Beth. Lashinsky, age 8, of Omaha, Nebraska, for her question:
What exactly is cosmic dust?
The stars in our skies belong to a teeming tribe called the Milky Way Galaxy. It has billions of starry suns plus enough hazy clouds to make billions more. This hazy material consists of cosmic gases and cosmic dust, and enormous clouds of it are strewn among the stars and between them.
The cosmos is the universe, the earth and havens as far as we can see and much, much farther. On a clear night, your eye can follow the pale arch of the Milky Way over the sky. This is a cosmic view. You are gazing out, far out across the teeming billions of stars that belong in our Galaxy. Together they form a cosmic sized cartwheel that spins around. Some of the traffic lanes are faster and some slower. And great stream¬ing arms spiral out from the center of the Big Wheel toward the edges.
The billions of stars, old and young, large and small all keep pace with the wheeling Galaxy, each in its proper place. But strewn among them there are vast clouds of gases and fragments of dust. Because these shapeless clouds belong to the cosmos, their contents are called cosmic dust and gases. They come between us and hosts of bright stars and hide them. The stars in front of the dark curtains often look extra bright.
But not all of the cosmic clouds are dark. Some of them happen to be near groups of starry suns. They borrow the bright starlight and glimmer and glow like blobs and blotches, streaks and streamers of hazy candlelight. All the cloudy masses of cosmic dust and gases are called nebulae. A dark nebula has no light; a bright nebula glows like a torn shred of candlelight. The material in these cosmic clouds is, of course, in the form of atoms and minia¬ture particles of atoms. The smallest of all atoms is hydrogen and the core or nucleus of a hydrogen atom is a proton particle. These hydrogen nuclei are especially preva¬lent in cosmic clouds. Helium and certain other gases are also present. There is plenty of elbow room between these tiny fragments. But they are highly charged ener¬getic fragments that dash around at tremendous speeds. Some collide and jam together
What exactly is cosmic to form bigger atoms and molecules, and eventually specks of dust may be formed. Cosmic dust also may come from certain stars.
The starry sky looks such a peaceful place. But this is not so at all. Scddntists say that our stars were formed from vast, shapeless clouds of cosmic dust and gases. New stars are being born while others grow old. All stars are seething furnaces pouring out energy and fragments of matter. Now and again, a star explodes and scatters its fragments far and wide. This star material becomes cosmic dust and a lot of it may mingle with the dark and the bright nebulae strewn through the galaxy.