NASA Astronomy Picture of the Day 2022-09-12: Red Sprites at 10% lightspeed

Historic planetary instability and catastrophe. Evidence for electrical scarring on planets and moons. Electrical events in today's solar system. Electric Earth.
Holger Isenberg
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NASA Astronomy Picture of the Day 2022-09-12: Red Sprites at 10% lightspeed

Unread post by Holger Isenberg » Thu Sep 15, 2022 8:12 pm

This statement is quite a nice surprise to read on a NASA website:
Research has shown that following a powerful positive cloud-to-ground lightning strike,
red sprites may start as 100-meter balls of ionized air that shoot down from about 80-km high
at 10 percent the speed of light.
https://apod.nasa.gov/apod/ap220912.html

The most interesting detail in that statement is the movements towards Earth. I have never heard about that direction regarding phenomena observed above clouds. Usually in articles about sprites, blue jets and related, it's about movement into space, which leads the reader to think about those observations as being results of lightning below and not considering the energy source above.

I did some calculations about that to estimate the energy needed for acceleration of one of those air spheres:
  • sphere radius: r=50m
  • air density at 80km: d=0.0000157005 kg/m^3 (near ground it is 1.225 kg/m^3)
  • speed: v=0.1c=299792000 m/s
  • sphere volume: V=4/3pi*r^3
  • sphere mass: m=V*d = 523598 m^3 * 0.0000157005 = 8.22 kg
  • energy for acceleration: E = 3.6938724981504E15 J = 1026 GWh
  • yearly electric energy consumption of Germany: 510 TWh
That means the energy needed to accelerate one of those ionized air spherules to 10% lightspeed is equivalent to 17.5 hours of electric energy consumption in Germany!

Difficult to imagine how hot air below clouds could cause this :)

jacmac
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Re: NASA Astronomy Picture of the Day 2022-09-12: Red Sprites at 10% lightspeed

Unread post by jacmac » Thu Sep 15, 2022 11:08 pm

It's simple really.....
The rising hot air creates a micro black hole under the clouds that causes gravity waves to suddenly drop down, leaving a transient gravity wave void above the clouds, which in turn sucks down the sprite. Any lightning strikes are additional effects of concentrating hot air molecules due to a high density of molecular collisions. This is sometimes referred to as the "land based tidal effect".
Jack

Holger Isenberg
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Re: NASA Astronomy Picture of the Day 2022-09-12: Red Sprites at 10% lightspeed

Unread post by Holger Isenberg » Thu Sep 15, 2022 11:29 pm

And I haven't even applied the relativistic equations. Just used the plain kinetic energy E = 1/2mv^2. Should I apply relativistic calculation? Maybe better not :)

I guess I found the source of the 10% lightspeed in
Electrical parameters of red sprites, MANOJ KUMAR PARAS and JAGDISH RAI, 2012:
https://citeseerx.ist.psu.edu/viewdoc/d ... 1&type=pdf
2. Velocity of red sprites
Stanley et al. (1999) adopted a high speed imaging technique and measured initial sprite velocities in excess of 10E7 m/s. McHarg et al. (2002) reported the velocity of propagation of downward and upward luminosity of the order of 10E7 - 10E8 m/s.
6. Results and discussions
Finally, we calculated the energy dissipated in the sprite body due to the quasi-electrostatic heating and runaway mechanism, which was of the order of 10E9 J, one order of magnitude less than the previously reported value of 10E10 J (Dowden et al., 1996).
That article only writes about the propagation of luminosity, not if actual matter or ions was moving. So the original quote about 100m plasma balls accelerating to 10% lightspeed is still missing.

The energy estimated there is with 1 to 10 GJ 100 to 1000 times less than needed for actual matter movements I calculated.

Holger Isenberg
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Re: NASA Astronomy Picture of the Day 2022-09-12: Red Sprites at 10% lightspeed

Unread post by Holger Isenberg » Thu Sep 15, 2022 11:31 pm

Same statement about 10% lightspeed of 100m ion spheres downwards motion was used on Feb 25, 2019:
https://science.nasa.gov/red-sprite-lig ... -kununurra refers to https://apod.nasa.gov/apod/ap190225.html

Holger Isenberg
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Re: NASA Astronomy Picture of the Day 2022-09-12: Red Sprites at 10% lightspeed

Unread post by Holger Isenberg » Thu Sep 15, 2022 11:52 pm

Found the original research. It only talks about propagation of ionization waves, not actual objects. But the interesting observation detail is the acceleration of the propagation. Why would a purely visual wave accelerate, i.e. start slow? That acceleration, i.e. some inertia preventing the immediate final velocity start, appears to be more a hint to moving matter.

High-Speed Observations of Sprite Streamers
H. C. Stenbaek-Nielsen, T. Kanmae, M. G. McHarg & R. Haaland
Surveys in Geophysics volume 34, pages 769–795 (2013)
Open Access, Published: 15 March 2013

https://link.springer.com/article/10.10 ... 013-9224-4
The observation that sprites start with a downward streamer was somewhat unexpected as models, for example Liu and Pasko (2004), predicted streamer formation with both a downward (positive) streamer propagating in the direction of the causal electric field, and simultaneously, an upward propagating (negative) streamer, so-called double-headed streamers.
Because of the rapid descent, the optical structure in the halo cannot represent features in the background atmosphere. We note that we have a number of other examples with significantly faster downward motion. While the main halo luminosity fades, the structure in the halo continues and eventually spawns a streamer which descends at 1.7 × 10E7 m/s. The streamer clearly forms after the main halo has faded, and it may be that the structure is actually the ionization wave proposed by Luque and Ebert (2009).
The velocity of sprite streamers is typically in the 10E6–10E8 m/s range (Stanley et al. 1999; Moudry et al. 2003; McHarg et al. 2002, 2007; Cummer et al. 2006). Upward streamers are generally slightly faster; the highest velocity we have observed is 1.4 × 10E8 m/s (almost half the velocity of light) (McHarg et al. 2002). As seen in Figs. 3, 5, and 6, the downward streamers accelerate after formation. Eventually, the streamers reach a maximum velocity after which they slow down and eventually fade at lower altitude. McHarg et al. (2007) find acceleration and deceleration values in the 10E5–10E10 m/s^2 range.
[edited: fixed the exp-numbers]
Last edited by Holger Isenberg on Fri Sep 16, 2022 12:10 am, edited 1 time in total.

Holger Isenberg
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Re: NASA Astronomy Picture of the Day 2022-09-12: Red Sprites at 10% lightspeed

Unread post by Holger Isenberg » Thu Sep 15, 2022 11:58 pm

Some earlier article from 2007 with the same 1/10 lightspeed, but only visual movement:

https://phys.org/news/2007-06-physicist ... rites.html
Study co-author David Sentman [...]

Sprites were predicted by Nobel laureate physicist C.T.R. Wilson in 1925. Their existence was confirmed in 1989 by University of Minnesota physicist John Winkler who caught them on videotape.

Sentman called them "sprites" shortly afterward and the name stuck.

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