Preliminary analysis of the Hayabusa2 samples returned from asteroid Ryugu | Hacker News Reader

Preliminary analysis of the Hayabusa2 samples returned from asteroid Ryugu

nature.com

139 pointsrobin_reala24 comments

I think the phrase "on-asteroid measurements" can already lay claim to the title "concise understatement of the year".

Seriously. Humans managed to send a robot to a rock hurtling through the universe, and then took pieces back to look at. And it feels so normal! This is awesome stuff.

As someone keyed into this stuff, it doesn’t feel so normal to me. Feels pretty momentous!

Oh, momentous for sure! I guess I meant that it's not surprising that we were able to do it successfully. "What, like it's hard?" vibes. :)

> A total of 5.424 ± 0.217 g was collected from Ryugu

That precision tho

Just reading up on Hayabusa and Hayabusa2, and the NASA's OSIRIS-REx. They all targeted large (~1km) Apollo group asteroids (Itokawa, Ryugu, Bennu respectively).

The asteroid that has had the highest probability of collision with Earth (1950 DA) was also an ~1km Apollo group asteroid, and Apollo asteroids are the source of almost all of the known Potentially Hazardous Objects for Earth.

The stated objectives for these missions is basic science, such as understanding the proto-planetary conditions of our solar system. That makes sense and also near-Earth asteroids are practical targets for missions!

But it seems likely to me that someone is also building profiles for interception, should we need it. So it's curious that hazard profiling isn't mentioned in the objectives for these missions (not that I can find.. correction appreciated!) That makes me wonder if there's something else out there not being talked about. And Osiris Rex would be King God of the Dead... shrug, nothing to see here ;)

We'd better figure out Apophis in the next 100 years...

And hope the current data is correct!

I happened upon Brian Cox's video earlier today where he relates the film "Don't Look Up" to real world concerns, [0] and he mentions the DART mission [1] is a test-run for deflecting an asteroid, the press release reads, "DART [...] will impact a known asteroid that is not a threat to Earth. Its goal is to slightly change the asteroid’s motion in a way that can be accurately measured using ground-based telescopes."

I suppose landing on comets/asteroids was the first step, now we can actually try moving them! (this first attempt is 160 meter diameter, I'm sure the result will be valuable to adjusting our simulations for larger hazards.)

My favorite part of the Brian Cox video is he mentions that the same tech for asteroid defense will be used for asteroid mining, maybe there is a profit motive to spur investment after all. Still, a botched asteroid capture could play out like the movie, we can only hope we have the chance to start small :)

[0] https://www.youtube.com/watch?v=ntaidEKs_Ks

[1] https://www.nasa.gov/press-release/nasa-spacex-launch-dart-f...

A key goal of these missions has been to understand the composition and structure of asteroids, which happens to also be pretty important for how they might be defended against.

If they're a loosely bound pile of dust, then it might be better to dig in and blow them apart into smaller pieces to mostly burn up, but if they're more solid, redirection would probably be the only viable solution.

I’d say lets nuke one, for science.

We probably would if it weren't for the test ban treaties.

I found the bit about whether the samples may have been altered in final transit interesting as well as the artificial crater created by landing—the rest, per my layman eye, is effectively reporting means, nothing interesting yet…

I find it extremely interesting that all remote sensing analysis was confirmed by onsite analysis. That means we can trust our remote sensing capabilities.

Tl;dr?

In scientific papers the bit headed Abstract is basically the tl;dr, you can skip the rest.

In typical papers, what the abstract says contradicts what the graphs say, and what the conclusion says; and the graphs contradict the conclusion.

Papers where they all match are exceptional and precious. But we cannot trust that just any paper is among them, even those published in Nature.

As far as I can tell: (1) Yes indeed, the composition of the samples was not degraded when they were collected and returned to earth. (2) The samples indicate that Ryugu is similar to Cl chondrites (break up easily when entering earth, therefore only small fragments collected on earth; rich in volatile elements, representative of the chemical composition of our solar system) BUT Ryugu is less reflective, more porous and more fragile even than Cl chondrites.

Therefore (in my non-expert opinion): well worth the effort to collect and study because we will never find anything similar from a Meteor so these samples will give us much more evidence about the solar system's chemical composition.

Picture is here (from last year): https://www.nature.com/articles/s41550-021-01585-9

Looks a little like coffee grounds in a grinder, only if you ground charcoal.

It's fascinating that the death of a star can bring life. Basically when a star dies there will be a lot of carbon, oxygen and hydrogen - the building blocks for life, and there are a lot of dead star remains floating around in space. It's almost like if the whole big bang process was made in order to create life.

Maybe life is just an efficient way to increase entropy and thus it will arise wherever the requisite conditions are available.

If you look at a result, then at the conditions that lead to it, you could always say that it’s almost as though those conditions were intended to lead to that result. It’s somewhat tautological.

And it takes several cycles of life and death for a planetary cloud to build up the heavier metals. I've only had my requisite college chemistry, but it has always seemed peculiar/lucky/surprising to me that every element on the periodic table occurs on Earth (save for those unstable lab-made concoctions). It's unclear to me how common this condition is in the universe, but of course in an infinite universe everything is inevitable :)

Yeh I've thought about that also that the earth has so many elements, while the Hayabusa2 asteroid is mostly carbon star-dust. However besides oxygen we are made mostly of carbon. And for example the amount of gold on earth is likely the same rate all across the universe give or take (it's not super common).

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