# Anti-matter/matter combination.

Ryan_m_b
Staff Emeritus
Using a Positronium as my example.
the mass of 1 electron is 9.10938291(40)×10−31 kg
the mass of 1 positron is 9.10938291(40)×10−31 kg

The two particles annihilate each other to produce two gamma ray photons after an average lifetime of 142 ns in vacuum.

leaving behind 2 photons, whose mass is so near 0 we say they have <1×10−18 eV

1 MeV: is about twice the rest mass-energy of an electron.

hence what is produced does not equal what we started with, 1+1 is not equaling 2, so where does the mass go?
The mass of a photon is not "near 0", it is 0. Photons are massless. The contribution to mass comes from the energy of a photon, this follows e=mc2.

This follows e=mc2.
That ^^ might be a little too much math for this guy to handle.

Danger
Gold Member
Hakon, I have no idea of your age or educational background, so I have to flat-out ask you—do you actually know what a "singularity" is? It does not seem so from your posting.

a singularity is a place where the gravity field is infinite.
which is in normal cases created by a blue star going super nova and then collapsing in on it's self, however can be created hypothetically on a smaller scale.

one thing i'm not sure on, does the speed of light remain a constant inside a singularity, or is that unknown at this stage?

Using a Positronium as my example.
the mass of 1 electron is 9.10938291(40)×10−31 kg
the mass of 1 positron is 9.10938291(40)×10−31 kg

The two particles annihilate each other to produce two gamma ray photons after an average lifetime of 142 ns in vacuum.

leaving behind 2 photons, whose mass is so near 0 we say they have <1×10−18 eV

1 MeV: is about twice the rest mass-energy of an electron.

hence what is produced does not equal what we started with, 1+1 is not equaling 2, so where does the mass go?
To my understanding, relativistic mass is the total energy divided by c^2. If you annihilate antimatter with matter, you create energy E = mc^2 and since energy itself has mass, and energy and mass are equivelent by the formula E = mc^2, the relativistic mass of the photons is E/c^2 = mc^2/c^2 = m; meaning the photons you end up with and the particles you started with have the same mass. I don't know where you took the mass of the photons, it depends on the energy they have.

http://en.wikipedia.org/wiki/Mass–energy_equivalence

a singularity is a place where the gravity field is infinite.
That's technically incorrect. A singularity is a mathematical anomaly due to the coordinate system chosen. It's not a physical entity. To describe the physics inside a singularity, you'll have to make some sort of coordinate transformation.

Danger
Gold Member
It's not a physical entity.
That's why it's so damed weird: it isn't a physical entity, but its existence and effect upon neighbouring matter are very real. The easiest way that I can think of it is that it is a 5-dimensional (or more) object that 4-dimensional brains are trying to understand.

And Hakon, I'm sorry that I missed this before—the ergosphere is indeed the region of a BH that is responsible for Hawking radiation (hair), but it isn't restricted to pure energy interactions. If you drop a load of garbage from your hypothetical ship within that region, you can absorb more energy than you give away, for a net gain that can be huge.

Drakkith
Staff Emeritus
Using a Positronium as my example.
the mass of 1 electron is 9.10938291(40)×10−31 kg
the mass of 1 positron is 9.10938291(40)×10−31 kg

The two particles annihilate each other to produce two gamma ray photons after an average lifetime of 142 ns in vacuum.

leaving behind 2 photons, whose mass is so near 0 we say they have <1×10−18 eV

1 MeV: is about twice the rest mass-energy of an electron.

hence what is produced does not equal what we started with, 1+1 is not equaling 2, so where does the mass go?
In a low energy collision, the rest mass of the electron and positron PLUS any kinetic energy is converted into momentum distributed evently between two photons. Each photon has about 511 KeV of momentum with more depending on the amount of kinetic energy each particle had before annihilation.