Hurricane on Saturn

http://www.nasa.gov/mission_pages/cassini/multimedia/pia14944.html

by karolisd • 13 years ago

256 51 13 years ago

I've linked the official NASA news release below as the explanation in this link didn't suffice for my interest in this!

http://www.nasa.gov/home/hqnews/2013/apr/HQ_13-121_Saturn_Hu...

netcraft• 13 years ago

Another link with a video: http://www.nasa.gov/mission_pages/cassini/whycassini/cassini...

btilly10• 13 years ago

A random note for those who might wonder what "N" and "S" mean on another planet.

Take your right hand out. Stick your thumb up. Curl your fingers around. Your thumb represents a planet's N pole, and your fingers point in the direction that the planet is spinning. (The Earth moves from W to E, and the result is that it looks like the Sun rises in the E. Sit down a globe and a flashlight if this comment makes no sense.)

For any spinning thing we can do the same exercise. Just wrap your fingers of your right hand around in the direction of the spin, stick your thumb up, and that is the North pole of that spin.

Now for the fun fact. Most of the stuff in the Solar System rotates roughly the same way. It doesn't matter whether you take the rotation of the Earth, the rotation of the Moon, the orbit of the Moon around the Earth, the orbit of the Earth around the Sun, the orbit of Saturn around the Sun, the rotation of Saturn, the orbits of Saturn's moons around Saturn - the north poles of all of these are reasonably well aligned.

They are not exactly aligned. For instance the Earth's rotational axis is tilted 23.5 degrees from the axis of its orbit around the Sun. (Hence our seasons.) And not everything follows the rule. Uranus is the best-known exception. But most of it lines up fairly well.

The only actual use that I've ever found for this fact is being able to explain to my son why the Moon rises later every night, but I've always thought that it was pretty cool.

EDIT: glurgh below corrected my understanding. It happens that for most of the planets, North corresponds to the right hand rule as I described. But that's not actually the way it is defined and Venus in particular does not work that way.

cefarix• 13 years ago

Good ol' cross-product and angular momentum!

btilly10• 13 years ago

Exactly. The right hand rule.

And it isn't coincidence that stuff tends to spin the same way. Because when you don't then tidal forces try to pull you back into alignment. Of course, being basically frictionless tops, the main effect is that the rotation precesses. (The Earth's rotation takes about 26,000 years to precess.) However there is a tiny tidal friction component that slowly tends to bring things into alignment, and which is trying to lock all spins to each other.

And the operative word here is "slowly". If the Moon had been thrown off, spinning the opposite way from the Earth, it would have remerged. Instead the Earth's rotation is being transferred into throwing the Moon into a higher orbit at about 4 cm/year. (For comparison, this is a bit under twice the rate that the North American Plate is moving.)

The main consequence here on Earth is that the UTC system that we all use is going to have to add leap seconds more and more often over time, and in a few thousand years either we'll need to reconsider either the length of the second, or our tying the measurement of time to astronomy. (My vote would be to remove the astronomical definition. Humans seem to be OK living with time zones that do not match the sky. Having to move those time zones every few centuries does not seem like that big a deal. There won't be an observable issue in a normal human lifespan from this until after longer than human civilization has existed so far.

Astronomers are in charge of UTC right now, and they would hate the change. But when you consider how much it would cost astronomy to cope compared with the real costs of software bugs that tend show up when they insert leap seconds in UTC, right now the tail is very much wagging the dog.

not_that_noob• 13 years ago

To add to your fun fact: the reason that most of the planets spin in the same direction is that the solar system formed from a single giant rotating disc of rocks and debris.

I have found that to be endlessly fascinating - that the reason the planets dance together in harmony is because of their common and violent birthing process.

btilly10• 13 years ago

And the stuff that happened to randomly go against the flow generally gets pulled into lockstep with the rest by tidal forces.

But not entirely - the amount of axial tilt turns out to be a chaotic system. About 20 years ago I ran across an estimate that if the Earth did not have the Moon, then every so often we would randomly wind up with a sufficient tilt to be extremely difficult for life. Therefore our Moon may have been critical for sustaining life as we know it.

See http://www.nytimes.com/1993/03/02/science/moon-may-save-eart... for confirmation of that tidbit.

pasbesoin• 13 years ago

https://en.wikipedia.org/wiki/Right_hand_rule#Direction_asso...

P.S. See you've now mentioned it in your response to another comment. That and this comment apparently passed in space without aggregating (into a combined rotation).

glurgh7• 13 years ago

This is only for minor bodies, not planets. The poles of planets are pretty much defined to be 'pointed the same way as the Earth's'. The north pole of Venus is roughly aligned with the north pole of the Earth despite the fact that Venus's rotation is retrograde.

See

http://en.wikipedia.org/wiki/Poles_of_astronomical_bodies

btilly10• 13 years ago

Thank you for the correction.

I tend to pick up fun trivia, but I'm not an expert, and always appreciate when someone corrects mistakes in my understanding.

SatvikBeri• 13 years ago

I never understood the right-hand rule in college, but somehow your explanation made perfect sense to me. Thank you.

dmix• 13 years ago

Shame it's not a wide angle shot. Would have made a beautiful desktop background.

Freaky• 13 years ago

Wider shot, sadly sans colour, but plus another awesome weather phenomenon: http://apod.nasa.gov/apod/ap130220.html

btipling• 13 years ago

Not discounting how amazing that picture is, but it is false color.

wmeredith• 13 years ago

It is a bit silly. "This thing we found resembles a rose, because after we found it, we colored it like a rose." WTF?

It's an amazing image to be sure, but why all that nonsense?

btilly10• 13 years ago

It is false color because it has to be.

If you're sending a camera from here to another planet, it makes no sense to send a camera that takes pictures in the same wavelengths that we see so you can claim true color. Instead you pick wavelengths that for whatever scientific reasons you think will be most informative.

And then once you have that information, for humans to understand it, it makes no sense to leave it as raw binary data. Instead you map some of the wavelengths that you've got onto wavelengths that our eyes can see, and trained human eyes can identify and understand features very quickly. But at that point you've got a false color picture.

ianstallings• 13 years ago

A big part of science is the dog and pony show to bring in even more funding down the road. Throw in the public funding of NASA and you see the need to publish these fantastic images - to justify a budget. And it works.

raverbashing• 13 years ago

Makes me wonder how distant planets can have such extreme meteorological phenomena while being so far from the sun.

In Earth this is powered mainly by the temperature differences caused by the Sun.

dsirijus• 13 years ago

Fastest recorded winds (to my knowledge) are on Neptune. The lack of energy actually perpetuates them by not stopping them, in essence.

jerf• 13 years ago

Why do you assume other planets don't have temperature differences powered by the Sun?

glurgh7• 13 years ago

Saturn is about ten times larger than the Earth in diameter while spinning more than two times faster. Additionally, Saturn is 'self-luminous', it generates more energy than it receives from the Sun.

"Saturn has a very hot interior, reaching 11,700 °C at the core, and the planet radiates 2.5 times more energy into space than it receives from the Sun. Most of this extra energy is generated by the Kelvin–Helmholtz mechanism of slow gravitational compression, but this alone may not be sufficient to explain Saturn's heat production. An additional mechanism may be at play whereby Saturn generates some of its heat through the "raining out" of droplets of helium deep in its interior" [Wikipedia]

nostromo• 13 years ago

Non-false color image: http://www.nasa.gov/mission_pages/cassini/multimedia/pia1494...

krschultz• 13 years ago

Good post. The false color images make me fear that actual space will be disappointing for people to look at.

habosa• 13 years ago

For some reason this small comment made me very sad. I'd hate to imagine that our human desire for sensationalism could make the sight of outer space bland to a desensitized public. I have the APOD set as my phone's background every morning and I am always astounded at the incredible array of colors and the degree of contrast. I never really thought that I was being fooled.

It sucks that I really do think the non-false color image is boring, because that should be really exciting to someone who enjoys thinking about the universe like I do. Although I still think my mind would fucking explode if I ever got to go deep into space.

alex_doom• 13 years ago

It's only because our eyes are not as evolved to see more of the color spectrum. Hurry up evolution!

prg318• 13 years ago

The Black Metal band "Fell Voices" [1] is using the uncolored image in OP as the album art for their next record "regnum saturni" [2]. Beautiful picture with or without color!

[1] http://fellvoices.blogspot.com/

[2] http://fellvoices.blogspot.com/2013/03/regnum-saturni-europe...

atgm2• 13 years ago

I was disappointed when I realized that the image of Africa in the background wasn't for scale.

DanBC• 13 years ago

A good point. Here's a website that lets you draw circles on maps.

(http://obeattie.github.io/gmaps-radius/)

atgm2• 13 years ago

Thanks!

Strange -- the storm is both larger and smaller than I would have expected.

kingkawn• 13 years ago

Reminds me of: http://www.surenmanvelyan.com/eyes/your-beautiful-eyes/?wppa...

barbs• 13 years ago

Anyone found a good high-quality version of 'the rose' suitable for use as a desktop background? The one they have on the site appears to be too small.

sidcool• 13 years ago

This is scary. That size of a storm can wipe out a big part of the country.

Hurricane on Saturn

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