Saturday, March 5, 2016
I'm not sure...
Curiosity is climbing!
Curiosity is climbing! The first picture below is looking behind its track, and it's easy to see that Curiosity is gaining some altitude as it climbs up the slopes of Mt. Sharp. The second photo shows the Naukluft Plateau it's currently climbing up to.
Comet 67P, blowing off some steam...
Comet 67P, blowing off some steam... Beautiful photo captured a few days ago by the Rosetta robotic explorer. It's still orbiting the comet, but later this year they're going to try to make a soft landing on the comet. This is something the orbiter was never designed to do, and there's a very good chance they'll break something on Rosetta when making the attempt. If they succeed, though, there's the chance they'll get to do some more interesting observations right from the surface...
Pluto and Charon...
Pluto and Charon... This is a recently downlinked photo taken by the New Horizons robotic explorer last July. Look how close to each other these two appear to be! I'm not sure what the plane of Charon's orbit is (relative to the camera), so some of this could be an illusion of sorts.
So I did a little research, and found this table. From that table, I computed a few ratios of distances to planets to moon diameters:
Pluto::Charon 16
Earth::Moon 111
Saturn::Titan 237
Jupiter::Ganymede 203
Mars::Phobos 231
So Charon really is unusually close to its planet. The next closest such ratio is that of our own moon, and it's seven times as large! If the moon was proportionally as far from Earth as Charon is from Pluto, it would be just 55,616 kilometers (33,370 miles) away. It would look huge in the sky – the full moon would span 3.6° in the sky, occupying 50 times the sky it does now. That what Charon would look like as seen from the surface of Pluto. Wow!
So I did a little research, and found this table. From that table, I computed a few ratios of distances to planets to moon diameters:
Pluto::Charon 16
Earth::Moon 111
Saturn::Titan 237
Jupiter::Ganymede 203
Mars::Phobos 231
So Charon really is unusually close to its planet. The next closest such ratio is that of our own moon, and it's seven times as large! If the moon was proportionally as far from Earth as Charon is from Pluto, it would be just 55,616 kilometers (33,370 miles) away. It would look huge in the sky – the full moon would span 3.6° in the sky, occupying 50 times the sky it does now. That what Charon would look like as seen from the surface of Pluto. Wow!