Starship Asterisk*

Chris Peterson wrote: ↑Sun Mar 12, 2023 3:13 pm

johnnydeep wrote: ↑Sun Mar 12, 2023 3:09 pm

Chris Peterson wrote: ↑Sun Mar 12, 2023 2:57 pm
I suspect that's because you're viewing it as an interpolation from now, as opposed to from the beginning. Like if I said "you started developing your own antibodies when you were two months old" as opposed to "when you were a fraction of a percent of your current age".

But that would imply that solar system formation is as well regulated and tightly controlled a process as embryonic or fetal development. Is that really true?

I think that between dating, computer models, and observations of planetary system formation elsewhere we have a pretty good idea of what was going on for the first few million years of our nascent solar system.

johnnydeep wrote: ↑Sun Mar 12, 2023 3:09 pm

Chris Peterson wrote: ↑Sun Mar 12, 2023 2:57 pm

johnnydeep wrote: ↑Sun Mar 12, 2023 2:54 pm

Maybe, but it still seems like an impossibly precise fraction of the overall time scale: 2/4500.

I suspect that's because you're viewing it as an interpolation from now, as opposed to from the beginning. Like if I said "you started developing your own antibodies when you were two months old" as opposed to "when you were a fraction of a percent of your current age".

But that would imply that solar system formation is as well regulated and tightly controlled a process as embryonic or fetal development. Is that really true?

Chris Peterson wrote: ↑Sun Mar 12, 2023 2:57 pm

johnnydeep wrote: ↑Sun Mar 12, 2023 2:54 pm

Chris Peterson wrote: ↑Sun Mar 12, 2023 2:49 pm
Models of planetary system formation, I imagine. But I haven't read the papers yet. There's a stack of them.

Maybe, but it still seems like an impossibly precise fraction of the overall time scale: 2/4500.

I suspect that's because you're viewing it as an interpolation from now, as opposed to from the beginning. Like if I said "you started developing your own antibodies when you were two months old" as opposed to "when you were a fraction of a percent of your current age".

johnnydeep wrote: ↑Sun Mar 12, 2023 2:54 pm

Chris Peterson wrote: ↑Sun Mar 12, 2023 2:49 pm

johnnydeep wrote: ↑Sun Mar 12, 2023 2:36 pm

How can they state with any certainty a time frame of a mere 2 Myr after the Solar System formed? That happened 4.5 Byr ago!

Models of planetary system formation, I imagine. But I haven't read the papers yet. There's a stack of them.

Maybe, but it still seems like an impossibly precise fraction of the overall time scale: 2/4500.

Chris Peterson wrote: ↑Sun Mar 12, 2023 2:49 pm

johnnydeep wrote: ↑Sun Mar 12, 2023 2:36 pm

Chris Peterson wrote: ↑Sun Mar 12, 2023 4:55 am

The first papers are coming out regarding the analysis of the material returned by the Hayabusa2 spacecraft from Ryugu. The probe collected 5g of particles. From that tiny sample, this is what they've figured so far: (ref: https://www.science.org/doi/10.1126/science.adh2109)

How can they state with any certainty a time frame of a mere 2 Myr after the Solar System formed? That happened 4.5 Byr ago!

Models of planetary system formation, I imagine. But I haven't read the papers yet. There's a stack of them.

johnnydeep wrote: ↑Sun Mar 12, 2023 2:36 pm

Chris Peterson wrote: ↑Sun Mar 12, 2023 4:55 am

orin stepanek wrote: ↑Sat Mar 11, 2023 9:13 pm A piece of Bennu coming for study! I hope we learn a lot from this asteroid!

The first papers are coming out regarding the analysis of the material returned by the Hayabusa2 spacecraft from Ryugu. The probe collected 5g of particles. From that tiny sample, this is what they've figured so far: (ref: https://www.science.org/doi/10.1126/science.adh2109)

Together, these studies constrain the history of the Ryugu material. Some of the organic molecules formed in the interstellar medium, so they predate the Solar System. About 2 million years (Myr) after the Solar System began to form, some material in its outer region collapsed under gravity to form a planetesimal, known as Ryugu’s parent body. About 3 Myr later, the decay of radioactive elements raised its internal temperature high enough to melt frozen water. The water reacted with the rock for a few million years, until the temperature fell again. Those aqueous alteration reactions modified the mineralogy and formed additional organic molecules. After about a billion years, an impact on the parent body ejected material into space; some of that rubble reaccumulated under gravity to form Ryugu. About 5 Myr ago, gravitational perturbations caused Ryugu to migrate into its current near-Earth orbit. A lot can be learned from just a few grams.

How can they state with any certainty a time frame of a mere 2 Myr after the Solar System formed? That happened 4.5 Byr ago!

Chris Peterson wrote: ↑Sun Mar 12, 2023 4:55 am

orin stepanek wrote: ↑Sat Mar 11, 2023 9:13 pm A piece of Bennu coming for study! I hope we learn a lot from this asteroid!

The first papers are coming out regarding the analysis of the material returned by the Hayabusa2 spacecraft from Ryugu. The probe collected 5g of particles. From that tiny sample, this is what they've figured so far: (ref: https://www.science.org/doi/10.1126/science.adh2109)

Together, these studies constrain the history of the Ryugu material. Some of the organic molecules formed in the interstellar medium, so they predate the Solar System. About 2 million years (Myr) after the Solar System began to form, some material in its outer region collapsed under gravity to form a planetesimal, known as Ryugu’s parent body. About 3 Myr later, the decay of radioactive elements raised its internal temperature high enough to melt frozen water. The water reacted with the rock for a few million years, until the temperature fell again. Those aqueous alteration reactions modified the mineralogy and formed additional organic molecules. After about a billion years, an impact on the parent body ejected material into space; some of that rubble reaccumulated under gravity to form Ryugu. About 5 Myr ago, gravitational perturbations caused Ryugu to migrate into its current near-Earth orbit. A lot can be learned from just a few grams.

orin stepanek wrote: ↑Sat Mar 11, 2023 9:13 pm A piece of Bennu coming for study! I hope we learn a lot from this asteroid!

Together, these studies constrain the history of the Ryugu material. Some of the organic molecules formed in the interstellar medium, so they predate the Solar System. About 2 million years (Myr) after the Solar System began to form, some material in its outer region collapsed under gravity to form a planetesimal, known as Ryugu’s parent body. About 3 Myr later, the decay of radioactive elements raised its internal temperature high enough to melt frozen water. The water reacted with the rock for a few million years, until the temperature fell again. Those aqueous alteration reactions modified the mineralogy and formed additional organic molecules. After about a billion years, an impact on the parent body ejected material into space; some of that rubble reaccumulated under gravity to form Ryugu. About 5 Myr ago, gravitational perturbations caused Ryugu to migrate into its current near-Earth orbit. A lot can be learned from just a few grams.

DonB312 wrote: ↑Sat Mar 11, 2023 8:44 pm

Chris Peterson wrote: ↑Sat Mar 11, 2023 4:12 pm De-anaglyphed version for those without glasses or who simply prefer this viewing method. Configured for cross-eyed viewing.

Thank you, Chris!

I really appreciate you providing these. Whenever an APOD is an anaglyph image, the first think I look for in the discussion is your version for crossed eyes (and/or wide eyes).

Chris Peterson wrote: ↑Sat Mar 11, 2023 4:12 pm De-anaglyphed version for those without glasses or who simply prefer this viewing method. Configured for cross-eyed viewing.

Chris Peterson wrote: ↑Sat Mar 11, 2023 4:12 pm De-anaglyphed version for those without glasses or who simply prefer this viewing method. Configured for cross-eyed viewing.
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de-anaglyph Bennu.jpg