[News] Lunar eclipse starts heavenly show

[intelliot]

By Leigh Dayton, Science writer
May 06, 2004
THE astronomically uninformed probably were startled by an unusual sight in yesterday's morning sky: a total eclipse of the moon.

"It had a slightly ghostly appearance," said Nick Lomb, curator of astronomy at the Sydney Observatory.

"It (looked) like a faint red disc, fairly low down in the sky," he said. "If you didn't know what it was it would be a complete mystery."

A lunar eclipse occurs when the moon passes into Earth's shadow as it orbits our planet.

Not all eclipses are total, due to a slight tilt in the moon's orbit with respect to Earth's orbit around the sun. So those missing yesterday's pre-dawn spectacle must wait until October 2005 for a reprise.

Astro-fans have more highlights ahead, with a double comet show expected beginning tonight. Comet Neat will be on it's closet approach to Earth, and at its brightest.

Mid-month, Comet Linear will hit it's visual prime. Like its partner, it will appear a smidgen from Sirius, the brightest star in the evening sky. If that's not enough, next June will see the first transit of Venus since 1881. As Captain James Cook observed in 1769, a transit occurs when the planet moves across the sun's disc.

Because it orbits between the Earth and the sun, Mercury also performs transits.

The transiting planets don't cover the entire sun, solar eclipse-style. Instead, they appear as dots, moving across the sun. While Dr Lomb says scientists have gleaned all they can from transits of Mercury and Venus, extra-solar transits may reveal planets circling other stars.

"Astronomers are scanning hundreds of thousands of stars nightly, looking for a planet moving in front of a star."

www.astronomy.org.au

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