Electric Clouds This Summer | Hacker News Reader

Electric Clouds This Summer

nautil.us

46 pointsyimby13 comments

The article mentions both rockets and volcanoes as causes of the increase, but carefully elides any mention of the exact numbers each contributes. I couldn’t easily find any concrete numbers on how much water vapor is involved in a typical rocket launch, but the 2022 Tonga underwater volcano eruption contributed an estimated 150 million tons of water vapor to the atmosphere, which is well beyond the scale of rocket launch contributions. So it’s almost all volcanic and only trivially aeronautic.

According to a random website[1] a Falcon 9 launch uses about 312 tons of liquid oxygen. Assuming that all gets converted into water that’s about 350 tons of water. Wikipedia[2] says there were 223 orbital rocket launch attempts in 2023. Almost half of those were Falcon 9, and if we assume for simplicity that the rest average out to around the same amount of water per launch that would give about 78 thousand tons total.

So about three orders of magnitude less than the one eruption.

[1] https://spaceimpulse.com/2023/06/13/how-much-does-rocket-fue...

[2] https://en.wikipedia.org/wiki/2023_in_spaceflight

Falcon 9 rockets burn RP-1, a hydrocarbon fuel, so the oxygen is being converted to CO2, and CO as well as H2O. [1]

Beyond that, I don't think the direct comparison of mass is definitive. Much of the rocket's fuel is expended at lower altitudes, and much of a volcano's ejecta return quickly to earth as ash or rain. It would be important to understand what percentage of a volcano's ejecta reaches the height of these clouds as well as what percentage of a rocket's exhaust is produced at that height.

Just to throw in some round figures:

noctilucent clouds are formed between 80 and 85 km altitude [2]

large volcanic eruption plumes top out somewhere between 31 and 45 km [3]

Falcon 9 launches stage at 80 km [4], meaning 23% of their propellant mass [5] is converted to exhaust at that altitude or higher.

So while I'm no expert on noctilucent cloud formation and happy to be given more info, the prima facia case seems to favor rocket launches seeding noctilucent clouds much more readily than volcanic eruptions.

[1] https://en.wikipedia.org/wiki/RP-1#Comparison_with_other_fue... [2] https://www.albany.edu/faculty/rgk/atm101/nlc.htm , though other sources give a wider range of 76-85 km. [3] https://volcano.oregonstate.edu/faq/how-high-can-explosive-e... [4] https://www.nasa.gov/wp-content/uploads/2018/07/spacex_nasa_... [5] https://en.wikipedia.org/wiki/Falcon_9#Design

NASA had a mission called AIM (Aeronomy of Ice in the Mesosphere) that observed noctilucent clouds, but it looks like the satellite stopped sending data in March of last year?

https://aim.hamptonu.edu/

I have more questions than answers after reading this.

"They’re lit by a twilight sun catching on ice crystals and seeded by rocket exhaust and space dust." and

"Exhaust from rockets, which have been launching in growing numbers lately, can also seed the clouds, as the AIM satellite research showed."

...are a pretty startling notion.

Should we expect, then, that this phenomena will be constant / worsening moving forward as the proliferation of rocket launches increases thereby pumping more water / alumina / particulates into the very upper atmosphere?

I'm not an alarmist normally, but taken further, then is it too hyperbolic to say that SpaceX and its high-frequency launch competitors are already changing the global weather within just a few years of ramping up operations?

Can we say with certainty that the occurrence of these clouds is not an harbinger / indicator of future weather changes? Like, does having more ultra-high altitude clouds increase or decrease greenhouse effects, for example?

If memory serves water vapor in the mesosphere is broken down by UV fairly readily and migrates into the thermosphere. I think the stratosphere would be in dire shape by the time the mesosphere had any real effect and would be the least of our worries. But I am going off of old memories from school days and am far from an expert.

I have a feeling it's a drop in the bucket and airplanes and cars have far greater impact on anything climate related.

I might have thought that too, however the article specifically called out rockets as a cause. So, if rockets are contributing a significantly more particulates such that it causes a phenomenon of more cloud cover at lower latitudes, is that a cause for concern? I don't know either way -- I was asking what we might think it meant.

I didn't get the impression that rockets were a significant cause. For example, they mention a volcano eruption which would dwarf rocket launches.

Why is this considered "worsening"? Seems like a harmless phenomenon (even though it does indicate climate change's progression) that actually looks quite beautiful!

I meant worsening from the perspective of becoming more and more over time, not necessarily making things "worse". a bad turn of phrase on my part.

If there is a constant cloud cover that only becomes thicker / more constant over time at very high altitude I wonder if there will be detrimental effects. That was my question. What does it mean if these clouds are constant?

Ooh, gorgeous photos and a reasonably scientific description of the phenomenon. Recommended!

Yeah, there seems to be a lot of noctilucent clouds this year.

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