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Maine's giant spinning ice disc looks like it's reforming

theguardian.com

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Re: Maine's giant spinning ice disc looks like it's reforming

#31

Post by riffraff »

jakeinspace wrote: post #30
k_sze wrote: post #26

Earlier quoted context omitted.

I assume that can be artificial. Just use a pump.

You can have a directed spray (maybe shot out of a giant fire hose at high pressure and flow), but without gravity, the liquid will disperse over a short distance. I don't see how that's avoidable because of entropy/diffusion. Gravity plus a container (river bed) create a perfect condition for the sorts of liquid flows we're accustomed to: a nearly identical acceleration on all particles, with a bounded displacement.

if you have a laminar flow, wouldn't some equivalent of surface tension keep it together?

Re: Maine's giant spinning ice disc looks like it's reforming

#32

Post by raverbashing »

k_sze wrote: post #22

I wonder if, in the absence of gravity (and thus no issue of buoyancy), a spherical ice ball would form in a stream of slow moving cold water...

I think it wouldn't, unless there was something making it (also) rotate in a different axis than the water flow

Re: Maine's giant spinning ice disc looks like it's reforming

#34

Post by codetrotter »

cgriswald wrote: post #15
stoops wrote: post #11

Earlier quoted context omitted.

Not that large

https://en.m.wikipedia.org/wiki/Saturn's_hexagon > Saturn's hexagon is a persisting hexagonal cloud pattern around the north pole of the planet Saturn, located at about 78°N.[1][2][3] The sides of the hexagon are about 14,500 km (9,000 mi) long,[4][5][6][7] which is more than the diameter of Earth[8] (about 12,700 km (7,900 mi).

Why do the two photos at the top of that article look so weird? They look like 3D renders almost. Is that what it actually looks like to the eye too, if one looked at Saturn from a spacecraft orbiting around it?

Re: Maine's giant spinning ice disc looks like it's reforming

#35

Post by danwills »

jayd16 wrote: post #33
k_sze wrote: post #22

I wonder if, in the absence of gravity (and thus no issue of buoyancy), a spherical ice ball would form in a stream of slow moving cold water...

Would it be akin to a river stone? Seems possible.

I'd say some similar long-term chipping dynamics would apply (between river-stone and certain types of icy-water flow) and sphere is then just one of many smooth shapes that you can get out of such a system.

Re: Maine's giant spinning ice disc looks like it's reforming

#36

Post by yorwba »

codetrotter wrote: post #34
cgriswald wrote: post #15

Earlier quoted context omitted.

https://en.m.wikipedia.org/wiki/Saturn's_hexagon > Saturn's hexagon is a persisting hexagonal cloud pattern around the north pole of the planet Saturn, located at about 78°N.[1][2][3] The sides of the hexagon are about 14,500 km (9,000 mi) long,[4][5][6][7] which is more than the diameter of Earth[8] (about 12,700 km (7,900 mi).

Why do the two photos at the top of that article look so weird? They look like 3D renders almost. Is that what it actually looks like to the eye too, if one looked at Saturn from a spacecraft orbiting around it?

They look like bad 3D renders because there are no walls and no sky in space, so all the light comes directly from the sun and shadows are absolutely black. The image looks different than with the naked eye though, because they filtered certain wavelengths. https://www.nasa.gov/jpl/cassini/pia18274

Re: Maine's giant spinning ice disc looks like it's reforming

#37

Post by mkl »

codetrotter wrote: post #34
cgriswald wrote: post #15

Earlier quoted context omitted.

https://en.m.wikipedia.org/wiki/Saturn's_hexagon > Saturn's hexagon is a persisting hexagonal cloud pattern around the north pole of the planet Saturn, located at about 78°N.[1][2][3] The sides of the hexagon are about 14,500 km (9,000 mi) long,[4][5][6][7] which is more than the diameter of Earth[8] (about 12,700 km (7,900 mi).

Why do the two photos at the top of that article look so weird? They look like 3D renders almost. Is that what it actually looks like to the eye too, if one looked at Saturn from a spacecraft orbiting around it?

Shadows in space are often very high contrast, as there's no ambient light. Simple 3D renderers don't handle ambient light either, as simulating it can be very computationally expensive (instead of e.g. one light source, pretty much everything in the scene acts as a light source with the light it reflects). These images in particular are also in near-infrared, so they may look a little different to colour images of Saturn you've seen.

Re: Maine's giant spinning ice disc looks like it's reforming

#39

Post by imron »

fctorial wrote: post #20
40four wrote: post #12

Earlier quoted context omitted.

I don’t know the earth is pretty big :) It is a near perfect circle, as are all the other planets & moons we observe. Maybe the rings of Saturn? Just kidding around really, but I have to imagine that pockets of circular water currents like this, are more common than we would think. We just can’t easily observe the dynamics of water flow until something like this happens, where a bunch of ice builds up and makes it ob…

Earth is a disk?

On the back of 4 elephants, then it's turtles all the way down.

Re: Maine's giant spinning ice disc looks like it's reforming

#40

Post by mkl »

ftvy wrote: post #4
dpflan wrote: post #2

An interesting phenomenon. Are we interested in it because it seems to be a rare and observable event that seems “magical”? Or is there a deeper search for meaning here?

I am certain that someone would have noticed this happening before. Maybe it is a symptom of climate change. Instead of ice being dammed up earlier in the river, it moves further down and freezes in the currents.

Ice circles are uncommon, but many people have noticed them before, going back a long time: https://en.wikipedia.org/wiki/Ice_circle

What's different about the modern day is that there are 1. way more people to look, 2. way more cameras to record, 3. the internet to disseminate any unusual thing widely.

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