the view from the internationalspace station, some 250 kilometres above earth. travelling at nearly 2900 kilometres an hour, it orbits the earth every ninety minutes. consider that if the earth was the size of a basketball, our atmosphere would be as thick as a sheet of paper. the reds and greens you see illuminating our atmosphere is the result of airglow (though in some of these it’s also the aurora). for more on airglow, see this post.
Described as a “dusty curtain” or “ghostly apparition”, mysterious reflection nebula VdB 152 really is very faint. The cosmic phantom is nearly 1,400 light years away and it lies along the northern Milky Way in the royal constellation Cepheus. Near the edge of a large molecular cloud, pockets of interstellar dust in the region block light from background stars or scatter light from the embedded bright star giving parts of the nebula a characteristic blue color.
Ultraviolet light from the star is also thought to cause a dim reddish luminescence in the nebular dust. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through space is very different from the cloud’s velocity. This deep telescopic image of the region spans about 7 light-years.