A geyser sprays water vapor from the surface of Saturn’s moon Enceladus
We’ve known for some time that geysers on Saturn’s moon Enceladus sprays water vaporthat eventually finds its way to Saturn. But this striking image lets us see that water vapor spilling into space.
Michael Benson composited this image from image fragments sent by the Cassini spacecraft, just one of the incredible bits of space porn from his upcoming book Planetfall: New Solar System Visions. The Enceladus geysers can blast 500 pounds of water vapor per second, and some of that water finds its way into Saturn’s atmosphere. It’s also believed that the vapor helps form one of Saturn’s outer rings, the “E” ring, in the form of ice. So far, this relationship of a satellite feeding materials into its planet, is unique to Enceladus and Saturn. We don’t know yet of other moons and planets with a similar relationship. (Note: Moralltach notes in the comments that materials from Io’s volcanic eruptions form the Io torus, a gas ring around Jupiter. Enceladus is believed to be responsible for the water that exists in Saturn’s atmosphere as well as around the planet, which is what makes it so unusual.)
For now, though, we can just focus in on the incredible beauty of Enceladus itself, and the glow of water vapor shooting into space. To see an enormous, detailed version of this image (and for details on how Benson assembled the image), head over to North Country Public Radio.
Volcano Shoots Geyser Of Water Up Into Space [North Country Public Radio via It’s Okay to be Smart]
A new study indicates that Mars’ mantle contains as much water deep underground as Earth’s
Despite claims in the 1890s that Mars with filled with canals teeming with water, research over the past several decades has suggest that in fact, Mars has only a tiny amount of water, mostly near its surface.Then, during the 1970s, as part of NASA’s Mariner space orbiter program, dry river beds and canyons on Mars were discovered—the first indications that surface water may have once existed there. The Viking program subsequently found enormous river valleys on the planet, and in 2003 it was announced that the Mars Odyssey spacecraft had actually detected minute quantities of liquid water on and just below the surface, which was later confirmed by the Phoenix lander.
Now, according to an article published yesterday in the journal Geology, there is evidence that Mars is home to vast reservoirs of water in its interior as well. The finding has weighty implications for our understanding of the geology of Mars, for hopes that the planet may have at some point in the past was home to extraterrestrial life, and for the long-term prospects of human colonization there.
The Surprisingly Strange Physics of Water
1. Race to the bottom
A logical person might assume that it would take longer for hot water to plunge down the temperature scale to 32 degrees Fahrenheit (0 degrees Celsius) and freeze than would cold water. But oddly enough, this is not always the case. As was first observed by a Tanzanian high school student, Erasto Mpemba, in 1963, hot water actually freezes faster than cold water when the two bodies of water are exposed to the same subzero surroundings.
And no one knows why.
One possibility is that the Mpemba effect results from a heat circulation process called convection. In a container of water, warmer water rises to the top, pushing the colder water beneath it and creating a “hot top.” Scientists speculate that convection could somehow accelerate the cooling process, allowing hotter water to freeze faster than cooler water, despite how much more mercury it has to cover to get to the freezing point.
2. Levitating liquid
When a drop of water lands on a surface much hotter than its boiling point, it can skitter across the surface for much longer than you’d expect. Called the Leidenfrost effect, this occurs because, when the bottom layer of the drop vaporizes, the gaseous water molecules in that layer have nowhere to escape, so their presence insulates the rest of the droplet and prevents it from touching the hot surface below. The droplet thus survives for several seconds without boiling away.
3. Empty space
Though the solid form of almost every substance is denser than its liquid form, due to the fact that atoms in solids normally pack tightly together, this does not hold true for H2O. When water freezes, its volume increases by about 8 percent. This is the strange behavior that allows ice cubes, and even gargantuan icebergs, to float.
When water cools to its freezing point, there’s less energy causing its molecules to slosh around, so that the molecules are able to form steadier hydrogen bonds with their neighbors, and gradually lock into position; this is the same basic process that causes all liquids to solidify. And just like in other solids, the bonds between molecules in ice are indeed shorter and tighter than the loose bonds in liquid water; the difference is that the hexagonal structure of ice crystals leaves a lot of empty space, which makes ice less dense than water overall.
The volume surplus can sometimes be seen in the form of “ice spikes ” on top of ice cubes in your freezer. These spikes are composed of the excess water that is squeezed out of a cube by the freezing (and expanding) ice around it. In a container, water tends to freeze from the sides and bottom toward the center and top, so that the ice expands toward the middle. Sometimes, a pocket of water gets trapped in the middle with nowhere to run, and squirts out of a hole in the top of the cube, freezing in the shape of a squirt.
4. One of a kind
As the saying goes, “no two snowflakes are alike.” Indeed, in the entire history of snow, every single one of these beautiful structures has been completely unique. Here’s why: A snowflake starts out as a simple hexagonal prism. As each freezing flake falls, it bumps into a unique range of shape-changing conditions, including different temperatures, humidity levels and air pressures. That’s enough variables that the crystal formation never happens in the same way twice.
That said, the cool thing about snowflakes is that their six arms grow in perfect synchrony, creating hexagonal symmetry, because each arm experiences the same conditions as all the others.
5. Where are you from?
The exact origin of our planet’s water, which covers about 70 percent of Earth’s surface, is still a mystery to scientists. They suspect that any water that conglomerated on the surface of the planet as it formed 4.5 billion years ago would have evaporated off from the intense heat of the young, blazing sun. That means the water we have now must have gotten here later.
How? Well, during a period around 4 billion years ago called the Late Heavy Bombardment, massive objects, probably from the outer solar system, hit Earth and the inner planets. It’s possible that these objects were filled with water, and that these collisions could have delivered gigantic reservoirs of water to Earth.
Comets a chunks of ice and rock with tails of evaporating ice that make long, looping orbits around the Sun — are likely culprits for what landed us with all this liquid. There’s one problem, however: Remote measurements of the water evaporating off of several major comets (Halley, Hyakutake, and Hale-Bopp) have revealed that their water ice is made of a different type of H20 (containing a heavier isotope of hydrogen) than Earth’s, suggesting that such comets may not be the source of all our wonderful water.
20 Things You Didn’t Know About Water
1 Water is everywhere—there are 332,500,000 cubic miles of it on the earth’s surface. But less than 1 percent of it is fresh and accessible, even when you include bottled water.
2 And “fresh” can be a relative term. Before 2009, federal regulators did not require water bottlers to remove E. coli.
3 Actually, E. coli doesn’t sound so bad. In 1999 the Natural Resources Defense Council found that one brand of spring water came from a well in an industrial parking lot near a hazardous waste dump.
4 Cheers! The new Water Recovery System on the International Space Station recycles 93 percent of astronauts’ perspiration and urine, turning it back into drinking water.
5 Kurdish villages in northern Iraq are using a portable version of the NASA system to purify water from streams and rivers, courtesy of the relief group Concern for Kids.
6 Ice is a lattice of tetrahedrally bonded molecules that contain a lot of empty space. That’s why it floats.
7 Even after ice melts, some of those tetrahedrons almost always remain, like tiny ice cubes 100 molecules wide. So every glass of water, no matter what its temperature, comes on the rocks.
8 You can make your own water by mixing hydrogen and oxygen in a container and adding a spark. Unfortunately, that is the formula that helped destroy the Hindenburg.
9 Scientists have a less explosive recipe for extracting energy from hydrogen and oxygen. Strip away electrons from some hydrogen molecules, add oxygen molecules with too many electrons, and bingo! You get an electric current. That’s what happens in a fuel cell.
10 Good gardeners know not to water plants during the day. Droplets clinging to the leaves can act as little magnifying glasses, focusing sunlight and causing the plants to burn.
11 Hair on your skin can hold water droplets too. A hairy leg may get sunburned more quickly than a shaved one.
12 Vicious cycle: Water in the stratosphere contributes to the current warming of the earth’s atmosphere. That in turn may increase the severity of tropical cyclones, which throw more water into the stratosphere. That’s the theory, anyway.
13 The slower rate of warming in the past decade might be due to a 10 percent drop in stratospheric water. Cause: unknown.
14 Although many doctors tell patients to drink eight glasses of water a day, there is no scientific evidence to support this advice.
15 The misinformation might have come from a 1945 report recommending that Americans consume about “1 milliliter of water for each calorie of food,” which amounts to 8 or 10 cups a day. But the report added that much of that water comes from food—a nuance many people apparently missed.
16 Call waterholics anonymous: Drinking significantly more water than is needed can cause “water intoxication” and lead to fatal cerebral and pulmonary edema. Amateur marathon runners have died this way.
17 Scientists at Oregon State University have identified vast reservoirs of water beneath the ocean floor. In fact, there may be more water under the oceans than in them.
18 Without water, ocean crust would not sink back into the earth’s mantle. There would be no plate tectonics, and our planet would probably be a lot like Venus: hellish and inert.
19 At the other end of the wetness scale, planet GJ 1214b, which orbits a red dwarf star, may be almost entirely water.
20 Recent evidence suggests that when the solar system formed 4.5 billion years ago, comets had liquid cores. If so, life may have started in a comet.
Bacteria Make Hydrogen Fuel From Water
Most of the renewable energy sources that are under consideration involve an obvious source of energy — light, heat, or motion. But this is the second time this year there has been a paper that has focused on a less obvious source: the potential difference between fresh river water and the salty oceans it flows into. But this paper doesn’t simply use the difference to produce some electricity; instead, it adds bacteria to the process and takes out a portable fuel: hydrogen.
Really, really hot water
In the Image : Exoplanet ‘Waterworld’ GJ1214b David A. Aguilar (CfA)
The James Webb Space Telescope may someday put Hubble out of business, but until then NASA’s old standby is still making new discoveries. Today, that comes to us in the form of the first exoplanet “waterworld”—a water-covered planet shrouded by a dense, steamy atmosphere, the first confirmed planet of its kind.
The planet, known as GJ1214b, was discovered in 2009 by ground-based observations. But at that time it was difficult to glean much from the data other than the fact that the planet was indeed out there orbiting a red dwarf and is roughly 2.7 times Earth’s diameter. But its nearness to its star—just 1.3 miles away—meant that scientists could be reasonably sure it is hot there, likely around 450 degrees.
When astronomers from Harvard-Smithsonian Center for Astrophysics more recently turned Hubble’s Wide Field Camera 3 toward GJ1214b while it was transiting its host star, they were able to analyze the light passing through the atmosphere for the first time. That analysis suggests that GJ1214b is swathed in a fairly consistent and dense atmosphere of water vapor. Further analysis of size and mass (and thus density) further suggest that GJ1214b contains more water than Earth, and less rock.
That’s not to say GJ1214b is the kind of watery paradise in which you’d want to go sailing, or even face down a cartel of hapless but well-armed future-thugs. Even if GJ1214b is exactly what the Hubble data suggests it is, it’s very hot there and the high pressures and temperatures would make for some conditions vastly different than those on Earth. Superfluid water and other exotic phenomena likely occur there regularly—things that would be cool to see from a distance but highly incompatible with life as we know it on this planet.
The CfA astronomers responsible for the Hubble research speculate that GJ1214b probably formed further away from its star where water ice is more plentiful. It then resettled into a closer orbit, becoming the steamy sphere Hubble sees today. That means at some point this waterworld would have had to pass through the star’s habitable zone, though there’s no telling how long it hung around there. More at CfA.
[Harvard-Smithsonian Center for Astrophysics]