Outer Solar System

Dione: The Last Close Flyby

August 18, 2015

We’re in the immediate aftermath of Cassini’s August 17 flyby of Saturn’s moon Dione. The raw image below gives us not just Dione but a bit of Saturn’s rings in the distance. As always, we’ll have better images than these first, unprocessed arrivals, but let’s use this new one to underscore the fact that this […]

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Reddish Arcs on Saturn’s Moon Tethys

July 30, 2015

Looking for a good science fictional link to Saturn’s moon Tethys (you’ll see why in a moment), I came up short until I recalled Harry Bates’ story ‘A Matter of Size.’ First appearing in the April, 1934 issue of Astounding Stories, the novelette tells the breathless tale of giant humanoid beings who live on Tethys, […]

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New Horizons: Thoughts on Looking Back

July 29, 2015

The New Horizons imagery has been breathtaking, and never more so than in the image below. Here we’re seeing Pluto seven hours after the July 14 closest approach, looking back at Pluto as it occults the Sun. The backlit atmosphere shows us layers of haze reaching 130 kilometers above the surface. Image: Pluto sends a […]

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New Horizons: New Mountains, Pluto’s Moons

July 22, 2015

We’ve already had the pleasure of naming features on Pluto, at least informally, highlighted by the moment when the heart-shaped area revealed by New Horizons was named Tombaugh Regio, after the world’s discoverer. The fact that two of Clyde Tombaugh’s children were in the audience during the news briefing where this occurred made it all […]

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Unusual Charon Closeup

July 16, 2015

The latest view of Charon shows us a 390-kilometer strip of Pluto’s largest moon with a unique feature, clearly visible below. We are looking at what Jeff Moore (leader of the New Horizons Geology, Geophysics and Imaging team, calls “a large mountain sitting in a moat.” Moore is the first to admit that the scenario […]

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Pluto: Encounter and Aftermath

July 15, 2015

Exoplanet hunter Greg Laughlin (UC-Santa Cruz), who could make a living as a poet (if it were possible to make a living as a poet) wrote recently of his hope for a Pluto image “ that will become a touchstone, a visual shorthand for distance, isolation, frigidity and exile.” We haven’t seen that one yet, […]

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Closest Approach!

July 14, 2015

Closest approach for New Horizons was at 0749:57 EDT (1149:57 UTC), with closest approach to Charon at about 0806 EDT. Mission operations manager Alice Bowman told the media briefing that we arrived at Pluto 72 seconds early and 70 kilometers closer than the aiming point, all of which was well within mission specs. Nice work. […]

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New Horizons Countdown

July 13, 2015

We’re under the 24 hour mark for the Pluto flyby. NASA will offer a news briefing for New Horizons (check NASA TV), covering mission status and what to expect during flyby, at 1030 EDT (1430 UTC) today, a schedule change that moves the time up by half an hour. On Tuesday morning, the agency will […]

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Charon: A Rugged, Cratered Surface

July 12, 2015

A chasm in Charon’s southern hemisphere turns out to be longer and deeper than Earth’s Grand Canyon, says William McKinnon (Washington University, St. Louis), deputy lead scientist with New Horizon’s Geology and Geophysics investigation team. “This is the first clear evidence of faulting and surface disruption on Charon. New Horizons has transformed our view of […]

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Last Look at Pluto’s ‘Far Side’

July 11, 2015

The side of Pluto that always faces its large moon Charon is the side that New Horizons won’t see when it makes its close flyby on July 14. That makes the image below what principal investigator Alan Stern is calling “the last, best look that anyone will have of Pluto’s far side for decades to […]

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