## Monday, November 17, 2014

### How can Uranus have storms hot enough to melt steel? A runaway greenhouse effect?

Here's a great question for CAGW enthusiasts:

According to recent reports, "giant storms on gassy Uranus have astronomers scratching their heads," because they are extremely large [~5,760 miles wide] and especially because they are extremely hot [2,800°F = melting point of steel].

How does that happen on a planet 30 times further from the Sun than Earth, and without any volcanic activity or SUVs?

From a Mannian/Hansenian runaway-greenhouse radiative-forcing effect?

Let's see if that's possible.

According to infrared images taken with the Keck telescope, these storms radiate at peak wavelengths of 1.6 - 2.2 microns. Using Wien's Displacement Law, we can calculate the temperature of a blackbody radiating at these peak wavelengths as:

1.6 microns → 1,538°C, or 2,800°F or 1,811°K [steel melts at 2,600 - 2,800
°F]

2.2 microns → 1,044°C or 1,911°F or 1,317°K

This is amazing considering that Uranus only receives a trifling 3.71 W/m2 energy from the Sun, which per the Stefan-Boltzmann Law is equivalent to a blackbody radiating at a temperature of -183°C, 90°K, or -298°F.

How do greenhouse gases violate the 1st law of thermodynamics to amplify 3.71 W/m2 incoming radiation from the Sun to 610,143 W/m2 radiated by a blackbody at 1,538C with peak emission at 1.6 microns, an amplification of outgoing radiation to space over incoming radiation from the Sun by a factor of 83,596 times?

Furthermore, how do greenhouse gases raise the outgoing radiating temperature by 1811°K - 90°K = 1721°K, a temperature increase of more than 20 times? [90°K is the Uranus equilibrium temperature with the Sun]

It's clearly impossible, unless you program a GIGO climate model to say so.

"the base of the troposphere on the planet Uranus is 320K, considerably hotter than on Earth [288K], despite being nearly 30 times further from the Sun. The base of the troposphere on Uranus is 320K at 100 bars pressure, despite the planet only receiving 3.71 W/m2 energy from the Sun. By the Stefan-Boltzmann Law, a 320K blackbody radiates 584.6 W/m2. This is 157.5 times the energy received from the Sun, due to the atmospheric temperature gradient produced within a planetary gravity field. The temperature at the base of the troposphere is determined by the ideal gas law PV=nRT, where pressure from gravity and atmospheric mass raise the temperature at the base of the troposphere from the equilibrium temperature with the Sun of Uranus of 89.94K to 320K, regardless of the atmospheric mixture of greenhouse gases."
Atmospheric mass/pressure/gravity establish the lapse rate/tropospheric temperature profile of all of the planets in our solar system with thick atmospheres, as demonstrated by a paper in Nature by Robinson and Catling. Convection dominates over radiative forcing in the troposphere of each of these planets as also demonstrated by Robinson and Catling.

Note also as stated by the report below,
"These storms on an usually quiet Uranus have astronomers scratching their heads, De Pater said. The three other gassy giant planets — Jupiter, Saturn and Neptune — all seem to have strong internal heat sources, and that energy could help stir up storms in the atmosphere. But Uranus doesn’t appear to have one — which means that the Sun must be mostly responsible for generating such disturbances in the planet’s atmosphere, astronomers had thought."
"But seven years after the equinox, there is not enough sun to explain these massive storms, De Pater pointed out. So it means that the inner workings of Uranus, which remain hidden from view, are more complex than scientists expected."
“Well, at least it tells us that the theories have to be adjusted,” De Pater said. “They are not representative of reality.”

Giant storms on gassy Uranus have astronomers scratching their heads

Infrared images taken with the Keck telescope at 1.6- and 2.2-micron wavelengths show storm systems on Uranus. The white spot is an extremely large storm that was brighter than any feature ever recorded on the planet in the 2.2-micron band. The cloud rotating into view at the lower-right limb

Storms peppering Uranus hint at mysterious processes in the planet's interior

It never rains but it storms on Uranus. Astronomers have spotted a slew of squalls on this usually quiet, distant planet — two of them giant storms that took professional and amateur astronomers by surprise.

The findings, presented this week at the American Astronomical Society’s Division of Planetary Sciences meeting in Tucson, show that the mysterious, blandly blue planet might be far more complicated than scientists had thought.

Team lead Imke de Pater, a planetary astronomer at UC Berkeley, said she and colleagues first spotted the strange activity in August while using the Keck Observatory in Hawaii to study weather patterns on Uranus — which they had been doing regularly for more than a decade.

To their surprise, they saw eight large storms, including the brightest tempest ever seen on the planet at 2.2 microns — the wavelength of light that picks up clouds hanging just below the tropopause (the boundary between the troposphere and the stratosphere).[and the tropopause is much colder than the base of the troposphere]

“It was just by chance I was observing and noticed these incredible storms that we really had never seen before,” De Pater said in an interview. “You always have to be looking, I guess, to see things like that — so this was one of those lucky times.”

The squalls were highly unusual, De Pater said. The scientists might have expected this kind of activity in 2007 — that’s when Uranus had its equinox (a once-in-42-years event) and the sun would have been shining directly over the equator.

But for such storms to brew up some seven years later?

“People had predicted that the maximum in cloud activity would be around 2007 … and indeed we did see cloud activity,” De Pater said. “But it was nothing compared to what we saw in August.”

The scientists wanted to study this strange phenomenon further, but they didn’t have a lot of telescope time. So they alerted the amateur astronomy community to the storms to see if its members could help.

Amateur astronomers picked up another bright feature, but this one was visible only at a wavelength of 1.6 microns — which meant that this storm was brewing deeper in the atmosphere. The scientists also later used the Hubble Space Telescope to find storm systems at a variety of depths and across a distance of 5,760 miles.

These storms on an usually quiet Uranus have astronomers scratching their heads, De Pater said. The three other gassy giant planets — Jupiter, Saturn and Neptune — all seem to have strong internal heat sources, and that energy could help stir up storms in the atmosphere. But Uranus doesn’t appear to have one — which means that the Sun must be mostly responsible for generating such disturbances in the planet’s atmosphere, astronomers had thought.

But seven years after the equinox, there is not enough sun to explain these massive storms, De Pater pointed out. So it means that the inner workings of Uranus, which remain hidden from view, are more complex than scientists expected.

“Well, at least it tells us that the theories have to be adjusted,” De Pater said. “They are not representative of reality.”

Newfound Mega-Storms on Uranus Pose Planetary Puzzle

Known for calm weather, the seventh planet from the sun is suddenly sporting a series of storms.

Andrew Fazekas for National Geographic

PUBLISHED NOVEMBER 13, 2014

A distant, icy, green giant—the planet Uranus—appears to have unexpectedly awakened from a long slumber. Astronomers have discovered a yet unexplained rash of extreme storms on the normally placid planet.

Peering through the world's most powerful telescopes, the Keck Observatory in Hawaii and the Hubble Space Telescope, a team of researchers based out of the University of California, Berkeley have spotted unusually bright cloud activity in the upper atmosphere of the seventh planet from the sun, which lies about 1.86 billion miles (3 billion kilometers) away.

Over a span of just two days in early August this year, the team spotted eight storms in the planet's northern hemisphere. One of the storms is now considered the brightest ever seen there, accounting for 30 percent of all the reflected light we can see coming off Uranus. (Related: "Auroras Seen on Uranus for First Time.")

Hubble looked at the planet just this past October 24 and found multiple giant storms extending more than 5,592 miles (9,000 kilometers) across, at various altitudes. That is roughly three-quarters of the diameter of Earth.

All these alien tempests appear to be happening above the main methane-laden part of the atmosphere, where the atmospheric pressures are about half of what they are here on Earth.

But one thing is for sure, this busy weather on Uranus has caught scientists completely off-guard.

This sky chart places Uranus in the constellation Pisces.

Seasonal Shocker

Forecasters predicted a peak in the planet's atmospheric activity during the 2007 Uranian equinox, when the sun shone straight down on its equator. The equinox is an event that happens once every 42 years, twice in the course of the planet's 84-year orbit around the sun.

Astronomers have been watching the weather on Uranus for more than a decade, charting swirling storms near its north pole. Since there is no internal heat source for these storms on the planet, these cloud activities were thought to be driven solely by sunlight.

For that reason, with the northern hemisphere turned away from the sun in recent years, the heating effect was expected to wane. But it hasn't.

Even the amateur astronomy community has sprung into action to document the surprising storms, turning their backyard telescopes on the green giant. Despite using much smaller instruments than their professional counterparts, amateurs were able to observe a different bright spot deeper in the atmosphere of Uranus.

"There definitely is a lot of dynamic activity in Uranus's atmosphere, and we have no idea why," said astronomer and team leader Imke de Pater, of the University of California, Berkeley, at a press conference at a meeting of the American Astronomical Society's Division for Planetary Sciences in Tucson, Arizona, this week.

"Predictions said they should fade away but they didn't, and we hope theorists will now take this mystery on and help explain what exactly is going on."

A simulated binocular view shows the position of the tiny green disk of Uranus in relation to the star Delta Pisces, faint to the naked eye.

See for Yourself

Backyard sky-watchers can see the giant green world for themselves on any clear night this month.

Uranus is four times as wide as Earth, but since it lies about 1.86 billion miles (3 billion kilometers) away from our planet, it's barely visible to the naked eye at magnitude 5.7-and only in very dark, pristine skies.

However, the planet makes for an easy target with binoculars and small scopes. Look for Uranus lying within the field of faint stars that make up the constellation Pisces, which is now rising above the eastern sky after local nightfall this week.

The faint blue-green disk will appear only 3 degrees to the lower right of the faint naked-eye star Delta Pisces, which shines at 3.5 magnitude. Their apparent separation will be equal to six full moons, making them both fit easily within the field of view of a standard pair of binoculars.

Happy hunting!

1. What happens is that the denser and more massive a gaseous atmosphere the greater the proportion of solar energy passing through is absorbed by those gases via conduction from the surface AND the longer the delay in the exit of solar energy to space for a higher surface temperature.

The consequence can be temperatures far higher than predicted by the S-B equation which is applicable only for a planet with no atmosphere, no conduction and no convection.

See here:

http://www.newclimatemodel.com/the-gas-constant-as-the-global-thermostat/

and to assist in understanding see here:

http://science.civicvoice.com/q1511__What_does_pv=mrt_mean.html

1. Well, except that Uranus is a gas planet and there is no "surface"

The entire greenhouse effect is generated by high pressures, stirred up slightly by the tiny 3.71 Wm-2 from the Sun

2. Higher density with depth provides adequate conduction up to the higher levels even without a truly solid surface but anyway, see here:

"Unlike other gas giants, Uranus most likely boasts a rocky core rather than a gaseous one. Temperatures inside it may reach 8,540 F (4,727 C), which sounds warm but is cooler than other planets — Jupiter's core may reach 43,000 F (24,000 C)."

and note:

"like most gas giants, the surface of Uranus is set where the pressure of the gas is equal to the pressure at sea level on Earth."

from here:

http://www.space.com/18707-uranus-temperature.html

but in general you are right to say that gases alone will rise in temperature when irradiated and subjected to pressure which is how suns form from gas clouds in space.

For a sun to form from gas clouds one only needs the cosmic background radiation to start the process of internal heating.

2. Joe Postma has a great new posting debunking the "Steel Greenhouse" and the so-called atmospheric "greenhouse effect" itself.

1. Agreed, I tweeted the link

3. I know this was a while ago, but can you tell me where the "2,800°F = melting point of steel" quote came from as I can't find any reference to it in the original article?
I would like to be able to quote it on other blogs, but I am having difficulty in justifying doing so.

1. http://www.engineeringtoolbox.com/melting-temperature-metals-d_860.html

2. Sorry, you mis-understood, I am looking for the Temperature of Gas Storms on Uranus, it was quoted on this thread as 2,800°F, but I can't find it in the original write up.

3. I had to calculate it using Wiens displacement law. I used this online calculator:

http://www.calctool.org/CALC/phys/p_thermo/wien

The article shows the shortest wavelength observed was 1.6 microns, so put 1.6 in the second blue box from the top and set the box to the right on microns

hit calculate and find the temperature at the bottom, select in F, C, or K

4. Thanks for that.

5. MS,

Where are you getting the temperature figures from Uranus from?

It is supposed to be the coldest planet as here:

http://www.space.com/18707-uranus-temperature.html

1. Stephen, as I say 2 comments above yours, I used Wien's displacement law based on the Keck observations of 1.6 microns to calculate the BB temperature of the OLR

Also see Wiki which says base of the troposphere on Uranus is 320K, 32K hotter than Earth.

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

Only possible explanation is gravity/pressure since Uranus only receives 3.71 W/m2 from the Sun

6. Its ok, just noticed the response to A C

7. So something was observed at a wavelength of 1.6 microns, but is the peak emmision of Uranus at 1.6 microns?