The constellation Cygnus, the Swan, rides high in the east just after dark during late summer. Just look for a large cross on its side. Easy.
Down and to the right from the west-most star in the cross is a faint star. That star is embedded in a faint arc of light, just visible in large astronomical binoculars away from city lights.
Nearby to the north is another faint arc. The two wisps of light, called the Veil Nebula, seem to form a broken circle.
In a large amateur telescope, they have the subtle look of smoke rising from a dying ember. Their detailed filaments, undulations, and cataracts of light are played out against the velvet blackness of space behind and intertwined within them.
During their long lives, stars combine hydrogen into helium in stupendous hydrogen-bomb explosions that last 10 billion years.
But that seething thermonuclear reaction is nothing compared to what happens to most stars at the end of their life cycles. Having used up their hydrogen supply, they self-destruct, sending their outer shells back into space, perhaps to establish the building blocks of new stars.
As stars exhaust the hydrogen in their hot centers, they expand to gigantic sizes and turn red. The normal evolution of a star is from a relatively stable yellow star like our sun to a bloated red giant, over 500 times our sun’s diameter.
Often, those red giants collapse into very dense balls, called white dwarfs, which are only a few thousand miles in diameter. Imagine most of the substance of our sun, which is over 950,000 miles in diameter, condensed into a sphere only half the diameter of Earth, about 4,000 miles across.
A small portion of the star’s substance, its outer shell of gas, is blown into space, forming a rapidly expanding shell of gas mainly composed of hydrogen.
One such dead star, the Ring Nebula, is visible telescopically to the west of Cygnus in the constellation Lyra, the Lyre.
Its expanding outer shell expresses itself as a weird and wonderful ring of glowing gas, a cosmic Cheerio surrounding a very dim white-dwarf star. When you observe it, you see the fate of your star, the sun, in five or six billion years.
Stars much more massive than our sun end their lives in a much more violent expansion. They explode with brilliance hundreds of millions of times greater than their original brightness.
Such explosions, or supernovas, are commonly observed in other galaxies. They briefly shine brighter than their home galaxy, often made up of hundreds of billions of stars.
The Veil Nebula is the remnant of such a cataclysm in our own galaxy, the Milky Way.
The heavier elements found on rocky planets like our Earth are forged in the inferno of such an explosion. Metals like copper and iron can be formed in no other way than in the belly of a supernova.
The gold you wear in the ring around your finger is the beautiful artifact of the spectacular death of a star billions of years ago.
And so is the iron in your blood and the calcium in your bones. You are the living embodiment of the long life and cataclysmic death of supergiant stars.
The supernova that caused the Veil happened about 40,000 years ago. It expelled its cloud at about 1,000 miles/second.
Currently, the expansion of those arcs of light has decreased to “only” 45 miles per second, slowed by the other dust and gas that inhabit the interstellar medium in the area.
In a few tens of thousands of years, they will no longer be visible. They will have blended into the gas and dust between the stars.
Perhaps their hydrogen will form new stars. Perhaps their metals will make up the substance of new planets, their gold to adorn the forms of new races.
Human life is short, a candle in the wind compared to the blazing conflagration we call a star. But with the investment of a few hundred dollars and a sleepless night or two, we can experience the full range of stellar life and death in the short flickering of our brief candles.
Tom Burns is the former director of the Perkins Observatory in Delaware.
