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hrherle
2004-Dec-06, 02:44 AM
Is there any direct evidence that the energy is converted into mass in the universe? :-?

Damburger
2004-Dec-06, 02:48 AM
Is there any direct evidence that the energy is converted into mass in the universe? :-?

If you get really high energy gamma rays, they can turn into an electron/positron pair. This has been seen happening in particle accelerators, so yes.

Evan
2004-Dec-06, 06:22 AM
Yes. In high energy collisions produced in particle accelerators the sum total energy of the collision byproduct particles equals the total energy of the particles involved in the collision, including the energy imparted to the particle by acceleration. This was the first clue to the neutrino since there is a very small amount of energy that was unaccounted for in hydrogen fusion. That energy is carried away by the neutrino.

swansont
2004-Dec-06, 12:17 PM
Yes. In high energy collisions produced in particle accelerators the sum total energy of the collision byproduct particles equals the total energy of the particles involved in the collision, including the energy imparted to the particle by acceleration. This was the first clue to the neutrino since there is a very small amount of energy that was unaccounted for in hydrogen fusion. That energy is carried away by the neutrino.

It was beta decay, not fusion. Not a whole lot of fusion research in 1930, which was when Pauli proposed the neutrino's existence.

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In nuclear reactors, the mass of the products is less than the original nucleus + neutron

papageno
2004-Dec-06, 12:27 PM
Is there any direct evidence that the energy is converted into mass in the universe? :-?

If you get really high energy gamma rays, they can turn into an electron/positron pair. This has been seen happening in particle accelerators, so yes.

I have seen the production of an electron-positron pair in a cloud chamber. 8)