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Comment by mjevans | Hacker News Reader

What if the origin of Osiris-Rex (Asteroid) is higher energy debris from a major impact to Earth during the early stages of organic life on the planet. Wasn't one theory (?) for our moon's creation such an impact and then a large mass splitting off to form the moon? I could easily imagine smaller bodies with higher local concentrations of energy being ejected from such an event.

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Rocks on Earth (and the Moon) are distinguished by being on a specific line on the oxygen isotope plot, the SMOW (Standard Mean Ocean Water) line. This may reflect a large, homogenizing event in the early history of the Earth (like a giant impact that formed the Moon).

The realization that meteorites come from multiple different parent bodies is that they are distributed widely, not all on one line on this plot. Bennu, like primitive meteorites, appears to be off the terrestrial line.

https://ntrs.nasa.gov/api/citations/20240000340/downloads/Fr...

From [0]:

> Bennu's basic mineralogy and chemical nature would have been established during the first 10 million years of the Solar System's formation [...]

> Bennu probably began in the inner asteroid belt as a fragment from a larger body with a diameter of 100 km. Simulations suggest a 70% chance it came from the Polana family and a 30% chance it derived from the Eulalia family. Impactors on boulders of Bennu indicate that Bennu has been in near Earth orbit (separated from the main asteroid belt) for 1–2.5 million years.

[0] https://en.wikipedia.org/wiki/101955_Bennu#Origin_and_evolut...

Perhaps it came from Earth when the Chuxhulub asteroid struck?

It's really too bad we weren't able to get a sample from the ['Oumuamua](https://en.wikipedia.org/wiki/%CA%BBOumuamua) asteroid when it flew through the system. It was definitely an extra-solar asteroid, so it would have had material completely unrelated to our own system's formation and history.

There will be more like that, but we need to get better at identifying them. Just like with exoplanets.

Not just identifying them, but also being able to catch them in time. They're coming in at solar escape velocities, and going out with same - and the odds of everything being aligned in such a way that we can take several years to do gravity assists are incredibly low.

I wonder if a one-way trip with an impactor would be useful. It would at least be easier than a roundtrip journey to and from solar escape velocity.

Also, it seems like the space base weapons treaty is being ignored now (https://spacenews.com/russia-vetoes-u-n-resolution-on-nuclea..., https://www.npr.org/2024/05/30/nx-s1-4975741/what-to-know-ru...). I wonder if there is an opportunity to do some science with space-based lasers and spectroscopy. The energy would be small, but then again we can learn a lot just from the off-gassing created by the sun’s photons as well.

Oh yeah, I don't think we're anywhere near "sample return" capability for an extra-solar object.

I doubt we're even near "impactor" capability, tbh. I think our best bet might be "catch up with something in the Oort somewhere around 2070, if we see something coming a decade ahead of time".

Never underestimate the ability of humans to throw something really hard ;)

I actually think if the object was on the right trajectory and we had enough time, that you could pretty much park an impactor in its path. You could probably do a lot of science based on the spectra of the resulting cloud.

I agree that gently landing and return a sample with that much delta V is out of our reach at this point. Maybe with enough shielding, you could park a second sample return vehicle in the path of debris.

> odds of everything being aligned in such a way that we can take several years to do gravity assists are incredibly low.

Project Lyra develops concepts for reaching interstellar objects such as 1I / 'Oumuamua and 2I / Borisov with a spacecraft, based on near-term technologies. [0]

Several technology options are outlined, ranging from a close solar Oberth Maneuver using chemical propulsion, and the more advanced options of solar and laser sails. [1]

0. https://i4is.org/what-we-do/technical/project-lyra/

1. https://arxiv.org/abs/1711.03155

It occurs to me since survivability isn't a problem for an unmanned probe, that a "cold" nuclear thermal engine vehicle could be used as a loitering interceptor: get it a solar orbit, and leave it till you see a target, then accelerate up to extra-solar escape velocity.

It solves the disposal problem neatly, since the probe and reactor are both leaving the solar system forever afterwards.

I don’t think there could have been life on Earth before the creation of the moon.

Why not? (I don’t know this field)

The Moon forming impact (4.5 Gyr) occurred ~100 million years after Earth's formation. The earliest solid grain comes from another ~100 million years after that (4.4 Gyr). The earliest signs of life (4.1 Gyr) are from ~300 million years after the earliest grain. Does not seem implausible that life could have arisen during the first 100 million years as well. We know very little about that era since the impact liquified the whole surface.

Wouldn’t the (pre Moon) Earth have been pretty hot after formation and probably no water either?

There's been some research from my alma mater that it might have had water even that early [1]. I haven't seen good data on the estimated temperature during this time (it was hot certainly, the question would be how frequently were there pockets where hyperthermophiles would be able survive). I like this paper's approach [2] - they end up with a small chance of life before the impact.

[1] https://archive.is/NZwpJ

[2] https://www.liebertpub.com/doi/pdf/10.1089/ast.2005.5.154

Ah ok, didn’t know the moon formed that quickly, thank you for your detailed answer, very interesting :)

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