Apr 26 2006, 05:34 PM
Failing having a space probe reach another star system in our lifetimes to report back to us just what possible landscapes would look like illumed by stars of different types, we have available to us a (not so handy) simulation.
During solar eclipses on earth, as the moon crosses the solar disk, it preferentially, in the latter stages, obscures more of the central portions of the solar disk as opposed to the edges.
There is also a substantial drop in total light levels too.
The effect mimics having the earth itelf at a farther distance from the sun and additionally, due to the solar limb darkening effect, mimics a star further down the main sequence.
I am thinking that during the latter stages of an eclipse, the landscape is illuminated by the equaivalent of a rather more distant k star, rather than our more familiar g sun.
Has anyone compared the overall light/color balance of the latter eclipse stages to the 'typical' k star?
(I also think the diamond ring effect might mimic a highly ancient white dwarf in our sky, but I am not super sure about that).
Not having a lander sending back surface pictures from a planet at tau Ceti, is this as close as we can get as to what it would look like?
Apr 26 2006, 06:22 PM
Interesting, but the difference of colour between the limb of the Sun and the center of the disk is minute, at least much less than the difference between a sun at the zenith and a sun near the horizon during sunset or sunrise. In more our eyes adapt the colour perception, so that the difference of colour if further attenuated (while being very visible into photos). For instance the colour of our tungsteen lamps is redder than that of a red dwarf, but we don't notice the difference with the bright day sun light. In the shadows, illuminated by the blue sky, the colours ressemble that of a white star like Sirius. But in all cases a sheet of paper appears white to us! But if we manage to twart the colour adaptation sytem, so we have really obvious differences of colours, as in the sunset, or clouds appearing blue from into a room lighted with a candle.
What would be more exotic is how colours would appear in a double star system (if it is possible to have life into such systems, which is another question). In most cases, one of the stars is weaker than the other, and could appear as dark as the moon shine on Earth, when the main star is hidden. But in the case where two stars appear of equal brightness in the sky, while being of different colours, we would have eirie coloured shadow limbs, as in a night club. In some cases, the contrast of colour twart our colour perception, and we see in the telescope a red and a green star (no star is really green). We should see the same colour around shadows, on a planet orbiting into such a system.
Interesting rendering work for artists!!
Apr 27 2006, 01:43 PM
Plenty of examples are to be found on the Web, but I also wanted to point
out a hardcopy book first published in 1987 that has many of the images the
original thread poster requested.
Cycles of Fire: Stars, Galaxies and the Wonder of Deep Space (Paperback)
by William K. Hartmann http://www.amazon.com/gp/product/089480502...glance&n=283155