Birth of stars: Clouds of gas collect And form stars. Young hot stars still with clouds of gas surrounding During Explosion After Explosion Death of a Star Supernova 1987A Explodes 170,000 Years ago a star explodes in a small nearby galaxy known as the Large Magellanic Cloud that lies just beyond the Milky Way. The star, known in modern times as Sanduleak 69202, was a blue supergiant 25 times more massive than the Sun. Such explosions distribute all the common elements such as Oxygen, Carbon, Nitrogen, Calcium and Iron into interstellar space where they enrich clouds of Hydrogen and Helium that are about to form new stars. They also create the heavier elements (such as gold, silver, lead, and uranium) and distribute these as well. Their remnants generate the cosmic rays which lead to mutation and evolution in living cells. These supernovae, then, are key to the evolution of the Universe and to life itself. What it looks like today (170,008 years ago) The Andromeda Galaxy 2Million LY away Is there life out there? Consider the possibilities… The Big Bang The Birth of the Universe About 15 bya All matter and energy was created Stars and galaxies are still flying out from the explosion (Doppler Red shift) First the universe was created Then it separated into galaxies Then the galaxies formed separate stars The stars formed their own solar systems Where do we go from here?