October 15, 2017
The night sky on your birthday is never quite the same twice — the planets shift, the constellations drift, the Moon wears a different phase.
On the Origin of Gold
Birthday · October 15, 2017
A little universe, just for you
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APOD published October 15, 2017. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
Where did the gold in your jewelry originate? No one is completely sure. The relative average abundance in our Solar System appears higher than can be made in the early universe, in stars, and even in typical supernova explosions. Some astronomers have suggested, and many believe, that neutron-rich heavy elements such as gold might be most easily made in rare neutron-rich explosions such as the collision of neutron stars. Pictured here is an artist's illustration depicting two neutron stars spiraling in toward each other, just before they collide. Since neutron star collisions are also suggested as the origin of short duration gamma-ray bursts, it is possible that you already own a souvenir from one of the most powerful explosions in the universe. Editorial Note: This "best of" APOD ran previously on 2011 September 11. News Note: The next APOD will debut during an NSF discovery announcement and press briefing on Monday.