The Flash #129 (1962)

In The Flash #129 from 1962, a comet strikes the sun, putting Earth-2 in danger of radiation. Jay Garrick, as the Golden Age Flash, is tasked by the President of The United States to find a way to absorb all the radiation with a meteor, but when he can't find it in Arizona, he travels to Earth-1 to search for a similar meteor. Meanwhile, on Earth-1, Barry Allen and Iris West attend a costume party where Captain Cold steals the proceeds with the Trickster's help. In comes the Silver Age Flash to investigate, and the two Flashes team up to pursue the fleeing felons. The Golden Age Flash finds a bigger meteor on Earth-1 and transports the fragments to Earth-2. Captain Cold and Trickster fall into the Flashes' trap and are defeated. The meteor fragments save all life on Earth-2, and the Golden Age Flash synthesizes the meteor metal for use on Earth-1 if it's ever similarly endangered. Trust us to give you the top-notch summaries of classic comic books like The Flash #129.