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Oumuamua wasn’t detected until after it passed by the Earth so it’s a hard challenge to detect from far away.
by plank_time 6y ago
Oumuamua wasn’t detected until after it passed by the Earth so it’s a hard challenge to detect from far away.
- eloff 6y agoI believe it came a close as 0.16 AU (tracing the path backward), which is 66 times further than the moon. Being an interstellar object though, it moves faster than the escape velocity to the sun, so it would pack a higher energy per unit of mass than a regular comet or asteroid. Fortunately such objects are also somewhat rare.
- AnimalMuppet 6y agoOK, crazy idea time. Couldn't we detect such things with radar? Given the right frequencies, rocks and dirt will reflect - that's how terrain-following radar works. So yes, I think we could, but there are some significant problems. 1. 1/r^2 power loss, in both directions. We would need a massive radiator, and very sensitive detectors. 2. The detectors are in the wrong place. You send out your signal, and several hours later the response comes back, by which time the earth has rotated. So where your detector has to be depends on the distance to the object, but you don't know the distance to the object! So we'd need a bunch of detectors at various points around the globe. And we'd need a huge power source. Which brings me to solar flares. They emit radio waves. Do they emit enough power at the right frequencies to be useful for this?