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Better get your star sights now

Jan 1, 2003

If the universe is really expanding at a constant speed, as a team of astronomers announced in February, it could mean that in a few years (several billion) there will be no more stars at which to point our sextants. Celestial navigators will be dinosaurs, rendered powerless not by satellite navigation but by the stars themselves.

This recent study supports the theory, which Albert Einstein first suggested and then later retracted as a mistake, that all matter is expanding outward at a constant speed, apparently unaffected by gravity as has been believed. If this is true, the night sky eventually will be dark, since stars will be too far away to see. Or, as Robert Kirschner, a member of the Harvard-Smithsonian Center for Astrophysics, said to the Associated Press shortly after the discovery: "The universe will be a very different place to look at. It will be very lonely."

Conventional physics tells us that after the Big Bang the universe would expand at a rate that would eventually be affected by the force of gravity. This force would ultimately serve to slow the expansion of the universeor so it was expected until scientists who were observing this expansion found that the opposite was true: all matter appears to be traveling at a constant speed. Astronomers used the Hubbell Space Telescope and ground-based telescopes in Chile, Australia, and Hawaii to analyze light from several supernovae that are seven to 10 billion light years away.

"As stars get farther away from us, we can measure the wavelengths of light and determine their speed," said Carl Brandon, a physics professor at Vermont Technical College in Warren, Vt. When a star moves away from us, which most stars are doing, Brandon explained, its light shifts toward the red end of the spectrum.

The astronomers in this recent study measured the so-called "red shift" of selected supernovae over time and applied the principles of the Doppler effect to determine that their speed was increasing. "Although this discovery itself is not new, we're getting better measurements," Brandon added.

This discovery might nonetheless give sailors pause when, on a peaceful, starry night during an offshore passage, the transient nature of our lives is being considered. No longer can we say with confidence, "At least the stars will always shine."