2.5.07

Moonrise



In this image, arguably the most beautiful yet from New Horizons, Europa rises over the cloudtops of Jupiter.

All the best images from New Horizons' Jupiter encounter so far seem to have been in black and white, which I think is a small shame, given how colourful the planet and its moons are. It's understandable, though, because Jupiter is a radically different environment from Pluto. As mentioned in the caption for this colour image of Io:

[The Multispectral Visible Imaging Camera] is designed for the very faint solar illumination at Pluto, and is too sensitive to image the brightly lit daysides of Jupiter's moons.

A quick bit of maths* suggests that the sunlight at Pluto is about 64 times dimmer than at Jupiter (and 1600 times dimmer than at Earth). Of course, any images of Pluto would be fantastic, compared to the meagre, pixellated offerings that are all we have at the moment, but I think that New Horizons' snapshots of Jupiter are only a hint of what it will have to offer us when it eventually reaches the tenth** planet/second dwarf planet/first Kuiper Belt Object/possibly second Kuiper Belt Object including Triton [delete as appropriate].

*Earth is 1 Astronomical Unit from the sun (by definition), Jupiter about 5 AU and Pluto 40 AU (with a lot of variation). Solar flux decreases proportional to the inverse square - ie. if you were twice as far from the sun, you would receive a quarter as much sunlight. There's a nice explanation of this here.
**Don't forget Ceres!

1 comment:

tinker said...

Lovely moonrise. Wouldn't it be interesting to see it's sunset? Well, at least if it were in color...