Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
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Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
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Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#2Estimate of density at 75 g/cm3 is a result of only a single study done in 2012 based on observed gravitational influence by 33 Polyhymnia on other Solar System bodies. Because asteroid is small and it's gravity is weak too, such measurements are highly imprecise and that's the most likely explanation.
Discovery of actual elements with such a density would have a profound impact on design of compact, low-yield nuclear weapons and potentially even pure fusion ones! But that's just a fantasy. No one will rush to build a space probe to 33 Polyhymnia, because it's nearly safe to assume that the 2012 study is simply an error.
Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#3[deleted]
Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#4Estimate of density at 75 g/cm3 is a result of only a single study done in 2012 based on observed gravitational influence by 33 Polyhymnia on other Solar System bodies. Because asteroid is small and it's gravity is weak too, such measurements are highly imprecise and that's the most likely explanation. Discovery of actual elements with such a density would have a profound impact on design of compact, low-yield nuclea…
I can understand how you could get a good estimate of an asteroid mass by observing its orbit but how could they accurately measure the volume from far away? Maybe they check how bright it is but then how do you control for differences in reflectivity?
Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#5I wonder what sort of instruments could get a better measurement of that object’s weight without being just a probe to it? I’m guessing we’d need to get lucky for it to be bright enough and located right to be resolvable by JWST. Or would sending something to it be the cheaper option.
Sure wish we had many more telescopes and instruments spread throughout the solar system.
Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#6I wonder what sort of instruments could get a better measurement of that object’s weight without being just a probe to it? I’m guessing we’d need to get lucky for it to be bright enough and located right to be resolvable by JWST. Or would sending something to it be the cheaper option. Sure wish we had many more telescopes and instruments spread throughout the solar system.
This is high school task, to measure "density of infinite layer of material" by measure its gravitational attractive force.
One don't need to touch material, but need to hang close to it and measure acceleration with some conventional instrument (for asteroid distance will be about few meters and acceleration around millimeters/s^2).
Most known appearance in Clarke Odyssey 2001.
Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#7Estimate of density at 75 g/cm3 is a result of only a single study done in 2012 based on observed gravitational influence by 33 Polyhymnia on other Solar System bodies. Because asteroid is small and it's gravity is weak too, such measurements are highly imprecise and that's the most likely explanation. Discovery of actual elements with such a density would have a profound impact on design of compact, low-yield nuclea…
I can understand how you could get a good estimate of an asteroid mass by observing its orbit but how could they accurately measure the volume from far away? Maybe they check how bright it is but then how do you control for differences in reflectivity?
By stellar occultations. Because angular speed of movement of asteroid on the sky is precisely known, observing a few occultations allows for precise measurement of it's diameter. That one is easy. But determining mass is not at all easy (and no you don't do it by observing it's orbit, it will be the same regardless of mass - you do it by observing orbits of all other things - especially those that happened to pass close to it). For heavy objects it's not that hard but for such a small thing, exceedingly hard.
Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#8Wikipedia 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.
Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#9Funny, just recently I was thinking about this since I have not heard about anything new regarding this in ages. Chemists call this an Island of stability.
https://en.wikipedia.org/wiki/Island_of_stability
But claiming, with very limited data, that this asteroid consists of ultraheavy, unknown elements of the periodic table violates Occams razor. I predict he is wrong.
Re: Paper posits ultradense asteroid 33 Polyhymnia has transuranic elements
#10Earlier quoted context omitted.
I can understand how you could get a good estimate of an asteroid mass by observing its orbit but how could they accurately measure the volume from far away? Maybe they check how bright it is but then how do you control for differences in reflectivity?
By stellar occultations. Because angular speed of movement of asteroid on the sky is precisely known, observing a few occultations allows for precise measurement of it's diameter. That one is easy. But determining mass is not at all easy (and no you don't do it by observing it's orbit, it will be the same regardless of mass - you do it by observing orbits of all other things - especially those that happened to pass c…
Some more info on asteroid occultations:
https://britastro.org/2018/observing-asteroid-occultations-w...