Why does this starfield photograph resemble an impressionistic painting? The effect is created not by digital trickery but by large amounts of interstellar dust. Dust, minute globs rich in carbon and similar in size to cigarette smoke, frequently starts in the outer atmospheres of large, cool, evolved stars. The dust is dispersed as the star dies and grows as things stick to it in the interstellar medium. Dense dust clouds are opaque to visible light and can completely hide background stars. For less dense clouds, the capacity of dust to preferentially reflect blue starlight becomes important, effectively blooming the stars blue light out and marking the surrounding dust. Nebular gas emissions, typically brightest in red light, can combine to form areas seemingly created on an artist’s canvas. Photographed above is the central part of the nebula IC 4603 surrounding the bright star SAO 184376 (actually 8th magnitude) which mostly illuminates the blue reflection nebula. IC 4603 can be seen near the very bright star Antares (1st magnitude) toward the constellation of Ophiuchus.
Image Credit & Copyright: Rolf Olsen
NASA/Goddard Space Flight Center - View of the Earth on September 21, 2005 with the full Antarctic region visible.
Eight million light years away lies galaxy NGC 2403. Spanning nearly 50,000 light years in diameter, the galaxy displays its incredible spiral arms with hot young stars in blue and glowing star-formation regions in red.
Credit: Canada-France-Hawaii Telescope/Coelum
#astronomy #galaxy #universe #science #stars
X-ray image of the SNR (Supernova Remnant): Puppis A by Gloria Dubner
Puppis A is a supernova remnant (SNR) about 10 light-years in diameter. The supernova ‘occurred’ (i.e. would have been seen on earth) approximately 3700 years ago. Although it overlaps the Vela Supernova Remnant, it is four times more distant.[**]
using nothing more than newton’s laws of gravitation, we astronomers can confidently predict that several billion years from now our home galaxy, the milky way, will merge with our neighbouring galaxy, andromeda. because the distances between the stars are so great compared to their sizes, few if any stars in either galaxy will actually collide.
any life on the worlds of that far off future should be safe, but they will be treated to an amazing billion-year-long lightshow.
a dance of a half a trillion stars, to music first heard on one little world, by a man who had but one true friend.
THE LONELY PLANET
Poor Neptune doesn’t get a lot of visitors. To date, Voyager 2 is the only spacecraft to visit this distant planet, and the data it gathered inspired this composite image created by Rolf Wahl Olsen.
Backlit by the Sun, some of Neptune’s interesting features are highlighted. Its moon, Triton, is visible close by on the right, as well as its very faint ring system, which was discovered during Voyager’s flyby. A dark band of clouds is visible as a spot right at the pole, with a vortex circling around it.
Due to the dearth of high-resolution images of the Neptunian system, Olsen scoured the freely available data from NASA’s Planetary Data System in order to stitch this lovely image together. By modelling the density based on available data, Olsen was able to fill in gaps where the ring system was too faint to be seen. He also worked out the corresponding position of the background stars and added a view of Triton from Voyager’s passage 3 days after the flyby. By carefully considering his calculations, Olsen was able to create this lovely image that gives us a glimpse of what this mysterious outer planet may have looked like through a slightly different lens.