Monday, March 29, 2004

Now for a little science

From Keep

Five planets were arrayed across the evening sky in Cape Canaveral, Florida on Tuesday in a spectacular night show that won't be back for another three decades.
For the next two weeks, Mercury, Venus, Mars, Jupiter and Saturn - the five closest planets - should be easily visible at dusk, along with the moon.
Myles Standish, an astronomer at Jet Propulsion Laboratory in Pasadena, California, says, "It's semi-unique. They're all on the same side of the sun and stretched across the sky and that's what is kind of pretty."
Standish missed Monday evening's opportunity, but said on Tuesday that he will gaze up when he walks his dog this week and next.
He expects mountains and bright city lights to hamper his view, however.
The planetary lineup will be visible to the naked eye every night for an hour after sunset through early April.
At the end of the year, the same five planets will reunite for a few weeks, but in the pre-dawn hours.
Standish said this particular planetary grouping may offer the best night-time views until 2036.

The US space agency has announced that its robotic Mars rover Opportunity is parked on what was once the shore of a salty Martian sea.
There is multiple evidence that the surface of Mars was awash with liquid water at some time in its past. But the latest findings from NASA's robot explorers on the Red Planet are fleshing out a picture of what Mars must have been like when it was wet.
Opportunity has been studying the rocks in a small crater since January.
Earlier in March, scientists announced that rocks at Opportunity's landing site at Meridiani Planum once had water seep slowly through them.
Professor Steve Squyres says, "What's happened since then is we have found what I believe to be strong evidence that the rocks themselves were sediments that were laid down in liquid water."
The earlier finding suggested a large quantity of liquid water had existed at Meridiani Planum.
The latest announcement confirms that there was either a sea, or a series of pools on the surface.
Squyres says, "It's a fundamental distinction. It's like the difference between water you can draw from a well and water you can swim in."
However, Squyres says it was possible that the rocks were laid down by water under a sheet of ice.
The US space agency NASA is clarifying the procedure for telling the President if the Earth is in danger of being hit by a newly discovered asteroid.
It follows the discovery on 13 January of a possibly dangerous object - 2004 AS1 - which for just a few hours had some observers worried it would hit us.
At the time some scientists were unsure at what stage to raise the alarm and who to call, but now the plan is clear.
If necessary, the President would start a Federal Emergency Response Plan.
Although the near-Earth object (NEO) 2004 AS1 was not the type of thing to have wiped out the dinosaurs or threaten our species, it could still have caused considerable damage had it exploded in the atmosphere.
Potentially, the loss of life could have been huge.
The first four observations of the object revealed it could be on a collision course with the Earth, but the uncertainties were large.
There were many possible orbits the object could be on, and the vast majority of them did not threaten the Earth.

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