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Wikipedia says no efforts to measure the mass of 33 Polyhymnia have been made since 2012. The scientist who estimated its mass at that time regarded the result
by ridgeguy 3y ago
Wikipedia says no efforts to measure the mass of 33 Polyhymnia have been made since 2012. The scientist who estimated its mass at that time regarded the result as nonphysical and in error.
Couldn't this mass be much more accurately estimated by sending a small probe of known mass by the asteroid at a known distance and velocity, and measuring the trajectory perturbation?
I think this could be done with a 5kg radar reflector. No guidance, no comms, no onboard electronics at all. Terrestrial radar measurements of position and velocity are extremely accurate. The launch wouldn't have to achieve super accurate trajectory, just good enough to see gravitational perturbation.
Not much of a launcher needed for this. It might even work as a ride-along payload. Could be a relatively low-cost way of resolving this weird density result.
- lend000 3y agoYou might as well send something more sophisticated, because most of the cost is going to be in getting it out of Earth's orbit.
- perlgeek 3y agoWait, you want to do a gravitational perturbation mission with 5kg, for a body of > 10^18kg? You'd have to do super duper precise measurements to notice anything (much more precise than anything we can do at the moment), and the reason we don't know the density is that we haven't done precise measurements yet. How about just doing some more precise measurements first? I'm 99.99% certain that the high density estimate stops existing afterwards Also, how exactly do you want to get an object without guidance or comms near enough to a main-belt asteroid? This is all just ridiculous. Some theoretical physicist does some calculation around the Island of Stability, comes up with a high density, and tries to give his paper more relevance by finding an improbably dense astronomical object, and then wildly speculates that the two are related. What are the chances that some rando asteroid consists of 100% of an element that we 1) don't know if it actually is stable 2) don't actually know the density of, besides a single paper about it 3) don't know any natural, plausible mechanism for synthesis as opposed to it just being not well studied?
- A_No_Name_Mouse 3y ago> Wait, you want to do a gravitational perturbation mission with 5kg, for a body of > 10^18kg? You'd have to do super duper precise measurements to notice anything I don't think so. We would measure the effect of 33 Polyhymnia on the probe, not the other way around. Which would work if it got just in the vicinity of the asteroid. The mass of the probe wouldn't even matter. You're right of course about the density being a wild guess, probably not worth pursuing because the odds of finding something interesting are just about 0.