moon wobble


Pluto has one large moon, Charon, and four smaller moons: Styx, Nix, Kerberos, and Hydra. Pluto and Charon actually orbit around each other because they are pretty similar in size. The four smaller moons spin wildly around the planetary system. Hydra, for example, rotates 89 times as it completes one trip around Pluto. T

he moons also wobble like “spinning tops,” thanks to the gravitational pulls of both Pluto and Charon. NASA thinks that the four wobbly moons are the results of mergers of two or more moons — meaning Pluto once had even more satellites than it does now.

— Loren Grush for The Verge

anonymous asked:

I was just wondering if you knew what episodes of Doctor Who feature Riversong, and also what order would they need to be viewed in to follow Rivers timeline (as opposed to the doctors timeline)? Any help would be appreciated! Thankies!


• Season 4: Silence in the Library, Forest of the Dead
• Season 5: The Time of Angels, Flesh and Stone, The Pandorica Opens, The Big Bang
• Season 6: The Impossible Astronaut, Day of the Moon, A Good Man Goes to War, Let’s Kill Hitler, Closing Time, The Wedding of River Song
• Season 7: The Angels Take Manhattan, The Name of the Doctor
• Season 9: The Husbands of River Song (Christmas special)


• A Good Man Goes to War
• The Impossible Astronaut/Day of the Moon
• Let’s Kill Hitler
• Closing Time
• The Wedding of River Song
• A Good Man Goes to War (Wibbly wobbly timey wimey)
• The Impossible Astronaut/Day of the Moon (once again, wibbly wobbly timey wimey stuff thanks Moffat)
• The Pandorica Opens/The Big Bang
• Time of the Angels/Flesh and Stone
• The Wedding of River Song (honestly this is why I hate the Moffat era)
• The Husbands of River Song
• Silence in the Library
• Forest of the Dead
• The Name of the Doctor

(If there’s any part of the timeline that anyone thinks I got wrong, let me know)


Something strange is happening inside Mimas.

The way the moon orbits around Saturn causes it to wobble, something called “libration”.

The problem? It’s not wobbling the right amount to make its orbit accountable. The moon wobbles twice as much as we expected, which means two things:

  • Mimas has a football-shaped core
  • Mimas has a subterranean liquid ocean

This is exciting. The number of places with liquid oceans (probable) has reached five. The number of places in the solar system we must search for alien life is growing rapidly. We may have just added another place to that list.

A Polar Ice Cap?

On April 29, NASA released a series of images showing broad areas of light and dark surface features on Pluto. A bright patch near the north pole was described as “suspiciously suggestive of a polar cap.” These images have been stabilized so Pluto remains centered, with a line showing the orientation of the planet’s north pole. In reality, the gravity of the large moon Charon makes Pluto wobble.


In the NFL, something that behaves like Pluto’s football-shaped moons might be called a wobbly duck. NASA simply calls them astonishing.

Instead of steadily rotating through their orbits, two of Pluto’s moons “wobble unpredictably,” the space agency says, citing new analysis of data from the Hubble Space Telescope.

The two moons, Hydra and Nix, are the largest of the four moons that move around Pluto and Charon — the “double planet” that is the destination of next month’s visit by NASA’s New Horizons spacecraft.

Pluto’s Moons Are ‘Tumbling In Absolute Chaos,’ NASA Says

Photo credit: M. Showalter (SETI)/G. Bacon (STScI)/NASA/ESA


Wibbly Wobbly Challenge | Favourite Two-Parter + Light and Dark | The Impossible Astronaut/Day of the Moon

“I’m going to need a SWAT team ready to mobilise, street maps covering all of Florida, a pot of coffee, twelve Jammy Dodgers and a fez.”