary condition to get big bang hydrogen/helium ratio is that although there must be very high energy density we must not have too much of gravitational confinement because that would spark fusion and mess up the ratio bringing to closer to what we have currently in the universe.
Massive stars end their lifecycle in a supernova explosion, which blasts much of their mass off into space. the remaining stellar core either forms a neutron star or a black hole. The mass that is blated off contains many heavy elements formed in the star by nuclear fusion, and contributes to nebula formation. These nebulas coalesce to form new stars and their associated planetary systems. We can actualy see this happening in various places throughout our galaxy, with nebulas in various stages of coalescing and with multiple stars forming within them. Absorbtion spectra tell us about the materials these nebulae are composed of.
There is some speculation that heavy elements such as iron are also produced and scattered about in nutron star collisions.
(1) http://en.wikipedia.org/wiki/Galaxy_collision (2) http://en.wikipedia.org/wiki/Andromeda_galaxy#Future_collisi...
Also because we know how much material is released in a mrger and how much material there is in our galaxy, we can work out how frequent neutron star mergers are and these results agree with other independent estimates of frequency of merger.
Why is it 4+ light years from any other stars? Did our sun pull everything out of that radius when it was forming leaving a whole bunch of empty interstellar space?
Note that the graph actually shows the estimated abundance of elements in the solar system (found that on Wikipedia), not the universe or the Milky Way. The article misrepresents that!
> The world is made up of four elements: Earth, Air, Fire and Water. This is a fact well known even to Corporal Nobbs. It's also wrong. There's a fifth element, and generally it's called Surprise.
Although the numbers are indeed not too far off.
The sun would have accumulated material from the nebula it formed in as it drifted though it. The stars near us now are not the ones our sun was near when it formed though (except by extemely unlikely co-incidence), as each star is on a slightly different course round the galaxy, like water droplets in a very slowly rotating cyclone.
If another star were to pass by very close, it could be disastrous for us as it could severely disrupt the planetary orbits in our system, but that's fairly unlikely and there's no prospect of that happening for many millions of years at least. The space between stars is vast, even by comparrison to the size of stars themselves and their solar systems.
EDIT - on that last point, 4 ly is ~250,000 AU (the distance from the earth to the sun). If we asume out solar system is 100 AU across, that's still only 1/2500 the distance to the next star.
You wanted non-radioactive gold for your jewlery and dental fillings? Oops, sorry about that....
D1 = {E,O} D2 = {E,O} *Where E and O are balanced in terms of possible outcomes that satisfy
Outcomes: {EE, EO, OE, OO} Odd outcomes: {EO, OE}
Half.
(Obvious spam/flames/etc. should just be downvoted, ofcourse.)
It seems like about half of ilovefood's comments are of the "wow! great article!" type. I'm not sure whether this indicates that comments saying "don't do that" are likely to be helpful or not...
(If it were 100%, I'd conclude that it's a would-be spammer's account, building up a bit of history before starting to try to fill HN with spam. But I don't think that's what's going on here.)
While water will break down at high temperatures I would find it surprising that 1st and 3rd most common elements in the whole universe, that readily combine to form water would not result in substantial amounts of water.
It's probably like saying we shouldn't find H2 because "nothing says they are found bound together"
http://www.popsci.com/technology/article/2011-06/herschel-sp...
I would expect that in planet formation situations
http://physicsworld.com/cws/article/news/2013/mar/13/cold-hy...
No, I never said it is a fact, it is, as you pointed, a conjecture, and I provided a source (ok, wikipedia) for the amount of water in the universe
If you or him knows of a reason for why the most common elements in the universe that combine easily wouldn't result in an abundance of their combination I'm all ears.
(Which doesn't mean the amount of water is going to be near the amount of H2 or just the amount of Hydrogen present in the stars)
