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shared by Mars Base on 19 Apr 13 - No Cached

Textbooks often cite that planetary nebulae (PNe, plural) represent an endstate for lower-mass single stars
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recent research suggests that most PNe stem from binary systems
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The lowest mass star theorized to form the typical PN is near 1 solar mass, and thus without a companion the Sun may not surpass the mass limit required to generate the hot glowing (ionized) nebula typically tied to PNe
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...5 more annotations...
New research continues to question our original understanding of how the Sun’s life may end.
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while the binary interaction model explains some of the anomalies associated with the observed planetary nebula population, this theory awaits final confirmation
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The traditional theory
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does not provide a natural explanation for the non-spherical
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observed for the great majority
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shared by Mars Base on 20 Jan 12 - No Cached

shared by Mars Base on 15 Feb 14 - No Cached

In 1924, Edwin Hubble wrote a letter to Harlow Shapley, which he concluded by saying, “...the distance [to the Andromeda nebula] comes out something over 300,000 parsecs.” Hubble discussed in the letter his measurement of the magnitudes of the Cepheid variable stars in the Andromeda nebula he had found and confirmed. He used their measured characteristics to calculate their distance, definitely about a million light years from our Solar System. This was the evidence that Andromeda was a separate galaxy, far beyond the Milky Way. This was the first proof of an “island universe.” After collecting more data, Hubble sent a paper read on 1 Jan 1925 to a meeting of the American Astronomical Society. Meanwhile, Shapley remained unconvinced, as when he debated Heber Curtis on 26 Apr 1920.
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Hubble notifies Shapley of Andromeda distance
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shared by Mars Base on 28 Mar 12 - No Cached

What is image processing?
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Hubble takes pictures which capture many more colours and gradations of light and dark than the human eye (or consumer digital cameras) can see
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are also quirks in how its cameras work
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designed to make scientifically useful observations rather than being optimised for pretty pictures.
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most of these quirks have already been corrected in the data you find in the archive,
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images are still scientific data rather than photographs like those from a normal digital camera
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still contain far more information than the eye can see.
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beautiful Hubble images that we all know have all been extensively tweaked and optimised by hand, in order to reveal as much of the data as possible
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brightening the glowing gas in nebulae or compressing the dynamic range of galaxy images so that the core and spiral arms can both be seen equally clearly
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Image processing is the name for this process of selecting data, adjusting colour, contrast and dynamic range to reveal the hidden detail in Hubble’s scientific data.
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shared by Mars Base on 07 Jun 12 - No Cached

shared by Mars Base on 11 Jan 14 - No Cached

This nebula with a giant star at its center
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th stars had identical rings of the same size and age, which were travelling at similar speeds; both were located in similar HII regions; and they had the same brightness
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no one can predict when a star will go supernova,
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But astronomers are certainly hoping they’ll have the chance to watch it happen.
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has striking similarities to a star that went supernova back in 1987, SN 1987A.
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SN 1987A is the closest supernova to that we’ve been able to study since the invention of the telescope and it has provided scientists with good opportunities to study the physical processes of an exploding star
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