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Stuart Robbins's user avatar
Stuart Robbins's user avatar
Stuart Robbins's user avatar
Stuart Robbins
  • Member for 10 years, 10 months
  • Last seen this week
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How rare is Tsuchinshan (C/2023 A3) like events? So that I can decide how much to spend to see it
I would not spend money at this point. As others say, something like this is every couple years on average, I think the last good one was 2020. HOWEVER: It's already fading, and the nearly full moon is already swamping it out. By this weekend when you'll get maybe 2–3 hrs after sunset, it is projected to no longer be naked-eye visible. Wait 'til the next one and plan ahead based on projections for that next one.
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Is there any idea how lunar craters size relate to the size of the meteorites which created them?
As a very gratuitous side-note, I will add it's always nice to see myself cited in Wikipedia. That 1.3M crater number comes from my lunar crater database.
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Could Pluto and Charon have extra-Solar origin?
To clarify, and I've made this comment on the OP, Pluto and Charon have an expected amount of cratering for bodies at the edge of the Kuiper Belt that are several billion years old. Impact speeds are much slower there, so craters are smaller from the same-sized impactor in the inner solar system, and their gravitational cross-section is much smaller than other, larger bodies on which you'd see more impact craters.
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Could Pluto and Charon have extra-Solar origin?
Pluto and Charon have an expected amount of cratering for bodies at the edge of the Kuiper Belt that are several billion years old. Impact speeds are much slower there, so craters are smaller from the same-sized impactor in the inner solar system, and their gravitational cross-section is much smaller than other, larger bodies on which you'd see more impact craters.
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How soon after the accretion did Mars experience the magma-ocean stage?
Just because ChatGPT said something does not mean it's true. I was at a concert last night where the opening act said they asked ChatGPT how many times they had performed there and it said once. The venue had records of 3 times. I suggest finding any sort of research paper that suggests a Mars magma ocean and go from that as your starting point.
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Could mars become volcanically active if it is pulled into a highly eccentric orbit
I should've written 1/r^3. It means that the amount of tidal force you get goes down as the cube of the distance from the body doing the tidal pulling. Gravity is a 1/r^2 force, by comparison. That means that as you go farther away from the sun, the tidal force goes down really fast. All things being otherwise equal, if Earth were 2 AU from the sun instead of 1 AU, the tidal force experienced by it from the sun would be 1/8 as much (as it is now, the sun's tides on Earth are about 45% as strong as the moon's).
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Could mars become volcanically active if it is pulled into a highly eccentric orbit
Tidal forces are proportional to r^3, meaning that at the distance of Mars, changing its already large eccentricity would not have the same effect as the same eccentricity change it would if Mars were at Earth's orbital distance. Mars is also smaller than Earth, and tidal force is the difference in gravity at one side of an object versus another, so again, conceptually, you'd have to increase eccentricity a lot more than you would for a larger planet.
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What is this cluster of light trails captured on long exposure images?
Starlink was my first guess, but I'm not sure.
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