Sure, but it sounded like you meant while not instadeath, it'll be eventua-death. I.e. the Simpsons view of plutonium, which is likely what's in most people's

Sure, but it sounded like you meant while not instadeath, it'll be eventua-death. I.e. the Simpsons view of plutonium, which is likely what's in most people's minds. Anyone encountering the probe will pretty much by definition be very advanced, to not only get to space but also intercept something going above their star's escape velocity. You'd expect them to wear gloves and stuff. Plutonium may not even be the most hazardous thing on there. They may be deadly allergic to gold. (though yes plutonium is the one thing on there we can pretty much guarantee is hazardous while existing in fairly large quantities) But who knows, maybe their equivalent of eyes get the equivalent of cancer from alpha radiation. Although by the time it reaches any aliens the plutonium is going to be all spent. Half life of 87.7 years. After only a thousand years all that's left is 0.037%. That's of course the thing about radioactivity: The more dangerous it is, the shorter a time it's dangerous. If Voyager were heading towards proxima centauri then it'd take 73 million years to get there. Lots of it is already gone: "As of June 17, 2022, Voyager 1 has 70.19% of the plutonium-238 that it had at launch. By 2050, it will have 56.5% left, far too little to keep it functional". After 73 million years it'll be 5.1e250573 times less. It was about 37.7kg at launch. If I calculate right then the last pu-238 atom decays after only about 7500 years or so. It's much less dangerous now than when it left earth, which is of course exactly why it's powering down. tl;dr: By the time they find it there may not even be a single plutonium atom left undecayed.