Truly Madly Deeply: June 2010

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Water, Hydrocarbons and Life on Saturn's Moons: Gallery

Rediscovering Titan

Titan, hidden under an atmospheric veil that was once impenetrable to the gaze of spacecraft, has enticed scientists for decades. Now, Cassini, and its probe Huygens, have revealed a craggy surface carved by liquid methane and pocked with methane lakes like the one pictured here, shining in the sun.

This moon's surface temperature (minus 290 F) is close to the triple point of methane, the temperature at it which can exist as a liquid, a solid and a gas. On Titan, methane behaves much like water behaves on Earth: It evaporates into the atmosphere, forms clouds and rains down on the surface, cutting riverbeds and collecting in basins as lakes.

NASA/JPL/UNIVERSITY OF ARIZONA/DLR

What Lies Beneath

This drawing of Titan's interior is based on evidence from Cassini and Huygens. Radio data and electric-field measurements suggest that the moon is a mixture of water ice and rock dusted with a sandy, and in places sodden, veneer of hydrocarbons (organic compounds consisting entirely of hydrogen and carbon) and pockets of water ice. The drawing shows the surface in cloudy ocher over a light gray layer of ice. That layer may be 300 miles thick and composed of nearly pure water ice. The blue layer underneath is, speculatively, a subterranean ocean of liquid water and ammonia. Beneath is a dark gray core of unstratified ice and rock.

Coloring the Titan Sinlap Crater

These images are clues to the composition of Titan's surface. Cassini snapped this radar image of the Sinlap impact crater (top of image) during a flyby of Titan in February 2005. Researchers overlaid the original black and white image with a color map of radiometric-brightness temperature readings from the spacecraft's synthetic-aperture radar.

The bottom half of this image shows part of a dielectric constant map, a measure of a material's ability to carry an electric current. This one is made from polarized radiometric data. The red square corresponds to the area of the image above. The dielectric constant for water ice is larger than three, therefore it appears red on this map. Titan's surface is blue and light blue, indicating that there is no water ice on the surface. The yellow areas in Sinlap show that the dielectric constant is higher there, closer to that of water. The suggestion is that whatever made the crater unearthed a pocket of water ice below the surface. And this is the only evidence for water discovered on Titan's surface so far.

Water Ice on the Surface?

On Cassini's flyby of Titan in April 2006, it shot the images that form this composite with its Visual and Infrared Mapping Spectrometer. The dark blue areas may contain water ice, though hydrocarbons are the dominant compounds on the surface. "Sinlap is the only place on [Titan's surface] where we have indications that there may be water ice," says Christophe Sotin, a senior research scientist at NASA's JPL in an interview. Findings like this begin to paint a picture of Titan as a ball of water ice covered entirely by organic chemicals.

It's Electric: Clues for an Ammonia-Water Ocean

In January 2005, Huygens parachuted to Titan's surface to measure the electric field there. It found an expansive, conductive layer underground, which researchers believe is a mixture of liquid water and ammonia.

The figures above show electrical-field measurements at different altitudes as the probe descended. Galactic and cosmic rays (GCR in the figures) account for the electrical readings until the probe reached the surface. The discrepancy could indicate an ocean buried about 45 kilometers below the surface.

The Allure of Enceladus

Enceladus appears here as a crescent dangled beside the broad curve of Saturn's surface. Sharp eyes will detect the haze of water-ice plumes erupting into space from the moon's bottom edge. The ice blows out of sinuous fissures, which NASA's researchers call "tiger stripes," near the moon's south pole. With images like this and other data, Cassini has answered questions that have puzzled researchers for decades, such as the moon's relationship to the ring it travels in, and raised new ones, such as the possibility of a liquid ocean under its surface.

Cassini revealed that Enceladus's ice plumes pile water into Saturn's magnetosphere and change the rotation of the planet's magnetic field. Cassini has detected water and organic chemicals in those plumes, prompting speculation about life in the moon's surface vents.

Cassini snapped this image of Saturn's moon Enceladus in visible light with its wide-angle camera at a distance of 10,000 miles (17,000 km) from the moon on Nov. 21, 2009.

NASA/JPL/SPACE SCIENCE INSTITUTE

Exploring the Bright, Strange Surface

These are the best visible-light images that Cassini will take of the erupting fractures before a years-long winter darkens the pole of Enceladus. The fractures are each named after Middle Eastern cites. Here, the Baghdad Sulcus is pictured with others nearby.

"We always knew that Enceladus was unusual," Buratti says. Voyager showed that it is bright as fresh snow and it is nestled in the densest part of Saturn's E Ring. "The theory was that the ring came from Enceladus," she says. "But we didn't see anything, just all these hints; intriguing hints." Now they can see that the moon likely spews out the material that makes up the ring, and they are beginning to understand how it does that.

The spacecraft took this wide-angle image of the south pole of Enceladus at a distance of 1200 miles (2000 km) during a flyby on Nov. 21, 2009.

NASA/JPL/SPACE SCIENCE INSTITUTE

Alien Faithful: Enceladus's Ice-Spewing Geyser

Cassini photographed more than 30 jets of water ice spewing from Enceladus's south pole in this composite of two narrow-angle images taken on Nov. 21, 2009.

In July 2005, the spacecraft yielded its first closeup views of the moon and these fractures. "What we saw was basically a boiling cauldron," Buratti says. "We saw a hotspot at the south pole, 70 kelvin [126 F] above what it should be."

NASA/JPL/SPACE SCIENCE INSTITUTE

Tiger Stripes, Liquid Oceans

This is a composite image of the erupting fissure called the Damascus Sulcus. It is a blend of images that Cassini took laid over a new topographic map Paul Schenk made at the Lunar and Planetary Institute in Houston, Texas.

The temperature in the fissures may be high enough for liquid water and the moon may hide an ocean of water underground. "There are a lot of arguments," Buratti says. "But I would say that there is consensus that there is liquid water, that there's a liquid ocean under the surface." If so, that liquid water may also erupt from the fissures.

NASA/JPL/SPACE SCIENCE INSTITUTE/UNIVERSITIES SPACE RESEARCH ASSOCIATION/LUNAR & PLANETARY INSTITUTE

Heat at Minus 140 F

This infrared image visualizes temperatures in the Baghdad Sulcus. It is the most detailed image to date of the heat emanating from the moon's interior through the fissures. The heat is squeezed into a strip about half a mile wide and reaches temperatures of minus 180 Kelvin (140 F). The narrow fissure in the center is probably warmer, possibly warm enough to melt water ice. Baghdad Sulcus is about 1600 feet deep and 109 miles long.

NASA/JPL/GSFC/SWRI/SSI

Dione's Influence

Two forces may drive the eruptions on Enceladus. Twice in its orbit around Saturn, it passes beside another moon, Dione, pictured here behind Enceladus. The gravitational pull from the planet and the other moon may propel powerful tides inside Enceladus and generate the heat required for eruptions.

There are other theories to explain the heat coming from Encaladus. Some suggest there are nuclear elements, such as uranium, in the rocks of the moon's interior that release heat as they decay. Others—the minority of researchers—say that chemical reactions could spark explosions that blow ice out of the interior.

NASA/JPL/SPACE SCIENCE INSTITUTE

But Is There Life?

Life on Earth may have first arisen from oceanic vents, Buratti says, and "the same conditions are there on Enceladus." This artist's rendering shows Cassini flying by the geysers at the moon's south pole. They contain the basic elements of life and may be warm enough for liquid water.

"We know that there are prebiotic elements like light hydrocarbons—simple molecules. The conditions for life are there," Buratti says. But, "the thing about Enceladus is that it really is an alien world. It's so cold out there."

Friday, June 18, 2010

at 11:00 PM

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Space

9 Wildest Exoplanets Ever Spotted

A team of European astronomers found 32 new exoplanets last week, bringing the total of planets found outside our solar system to 403. These extreme worlds continue to shape astronomer's ideas about how planets form. Here, we've combed through the hundreds to pick the 9 hottest, biggest, most eccentric alien worlds ever found.

A team of European planet hunters has uncovered a bonanza of 32 new exoplanets, planets outside our solar system. Using a precise spectrograph at the Very Large Telescope in northern Chile, the astronomers spotted enough planets to bring the total number of known exoplanets up by nearly 10 percent—to 403. Most of these hundreds of exoplanets are gas giants, but in the mix there are also super-Earths, planets with masses that are up to 20 times that of Earth. These are especially difficult to find because they are so much smaller than the giant Jupiter-like gaseous planets.

Scientists usually spot exoplanets by detecting changes in the motion of the star the planets are orbiting. But because the gravity of an orbiting super-Earth tugs so weakly on its star, the changes are harder to observe. The spectrograph that made this discovery possible was the first instrument able to detect the tiny changes from these planets. These 32 exoplanets have also supported the idea that super-Earths are much more common than they were once thought to be. Scientists now think that super-Earths may be found near more than 60 percent of stars similar to our sun. At that rate, Stephane Udry, an astronomer at the University of Geneva in Switzerland who announced the discovery, believes it is very likely that life exists on other planets. The elements that make up rocky planets can only be made in stars, and some of these elements are also the elements needed for life. "There are many planets," he says, "and I am convinced we will find life."

The Most Massive:
HD 43848

Discovered in 2008, this exoplanet has a mass that is 25 times the mass of Jupiter. Orbiting around a star that is a just a bit smaller than our sun, HD43848 is nearly 8000 times as massive as Earth.

The Smallest:
CoRoT-7b

This planet is less than twice the size of Earth, and its density is similar to Earth's. Discovered in February 2009, CoRoT-7b takes 20.4 hours to orbit a star that is slightly smaller, cooler and younger than our sun.

The Most Likely to Have Life:
Gl 581 e

Of the four planets that orbit the star called Gliese 581, two are near the edges of what astronomers called the habitable zone, where liquid water may exist. One of these planets is near the cool edge of the zone, but Gl 581 e, spotted in April 2009, is in a warmer spot.

The Biggest Radius:
CT Cha b

This gas giant has a radius that is more than twice as large as our largest planet, Jupiter, and 17 times as massive.

The Hottest:
WASP-18b

Although the data is still preliminary, this 2009 discovery may be the hottest, says University of Central Florida professor Joseph Harrington, stealing the title from another planet that Harrington calculated to be the hottest in 2007. This speedy planet, which is 10 times the size of Jupiter, hauls its mass around its star in less than an Earth day. But title of "hottest" may still be under contention—because it is so close to its star, WASP-18b is likely to spiral into it within the next million years.

The Most Eccentric Orbit:
VB 10 b

A planet that orbits its star in a perfect circle would have an eccentricity designated as 0. The eccentricity of Earth's orbit is 0.0167—a very slight oval. The orbit of VB 10 b is the most elliptical orbit known—with an eccentricity of nearly 0.98, it is even more stretched out than the orbit of Haley's comet.

The Baby:
Fomalhaut b

Only 25 light-years away, Fomalhaut is a neighbor of our sun. In 2005, astronomers discovered the exoplanet Fomalhaut b hiding amid the interstellar dust surrounding Fomalhaut. The presence of the dust means that the system is still very young and is likely to have more planets form within it—Fomalhaut b may be just the first-born. And just like a baby, this planet is crawling; it takes about 876 years to orbit its star.

The Farthest From its Star:
UScoCTIO 108 b

This planet, which has 14 times the mass of Jupiter, spends its days at about 670 astronomical units—about 64 billion miles—away from its star. That's about 17 times farther away than dwarf planet Pluto is from our sun.

The Farthest from Earth:
OGLE-05-390L b

At 21,450 light-years away, this is the farthest exoplanet scientists have found. It is five times the mass of the Earth and twice the distance from its star and it trundles slowly around, taking 3500 days to orbit.

at 10:58 PM

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Space

NASA Solar Observatory Tries to Play Weatherman With Our Star: Gallery

The $850 million Solar Dynamics Observatory may help scientists find the causes of solar weather events that disrupt technologies on Earth—while taking unprecedented high-resolution pictures of the sun. Here are some of the latest images from the new observatory.

For most of us, the sun is a big static yellow ball that helps plants grow and skin tan, but a closer look reveals a maelstrom of movement, storms and explosions. The magnetic field on the solar surface shifts constantly, impacting the conditions in the outer atmosphere, called the corona. Sometimes the fluctuations are dramatic enough to produce high-energy explosions, called solar flares, or even to release material from the solar atmosphere, known as a coronal mass ejection—events that last only a few seconds but that can disable satellites and disrupt power grids and communications equipment on Earth. NASA's new Solar Dynamic Observatory (SDO) combines the ability to take rapid-fire photographs of the Sun with the capacity to comprehensively monitor its electromagnetic activity. On May 14, the SDO completed its post-launch check and officially began its 5-year, $850 million mission. Here are some of the stunning new images coming from the observatory—and what they mean to humans.

(PHOTO BY NASA)

Every 10 seconds, the atmospheric imaging assembly (AIA) uses four telescopes to take high-definition photos of the corona. Because of its high resolution and speed, NASA describes the AIA as "like an IMAX camera for the Sun." This photo, taken by the AIA on March 30, 2010, shows a prominence eruption.

(PHOTO BY NASA)

The underlying cause of eruptions like this remain unknown to scientists. Prominence eruptions often remain anchored to the sun, but some give rise to coronal mass ejections.

(PHOTO BY NASA)

The sun is made up of plasmas—extremely hot gases composed of electrons, as well as atoms of elements like helium and iron with varying numbers of electrons removed from them (technically making them ions). The plasmas differ in temperature depending on their composition, and each temperature produces a different wavelength of light. "The solar corona contains plasma at many temperatures because the heating of the gas by the magnetic field is extremely complicated," SDO project scientist Dean Pesnell says. Here, the AIA is zoomed in on a flaring region and has filtered out all wavelengths except 171 angstroms, the light emitted by a 1 million Kelvin (1.8 million degree Fahrenheit) plasma made of iron atoms, called Fe IX, that have had 8 electrons removed.

(PHOTO BY NASA)

The hope is that the speed and resolution of the AIA, combined with the sensitivity of the extreme ultraviolet variability experiment (EVE) to the most variable and unpredictable part of the solar spectrum (called the extreme ultraviolet), will help researchers better understand how these complex heating patterns emerge. Here again the AIA is zoomed in on a flaring region, this time imaging the sun in the light of Fe XX, an iron atom with 19 electrons removed. The wavelength is 131 angstroms, and the temperature of the plasma is a scorching 10 million Kelvin (18 million degrees Fahrenheit). In this image, the colors were artificially intensified to bring out certain details.

(PHOTO BY NASA)

Every day, the SDO sends NASA researchers multiple images of the sun, seen in each of 10 selected wavelengths. This one corresponds to 193 angstroms. These images are enhanced with artificial colors to more clearly differentiate them.

(PHOTO BY NASA)

An image of the sun, taken by the AIA, with all light except that of 211 angstrom wavelength filtered out. The image is enhanced with artificial color.

(PHOTO BY NASA)

An image of the sun, taken by the AIA, with all light except that of 171 angstrom wavelength filtered out. The image is enhanced with artificial color.

(PHOTO BY NASA)

This image is a composite of the images taken at 193, 211 and 171 angstroms (the three previous images respectively). The artificial colors highlight different temperatures. The reds (about 107,540 degrees Fahrenheit) are somewhat cool when compared to the blues and greens (greater than 1,799,540 degrees Fahrenheit).

(PHOTO BY NASA)

An image of the sun, taken by the AIA, with all light except that of 304 angstrom wavelength filtered out. The image is enhanced with artificial color.

(PHOTO BY NASA)

Another three-wavelength composite, this time of images taken at 304, 211 and 171 angstroms.

(PHOTO BY NASA)

An image of the sun, taken by the AIA, with all light except that of 094 angstrom wavelength filered out. The image is enhanced by artificial color.

(PHOTO BY NASA)

An image of the sun, taken by the AIA, with all light except that of 394 angstrom wavelength filtered out. The image is enhanced with artificial color.

(PHOTO BY NASA)

Another three-wavelength composite image, this time of images taken at 094, 335 and 193 angstroms.

(PHOTO BY NASA)

This image, taken by the AIA, shows the sun in 4500 angstrom wavelength light, which is within the section of the spectrum visible to the human eye (about 3900 to 7500 angstroms).

(PHOTO BY NASA)

The helioseismic and magnetic imager (HMI) will develop maps of solar magnetic fields, like this one, called magnetograms. The HMI will also examine the interior of the sun to help scientists better understand the physics of the sun's magnetic dynamo, which scientists believe is the source of magnetic fields on the surface.

(PHOTO BY NASA)

In this image, taken by the HMI, the Earth is eclipsing the sun. Earth's atmosphere refracts the light, causing the sun's shape at the edge of the shadow to bend.

(PHOTO BY NASA)

at 10:55 PM

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Space

UFO Footage: Videos of Unexplained (and Easily Explained) Phenomena

Images of UFOs were caught on video and spread to the public long before YouTube made it easy. They're caught in parking lots and on rooftops by avid UFO-spotters or passersby with camera phones. These particular videos show meteors, clouds, military flares and camera tricks that some claim are sightings in all their grainy, handheld glory.

Stephenville, Texas became the center of UFO-sighting in the United States when, on January 8, 2008, red orbs were spotted in the sky by a number of observers. The next day, the Stephenville Empire-Tribune published one account and, soon after, the town had made national news. "Texas Town Abuzz Over Dozens of UFO Sightings," wrote Foxnews.com. "Are UFOs Invading Texas?" asked Texas Monthly.
Phoenix Lights

At 10 pm on Mar. 13, 1997, thousands of residents of Phoenix, Arizona witnessed a string of bright lights disappearing over the Estrella mountain range. The Air Force at first denied any warplanes in the area, but later recanted, saying a pilot dropped 10 decoy flares in the area that evening.
Hudson Valley Boomerang

More than 300 people in the Hudson Valley reported seeing V- and boomerang-shaped lights in March 1983. The incident turns out to be a hoax by pilots who rigged their planes with extra lights before formation flights.
Military Flare Exercises
Two Lockheed AC-130 planes drop flares in this video. These aircraft have a Countermeasures Dispenser System, that make use of a computer controlled system to dispense decoys for to shake infrared and electronic targeting.
Decoy flares, as seen on this F-16 fighter, give heat signatures that resemble airplanes. Some decoys come with thrusters, according to Dennis Clark, a countermeasures engineer at BAE Systems. New missiles have sensors that use color to distinguish target airplanes as well, and other flares have the ability to change colors to shake these weapons.
Camera Tricks
David Caron from Stephenville, Texas videotaped squiggling, multicolored lights on Jan. 19, 2008. "You could see it much better through the camera than just with the naked eye," he told the Stephenville Empire-Tribune. In this video that he shot, Caron was likely filming a distant, stationary light. The handheld exposure of a bright light results in light streaks from camera movement that could explain these images, says George Reis of Imaging Forensics. The color shift may be from color mosaic filtration on the cameraÂ¹s CCD chip, Reis says.

In a series of images showing "long exposure of very distant lights," Bruce Maccabee, a UFO expert, explores exposure times and their impact on capturing bright objects at night with cameras. Here, he shows examples of how exposure effects-on a river-side power plant and images of Mars-can create the illusion of a fast-moving object.
Natural Phenomena
A. Meteors
In November, 2008, a meteor hit the ground in central Alberta. Residents all over Western Canada got an extraordinarily bright light show in the early evening on Nov. 20. Multiple fragments of the recovered meteorites measured up to 8 cm in diameter. Some 25 million meteors enter Earth's atmosphere every day.
The Peekskill meteor of 1992 was captured by 16 different video cameras before it struck a car in Peekskill, NY. Popular Mechanics senior science editor, Jennifer Bogo, was one of many witnesses to the spectacular event. Like the person who took this video, she too watched the meteor blaze across the sky over a high school football game in Pennsylvania--about 120 miles from Johnstown, where this footage was shot. "It was the homecoming game, and this giant ball of fire streaked right into the end zone," Bogo says. "It was the closest thing to a touchdown our team had seen in years."

The Peekskill Meteorite Car became famous shortly after it ate meteor, even going on a world tour to show off its extraterrestrial body damage.
B. Lenticular Cloud, aka Altoculus Standing Lenticularis

Moist air forced to flow upward around mountain tops can create Lenticular clouds. When fast moving air is forced up and over a barrier-like these clouds moving over Mt. Rainier in Washington-perpendicular to the direction that the upper winds are blowing, these seemingly stationary, saucer-like Lenticular clouds form.

at 12:06 AM

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UFO Central

6 Top-Secret Aircraft that are Mistaken for UFOs

The CIA estimates that more than half of the UFOs reported in the 1950s and 1960s were really American spy planes. Here are six (no longer) secret aircraft that people have mistaken for extraterrestrial flying saucers.

Spy and stealth planes--some with bizarre, bat-shaped wings, others with triangular silhouettes that imply otherworldly designs--have long generated UFO sightings and lore. And official denials feed rumors that the government isn't telling us about alien ships. The CIA estimates that over half of the UFOs reported from the '50s through the '60s were U-2 and SR-71 spy planes. At the time, the Air Force misled the public and the media to protect these Cold War programs; it's possible the government's responses to current sightings of classified craft--whether manned or remotely operated--are equally evasive. The result is an ongoing source of UFO reports and conspiracy theories. Here are the Earth-built craft that likely have lit up 911 switchboards over the years.

1. RQ-3 Darkstar

Manufacturer: Lockheed Martin/Boeing First Test Flight: 1996Deployment: None (it was canceled in 1999) Declassified: 1995 Size:15 ft long; 69-ft wingspan Performance: 288 mph (cruising speed); 45,000+ ft (max. alt.)

UFO Link: The official life span of this unmanned spy plane was brief and disappointing, with a crash and a program cancellation after just three years. But in 2003, Aviation Week reported that a similar stealth UAV was being used in Iraq--fueling speculation that the government scrapped the craft publicly only to secretly resurrect it for clandestine missions.

2. U-2
U-2

Manufacturer: Lockheed Martin First Test Flight: 1955 Deployment:1957 to present Declassified: 1960 Size: 49 ft long; 80-ft wingspanPerformance: 410 mph (max. speed); 85,000 ft (max. alt.)

UFO Link: Designed for high-altitude reconnaissance, the U-2's long, gliderlike wings and silver color would have been notable to observers on the ground and in the sky. In the 1960s the airplane was painted black to avoid reflections. The U-2 is also famous for being among the first classified planes to be flown from the Air Force's secret test facility at Groom Lake, Nev.--aka Area 51.

3. SR-71 Blackbird

Manufacturer: Lockheed Martin First Test Flight: 1964 Deployment:1966 to 1990, 1995 to 1998 Declassified: 1964 Size: 107 ft long; 56-ft wingspan Performance: 2432 mph (max. speed); 85,000 ft (max. alt.)

UFO Link: The tailless spy plane has an even more unusual cross section than the U-2. This Area 51 alum was briefly reactivated in the 1990s, and rumors of a followup--the now-legendary Aurora project--have supplied both UFO believers and skeptics with a possible source of unexplained sightings.

4. P-791
SR-71 Blackbird

Manufacturer: Lockheed Martin First Test Flight: 2006 Deployment:Unknown

UFO Link: Plane spotters' photos and videos blew the top-secret cover off a 5-minute inaugural flight in Palmdale, Calif. The hybrid airship--it uses gas and a wing shape for lift--fuels speculation that classified airships quietly roam the night skies.

5. F-117A Nighthawk

Manufacturer: Lockheed Martin First Test Flight: 1981 Deployment:1983 to 2008 Declassified: 1988 Size: 107 ft long; 56-ft wingspan

UFO Link: This long-range stealth fighter, which could stay aloft indefinitely thanks to midair refueling, remained classified through much of the 1980s during test flights at Tonopah Test Field Range in Nevada, 80 miles from the legendary Area 51 Groom Lake facility. Along with the B-2 Spirit, the batlike F-117A was a perfect candidate for triangular UFO sightings.

6. B-2 Spirit
SR-71 Blackbird

Manufacturer: Northrop Grumman First Test Flight: 1989 Deployment:1997 to present Declassified: 1988 Size: 69 ft long; 172-ft wingspan

UFO Link: Although the long-range bomber was never a true "black aircraft," since it was displayed to the public approximately eight months before its first flight, an airborne B-2 is a UFO report waiting to happen. It looks like an alien craft from nearly any angle and specifically like a flying saucer when viewed head-on or in profile.

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Water, Hydrocarbons and Life on Saturn's Moons: Gallery