“For dust you are, and to dust shall you return.”
God said that to Adam in the Garden of Eden, so the Bible says. And according to Dr. Annelia Sargent, an astronomer from Caltech who spoke at University College last week, in a lecture called “From dust to us: searching for the origins of planetary systems,” modern science affirms the sentiment that our origins and our fate lie in dust.
Dust used to be a bother to astronomers—it blocks light and screws up calculations. But scientists are now realizing that dust holds the key to many questions about life, the universe, and everything. “I used to hate it a lot, but I have come to love the dust,” said Sargent.
Accepted science teaches that in the beginning was the Big Bang. That immense explosion produced the early universe—a cosmic soup of hot, seething, formless matter which eventually calmed down a bit and coalesced into a handful of light elements, mostly hydrogen. Clouds of matter then came together to form stars, and in them atoms fused to create heavier elements. Some big stars collapsed under their own weight and exploded into supernovae, sending out clouds of gas and dust into the interstellar space.
Under the right conditions, dust coalesced into larger bodies, some of which became planets. The dust of stars forms the seeds of planets.
It is dust, said Sargent, that we must study in order to truly understand our origins. And it requires more than just a single telescope to probe the universe thoroughly for dust—arrays of connected telescopes are needed for optimal sensitivity.
Sargent outlined plans for the Atacam Large Millimeter Array (ALMA), a huge radio telescope network to be completed in South America by 2008. The project is a joint venture amongst Europe, the United States and Canada. (Canadian funding for ALMA came through in the recent federal budget.)
Sargent hopes that by examining dust clouds around young stars, we may gain insight into how planets like Earth form, and maybe how to search for extraterrestrial life. Dust particles serve not just as the bedrock of new planets, they also act as chemical catalysts. The surfaces of tiny dust grains are where many of the elements created in the hearts of stars come together to form compounds. Compounds like molecular hydrogen, carbon dioxide, ethyl alcohol and water make life possible, so in a sense we are all born of stardust. As Walt Whitman put it, “A leaf of grass is no less than the journey-work of the stars.”
But it doesn’t end there. All stars age and eventually burn out, and when they do they create an envelope of gas around themselves, engulfing any nearby planets. When the star explodes, so do the planets, spewing its contents into interstellar space. There, new stars form, new planets form, and maybe new life forms. The cycle continues. All life, all matter, all energy is recycled in the great cosmic dance. Ashes to ashes, dust to dust, as they say.
