morner

Just pissing in the wind here. If (from stationary observer's point of view) both ships increase in mass relativistically, and their mutual gravitational attraction also increases likewise, no net change in gravitational acceleration between the ships would be observed. From stationary observer's point of view: Each ship would excert a greater force due to gravity, as gravity is proportional to the mass which has been relativistically increased. However, the other ship would have an identical increase in mass, so the increased gravity would be working to move a larger mass. I expect this would work out to produce a mutual gravitational acceleration of 'a'. From crew's point of view: Other ship is at rest. No funky relativity has to be considered. Each ship is attracting the other with an acceleration of 'a', due to accepted gravitational theory. The 'a' terms are equal, so nothing weird happens with the observer seeing the ships collide before the crew do, or anything. It all cancels out nicely.

First off, the 'cleaning' you describe should really be modelled as a differential equation, so it will take somewhat longer than 6 donations to bring blood toxicity down to 50%. I'd figure out how long it'd take, but I'm tired and can't be bothered with solving a DE just now. Or ever. Then there's the issue that the toxins in your blood are water-soluble, so your body will be excreting them all the time. Assuming the levels of toxins are constant, or even increasing as you say, this implies that you're ingesting enough toxin that no number of blood donations will clean you out. If by "products that aren't suppose to be there" you also mean the far more insidious fat-soluble toxins we're all exposed to, then again the blood donation wouldn't really help; those products dissolve in the lipids found in all your cells, not just in your blood. I'm not an anatomist, but I imagine the number of 'other' cells in a human body vastly outnumbers the number of blood cells. While removing blood would remove some of those poisons, you wouldn't get rid of anywhere near 10% of them for each 10% blood you disposed of. Your detox course would therefore take a much longer time to reach even the suggested 50% mark, if it even got that far at all. Finally, all that blood you're donating goes somewhere. Is it ethical, assuming your initial assumptions to be correct, to deliberately and knowingly give other people your poisoned blood?