October 20, 2015
The elements that make you — the calcium in your bones, the oxygen in your lungs — were scattered across space by dying stars long before...
When Black Holes Collide
Birthday · October 20, 2015
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APOD published October 20, 2015 · Video still. Credit: Simulating Extreme Spacetimes Collaboration. A publication-date match, not a photo taken on your date. Independent of NASA.
What happens when two black holes collide? This extreme scenario likely occurs in the centers of some merging galaxies and multiple star systems. The featured video shows a computer animation of the final stages of such a merger, while highlighting the gravitational lensing effects that would appear on a background starfield. The black regions indicate the event horizons of the dynamic duo, while a surrounding ring of shifting background stars indicates the position of their combined Einstein ring. All background stars not only have images visible outside of this Einstein ring, but also have one or more companion images visible on the inside. Eventually the two black holes coalesce. The end stages of such a merger may provide a strong and predictable blast of gravitational radiation, a much sought after form of radiation different than light that has never yet been directly observed. Space Music Video: APOD images from September 2015
Image credit: Simulating Extreme Spacetimes Collaboration