APOD: Orion and the Ocean of Storms (2023 Dec 07)

[APOD Robot]

Orion and the Ocean of Storms

Explanation: On December 5, 2022, a camera on board the uncrewed Orion spacecraft captured this view as Orion approached its return powered flyby of the Moon. Beyond one of Orion's extended solar arrays lies dark, smooth, terrain along the western edge of the Oceanus Procellarum. Prominent on the lunar nearside Oceanus Procellarum, the Ocean of Storms, is the largest of the Moon's lava-flooded maria. The lunar terminator, shadow line between lunar night and day, runs along the left of this frame. The 41 kilometer diameter crater Marius is top center, with ray crater Kepler peeking in at the edge, just right of the solar array wing. Kepler's bright rays extend to the north and west, reaching the dark-floored Marius. On December 11, 2022 the Orion spacecraft reached its home world. The historic Artemis 1 mission ended with Orion's successful splashdown in planet Earth's water-flooded Pacific Ocean.

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[Mulk]

What is the "smoke" coming off the solar array? Damage?

[slim]

Whole area below looks a whiter shade of pale to me.

[Rauf]

What is the "smoke" coming off the solar array? Damage?

I think you're mistaking crater rays for smoke?

[johnnydeep]

What is the "smoke" coming off the solar array? Damage?

I think you're mistaking crater rays for smoke?

Neither smoke nor rays. I think Mulk was noticing the cable loops connecting the two solar panels:

[Rauf]

What is the "smoke" coming off the solar array? Damage?

I think you're mistaking crater rays for smoke?

Neither smoke nor rays. I think Mulk was noticing the cable loops connecting the two solar panels:


cable loops on orion solar panels.jpg

That doesn't look like smoke though!

[Chris Peterson]

I think you're mistaking crater rays for smoke?

Neither smoke nor rays. I think Mulk was noticing the cable loops connecting the two solar panels:


cable loops on orion solar panels.jpg

That doesn't look like smoke though!

Well, regardless of what feature in the picture is giving that impression, the one safe answer is "There is no smoke. Anywhere."

[Avalon]

Is there any way to gauge how long ago the Kepler crater was formed? Even a wild guess?

[Chris Peterson]

Is there any way to gauge how long ago the Kepler crater was formed? Even a wild guess?

There are estimates based on layering and overlying crater counts. Somewhere between 100 and 800 million years?

[Ann]

Is there any way to gauge how long ago the Kepler crater was formed? Even a wild guess?

There are estimates based on layering and overlying crater counts. Somewhere between 100 and 800 million years?

So maybe some dinosaurs looked up and thought, Wow, that's a bright impact on the Moon?

Credit: Teemu Öhman/Journal of Geophysical Research

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That's bright!

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Ann

[FLPhotoCatcher]

I know this comment is a little late, but... Could the unusual mountains opposite the orbiter near the lunar terminator be remnants of the original body that slammed into the earth, or even part of Earth's crust? Or did the original moon have to have been totally liquid rock?

[Chris Peterson]

I know this comment is a little late, but... Could the unusual mountains opposite the orbiter near the lunar terminator be remnants of the original body that slammed into the earth, or even part of Earth's crust? Or did the original moon have to have been totally liquid rock?

That collision left no original material larger than dust grains. The entire surface of the Moon is reformed.

[johnnydeep]

I know this comment is a little late, but... Could the unusual mountains opposite the orbiter near the lunar terminator be remnants of the original body that slammed into the earth, or even part of Earth's crust? Or did the original moon have to have been totally liquid rock?

That collision left no original material larger than dust grains. The entire surface of the Moon is reformed.

And I think it's still debated how much of the Moon's material is from the presumed impactor ("Theia") and how much is from the proto-Earth. Although this paragraph from Wikipedia seems to imply that none of Theia remained to become part of the moon? :

The standard giant-impact hypothesis suggests that a Mars-sized body, called Theia, impacted the proto-Earth, creating a large debris ring around Earth, which then accreted to form the Moon. This collision also resulted in the 23.5° tilted axis of the Earth, thus causing the seasons.[1][irrelevant citation] The Moon's oxygen isotopic ratios seem to be essentially identical to Earth's.[4] Oxygen isotopic ratios, which may be measured very precisely, yield a unique and distinct signature for each Solar System body.[5] If Theia had been a separate protoplanet, it probably would have had a different oxygen isotopic signature than proto-Earth, as would the ejected mixed material.[6] Also, the Moon's titanium isotope ratio (50Ti/47Ti) appears so close to the Earth's (within 4 parts per million) that little if any of the colliding body's mass could likely have been part of the Moon.[7]

[Chris Peterson]

I know this comment is a little late, but... Could the unusual mountains opposite the orbiter near the lunar terminator be remnants of the original body that slammed into the earth, or even part of Earth's crust? Or did the original moon have to have been totally liquid rock?

That collision left no original material larger than dust grains. The entire surface of the Moon is reformed.

And I think it's still debated how much of the Moon's material is from the presumed impactor ("Theia") and how much is from the proto-Earth. Although this paragraph from Wikipedia seems to imply that none of Theia remained to become part of the moon? :

The standard giant-impact hypothesis suggests that a Mars-sized body, called Theia, impacted the proto-Earth, creating a large debris ring around Earth, which then accreted to form the Moon. This collision also resulted in the 23.5° tilted axis of the Earth, thus causing the seasons.[1][irrelevant citation] The Moon's oxygen isotopic ratios seem to be essentially identical to Earth's.[4] Oxygen isotopic ratios, which may be measured very precisely, yield a unique and distinct signature for each Solar System body.[5] If Theia had been a separate protoplanet, it probably would have had a different oxygen isotopic signature than proto-Earth, as would the ejected mixed material.[6] Also, the Moon's titanium isotope ratio (50Ti/47Ti) appears so close to the Earth's (within 4 parts per million) that little if any of the colliding body's mass could likely have been part of the Moon.[7]

Yeah, I think the strong evidence that the Earth and Moon are made of nearly identical material must mean either that Theia wasn't incorporated, or was equally incorporated in both bodies. And simulations and other physical measurements argue against the latter.

[johnnydeep]

That collision left no original material larger than dust grains. The entire surface of the Moon is reformed.

And I think it's still debated how much of the Moon's material is from the presumed impactor ("Theia") and how much is from the proto-Earth. Although this paragraph from Wikipedia seems to imply that none of Theia remained to become part of the moon? :

The standard giant-impact hypothesis suggests that a Mars-sized body, called Theia, impacted the proto-Earth, creating a large debris ring around Earth, which then accreted to form the Moon. This collision also resulted in the 23.5° tilted axis of the Earth, thus causing the seasons.[1][irrelevant citation] The Moon's oxygen isotopic ratios seem to be essentially identical to Earth's.[4] Oxygen isotopic ratios, which may be measured very precisely, yield a unique and distinct signature for each Solar System body.[5] If Theia had been a separate protoplanet, it probably would have had a different oxygen isotopic signature than proto-Earth, as would the ejected mixed material.[6] Also, the Moon's titanium isotope ratio (50Ti/47Ti) appears so close to the Earth's (within 4 parts per million) that little if any of the colliding body's mass could likely have been part of the Moon.[7]

Yeah, I think the strong evidence that the Earth and Moon are made of nearly identical material must mean either that Theia wasn't incorporated, or was equally incorporated in both bodies. And simulations and other physical measurements argue against the latter.

So then what did happen to the stuff that made up Theia? Was it just ejected away from the Earth-Moon system? It would seem very unlikely that none of Theia was incorporated.

[Chris Peterson]

And I think it's still debated how much of the Moon's material is from the presumed impactor ("Theia") and how much is from the proto-Earth. Although this paragraph from Wikipedia seems to imply that none of Theia remained to become part of the moon? :

Yeah, I think the strong evidence that the Earth and Moon are made of nearly identical material must mean either that Theia wasn't incorporated, or was equally incorporated in both bodies. And simulations and other physical measurements argue against the latter.

So then what did happen to the stuff that made up Theia? Was it just ejected away from the Earth-Moon system? It would seem very unlikely that none of Theia was incorporated.

The simulations I've seen involve glancing blows where most of the colliding body (now melted) continues on its way. But there are lots of possible scenarios.

[johnnydeep]

Yeah, I think the strong evidence that the Earth and Moon are made of nearly identical material must mean either that Theia wasn't incorporated, or was equally incorporated in both bodies. And simulations and other physical measurements argue against the latter.

So then what did happen to the stuff that made up Theia? Was it just ejected away from the Earth-Moon system? It would seem very unlikely that none of Theia was incorporated.

The simulations I've seen involve glancing blows where most of the colliding body (now melted) continues on its way. But there are lots of possible scenarios.

Ok. I guess "the jury is still out" as the saying goes.

[alter-ego]

So then what did happen to the stuff that made up Theia? Was it just ejected away from the Earth-Moon system? It would seem very unlikely that none of Theia was incorporated.

The simulations I've seen involve glancing blows where most of the colliding body (now melted) continues on its way. But there are lots of possible scenarios.

Ok. I guess "the jury is still out" as the saying goes.

Sky & Tel: Bits of Theia Might Be in Earth's Mantle
LInked Nature article: Moon-forming impactor as a source of Earth’s basal mantle anomalies

[johnnydeep]

The simulations I've seen involve glancing blows where most of the colliding body (now melted) continues on its way. But there are lots of possible scenarios.

Ok. I guess "the jury is still out" as the saying goes.

Sky & Tel: Bits of Theia Might Be in Earth's Mantle
LInked Nature article: Moon-forming impactor as a source of Earth’s basal mantle anomalies

Interesting. The statement that the cores of proto-Earth and Theia likely merged would seem to rule out a "glancing blow". It's also not clear to me how much of Theia ended up in the moon. The graphic in the article shows the Moon as a color that appears to be a mix of the colors of the two mantles, but yet different from the color of the mantle of the post-impact Earth:

This diagram outlines the evolution of Earth's mantle. Theia hits Earth, the cores merge, and the Moon as a result of the impact. However, Theia's mantle is denser than Earth's so it doesn't mix in; instead it sinks over time, glomming together on either side of the core. - Qian Yuan / ASU

---

The simulations suggest that Theia might have been much larger than previously suspected, perhaps four times as massive as Mars, and denser too. The Apollo samples support the high density. Lunar rocks exhibit a relatively low ratio of heavy hydrogen (deuterium) to light hydrogen, from which the team calculates that Theia's mantle must have been between 2% and 3.5% denser than Earth in order to retain the light gas. This estimate is consistent with the high density required by their simulations.

[Chris Peterson]

Ok. I guess "the jury is still out" as the saying goes.

Sky & Tel: Bits of Theia Might Be in Earth's Mantle
LInked Nature article: Moon-forming impactor as a source of Earth’s basal mantle anomalies

Interesting. The statement that the cores of proto-Earth and Theia likely merged would seem to rule out a "glancing blow". It's also not clear to me how much of Theia ended up in the moon. The graphic in the article shows the Moon as a color that appears to be a mix of the colors of the two mantles, but yet different from the color of the mantle of the post-impact Earth:

This diagram outlines the evolution of Earth's mantle. Theia hits Earth, the cores merge, and the Moon as a result of the impact. However, Theia's mantle is denser than Earth's so it doesn't mix in; instead it sinks over time, glomming together on either side of the core. - Qian Yuan / ASU

---

The simulations suggest that Theia might have been much larger than previously suspected, perhaps four times as massive as Mars, and denser too. The Apollo samples support the high density. Lunar rocks exhibit a relatively low ratio of heavy hydrogen (deuterium) to light hydrogen, from which the team calculates that Theia's mantle must have been between 2% and 3.5% denser than Earth in order to retain the light gas. This estimate is consistent with the high density required by their simulations.

There are several very plausible simulations that start with very different situations and end up with what we currently observe. I don't think we're going to really be able to narrow things down until we have a lot more lunar samples.

[alter-ego]

Sky & Tel: Bits of Theia Might Be in Earth's Mantle
LInked Nature article: Moon-forming impactor as a source of Earth’s basal mantle anomalies

Interesting. The statement that the cores of proto-Earth and Theia likely merged would seem to rule out a "glancing blow". It's also not clear to me how much of Theia ended up in the moon. The graphic in the article shows the Moon as a color that appears to be a mix of the colors of the two mantles, but yet different from the color of the mantle of the post-impact Earth:

This diagram outlines the evolution of Earth's mantle. Theia hits Earth, the cores merge, and the Moon as a result of the impact. However, Theia's mantle is denser than Earth's so it doesn't mix in; instead it sinks over time, glomming together on either side of the core. - Qian Yuan / ASU

---

The simulations suggest that Theia might have been much larger than previously suspected, perhaps four times as massive as Mars, and denser too. The Apollo samples support the high density. Lunar rocks exhibit a relatively low ratio of heavy hydrogen (deuterium) to light hydrogen, from which the team calculates that Theia's mantle must have been between 2% and 3.5% denser than Earth in order to retain the light gas. This estimate is consistent with the high density required by their simulations.

There are several very plausible simulations that start with very different situations and end up with what we currently observe. I don't think we're going to really be able to narrow things down until we have a lot more lunar samples.

Certainly. Just food for thought.