Letter From Discover

Thursday, December 01, 2005

Blow Your Mind

Photo courtesy Yael Naze and You-Hua Chu/Univ. of Liege, Belgium & Illinois at Urbana/NASA/ESA

Infant stars in the N44 nebula shed hot gas and ultraviolet rays, carving a huge hole into the cloud from which they were born.


 "Do you really believe this is true?"

We get some version of this question every time we publish an article about recent discoveries in cosmology and astronomy. No matter how confidently scientists talk about black holes, dark matter, dark energy, the Big Bang, and the likelihood of more than one universe, readers' heads start spinning. Well, our heads are spinning too. And if it makes you feel any better, even the researchers themselves are often left feeling a bit dizzy. "A part of me is always surprised," says Patrick Petitjean, an astronomer at the Paris Observatory who studies quasars. "I cannot stop asking, 'Why is the universe like this?'"

Pervasive disbelief has become a defining problem of the modern scientific era. As we build better and better devices for examining the universe, we have no equivalently clever tricks for expanding the human imagination to make sense of what those tools tell us. As a result, each new telescope and satellite seems to take astronomy not only beyond the world of common sense but even beyond the world of science fiction.

Part of the problem is that the new instruments reach almost comically beyond the capabilities of human biology. The Swift gamma-ray satellite, for example, spots gamma-ray bursts, flashes of cosmic energy completely mopped up by the atoms in Earth's upper atmosphere before they get to us. Swift sees what human eyes cannot see. The Jodrell Bank Observatory in Cheshire, England, scrutinizes a dark galaxy by tuning in to its radio emissions. Those same emissions are passing right through us right now, completely unnoticed.

Furthermore, the discoveries we make these days involve scales of time and distance that bear no relationship to anything in everyday life. We have a hard enough time envisioning what the world was like at the height of the Roman Empire. We have far less hope of imagining the universe a split second after the Big Bang. Nor can we comprehend when that was: Does it help to know the universe came into being 550 million generations ago instead of 13.7 billion years ago?

But there is a way to begin taking in these swirling cosmic concepts. Look at it bit by bit, the way a vacationer in the Serengeti makes sense of dozens of animals she has never seen before. Every black hole, like every spotted hyena, has a backstory about the people who first spotted it, hunkered down to observe it, and slowly began to understand it. True, you can't go to the local museum to see a black hole the way you can visit a zoo to see a hyena. But at least you can visit one of the 1,100 planetariums in North America and "see" the location of that black hole in the night sky. Geography has a marvelous way of anchoring awe and wonder.

To further help you on this profound journey, we offer our cover story, which begins on the following page. There's nothing quite like a field guide to help you keep hyenas or black holes straight as you forge headlong into unknown territory.

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