Life After Death

Not so very long ago, a new star shone in the sky. It happened eighty-seven years ago, so our parents or grandparents probably saw it -- maybe even some of us saw it though we wouldn't have known then why it was special. It wasn't dim, and it wasn't hard to find. For the months that it shone, it was the brightest star in the sky, and it was right in the constellation of Aquila the eagle, at the southern tip of the summer triangle. It shone brightly in June, 1918, when Aquila was high in the sky. It was a nova.

When a star like our sun dies, when it has exhausted all of its fuel and its nuclear fires are extinguished, it begins to contract under the force of gravity until it is no larger than the earth. It is called a white dwarf. As it radiates its remaining heat into space, it shines dimly, first as a white dwarf. Then it becomes a red dwarf, a brown dwarf, and finally winks out as a cinder. This will be the ultimate fate of our own Sun, some five billion years from now.

However, all stars are not like the Sun. Our Sun is alone. But about two-thirds of the stars in the sky are not. They are stellar systems, two or more stars circling each other. And sometimes they are very close to each other. Now if one has died, and become a white dwarf, and if another is very close, spectacular things can happen.

They still circle one another, one the corpse of a dead star, one a blazing ball of hydrogen gas. They are so close that the gravity of the dwarf pulls gas from the living star. The corpse reawakens, igniting the new fuel.

Briefly 1918 Nova Aquila was a half million times brighter than the sun. Then it faded. But even at the fantastic distance of twelve hundred light years - seventy thousand trillion miles -- 1918 Nova Aquila was the brightest star in the sky.

(08/17/05)