| On your other point - would we have a chance to detect something that small? No, absolutely no way, even considering that there would be a continuous 'stream' of these things spread out like beads on a string. Say each one weighs a gram, and is 1m across - that's just impossibly small. The Hubble ST's resolving power means that it can resolve a 1m object (ie, make one pixel = 1m²) at something like 4000km away. In space terms, that is practically touching. In interstellar terms, that might as well be inside the planet! Any transmitting that it might be doing would necessarily be very low power, which means it would need to be highly directional and pointed back the way it had come, behind what must be a reflector more reflective by far than anything we know how to build. Unless you managed to get its transmission pointed directly at you by being behind it, there'd be no way to see it. After decades or more in the interstellar void, it would be about as equal to the ambient temperature as it's possible to be, and in any case, it's not made of very much 'stuff', so it would have no heat signature to detect. Lastly, at 20% light speed, they would cover the average distance from Pluto to Earth in something like 36 hours. That's not a lot of time to search! The only possible method I can think of would be to detect the results of these things crashing into dust within the solar system. How much of a 'puff' a gram of diffuse something travelling at 0.2c hitting a speck of rock makes I don't know. Still way too small to spot, I'm sure. |