Friday, June 20, 2008

Ice


Today's biggest news is the discovery of water ice just beneath the surface of Mars. The Phoenix lander needed to dig just a few centimetres to find this white stuff, which evaporated a few days later just like water. This behaviour has led scientists to rule out frozen CO2 or salt. The fact that Phoenix found water so quickly suggests that it could be ubiquitous in the polar region, covered by just a thin layer of dust. Satellite data suggests that 1/4 of Mars could have water beneath the surface. Though scientists suspect that it exists on many worlds, this is the first positive find of water on another planet.

Scientists at University of California Santa Cruz have found that Enceladus could not possibly produce enough tidal heat to keep its South pole warm. The pole, which should be the coldest region, is the hottest! Enceladus' orbit is free of tidal stresses. Radioactive decay could account for no more than 0.32 gigawatts, yet Enceladus gives off 5.8 gigawatts! This has led scientists to conclude that the moon should freeze up in a few million years. Perhaps we should consider that something else is going on.

Enceladus' core can be modelled with a central mass of about 10^12 kg. This mass is typical for a primordial singularity. This object consumes only 2.8 kg per year and generates 10^9 watts of radiation. Water and other molecules near this centre are heated to a plasma. Electrons are stripped from atoms, and the resulting ions are drawn into circular orbits. The resulting current generates a magnetic field with the "positive" pole in the South. Electrons and positively charged ions spiral along magnetic field lines to form bipolar jets, the classic sign of a Black Hole.

The Northern jet is composed of electrons which are absorbed by the moon's interior. More energetic ions of the Southern jet penetrate these layers to warm the South Pole. Escaping ions spiral into Space, exactly as observed by Cassini. Unless Saturn's Rings are replenished, they would decay within 100 million years. Then we would face the anthropic question of why they exist in the right time for humans to view them. Thanks to the Cassini spacecraft, we have witnessed the E Ring being resuppllied from a moon. This observation suggests that similiar processes maintain the rings indefinitely.

Not long ago Earth was thought to be the only place with water in the solar system. Today we have found evidence for water on Mars, asteroids like Ceres, and moons like Europa and Enceladus. Ice on Mars shows conditions that might support life. Water could provide drinks and fuel for future settlers. Enceladus polar water is a mystery that could lead to a Black Hole. The water that we sometimes take for granted is today's most important discovery.

Check out the new Carnival of Space!

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8 Comments:

Blogger CarlBrannen said...

"This has led scientists to conclude that the moon should freeze up in a few million years." -- snort, snort, LOL.

Kind of convenient that their grants will run out well short of that time frame.

8:25 PM  
Blogger Kea said...

Gee, that's a discrepancy of quite a few gigawatts! The planetary scientists must be beginning to wonder what all those crazy physicists are actually doing with their grants. And I just love that Mars photo! It looks so homely, like a construction site just down the road.

8:47 PM  
Blogger nige said...

It's exciting news and a nice down-to-Earth type photo of the evidence, as previous commenters have pointed out. If there really is ice just under the surface of Mars, then by solar powered electrolysis you have oxygen to breathe, plus hydrogen as fuel.

Didn't the Phoenix lander have any sensor to detect the surface composition directly?

I know that previous probes (sent decades ago) could analyse soil or ice samples by measuring the backscattered or secondary radiation spectrum when a soil sample is exposed to alpha particles or neutrons from a small source in the spacecraft. This allows the soil composition to be determined without any guesswork, because different nuclei respond to irradiation in different and known ways.

I think that it would be scary in the long term to live on another planet if that planet was totally hostile to life, with no ready means of getting basic vitals like water and oxygen. But if you can easily extract these, then Mars becomes a more attractive place.

One of my favourite books was Samuel Glasstone's "The Book of Mars" published for NASA in 1968.

Glasstone was author of many chemical treatises and textbooks, as well as co-editor with Philip J. Dolan of the U.S. Department of Defense's heavyweight "Effects of Nuclear Weapons" book, and the NASA book "Sourcebook on the Space Sciences".

I think he was commissioned to write "The Book of Mars" in 1968 by NASA because NASA was on course for the Moon, next destination Mars.

Of course if it hadn't been for the costs of fighting insurgent communists in Vietnam and other issues down to Earth, and if the USSR had tried to get to Mars first, NASA would probably have had the funds and would have sent manned missions to Mars by now.

It's all about money and that means politics. Unless there is a competitor and a race, there is little interest and everyone finds lots of more down-to-Earth things to spend or squander money on instead of long-term scientific exploration projects that really capture the imagination.

Since Mars has practically no air pressure and a surface gravity of only 40% of Earth's, it's actually likely to be quite a fun place. Aircraft would be impossible because of the low air pressure, but the low gravity would allow fairly heavy compressed air tanks to be carried around.

The low air pressure would be an advantage for allowing high speed surface craft to move without atmospheric drag (just wheel friction).

5:26 AM  
Blogger L. Riofrio said...

At her talk at the American Geophysical Union last December, a woman scientist (junior scientist, naturally) pointed out that "radioactive decay" could not possibly account for Enceladus.

Science has become so specialised that cosmologists know nothing of planet formation and geologists know nothing of Black Holes.

Phoenix must dump a soil sample into its hopper to analyse whether it has ingredients for life.

7:33 PM  
Blogger nige said...

Hi Louise,

I don't understand the details the black hole mechanism for heat release you mention.

Enceladus, a moon of Saturn, may generate heat in various ways. I don't see how you can rule out radioactivity as a source of heat; potassium-40, uranium and thorium-232 abundances in it are not known. Before radioactivity was known, Kelvin worked out that tidal action wouldn't generate enough heat inside the earth to account for volcanic action and the temperature at the bottom of deep mineshafts, so he simply made up a theory that the earth's internal heat was mainly due to the latent heat given off by lava as it solidified (like the latent heat energy given off when steam condenses). This was the basis for Kelvin in 1862 trying to disprove Darwin's 1859 theory of evolution by "proving" that the Earth couldn't be more than 100 million years old, which wasn't enough time for evolution in Darwin's theory. Then in 1897, Bequerel discovered radioactivity. Although you can measure the radioactivity in surface rocks, you are limited in what you can deduce about the amount of radioactivity in the core of the Earth, so the theory isn't completely checkable. However, the antineutrinos emitted in radioactivity within the Earth are detectable and provide limits.

What I don't understand about the black hole heat source idea you mention, is what the mechanism is for its stable consumption of 2.8 kg of matter per year. What stabilises it, preventing the black hole from either evaporating faster than it can suck in matter, or alternatively, sucking in matter faster than it can radiate energy?

Surely if a such a black hole was surrounded by a lot of matter, all the matter would soon fall into it, and the black hole would either grow or explode. Why should it remain stable? Why should just 2.8 kg of the surrounding matter drip into the black hole over the course of a year? This seems strange.

But on the fundamental particle level, this stability question can be solved if the Hawking radiation is gauge boson exchange radiation: the fundamental particle as a black hole is stable because it is in an equilibrium, receiving and emitting gauge boson radiations. Radiation continually falls in and is continually radiated out, giving a mechanism for the Yang-Mills theory of exchange radiation.

1:56 AM  
Blogger Stephen said...

Water ice is conveniently near the surface in the deep north. So that might be a good spot to land humans. On Earth, Antarctica is considered a "hostile environment". Funny that that might be where we want to go on the Moon or Mars.

Perhaps we'll see just how hospitable the martian winter is near the pole. Estimates are that Phoenix will be up to it's elbows in ice. One quote is that Phoenix will be crushed. But if "lazarus mode" works, and we hear from it next summer, that would be, uhm, cool.

4:23 AM  
Blogger L. Riofrio said...

As we recently saw with the LHC, there are a lot of misconceptions about Black Holes eating everything in sight. 10^9 GW is an immense amount of radiation, enough to prevent all but a tiny amount of matter from falling in. The calculations are too lengthy to include here, but outward pressure from radiation opposes the inward pull of gravity until an equilibium is achieved.

7:17 AM  
Blogger nige said...

Louise, thanks for the explanation. It seems very interesting.

5:47 AM  

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