1st Post: Severe Weather on Other Planets

[Saul Trabal]

Hi!

I've lurked on this board for a couple of weeks now, extremely fascinated by the chase reports, and various discussions on severe weather. I'm not a chaser, though. I'm just a person who's had a long-standing interest with extreme weather. When I was a little boy, I wanted to be a meteorologist, and I read up on all sorts of books. Violent weather, in particular, fascinated me.

I'm a writer, and am working on trying to get some stories published. Severe weather is still something that fascinates me. I have a couple of tornado videos. I also saw the movie TWISTER, which was laughable uke: The ONLY tornado in that film that looked somewhat authentic was that F5.

One subject that has been catching my interest more and more is severe weather on other planets. Let's start with Jupiter-the largest planet in our solar system.

Jupiter's thunderstorms are perhaps the most violent thunderstorms in the solar system. They can reach 50 miles in height, and can grow to 2,500 miles wide. Lightning in these storms is 1,000 times more powerful than Earth's. It's too bad our technology wasn't advanced enough to create a probe with a camera that could be dropped in an area where these massive storms could be viewed from afar.

The rain from these ferocious storms evaporates as it gets into the hotter depths, and is circulated back into the atmosphere, creating a continuous cycle. A lot of convection has been detected at the poles as well.

Saturn, the second largest planet in the solar system, has winds that top out at 1,000 miles an hour. Given its distance from the sun, my guess is that these supersonic winds are created by the vast temperature differences on the planet. I'm also wondering if these temperature differences create thunderstorms that are even more violent than Jupiter's. Huge explosions of white clouds along the gas giant's equator have been seen from earth-bound telescopes, and I'm wondering if these are massive thunderstorm complexes. The Cassini probe should hopefully answer these questions.

The stormiest planet without a doubt is Neptune. It's the windiest planet in the solar system, with winds reaching 1,250 mph. However, a few years back, there was a huge dark spot in Neptune's atmosphere that resembled Jupiter's Great Red Spot. The Voyager probes found that the winds in this spot reached 1,500 miles an hour!! :shock: That's almost TWICE the speed of sound!! :shock:

Lightning exists on Jupiter, Saturn, Uranus and Neptune. Lightning has only been photographed at Jupiter by the Galileo spacecraft. Cassini will try and photograph Saturn's night side to see if it spots lightning flashes in the clouds, like at Jupiter.

Anyway, enough of my rambling. I won't be posting here too much, but I will drop by often to see what's being talked about in the world of weather. I'm here to learn stuff.

Take care.

Saul Trabal

 

[Tim Vasquez]

I think one aspect of chasing on other planets would be whether you're after the visual motion or the destructive force. While the visual motion would be directly proportional to the velocity, the destructive force of the winds is a function of density. So a 2500 mph wind at 5 mb would probably feel like a refreshing breeze.

The formula (I believe) is:
pressure = 0.5 * density * velocity^2

The only question is what the corresponding densities are for all those velocities.

Tim

 

[Saul Trabal]

I think one aspect of chasing on other planets would be whether you're after the visual motion or the destructive force. While the visual motion would be directly proportional to the velocity, the destructive force of the winds is a function of density. So a 2500 mph wind at 5 mb would probably feel like a refreshing breeze.

The formula (I believe) is:
pressure = 0.5 * density * velocity^2

The only question is what the corresponding densities are for all those velocities.

Tim

Mars has winds that reach 300 mph, but its surface pressure is only 7 millibars. Temperatures range from 0 to -200 degrees Fahrenheit.

Another interesting thing that I've never seen discussed is tornadoes on other planets. With gas giants, there is no surface-unless you talk about the scalding ocean of liquid hydrogen below the clouds-and I'm not sure a funnel could reach that far down. I could be wrong. We don't know how far down Jupiter's Great Red Spot goes. As far as we know, the GRS is an anti-cyclonic hurricane, with winds reaching 300 mph.

I'd image that the thunderstorms on Jupiter, Saturn, and perhaps Uranus and Neptune, create tornadoes that are FAR more destructive than anything seen on Earth.

:shock:

 

[Zach Bailey]

I think one aspect of chasing on other planets would be whether you're after the visual motion or the destructive force. While the visual motion would be directly proportional to the velocity, the destructive force of the winds is a function of density. So a 2500 mph wind at 5 mb would probably feel like a refreshing breeze.

The formula (I believe) is:
pressure = 0.5 * density * velocity^2

The only question is what the corresponding densities are for all those velocities.

Tim

I believe you might have the order of your space wrong. Pressure is a two-dimensional quantity, measured in Pascals, or newtons per sqaure meter. I believe the formula is:

pressure (or drag) = .5 * A * V^2

where A = cross sectional area and V = velocity.

The forumla you gave would resolve to units of (kg*m^2)/(L*s^2), which AFAIK is something else besides pressure.

A little more info...

1 bar = 10 N/(cm^2) (100 kPa), and of course 1 bar = 1000 millibars.
And I'm sure you all know 1000 millibars is about 760mm of Hg, or around 29.92in of pressure for all you crazy non-SI folks.

so a pressure of 1000 millibars is the same force as having a 1kg book resting on a table of 1 square cm. (1kg*9.8m/s^2)/1cm^2.

 

[Tim Vasquez]

Thanks for the correction... I could never keep that stuff straight.

 

[Thomas Loades]

I know that Saturn and Neptune have had storm spots like Jupiter’s observed on numerous occasions, as well as cirrus clouds made of methane on Neptune (althought that’s not quite severe). Mars has dust devils, and some big hurricane-esque things whirling near its northern ice cap, and I also recall seeing time-lapse sequences of big, tornado-shaped whirlwinds springing off the Sun’s surface.

 

[B Ozanne]

Given it's size and air pressure I think earth has some of the most extreme weather in the solar system.

Jupiter's thunderstorms are perhaps the most violent thunderstorms in the solar system. They can reach 50 miles in height, and can grow to 2,500 miles wide.

Impressive but Jupiter is many, many times larger than Earth. If you scaled Earth to the size of Jupiter our storms are way more impressive. Everything being equal Earth's weather rules! I'm surprised the very smart people at NASA fail to recognize this when they balk at the meteorological extremes on other planets.

Not to mention on Earth I can walk around with shorts and a t-shirt quite comfortably (in the summer). On Jupiter I would have to negotiate metallic hydrogen, forget about wearing sandals.

 

[Saul Trabal]

Given it's size and air pressure I think earth has some of the most extreme weather in the solar system.

Jupiter's thunderstorms are perhaps the most violent thunderstorms in the solar system. They can reach 50 miles in height, and can grow to 2,500 miles wide.

Impressive but Jupiter is many, many times larger than Earth. If you scaled Earth to the size of Jupiter our storms are way more impressive. Everything being equal Earth's weather rules! I'm surprised the very smart people at NASA fail to recognize this when they balk at the meteorological extremes on other planets.

Not to mention on Earth I can walk around with shorts and a t-shirt quite comfortably (in the summer). On Jupiter I would have to negotiate metallic hydrogen, forget about wearing sandals.

Can you imagine flying through a massive canyon of Jovian thunderstorms that extends for hundreds, perhaps thousands of miles?! :shock: I wrote an SF piece that deals with storm chasing on Jupiter. I can't help but be annoyed at the fact that there are no probes that could dropped into Jupiter, which were equipped with cameras.

The BBC, I believe, put out a MOST excellent show caled PLANET STORM. It dealt with severe weather on other planets-and for Jupiter, they came up with some VERY impressive graphics that illustrated what a stormy planet it is. They also showed what it would be like to fly a plane by such ferocious thunderclouds. The plane was struck by lightning, and it went down into the maelstrom below!! :lol:

Nuts-if I could ONLY get this show on a DVD. I HIGHLY recommend it.

 

[Glen Romine]

Hmm..., Here is Tim's formula:

pressure = 0.5 * density * velocity^2

and here is Zach's:

pressure (or drag) = .5 * A * V^2


But, I'm afraid neither gives the correct units for pressure - recall 1 Pa = 1 kg/(m*s^2) = 1N/(m^2). Tim's eqn gives units of N (newtons), so it needs to be divided by area to get pressure, whereas Zach's formula gives units of m^4/(s^2), so instead divide by area (m^2) and multiply by density (kg/(m^3)) of the medium. There is also often a drag coefficient added into the mix, such as for Rayleigh's drag law, which represents the surface that the air flow is interacting with.

Glen

 

[Zach Bailey]

Hmm..., Here is Tim's formula:

pressure = 0.5 * density * velocity^2

and here is Zach's:

pressure (or drag) = .5 * A * V^2


But, I'm afraid neither gives the correct units for pressure - recall 1 Pa = 1 kg/(m*s^2) = 1N/(m^2). Tim's eqn gives units of N (newtons), so it needs to be divided by area to get pressure, whereas Zach's formula gives units of m^4/(s^2), so instead divide by area (m^2) and multiply by density (kg/(m^3)) of the medium. There is also often a drag coefficient added into the mix, such as for Rayleigh's drag law, which represents the surface that the air flow is interacting with.

Glen

D'oh! You're right, Glen. Knew I forgot something. Looks like we were both on the right track (we both knew a peice of the puzzle). So the final equation would look something like:

P = (Cd)*(rho)*A*V^2

where Cd = drag coeff., rho = density of the medium, A = cross sectional area, and V = velocity. Does that resolve to the correct units?

 

[Saul Trabal]

I know that Saturn and Neptune have had storm spots like Jupiter’s observed on numerous occasions, as well as cirrus clouds made of methane on Neptune (althought that’s not quite severe). Mars has dust devils, and some big hurricane-esque things whirling near its northern ice cap, and I also recall seeing time-lapse sequences of big, tornado-shaped whirlwinds springing off the Sun’s surface.

Sun tornadoes! I wonder how violent they are. :shock:

Neptune's lightning is something of a mystery. I read that the strength of its lightning is similar to Earth's. Still, I'd prefer to get more thorough information from a spacecraft orbiting the planet.

Hopefully, I'll learn the answer in my lifetime.

 

[Scott Freeman]

I can not remember the name of the show. I think it was "Extreme Storms. But that show was on discovery channel several years ago,, and it was something like trying to describe the storms on the planets,, Jupiter saturn, Mars,,and trying to equivalte them to earthen standars. It was interesting. Speculation,,,but interesting.

 

[Saul Trabal]

I can not remember the name of the show. I think it was "Extreme Storms. But that show was on discovery channel several years ago,, and it was something like trying to describe the storms on the planets,, Jupiter saturn, Mars,,and trying to equivalte them to earthen standars. It was interesting. Speculation,,,but interesting.

The show was PLANET STORM. While it was shown on the Discovery Channel, it was a British-made show.