Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: jccc on 16/07/2014 07:31:00

Title: How is hydrogen atoms formed?
Post by: jccc on 16/07/2014 07:31:00
Imagine the early universe as a big soup of quarks and electrons (ignore all the other particles for the time being). At a certain temperature, their random thermal motions are greater than the attractive forces wanting to pull them together, so the universe stays a "soup". At a certain point, however, the quarks can start staying together to form protons, neutrons, and a slew of other subatomic particles. So every time two ups and a down got together, we made a proton. Note that almost all of the other elementary particles have short lifetimes, less than 10^-11 seconds (the exception being the neutron, which has a free lifteime of ~800s). So things quickly become proton dominated. After the universe cools down some more, the electrons just get snagged up by the protons and.. voila. Hydrogen.

Read more: http://www.physicsforums.com

Best answer I find so far. Agree?

I agree too. But how electrons get snagged up by protons? What's mechanism? The process?

They attract each other and collide? They orbiting each other? How exactly hydrogen atom is formed?
Title: Re: How is hydrogen atoms formed?
Post by: evan_au on 16/07/2014 10:36:50
The big bang theory assumes that the universe started very hot. Under these conditions, the thermal energy is so great that no electron will stay associated with a given proton. This soup of protons and electrons is called a plasma. We are familiar with this state in lightning bolts and the visible surface of the Sun.

However, as the universe expanded, it cooled. When the thermal energy dropped below the ionisation energy of hydrogen, an electron encountering a proton will radiate a photon and drop into an orbit around the proton, forming a Hydrogen neutral atom. Sometimes an electron can be struck by a photon and is liberated from its proton, but overall, most stay as neutral atoms.
Title: Re: How is hydrogen atoms formed?
Post by: jccc on 16/07/2014 13:46:08
An electron encountering a proton will radiate a photon and drop into an orbit around the proton, forming a Hydrogen neutral atom.

Assume that is true.

Is electron keep orbiting? Or what else? Why not stick together?
Title: Re: How is hydrogen atoms formed?
Post by: chiralSPO on 16/07/2014 16:53:49
A proton "captures" the electron to become a hydrogen atom. The electron "falls" into the electrostatic well around the proton until it can't fall any farther, and it just occupies the lowest energy level around the proton. Saying that the electron orbits around the proton is not really true, but as far as classical analogies to quantum phenomena go, I think this is one of the better ones. As we have discussed before, the electron is most stable occupying a space very close to the proton, but with the freedom to move. This situation is more stable than the one in which the electron is "stuck" to the proton unless there is enormous pressure to hold the electron in (see neutron star).
Title: Re: How is hydrogen atoms formed?
Post by: jccc on 16/07/2014 17:59:44
A proton "captures" the electron to become a hydrogen atom. The electron "falls" into the electrostatic well around the proton until it can't fall any farther, and it just occupies the lowest energy level around the proton. Saying that the electron orbits around the proton is not really true, but as far as classical analogies to quantum phenomena go, I think this is one of the better ones. As we have discussed before, the electron is most stable occupying a space very close to the proton, but with the freedom to move. This situation is more stable than the one in which the electron is "stuck" to the proton unless there is enormous pressure to hold the electron in (see neutron star).
We are making circles.

There is a attraction force between proton and electron all the time. The closer the stronger attraction force.

Without other force interact, the two particles will closer and closer faster and collide. 

The fact that they are apart puzzles everyone, and comes QM. Do you really understand it?

What's the mechanism of the well? What is energy level? Why electron falls half way and stopped on the well?
Title: Re: How is hydrogen atoms formed?
Post by: chiralSPO on 16/07/2014 21:03:30
At this point I recommend you read a textbook on the subject (some books take a more historical approach, which I think might be better for you than the ones that just show the equations and assume the algebraic proof is sufficient for the reader.)

QM really does explain this very well, and it does make a lot of sense, you just have to let go of the expectation that microscopic things will follow all of the classical rules that macroscopic things appear to obey...
Title: Re: How is hydrogen atoms formed?
Post by: jccc on 17/07/2014 01:43:20
At this point I recommend you read a textbook on the subject (some books take a more historical approach, which I think might be better for you than the ones that just show the equations and assume the algebraic proof is sufficient for the reader.)

QM really does explain this very well, and it does make a lot of sense, you just have to let go of the expectation that microscopic things will follow all of the classical rules that macroscopic things appear to obey...

You be helping million/billion people, if you explain this well and make a lot of sense. Since you really understand QM.

QM seems is religion not science, agree?
Title: Re: How is hydrogen atoms formed?
Post by: chiralSPO on 17/07/2014 02:06:08
QM is a **model** not a religion. There are some key assumptions that may seem like a leap of faith, but I would argue that QM is very different on three grounds:

1) It makes verifiable predictions. I know this does not prove truth, but it does offer an opportunity to disprove, which hasn't happened yet.

2) It is self-consistent.

3) No one will kill for saying QM is wrong; they will only ask for evidence, and ignore you if you don't have anything to back yourself up.
Title: Re: How is hydrogen atoms formed?
Post by: jccc on 17/07/2014 02:16:35
You win. I believe you now.