November 18, 2017

05.02.11: Postcards from Saturn.

Rhea and friends…(Credit: Cassini/NASA/JPL).

Ahhhh, but to be a fly aboard a Saturn-circling mission… this weekend, I want to turn your attention to some fairly amazing imagery coming from NASA’s Cassini spacecraft in orbit about Saturn. Cassini has just completed a flyby of several moons, including Enceladus, returned some first ever images of the tiny moon Helene, and on January 11th, took the close-up of Rhea pictured above. [Read more...]

Astro-Challenge: See Saturn’s Moons in 1 to 7 Order.

Saturn's moons on July 31st. (Created by the Author in Starry Night).

Saturn's moons on July 31st. (Created by the Author in Starry Night).


    This week’s challenge may also give you a unique photographic opportunity. On the evening of July 31st (my birthday!) Saturn’s moons will be in 1 to 7 order. This will occur from 6:45 to 11:15 Universal Time, and favor viewers in Australia and the Far East. Later in the evening over North America, only speedy Mimas and Enceladus will be out of order… now is the time to brush up on and perhaps nab some of those hard to spot moons; in descending magnitude, difficulty, and order number (#)  they are: [Read more...]

05.11.09:A Low Pass of Enceladus.

Cassini has completed another close reconnaissance pass of one of Saturn’s most intriguing moons; Enceladus. On November 2nd at 7:40 AM UTC, Cassini passed 62 miles above the icy surface of the south polar region, completing a carefully timed plunge through one of its liquid plumes. This was one of its most comprehensive passes of the moon out of the seven completed so far, enabling the spacecraft to utilize its array of infrared and ultraviolet detectors to analyze speed and particle size. Cassini itself is whizzing along at 5 miles per second. Sodium, water, and carbon dioxide have been detected in the out-gassing, tantalizing evidence that more complex organic chemistry may exist below the surface. Enceladus is heated from tidal flexing caused by Saturn’s gravity squeezing it like a rubber ball. Along with Jupiter’s moon, Europa, Enceladus has been proposed as deserving of future scrutiny as a possible abode of life. Enceladus is a tiny world, about 310 miles in diameter, or about 15% the diameter of our Moon. Two subsurface oceans in one solar system also poses the intriguing question; are environments like Enceladus and Europa more common throughout the universe than Earth? Cassini has phoned home after the recent pass and is reported in good health. Scientists are currently poring over the results; watch for another pass of Enceladus on April 28th of next year. What ever the outcome, Enceladus is proving to be a dynamic place, worthy of future study!

24.10.09: Enceladan Seas?

Move over Europa ; yet another moon may harbor a subsurface sea. Saturn’s moon Enceladus has been inching its way up the charts as of late as a candidate world for extraterrestrial life. Barely 300 miles in diameter, the tiny world is repeatedly flexed by Saturn’s gravity and an increased orbital eccentricity pumped up by the nearby moon Dione. This has caused the tiger-striped surface seen by the Cassini space probe, a surface that shows evidence of repeated fissuring and freezing that almost certainly covers a liquid interior. In fact, Cassini has caught several of the geysers in the act during four recent flybys of the moon. One flyby was close enough that Cassini actually flew through a geyser plume! Activity on Enceladus is now known to almost exclusively contribute to Saturn’s E ring…and recently, a much broader ring system has been revealed by the Spitzer space telescope. Sodium chloride has also been detected in the E ring, presumably from the interior of Enceladus…clearly, the Saturnian system is a dynamic place warranting more scrutiny. Let’s hope that NASA approves Cassini’s seven year mission extension!

AstroNews & Notes: September 2008.

Virgin Galactic 2.0: Sir Richard Branson and Burt Rutan recently unveiled Virgin Galactics’ newest flagship; Mother ship “Eve,”

[Read more...]