Outer Solar System

Jupiter in the Public Eye

January 23, 2017

Have a look at Jupiter as seen by the Juno spacecraft on its third close pass. A view as complex as the one below reminds us how images can be manipulated to bring out detail. This happens so frequently in astronomical images that it’s easy to forget this view is not necessarily what the human […]

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New Horizons: Going Deep in the Kuiper Belt

December 29, 2016

We’ve retrieved all the data from New Horizons’ flyby of Pluto/Charon in 2015, the last of it being acquired on October 25 of this year. But data analysis is a long and fascinating process, with papers emerging in the journals and new discoveries peppering their pages. The New Horizons science team submitted almost 50 scientific […]

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A New Look at Ice on Ceres

December 16, 2016

Ceres, that interesting dwarf planet in the asteroid belt, is confirmed to be just as icy as we had assumed. In fact, a new study of the world, led by Thomas Prettyman (Planetary Science Institute), was the subject of a press conference yesterday at the American Geophysical Union fall meeting in San Francisco. Prettyman and […]

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Shifting Perspectives on Pluto’s ‘Heart’

December 2, 2016

One of the great pleasures of doing this site is watching researchers matching ideas in peer-reviewed papers. A paper can meet the highest standards for publication but still present an argument that subsequent researchers question, igniting a new round of debate. Trying to get at the heart of a scientific question requires patience, but it’s […]

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Saturn: ‘Grazing’ the Rings

November 29, 2016

What the Jet Propulsion Laboratory refers to as ‘the first phase of the mission’s dramatic endgame’ begins tomorrow for the Cassini Saturn orbiter. Having given us an ocean within Enceladus and numerous images of Titan’s lakes and seas (not to mention ring imagery of spectacular beauty), Cassini now enters a phase in which it encounters […]

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Pluto: Sputnik Planitia Gives Credence to Possible Ocean

November 16, 2016

We’ve been looking at the idea of an ocean beneath Pluto’s icy surface for some time, including interesting work on the thermal evolution of the dwarf planet’s ice shell from Guillaume Robuchon and Francis Nimmo (University of California at Santa Cruz). Back in 2011, The Case for Pluto’s Ocean looked at their view that the […]

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Ring Formation: Clues from the Late Heavy Bombardment

November 2, 2016

Let’s circle back this morning to ring systems, which were the subject of Monday’s post. In particular, I was interested in new work on the rings of Uranus, for Voyager data, newly analyzed, has revealed patterns that indicate the presence of small ‘shepherding’ moons. We’ve seen the same phenomenon at Saturn, but what similarities exist […]

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Uranus: New Work from Voyager Data

October 31, 2016

The ring system of Uranus was the second to be discovered in our Solar System. You would assume this came about because of Voyager, but the discovery was actually made in 1977 through ground-based observations involving occultations of distant stars. The rings of Uranus are narrow — between 1 and 100 kilometers in width — […]

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Titan’s Seasons Studied as Cassini Team Plans ‘Grand Finale’

October 21, 2016

Witnessing Titan’s ever-changing seasons has been a major payoff of the Cassini mission, whose end is now close enough (September, 2017) to cause us to reflect on its accomplishments. We now see winter settling in firmly in the southern hemisphere, along with a strong vortex now developing over the south pole. When Cassini arrived in […]

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New Work on Planet Nine

October 20, 2016

Considering how long we’ve been thinking about a massive planet in the outer Solar System — and I’m going all the way back to Percival Lowell’s Planet X here — the idea that we might find the hypothetical Planet Nine in just three years or so is a bit startling. But Caltech’s Mike Brown and […]

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