SJAA Ephemeris April 2007 | SJAA Home | Contents | Previous | Next

The Last 28 Days in Astronomy

Photo courtesy of NASA/JPL


FEB–19–07 • Heliophysical Year Begins • The International Heliophysical Year has started. A ceremony in Austria kicked off this year of study of space weather. Comparisons are being made to the International Geophysical Year in 1957–58 which saw the first artificial satellites.

FEB–26–07 • Shuttle Hailed the Bad Way • A hail storm damaged the space shuttle Atlantis and it’s fuel tank. As we go to the printer it isn’t known when the shuttle will be able to fly but mid–April is the earliest and June is a possibility.

MAR–01–07 • New Views of Saturn • “Finally, here are the views that we’ve waited years for ... it’s so utterly breath–taking, it almost gives you vertigo.” That’s how Dr. Carolyn Porco, the Cassini imaging team leader, described new pictures of Saturn taken from above and below the plane of Saturn’s rings. If you haven’t done so already, you simply must check out the Cassini photo essay. Go to and click on Cassini Photo Essay in the upper right hand part of that web page. To get more info on these latest images see

MAR–05–07 • Meteorite Hits Home • A meteorite crashed into a house in Bloomington, Illinois. Initial reports indicate that it was a true meteorite about the size of a deck of cards. Further testing will be done to prove its origins. •

MAR–07–07 • YORP Proven • An astronomical effect that causes asteroids to spin faster because of sunlight has now been directly shown and measured. The effect is sometimes called the Yarkovsky effect (named after one of the researchers to describe it) or the YORP effect (an acronym formed from all 4 researchers who are credited with discovering this effect). The effect is not completely unlike that of a radiometer – a children’s toy consisting of black and white vanes spinning inside of a vacuum chamber shaped like a light bulb and slightly larger. But YORP can also cause asteroids to change orbits – enough to move an asteroid into an Earth–orbit crossing threat. The effect was measured on asteroid 2000 PH5. The measured spin increase is just a fraction of a second per year. But asteroid 1862 Apollo has been YORP–ed up to one extra spin per orbit over a 40 year period. •

MAR–09–07 • Pluto Replanetization in New Mexico • A representative of the New Mexico State House has introduced a resolution to declare Pluto to be a planet. Why New Mexico? Clyde Tombaugh went to New Mexico University (after discovering Pluto) and he lived much of his life in that state.


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