Freethought & Rationalism Archive

Gauge Boson · 11-18-2002, 07:05 PM

Quote:

Originally posted by lpetrich:


That must be a typo -- the Sun will become a Red Giant about 5-7 billion years (10^9) from now, and will become a white dwarf and slowly cool off afterwards.

My bad. That was a typo.

[ November 18, 2002: Message edited by: Gauge Boson ]

Gauge Boson · 11-18-2002, 07:10 PM

Quote:

Originally posted by Kharakov:


I thought electrons and positrons annihilate eachother to form photons (high energy- gamma).

Under current conditions, yes, matter and antimatter cannot 'bind' together. It is interesting to note, however, that pseudo-atoms composed of and electron and positron orbiting eachother have been briefly created in labs. I actually don't know how this would happen in the future universe. I surmise that it is somehow related to the vacuum energy. My source (see source (1) from that post) says "10^85: Electrons and positrons bind to form a new kind of matter". I've been doing quite a bit of reading of research articles on xCDM lately and have a few dozen (!) still to get to, so I may find a primary source yet.

[ November 18, 2002: Message edited by: Gauge Boson ]

Defiant Heretic · 11-19-2002, 12:57 AM

Ok, I should probably finish reading that issue before writing any more theories.

Shadowy Man · 11-19-2002, 08:58 AM

Quote:

It is interesting to note, however, that pseudo-atoms composed of and electron and positron orbiting eachother have been briefly created in labs.

Yes, it is called positronium and has been well-studied. I even have had questions on Quantum Mechanics tests about it.

Gauge Boson · 11-20-2002, 01:00 AM

Quote:

Originally posted by Shadowy Man:


Yes, it is called positronium and has been well-studied. I even have had questions on Quantum Mechanics tests about it.

I am aware of that. I don't start QM until next semester.

Now I know who to defer questions to when I don't have anything substanitive to say.

Friar Bellows · 11-20-2002, 03:21 AM

Quote:

Originally posted by Gauge Boson:
I am aware of that.

I wasn't. Thanks Shadowy Man.

Shadowy Man · 11-20-2002, 09:18 AM

Friar: It's like a hydrogen atom, but replace the proton with a positron. All the energy states get shifted because the reduced mass of the system is quite different than hydrogen.

Gauge Boson · 11-20-2002, 01:46 PM

Shadowy Man,
Just out of curiosity, how long can positronium survive before the electron and positron annihilate? I know, this information is useless, but I can't help it.

Shadowy Man · 11-21-2002, 07:47 AM

Gauge:

I'm not really up on this (the lifetime of positronium is an active area of research) but I think that the lifetime is in the nanosecond range, and it differs between ortho- and para-positronium.

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11-19-2002, 12:57 AM	#13
Defiant Heretic Veteran Member Join Date: Jul 2002 Posts: 1,288	Ok, I should probably finish reading that issue before writing any more theories.

11-20-2002, 09:18 AM	#17
Shadowy Man Veteran Member Join Date: Jun 2002 Location: A Shadowy Planet Posts: 7,585	Friar: It's like a hydrogen atom, but replace the proton with a positron. All the energy states get shifted because the reduced mass of the system is quite different than hydrogen.

11-20-2002, 01:46 PM	#18
Gauge Boson Junior Member Join Date: Nov 2002 Location: California Posts: 53	Shadowy Man, Just out of curiosity, how long can positronium survive before the electron and positron annihilate? I know, this information is useless, but I can't help it.

11-21-2002, 07:47 AM	#19
Shadowy Man Veteran Member Join Date: Jun 2002 Location: A Shadowy Planet Posts: 7,585	Gauge: I'm not really up on this (the lifetime of positronium is an active area of research) but I think that the lifetime is in the nanosecond range, and it differs between ortho- and para-positronium.

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