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MASSIVE HURRICANE ON SATURN: NASA's Cassini spacecraft has spotted a gigantic hurricane at Saturn's north pole. High-resolution pictures and video reveal a tempest 20 times larger than the average hurricane on Earth. The hurricane swirls inside a large, mysterious, six-sided weather pattern known as the hexagon.
SUNSPOT EVOLUTION: The number of dark cores inside sunspot AR1731 is rapidly multiplying, causing the sunspot to fragment and sprawl over a wider expanse of solar terrain. Click to view a 48 hour movie of the sunspot's evolution:
As the underlying architecture of the sunspot changes, its overlying magnetic field is changing, too. A solar flare could be in the offing as magnetic field lines twist into explosive configurations. NOAA forecasters estimate a 25% chance of M-flares on April 29th. Solar flare alerts: text, voice.
SPACE WEATHER BALLOON POPS: Last week, we reported on a group of high school students in Bishop, CA, who are launching "space weather balloons" to the edge of space to study the effect of solar flares on Earth's ozone layer. This is what it looks like when a space weather balloon pops:
A camera atop the balloon's payload recorded the explosion at 60 frames per second, allowing the student researchers to create a slow-motion movie of the balloon tearing itself to ribbons. This was their 22nd flight to the stratosphere since 2010, so they've seen this happen many times: another movie highlights some of the best explosions so far.
The popping of the balloon is an intentional part of the mission profile. It happens at an altitude of approximately 120,000 feet above Earth's surface, well inside the ozone layer that the students wish to study. The payload then parachutes back to Earth, where students find it (often in exotic places such as Death Valley) using GPS trackers.
The name of the group is "Earth to Sky Calculus." Check their Facebook page for more information about the space weather balloon program and other activities.
SATURN'S RINGS SURGE IN BRIGHTNESS: This week Saturn is at opposition--that is, opposite the sun in the skies of Earth. Saturn rises at sunset and soars almost overhead at midnight, up all night. This arrangement has a striking effect on Saturn's rings. It makes them bright. Amateur astronomer Christopher Go of the Philippines photographed the phenomenon on April 28th:
"The rings are very bright due to the Seeliger Effect," says Go. Also known as the "opposition effect," the Seeliger effect has been observed on the Moon, Earth and Mars. It happens when sunlit objects (such as the icy particles that make up Saturn's rings) hide their own shadows. A process called coherent backscattering may also contribute to the extra luminosity.
Whatever the details may be, the net result is beautiful. The Seeliger Effect should be operative for a few more days. Readers with backyard telescopes should take a look: sky map.
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