TOP 100 SCIENCE SITES
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| Letters: Acupuncture and Science (1 Letter) A letter to the editor. feeds.nytimes.com |
Melting sea ice forces walruses ashore in Alaska By 2010-09-13T17:41:26ZWASHINGTON (AP) -- Tens of thousands of walruses have come ashore in northwest Alaska because the sea ice they normally rest on has melted.... hosted.ap.org |
Soyuz capsule lands in Kazakh steppe with 3 aboard By PETER LEONARD 2010-09-25T19:26:25ZALMATY, Kazakhstan (AP) -- A Russian Soyuz capsule carrying three astronauts who lived six months on the International Space Station touched down safely, but one day late, Saturday morning in the cloudy, central steppes of Kazakhstan.... hosted.ap.org |
Starwatch: Comet Hartley Jupiter, resplendent low in the ESE at nightfall and climbing into the S by midnight, is the only bright planet on view tonight. Through binoculars view a dim star just a Moon's width above and to its left, while the planet Uranus stands three moonwidths away in the same direction.Binoculars should also reveal a comet swooping within 19 million km of the Earth on the 20th on its way to perihelion eight days later. Comet Hartley 2, or formally 103P/Hartley, was discovered from Australia by the British-born astronomer Malcolm Hartley in 1986 and takes 6.46 years to orbit the Sun, roughly between the paths of the Earth and Jupiter. Perihelion lies 158 million km from the Sun, outside the Earth's orbit so we are in no danger of a collision.It is only a small comet and lacks any appreciable tail. Instead, a small knot of greenish luminosity surrounding its icy nucleus is set within an extensive circular glow. The latter is hard to see unless the sky is free of light pollution and moonlight. It is certainly growing, though, appearing wider than the Moon last week and helping to make the comet a naked eye object for those under ideal skies. I suspect, though, that most of us will need binoculars.Our chart shows a 70°- high window of our E sky at midnight and shows Comet Hartley's motion from Perseus, through Auriga and Gemini. Ticks along its path mark its place every two nights, beginning tonight when it lies 5° above-let of Mirfak, the brightest star in Perseus, and stands 20 million km away. Note that it sweeps less than 3° to the right of Capella on the 18th though by then moonlight is becoming an issue.The comet is the target for Nasa's Epoxi mission, with a fly-by planned for 5 November. Epoxi is the name for the extended mission of the Deep Impact spacecraft that visited Comet Tempel 1 in 2005 and watched the explosive results as it fired a projectile into the nucleus. Next month, though, there will be no such impact and only the briefest of inspections as the probe speeds to within 700 km of Hartley's nucleus at 12.3km per second.The stars on our chart climb higher during the night so that Capella stands overhead by 05:00 as Orion straddles the meridian. It may be interesting to check the brightness of the variable star Algol in Perseus. This usually shines at magnitude 2.1, a little fainter than Mirfak, but every 2 days and 21 hours it fades threefold in brightness to magnitude 3.4 as the fainter of its two component stars eclipses its companion. Each dip in light lasts ten hours and takes Algol below the mag 2.9 of Epsilon (see chart).SpaceSpace technologyAlan Pickupguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Water Scarcity a Bond Risk, Study Warns Researchers say that many municipal bonds may be riskier than investors realize because ratings do not adequately reflect the risks of water shortages. feeds.nytimes.com |