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NASA Unveils Historic Pictures of Pluto
An anonymous reader writes: The New Horizons team held a press briefing today and released new data and high-resolution photographs of Pluto. Alan Stern, lead researcher of New Horizons said: "We now have an isolated, small planet that's showing activity after four and a half billion years. We've settled the fact that these very small planets can be active for a long time, and I think that's going to send a lot of geophysicists back to the drawing board."
I TOLD you it was a planet. :)
I've fallen off your lawn, and I can't get up.
TFS contains a link to tha NASA main page, and to a finished
live stream on an unrelated media site, now without content.
Way to go!
NASA press release, with picture.
The detailed image showing Pluto's mountains is, according to one of the NASA scientists, one the youngest looking bodies in the solar system. The surface features appear to be less than 100 million years old. Very strange. Are there even any viable theories on what is providing the energy to resurface such an old, far-out, isolated body? A major impact of some kind is the only thing I can think of. Pluto is too small for the heat to be internally generated, and there is no massive nearby body to cause tidal forces and the like.
Better known as 318230.
The main imager (LORRI) is a 208mm diameter telescope with a 2630mm focal length, or f/12.6. The spider and secondary obscure 11% of the area, so that's equivalent to f/13.4 in terms of light gathering for photographic purposes. Exposure times are 50-200 ms, or 1/20 to 1/5 sec.
On Earth, the sunny 16 rule says on a sunny day the proper exposure at f/16 is when your shutter speed is 1/ISO. So f/16, 100 ISO, 1/100 sec. The atmosphere absorbs roughly half the sunlight, so in earth orbit that would become f/16, 100 ISO, and 1/200 sec.
Pluto is about 32.6 AU from from the sun right now, so the sun's brightness there is 1/32.6^2 = 1/1063 what it is at Earth.
Going from f/16 to f/13.4 gets you about 1.43x more light.
Increasing exposure time from 1/200 sec to 1/10 sec gets you 20x more light.
That leaves a deficit of 37.2x, which you can get by increasing CCD sensitivity to ISO to 3,720.
ISO 3200 was easily attainable by high-end consumer digital camera sensors 10 years ago, much less a commercial one specially designed for scientific purposes.