# Nature of e=mc^2 and other miscelaneous questions

1. Feb 20, 2005

### Aphex_Twin

If you have 1 kg of matter, what is the energy equivalent of it in say joules?

How much of the matter (heavy hidrogen?) that goes into a fusion reaction is transformed to energy?

And to the point...

Last year there was this discussion about what would happend if the Galileo orbiter would crash into Jupiter. More precisely, there were some (I don't know if actual physicists) that hinted that the uranium present on board of the craft (from the reactor powering it) would explode with enough power to trigger a fusion reaction within the Jupiter lower atmosphere.

Now, theoretically speaking, is it possible for an explosion within Jupiter (or what should Jupiter be like) to create a powerful enough pressure shock front, to trigger the fusion of the hydrogen atoms in it's path, and if it's possible to create a chain reaction this way...

2. Feb 20, 2005

### dextercioby

For the last question,well i don't know,it may be pure speculation,though...For the first,approximately $9\cdot 10^{16}J$,as for the second,well,look for the reaction in a book,then for the rest masses of proton (H nucleus) and the alpha particle and compute the mass defect.

Daniel.

3. Feb 21, 2005

### Aphex_Twin

What is the energy required to heat up one H2 and one H3 from a given temperature n (Kelvin), up to 10^9 K (required for fission)?

How does the density of an object bound solely by it's gravitational compression and electron repulsion vary? My guess is that it should be cubic or quadratic-like as we start moving inwards from the surface but aproaching a finite limit as we aproach the center of mass. How do you put this into a relation?

So the energy output of a fusion reaction (deuterium-tritium) is 17.6 MeV
The mean density of Jupiter is 1.326 g/cm^3.