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Pulsars slow down as they get older, and eventually the flashes fade. Millisecond pulsars (flashing about 1,000 times a second) are thought to be more than a billion years old. A few pulsars, one (estimated to be 1,000 years old) in the Crab nebula and one (estimated to be 11,000 years old) in the constellation Vela, give out flashes of visible light.
The number of stripes changed frequently until around 1800. Red, white, and blue became the colours of liberty and an inspiration for other revolutionary flags around the world. Effective date: 19 February 1937.
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