Monster Hurricane on Saturn Spied by NASA Spacecraft
by Mike Wall
Spectacular new images from a NASA spacecraft orbiting Saturn have captured the most detailed views ever of an enormous hurricane churning around the ringed planet’s north pole.
The stunning new images and video of the Saturn hurricane, which were taken by NASA’s Cassini probe, show that the storm’s eye is 1,250 miles (2,000 kilometers) wide — about 20 times bigger than typical hurricane eyes on Earth. And the Saturn maelstrom is more powerful than its Earth counterparts, with winds at its outer edge whipping around at 330 mph (530 km/h)…
This image covers many shallow irregular pits with raised rims, concentrated along ridges and other topographic features. How did these odd features form?
One idea is that they could be from sublimation of shallow lenses of nearly pure ice, but why do the pits have raised rims? They can’t be impact craters with such fortuitous alignment and irregular margins. They aren’t wind-blown deposits because there are many boulders, too big to be moved by the wind. There are younger wind-blown drifts on top of the pits, and there’s no clear connection to volcanism.
Some speculate that there were ancient oceans over this region—could that somehow explain these features? Ancient glaciation is another possibility, perhaps depositing ice-rich debris next to topographic obstacles.Future images of this region may provide clues, but for now this is a mystery.
(via: HRISE - University of Arizona) (image: NASA/JPL/U of Az)
NASA Announces the Discovery of the Most Interesting Planetary System Outside Our Own
Meet Kepler 62, a system of five planets circling a red star, 1,200 light years away.
by Alexis C. Madrigal
The Kepler Space Telescope has been in orbit looking for planets around other stars since 2009, and it’s started to find some startlingly interesting solar systems out there.
Today, the Kepler team announced the discovery of star system Kepler 62, a group of five planets circling a red star, two of which may be capable of supporting life. That doubles the number of Earth-like planets in the habitable zone that Kepler has confirmed in the cosmos. And they’re the smallest, and therefore closest to Earth size, that astronomers have detected. The system is 1,200 light years away…
This mosaic of WFPC-2 images shows the evolution of the G impact site on Jupiter (the 21 comet fragments of Shoemaker-Levy 9 were each assigned a corresponding letter to identify the impact site; G represents the 7th fragment to strike the planet. It was also the largest impact.).
The images from lower right to upper left show: the impact plume at 07/18/94 07:38 UT (about 5 minutes after the impact); the fresh impact site at 07/18/94 at 09:19 UT (1.5 hours after impact); the impact site after evolution by the winds of Jupiter (left), along with the L impact (right), taken on 07/21/94 at 06:22 UT (3 days after the G impact and 1.3 days after the L impact); and further evolution of the G and L sites due to winds and an additional impact (S) in the G vicinity, taken on 07/23/94 at 08:08 UT (5 days after the G impact).
The International Astronomical Union (IAU) — the official body that governs the designations of all celestial bodies — in their capacity of purveyors of all things “official” has deemed attempts at crowdsourcing names for exoplanets illegitimate. “In the light of recent events, where the possibility of buying the rights to name exoplanets has been advertised, the International Astronomical Union (IAU) wishes to inform the public that such schemes have no bearing on the official naming process,” writes Thierry Montmerle, General Secretary of the IAU in Paris, France.
So… my exoplanet nomination “The Quibble” won’t be official? Spoilsports.
Dramatic underground explosions, perhaps involving ice, are responsible for the pits inside these two large martian impact craters, imaged by ESA’s Mars Express on 4 January.
The ‘twin’ craters are in the Thaumasia Planum region, a large plateau that lies immediately to the south of Valles Marineris, the largest canyon in the Solar System. The northernmost (right) large crater in this scene was officially given the name Arima in early 2012, but the southernmost (left) crater remains unnamed. Both are just over 50 km wide and display intricate interior features.
Multiple terraces slump from the crater walls onto a flat floor, but perhaps the most striking feature is the central pit, a feature it shares with Arima crater to its north.
Central pit craters are common on Mars, as well as on the icy moons orbiting the giant planets in our Solar System. But how did they form? When an asteroid hits the rocky surface of a planet, both it and the surface are compressed to high densities. Immediately after the impact, the compressed regions rapidly depressurise, exploding violently…
A plume of material erupts from the surface of Mercury’s southern hemisphere.
Nasa’s Messenger spacecraft team are currently analyzing images of the eruption. One hypothesis under consideration is that the brightness indicates the presence of a fire fountain, an eruption during which lava is ejected from depth in a jet-like spray of molten rock.
The colorful globe of Saturn’s largest moon, Titan, passes in front of the planet and its rings in this true color snapshot from NASA’s Cassini spacecraft. The north polar hood can be seen on Titan (5,150 km across or 3,200 mi) and appears as a detached layer at the top of the moon here. This view looks toward the northern, sunlit side of the rings from just above the ring plane.
Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft narrow-angle camera on 21 May 2011, at a distance of approximately 2.3 million km (1.4 million mi) from Titan. Image scale is 14 km (9 mi) per pixel on Titan.
As NASA’s Dawn spacecraft makes its journey to its second target, the dwarf planet Ceres, Marc Rayman, Dawn’s chief engineer, shares a monthly update on the mission’s progress.
In the depths of the main asteroid belt between Mars and Jupiter, far from Earth, far even from any human-made object, Dawn remains in silent pursuit of dwarf planet Ceres. It has been more than six months since it slipped gracefully away from the giant protoplanet Vesta. The spacecraft has spent 95 percent of the time since then gently thrusting with its ion propulsion system, using that blue-green beam of high velocity xenon ions to propel itself from one alien world to another.
The ship set sail from Earth more than two thousand days ago, and its voyage on the celestial seas has been wonderfully rewarding. Its extensive exploration of Vesta introduced humankind to a complex and fascinating place that had only been tantalizingly glimpsed from afar with telescopes beginning with its discovery 206 years ago today. Thanks to the extraordinary capability of ion propulsion, Dawn was able to spend 14 months orbiting Vesta, observing dramatic landscapes and exotic features and collecting a wealth of measurements that scientists will continue to analyze for many years…
This was obtained during the tenth orbit of Jupiter by NASA’s Galileo spacecraft. Io, which is slightly larger than Earth’s moon, is the most volcanically active body in the solar system. In this enhanced color composite, deposits of sulfur dioxide frost appear in white and grey hues while yellowish and brownish hues are probably due to other sulfurous materials.
Bright red materials, such as the prominent ring surrounding Pele, and “black” spots with low brightness mark areas of recent volcanic activity and are usually associated with high temperatures and surface changes. One of the most dramatic changes is the appearance of a new dark spot (upper right edge of Pele), 400 kilometers (250 mi) in diameter which surrounds a volcanic center named Pillan Patera. The dark spot did not exist in images obtained 5 months earlier, but Galileo imaged a 120 km (75 mi) high plume erupting from this location during its ninth orbit.
North is to the top of the picture which was taken on September 19, 1997 at a range of more than 500,000 kilometers (310,000 miles) by the Solid State Imaging (SSI) system on NASA’s Galileo spacecraft.
The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA’s Office of Space Science, Washington, DC.
This five-frame sequence of New Horizons images captures the giant plume from Io’s Tvashtar volcano. Snapped by the probe’s Long Range Reconnaissance Imager (LORRI) as the spacecraft flew past Jupiter earlier this year, this first-ever “movie” of an Io plume clearly shows motion in the cloud of volcanic debris, which extends 330 kilometers (200 mi) above the moon’s surface. Only the upper part of the plume is visible from this vantage point — the plume’s source is 130 kilometers (80 mi) below the edge of Io’s disk, on the far side of the moon…
Unlike the rest of the Solar System’s planets, which travel in circles on a flat plane around the sun, Pluto has an elliptical orbit that’s tipped at an angle from the others, making exploration difficult. In July of 2015, after a 9.5 year journey, the New Horizons space probe will pass Pluto, photographing the icy surface for the first time.
Pluto has a thin atmosphere, made up of ice that has sublimated (gone straight from solid to gas with no liquid stage)… but when Pluto is at the farthest points of its 284 year orbit it gets cold enough for the gas to freeze and fall back to the surface. Scientists have estimated Pluto’s surface temperature to be around -230°C (-382°F). This artist’s rendition depicts Pluto’s icy surface; Pluto’s moon Charon is to the left, and the sun, which is about 1000 times fainter on Pluto than it is on Earth, is at the upper right.
The case for water ice hidden in permanently shadowed regions at the north pole of the planet Mercury received another boost recently. On Wednesday March 20, 2013 at the Lunar and Planetary Science Conference, Nancy Chabot presented the very first visible-light images of what is in the shadows of these polar craters.
As Emily reported previously, radar return from Arecibo shows signals consistent with, but not unique to, large deposits of water ice inside the permanently shadowed regions at Mercury’s poles. Numerical models suggest temperatures plenty cold to maintain water ice for millions of years, exactly where the radar signals show potential ice. Measurements of neutron depletion are consistent with hydrogen-bearing molecules, such as water, at the poles, but cannot resolve their exact location in the same way as radar can.
The final piece of the pre-existing story is the strength of the reflection from the MESSENGER Laser Altimeter instrument, which measures the strongest reflection from its 1064 nm infrared laser in the coldest parts of permanent shadow…
The Spring and Summer Northern Hemisphere skies play host to some real treasures for anyone willing to hunt them down. It is also a great opportunity to do some astronomy without being wrapped up in thermals, fleeces, hats and gloves — Spring and Summer astronomy can be really quite pleasant. The downside of course is that you have to wait a little longer for the sky to get dark, if indeed it does get sufficiently dark at your location.
Even so, take the time to get out in the warmer months ahead to hunt down these astronomical beauties…
This Voyager 1 picture of the great red spot shows a white oval with its “wake” of counter-rotating vortices. North is at the top and the distance from top to bottom is about 24,000 km. This enhanced color view emphasizes red and blue at the expense of green. Note the puffy features inside the GRS, and the “reverse-S” spirals inside both the GRS and the oval. The large white feature extending over the northern part of the GRS was observed to revolve about the GRS center with a period of 6 days.