2017年3月9日 星期四

Cassini, with only a half-year to go at Saturn, just keeps dropping awesome images


Cassini, with only a half-year to go at Saturn, just keeps dropping awesome images

Posted By Jason Davis

09-03-2017 11:38 CST

Topics: pretty pictures, Cassini, Saturn's small moons, Saturn's moons, Saturn

The Cassini mission at Saturn ends in 6 months and 5 days.

On September 15, after 13 years in orbit, Cassini will plunge into Saturn's atmosphere, preventing it from accidentally colliding with the potentially habitable moons of Enceladus and Titan.

Right now, the spacecraft is in the midst of 20, ring-grazing orbits, after which it will maneuver itself into a path that will take it between the rings and the planet itself on April 22.

At the moment, Cassini's outer ring orbits are revealing some wild, high-resolution shots of some of Saturn's most enigmatic worlds. Most recently, that was the 35-kilometer-wide moon Pan. On March 7, Cassini got its best view yet of the ravioli-shaped moon, which orbits inside the A ring's Encke gap.

Saturn's moon Pan (closeup 1)

NASA / JPL-Caltech / Space Science Institute

Saturn's moon Pan (closeup 1)

Saturn's moon Pan, as seen on March 7 by Cassini.

How amazing is that? Scientists think the smooth equatorial bulge is ring material that has accreted around Pan's surface. Here's another shot, from 25 minutes later:

Saturn's moon Pan (closeup 2)

NASA / JPL-Caltech / Space Science Institute

Saturn's moon Pan (closeup 2)

Saturn's moon Pan, as seen on March 7 by Cassini. This shot was taken 25 minutes after the first closeup.

Here's an incredible image that was captured last month of a "propeller" inside Saturn's A ring:

Santos-Dumont propeller

NASA / JPL-Caltech / Space Science Institute

Santos-Dumont propeller

Two images of a propeller inside Saturn's A ring, as seen by Cassini on Feb. 21, 2017.

What you're seeing is a tiny moonlet inside the rings that have pried open the surrounding ring material by gravity. (The NASA Photojournal site explains this in more detail.)

Here's the same two images, aligned and cropped:

Santos-Dumont propeller, cropped and aligned

NASA / JPL-Caltech / Space Science Institute

Santos-Dumont propeller, cropped and aligned

Two images of a propeller inside Saturn's A ring, as seen by Cassini on Feb. 21, 2017. The images have been cropped and aligned.

For a better idea of how Saturn's tiny worlds gravitationally perturb ring material, check out this mosaic of the moon Daphnis. Emily posted about this image back in January; this is a newer mosaic combining multiple shots:

Daphnis makes waves

NASA / JPL-Caltech / SSI

Daphnis makes waves

A mosaic of Daphnis images captured on Jan. 16, 2017 by the Cassini spacecraft.

Since earlier this year, I've been following the Twitter account @RawCassini, created by Kevin Gill. (I only recommend this if you use an app like TweetDeck to filter your feed; personally, I created a special "OMG Cassini" column just for this account.)

Here are a few more moon images that have recently caught my attention. Enjoy them while you can! In a mere six months, the Saturn system goes dark.

Epimetheus on Jan. 30, 2017

NASA / JPL-Caltech / Space Science Institute

Epimetheus on Jan. 30, 2017
Mimas on Jan. 30, 2017

NASA / JPL-Caltech / Space Science Institute

Mimas on Jan. 30, 2017
Enceladus on Feb. 8, 2017

NASA / JPL-Caltech / Space Science Institute

Enceladus on Feb. 8, 2017

 

See other posts from March 2017


 

Read more blog entries about: pretty pictures, Cassini, Saturn's small moons, Saturn's moons, Saturn

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