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Question Enceladus

Nov 25, 2019
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If a probe were sent to land on Enceladus and it turned its back to the sun and pointed its camera towards a water vent, would we potentially see a rainbow?
If yes - would it have the same colour characteristics and curvature as those observed on earth?
 
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MMohammed

Assistant Community Manager
Staff member
Oct 10, 2019
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Sheesh, that's a great question. My guess is it would depend on the shape of the water droplets, perhaps?
 
Nov 25, 2019
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Sheesh, that's a great question. My guess is it would depend on the shape of the water droplets, perhaps?
yeah, thinking about it I don't really know enough about rainbows on earth to know where the differences might be.
I was wondering if there was a difference in the refractive index of the atmosphere... if that's a thing! Or even whether you need an atmosphere? If you took a water vapour aerosol can to the moon and did the same - would you get a rainbow?
Thanks for answering..
 
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Is this getting close:
"Another Saturn's moon, Enceladus, is a very active world with water ice plumes dashing through the cracks in its icy surface. Water ice crystals are not the same as water droplets, but combined with the sunlight they are known to produce a family of optical phenomena here on Earth called halos. "
 
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Nov 25, 2019
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Is this getting close:
"Another Saturn's moon, Enceladus, is a very active world with water ice plumes dashing through the cracks in its icy surface. Water ice crystals are not the same as water droplets, but combined with the sunlight they are known to produce a family of optical phenomena here on Earth called halos. "
Perfect.... many thanks for this!
 
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Dec 29, 2019
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A rainbow needs the water droplets to be liquid. I suspect (but do not know) the water turns to ice very quickly but perhaps can exist for a short time after ejection as liquid (droplets) and maybe a bit more time as supercooled liquid - maybe long enough to make a rainbow if viewed from the right place. But it is effectively vacuum there and droplets will be trying to boil - so perhaps won't stay clear enough for light to travel through and refract for more than a brief moment?
 
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" For a droplet freezing on PMMA, the freezing time (τf approximately 41 s) is much larger than the vapor diffusion time (τD approximately 0.1 s)."

And if you check:
Frost halos from supercooled water droplets
Stefan Jung, Manish K. Tiwari, and Dimos Poulikakos
you will find a pretty little droplet with a halo.

Frost halos from supercooled water droplets. - NCBI
www.ncbi.nlm.nih.gov › pubmed
by S Jung - ‎2012
where you will find these pictures:


by S Jung - ‎2012
 
Nov 25, 2019
46
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" For a droplet freezing on PMMA, the freezing time (τf approximately 41 s) is much larger than the vapor diffusion time (τD approximately 0.1 s)."

And if you check:
Frost halos from supercooled water droplets
Stefan Jung, Manish K. Tiwari, and Dimos Poulikakos
you will find a pretty little droplet with a halo.

Frost halos from supercooled water droplets. - NCBI
www.ncbi.nlm.nih.gov › pubmed
by S Jung - ‎2012
where you will find these pictures:


by S Jung - ‎2012
Perfect, thanks for the research Cat..
Andrew
 
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Dec 29, 2019
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" For a droplet freezing on PMMA, the freezing time (τf approximately 41 s) is much larger than the vapor diffusion time (τD approximately 0.1 s)."

And if you check:
Frost halos from supercooled water droplets
Stefan Jung, Manish K. Tiwari, and Dimos Poulikakos
you will find a pretty little droplet with a halo.

Frost halos from supercooled water droplets. - NCBI
www.ncbi.nlm.nih.gov › pubmed
by S Jung - ‎2012
where you will find these pictures:


by S Jung - ‎2012
Those are ice crystal halos that would inhibit light forming rainbows as they form - "a condensation halo around the droplet, which crystallizes and drastically affects the surface behavior".
 
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Just came across this:
https://www.atoptics.co.uk/halosim.htm

"Ice halo displays range from the familiar circle around the sun or moon to rare and prized events when the whole sky is webbed by intricate arcs.
Tiny ice crystals in the atmosphere create halos by refracting and reflecting light.
Halos bestow a delicate beauty to the skies and tell us about the crystals inhabiting the clouds.
Find out how halos are formed, when and where to see them in the skies.

Create your own halo displays by downloading the full colour simulator program, HaloSim."

I haven't tried it, but I thought the bottom line might interest you.
 
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Nov 25, 2019
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Just came across this:
https://www.atoptics.co.uk/halosim.htm

"Ice halo displays range from the familiar circle around the sun or moon to rare and prized events when the whole sky is webbed by intricate arcs.
Tiny ice crystals in the atmosphere create halos by refracting and reflecting light.
Halos bestow a delicate beauty to the skies and tell us about the crystals inhabiting the clouds.
Find out how halos are formed, when and where to see them in the skies.

Create your own halo displays by downloading the full colour simulator program, HaloSim."

I haven't tried it, but I thought the bottom line might interest you.
Thanks for this Cat, have tried it out and I must admit that I had some difficulties understanding the parameter values.
This is me and not the program! more study required(!) Thanks again
Andrew
 
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https://wonderdome.co.uk/space-rainbows/

QUOTE
Another Saturn’s moon, Enceladus, is a very active world with water ice plumes dashing through the cracks in its icy surface. Water ice crystals are not the same as water droplets, but combined with the sunlight they are known to produce a family of optical phenomena here on Earth called halos. Would anyone like to travel 7 years to check if there are beautiful icy rainbows on Enceladus?

How about Jupiter’s moon Europa? We sure do remember the recent NASA reports about the discovery of the water plumes on the Jovian moon? Maybe the upcoming NASA Europa Clipper mission will return some beautiful photographs of Europa’s rainbows and halos! We cannot wait!
QUOTE

Is this real??
 
Last edited:
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Nov 25, 2019
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https://wonderdome.co.uk/space-rainbows/

QUOTE
Another Saturn’s moon, Enceladus, is a very active world with water ice plumes dashing through the cracks in its icy surface. Water ice crystals are not the same as water droplets, but combined with the sunlight they are known to produce a family of optical phenomena here on Earth called halos. Would anyone like to travel 7 years to check if there are beautiful icy rainbows on Enceladus?

How about Jupiter’s moon Europa? We sure do remember the recent NASA reports about the discovery of the water plumes on the Jovian moon? Maybe the upcoming NASA Europa Clipper mission will return some beautiful photographs of Europa’s rainbows and halos! We cannot wait!
QUOTE

Is this real??
blimey, thanks cat - wonder whether they read my question!
 
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