I can't describe it in terms which would have any relation to your present knowledge of physics. All I can say is that life here is intimately bound up with the higher laws of electro-magnetism which at present are only being guessed at on your level. It's not the radioactivity which you know as such which causes the trouble—there are neutralizing devices throughout the planetary system to take care of that. The damage is caused by an ultra-ultra-short wave radiation which not even the most sensitive scintillometer you have can pick up, a very subtle by-product of every chain reaction.
It doesn't have too much immediate effect on the lower forms of life—including human beings, if you'll pardon the expression. But here, it causes a ghastly carnage, so ghastly it sickens me even to think about it for a second.
The incredible thing is that the people here could stop Earth from firing another shot if they wished to, and at 24 hours' notice, but their philosophy is totally opposed to force, even when it means their own destruction. That will give you an idea of the kind of people they are.
(Here they say that Einstein was on the fringe of discovering the theory involved when he died, but was having trouble with the mathematics. Remember how Einstein always complained that he was really a poor mathematician?)
But with atomic warfare threatening to break out on Earth at any minute, they have got to do something.
This is what they plan to do—this is what they are going to do.
Starting within a few hours after you receive this message, a mass removal of key scientists will begin. They will take 20, 30, or 40—roughly equal numbers from both sides—every few hours as technical conditions allow. That will go on until East and West agree to drop this whole mad weapons race. It will be done quietly, peacefully. Nobody will be hurt except by a fluke. But if needs be, they will lift every major scientific brain off the face of Earth to stop the present drift to disaster for everybody. There are no weapons, no devices that you have at present, which can stop this plan going into effect. There it is—it's as simple as that.
If you knew what you were really headed for, it would need no steps from here to make both sides on Earth stop this horrible foolishness in a moment.
The lesson of Mars is part of the orientation course here. (I'm not on Mars). I'm using up space, so I'll go into note form for a bit. Martians had an atomic war—forgot they had to breathe ... destroyed 60 per cent of their atmosphere ... canals on Mars aren't ... they're closely-spaced line of shafts leading to underground cities ... view from Earth telescopes, shaft mouths appear as dots which run together into lines due to eye-fatigue ... British Royal Astronomical Society figured that out 30 years ago at least ... see papers on their proceedings ... photographs here show monsters created by wholesale mutations ... lasted about four generations before reproduction failed ... now only vegetation on Mars ... saw pictures of last survivors ... horrible ... I was ill for days after ... imagine having to take 40 separate breaths after making a single step!