January 11, 2015
In the time it took you to read this, the Earth moved another thousand miles through space. You are not standing still. You never have been.
Cataclysmic Dawn
Birthday · January 11, 2015
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APOD published January 11, 2015. Credit: Mark A. Garlick (Space-art.co.uk). A publication-date match, not a photo taken on your date. Independent of NASA.
Will this dawn bring another nova? Such dilemmas might be pondered one day by future humans living on a planet orbiting a cataclysmic variable binary star system. Cataclysmic variables involve gas falling from a large star onto an accretion disk surrounding a massive but compact white dwarf star. Explosive cataclysmic events such as a dwarf nova can occur when a clump of gas in the interior of the accretion disk heats up past a certain temperature. At that point, the clump will fall more quickly onto the white dwarf and land with a bright flash. Such dwarf novas will not destroy either star, and may occur irregularly on time scales from a few days to tens of years. Although a nova is much less energetic than a supernova, if recurrent novas are not violent enough to expel more gas than is falling in, mass will accumulate onto the white dwarf star until it passes its Chandrasekhar limit. At that point, a foreground cave may provide little protection, as the entire white dwarf star will explode in a tremendous supernova.
Image credit: Mark A. Garlick (Space-art.co.uk)