Question: I'm just throwing this out there for discussion/answering:

If person A sat in a chair all his life, in a house on earth (let's say 100 years),
and person B flew around in earth's atmosphere at let's say 1000km/h or 1000mph (which ever is easiest to comprehend) for 100 years. 

Would there be a time difference for those people at the end of their life? would person B's clock have ran slower than person A, as person B was traveling at a speed closer to the speed of light, or is this speed too slow to be relevant?

Answer: 
> 
> Let's say a field of stars all die within a short amount of time. Just
>  for argument's sake they produce a debris field of iron ( or any other
>  heavy element). Provided that there is enough time the debris will
>  agglomerate, we know this.
> 
> 
> My question: Given enough mass, will this agglomeration of heavy
>  elements fuse into even heavier elements?
> 
> 
> 

Short answer, no, as others have said. At least, not in the stellar fusion sense, because heavier than Iron doesn't fuse in stellar fusion. Heavier than Iron fuses in supernova explosions.

Quick Source: <http://curious.astro.cornell.edu/copyright-notice/85-the-universe/supernovae/general-questions/418-how-are-elements-heavier-than-iron-formed-intermediate>

More info here: [Origin of elements heavier than Iron (Fe)](https://physics.stackexchange.com/questions/7131/origin-of-elements-heavier-than-iron-fe)

> 
> To be plain, I am not talking about stellar fusion or whether there is
>  enough latent energy to continue fusion at an already existing core. I
>  want to know if there was enough collective mass in the debris field,
>  could the field itself, coalesce to the point where the heavy elements
>  will fuse.
> 
> 
> 

Lets examine what happens when the iron coalesces, and in reality, it's unlikely that you'd have Iron and nothing else. It's hard to imagine a share of hydrogen, helium, carbon, etc, wouldn't be present, but assuming just Iron: 

First, you get something similar to a planet or a planet core. That gets bigger as more coalesces. Then something cool happens (or, well, hot more specifically), but it's kinda neat. At a certain point, the planet stops getting bigger and starts getting smaller, and as it gets smaller, it gets hotter, not from fusion, just the energy of coalescing. In time, it could glow hot like the sun, but much smaller than a sun. If I was to guess, the peak size might be around the size of Neptune. (Peak hydrogen planet size is about the size of Jupiter, peak Iron planet size would, I would think, be a fair bit smaller).

Eventually, with enough mass, you get something something similar to a white dwarf. Iron white dwarfs don't exist because stars that become white dwarfs don't get to the Iron creation stage. There's some metallicity, but essentially, white dwarfs are carbon/Oxygen, or, smaller ones can be made of Helium and sometimes, there's some Neon, Magnesium - more on that here: <https://en.wikipedia.org/wiki/White_dwarf>

Your scenario would essentially become an Iron white dwarf.

Then, as with any white dwarf, at a certain mass, it reaches the Chandrasekhar limit and the inside of the star would begin to degenerate into a Neutron Star and once that process begins, it moves quickly and you basically have a really really really big boom and a type 1a supernova. And during the supernova, a lot of the Iron would fuse into heavier elements, but it would kind of happen all of a sudden, in the reasonably short period of time.
As I understand it regular fusion in a star takes light elements as input and the output is heavier elements and energy. There are several potential steps in the regular process, e.g:

* Hydrogen fusing to helium **and producing energy** which keeps the star from collapsing.
* After a lot of hydrygen is spent and helium has collected in the center of the star the hydrogen fusion reactions tapers off. The star shrinks. **Pressure and heat increase in the core**. The core starts burning helium.
* Repeat for heavier elements. E.g. up to oxygen/carbon.

Now I stressed a few points in the regular process:

* "and producing energy": The reaction is endothermic. If you needed to add energy instead then processes tend not to work or much slower.
* Add to that that fusing iron does **not** produce energy. Lighter element than iron/tin produce energy if fused. Heavier elements produce energy when split. Iron/Ni is the most stable element.
* "Pressure and heat increase in the core": There is no fusion to produce heat, but you can increase pressure by just adding a lot of mass. If you add enough mass then you will get very dense iron. At some point the mass gets big enough to that it is not merely resisted by the electric charges of the charged iron aton cores, but also by the pressure of electrons. (See [Degenerate matter](https://en.wikipedia.org/wiki/Degenerate_matter)).  

Add enough and you might get neutronium rather than heavier elements.

> 
> To be plain, I am not talking about stellar fusion or whether there is enough latent
>  energy to continue fusion at an already existing core. I want to know if there was 
>  enough collective mass in the debris field, could the field itself, coalesce to the
>  point where the heavy elements will fuse. 
> 
> 
> 

Well, yes and no. Add enough and it will change to a neutron star or beyond. I guess you could consider that a technical yes with a single star sized atom. It also feels as if I am playing word games.

Everything I have read (but I am not a physic person) seems to say that fusion stops. You will get very many iron atoms close to each other. Statistically I guess some might fuse and thereby cool the coalicing mass of iron. But intuition tells me that most will stay iron. Add more and it just gets denser and denser until it become energytically advantageous to capture elctrons and change to neutronium. (which, though very heavy/dense) is the opposite. It goes to element 0, not to classic 'heavier' elements.