What is the surface of Uranus like?

[Urge]

When reading about the gas-giants on wikipedia, I got the impression that Uranus is the friendliest one among them.

Even though the atmosphere is thick, the pressure is only about 100 bars at the bottom, and here the gas stops, and a ocean of ice and water begins - or so the scientists believe.

Would it be possible to dive into that water, take some photos and go back up? I imagine it will be very dark and windy, so it might not be the most interesting of places.

But with such a thick atmosphere, it might be a lot of global warming, so despite the top-layer of the atmosphere being very cold (as it is here on Earth as well, isnt it minus fifty or something?) it could be that the surface-sea is hot, clammy and dark, rather than cold and dark. But definitely windy.

Or am I completely wrong? Wikipedia claims there is water and ice at the surface (meaning that it is not too cold, with only a hundred bars, it is not enough to drastically change the freezing-point of water, according to the wikipedia overview of the relationship between pressure and when water freezes) but it also says elsewhere that this water-ice will not be a water-ice ocean like one finds around the polar regions on Earth. But why not? Also: The water-ice mix has a lot of ammonia in it. Could that affect the freezing-point?

So I am a bit confused regarding the surface of Uranus

 

[iguana_tonante]

It's smooth and rosy.

 

[Satyrquaze]

It's a bit hairy, but soft and comfortable.

 

[Chaos Descending]

Yes, Ammonia will change the temperature around which the ice/water mixture stabilizes.

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


Add in the pressure, and it's not going to be at all similar to Earth.

 

[Lindley]

despite the top-layer of the atmosphere being very cold (as it is here on Earth as well, isnt it minus fifty or something?)

That's a simplification. The atmosphere generally cools with altitude in the troposphere (the lowest level) and the mesosphere (the third level). The stratosphere and thermosphere are characterized by increasing temperature with altitude. Of course, by the time you get to the thermosphere, increasing temperature (as high as 4,500 degrees F) doesn't mean much in practice, since it's just a function of molecular kinetic energy but there aren't enough molecules around for it to "feel" hot. (The ISS is in the thermosphere).

Jetliners usually fly around the tropopause due to stable, cold temperatures. However, the coldest part of the atmosphere is the mesopause, where temperatures can drop below 130 K.

 

[Christopher]

Would it be possible to dive into that water, take some photos and go back up? I imagine it will be very dark and windy, so it might not be the most interesting of places.

At a pressure of 100 bars? That's pretty crushing. You'd probably need to be in a submersible or something rather than just diving.

But with such a thick atmosphere, it might be a lot of global warming...

The term you want is "greenhouse effect." "Global warming" refers to the trend of increasing temperatures on Earth over time due to the increase in the greenhouse effect or other environmental changes.


And to those of you attempting to turn the thread title into a dirty joke: it's pronounced YOOR-uh-nus.

 

[SchwEnt]

It's sideways.

 

[CorporalCaptain]

And to those of you attempting to turn the thread title into a dirty joke: it's pronounced YOOR-uh-nus.

The other pronunciation is accepted, too.

http://www.merriam-webster.com/dictionary/uranus.

 

[iguana_tonante]

Well, everybody with a even a smattering knowledge of Latin must know that it should be pronounced "OOH-rah-noos".

 

[CorporalCaptain]

Actually, OOrahnoose tickles my fancy just fine. I'd use it, only people around here would non-groky. I'll keep it in reserve.

 

[scotpens]

It’s always been my understanding that gas giant planets have no “surface” per se. There’s no definable boundary between the gaseous atmosphere and the fluid ocean; as you descend in the atmosphere, it just gets gradually denser until it becomes a liquid.

It's sideways.

“Did you know Uranus is sideways? Heh-heh, heh-heh-heh.”

. . . And to those of you attempting to turn the thread title into a dirty joke . . .

Really! As if any of us would do such a thing.

 

[The Dominion]

And to those of you attempting to turn the thread title into a dirty joke: it's pronounced YOOR-uh-nus.

The other pronunciation is accepted, too.

http://www.merriam-webster.com/dictionary/uranus.

I've always thought the other one is just as bad. Urine-us? Poor planet just can't win.

 

[CorporalCaptain]

And to those of you attempting to turn the thread title into a dirty joke: it's pronounced YOOR-uh-nus.

The other pronunciation is accepted, too.

http://www.merriam-webster.com/dictionary/uranus.

I've always thought the other one is just as bad. Urine-us? Poor planet just can't win.

---

OK. Trying to be serious, now:

It’s always been my understanding that gas giant planets have no “surface” per se. There’s no definable boundary between the gaseous atmosphere and the fluid ocean; as you descend in the atmosphere, it just gets gradually denser until it becomes a liquid.

Now, wouldn't a discrete phase change, from gas to liquid, happen at a certain depth?

 

[Wanderlust]

Frekken jerks deriding this poor planet.

Everywhere i go we can't have a serious discussion about this very real place.

 

[Christopher]

It’s always been my understanding that gas giant planets have no “surface” per se. There’s no definable boundary between the gaseous atmosphere and the fluid ocean; as you descend in the atmosphere, it just gets gradually denser until it becomes a liquid.

Now, wouldn't a discrete phase change, from gas to liquid, happen at a certain depth?

No, it's a more gradual transition -- first you have a gas, then you have a gas with droplets of liquid suspended in it, then the droplets get bigger and more numerous until it's more like a liquid with gas bubbles suspended in it, and then the gas bubbles get less and less numerous until it's all liquid. This Escher lithograph is a good analogy:

http://www.mcescher.com/Gallery/switz-bmp/LW308.jpg

 

[CorporalCaptain]

^ Very interesting.

Now is this structure a result of the dynamic nature of the planet, for example, the fluctuations in temperature, pressure, and other local conditions?

 

[B.J.]

Frekken jerks deriding this poor planet.

Everywhere i go we can't have a serious discussion about this very real place.

Just rename it then, like they did in Futurama. They changed it to Urectum!

 

[sojourner]

rectum? damn near killed'em!

 

[Christopher]

^ Very interesting.

Now is this structure a result of the dynamic nature of the planet, for example, the fluctuations in temperature, pressure, and other local conditions?

No, I think it's because of the proximity to the triple point or some such thing. I don't really remember the precise explanation offhand, but it's not about fluctuations, since it's a continuous state of affairs. I think it's just that the pressure is so great that there ends up being little difference between the gas and liquid phases.

 

[Knight Templar]

Read the short story "Into The Blue Abyss" for an excellent possible description. Of the ecosystem as well.