Thursday, March 10, 2011

What Is a 'SuperMoon'?

Biggest Full Moon Possible Will Be Visible March 19

Next week -- on March 19 -- the moonwon't just be at its closest approach to Earth in its elliptical orbit, enthusiasts say it will be closer to Earth than it's been in 18 years.
The moon's orbit around us is slightly elliptical, and when the moon is at the near point it is known as a lunar perigee. But on the Internet, astronomy andastrology fans are calling this upcoming lunar event a "supermoon."
For the past few days, they've not only been buzzing about the mega moon, but the meteorological mayhem they expect it to cause.
Floods! Earthquakes! Volcanic eruptions! To hear it on the Internet, this so-called super moon could cause a climatological reign of terror on the entire planet.

But no need to grab your survival kit just yet -- scientists say it just isn't so.

Where Did 'Supermoon' Come From?

AccuWeather blogger Mark Paquette said he thinks the phrase "supermoon" originated on the website of astrologer Richard Nolleand spread to astronomers online.
In a blog post earlier this month, Paquette said a new or full moon at 90 percent or more of its closest perigee qualifies as a "supermoon." Next weekend's full moon won't just be a supermoon but an extreme supermoon, he said, because the moon will be almost precisely at its closest distance to Earth.
According to "new age" forecasts, he said, the supermoon is expected to bring strong earthquakes, storms or unusual climate patterns.
"There were supermoons in 1955, 1974, 1992 and 2005. These years had their share of extreme weather and other natural events. Is the Super Moon and these natural occurrences a coincidence?" he wrote. "Some would say yes; some would say no. I'm not here to pick sides and say I'm a believer or non-believer in subjects like this, but as a scientist I know enough to ask questions and try to find answers."

Astronomer: No Scientific Reason to Expect Extreme Weather

Paquette told that he wants to remain "neutral" on the topic but said, "I do think it's possible that it could bring earthquakes, volcanic eruptions or anything weather-related as well."
But NASA astronomer Dave Williams said there's no reason to believe that anything out of the ordinary -- aside from an especially big and bright full moon -- will take place next week.
"There's nothing really special about this," he said.
For starters, although the moon will be closer than it's been for 18 or 19 years, it will only be one or two percent closer.
"It's nothing you could notice unless you made really accurate measurements," he said. "It's a few thousand miles closer, but as far as the moon's orbit is considered, that's nothing."

Moon Will Be as Big as It Gets

The moon orbits the Earth every 29 1/2 days, so it reaches perigee more than once a month. The orbit of the moon changes slightly over time, so the distance between Earth and the moon also changes -- but only slightly, Williams said.
On March 19, it will probably be only about half a percent closer than it ever is every 18 years, he said, which is a "very, very small amount."
And though the gravitational effect of the moon causes the tides (when the moon is closer, the tides are slightly larger), he said there's "no scientific reason whatsoever" to expect that this supermoon will result in floods or other extreme conditions.
But, Williams said, on the night of March 19, you will want to peek up at the sky.
"Because it's a full moon at its closest approach, it's going to be big and really bright. It should be noticeably brighter than a normal full moon. I would suggest that you take the opportunity and go out at night," he said. "This is the biggest full moon that you will ever see. You will see this moon again, but this is as big as it gets."

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