Saturday, March 19, 2011

Spring 2011 & The Supermoon




Thanks to a fluke of orbital mechanics that brings the moon closer to Earth than that it has been in more than 18 years, the biggest full moon of 2011 will occur on Saturday, leading some observers to dub it a "supermoon."
The moon has not been in a position to appear this large since March 1993.

On Saturday, March 19th at 3 p.m. Eastern Daylight Time, the moon will arrive at its closest point to the Earth in 2011: a distance of 221,565 miles (356,575 kilometers) away. And only 50 minutes earlier, the moon will officially be full.
At its peak, the supermoon of March may appear 14 percent larger and 30 percent brighter than lesser full moons (when the moon is at its farthest from Earth), weather permitting. Yet to the casual observer, it may be hard to tell the difference.
The supermoon will not cause natural disasters, such as the Japan earthquake, a NASA scientist has stressed. So for all you stargazers - be sure to check it out tonight!

Source: space.com
Image by: David De Bacco
FROM NASA.Gov website. Goddard's Chief Scientist Dr. James Garvin (a more scientific approach)...

Dr. James Garvin, chief scientist at NASA's Goddard Space Flight Center, answers your questions about the 'supermoon' phenomenon.

Question: What is the definition of a supermoon and why is it called that?

'Supermoon' is a situation when the moon is slightly closer to Earth in its orbit than on average, and this effect is most noticeable when it occurs at the same time as a full moon. So, the moon may seem bigger although the difference in its distance from Earth is only a few percent at such times.

It is called a supermoon because this is a very noticeable alignment that at first glance would seem to have an effect. The 'super' in supermoon is really just the appearance of being closer, but unless we were measuring the Earth-Moon distance by laser rangefinders (as we do to track the LRO [Lunar Reconnaissance Orbiter] spacecraft in low lunar orbit and to watch the Earth-Moon distance over years), there is really no difference. The supermoon really attests to the wonderful new wealth of data NASA's LRO mission has returned for the Moon, making several key science questions about our nearest neighbor all the more important.

Are there any adverse effects on Earth because of the close proximity of the moon?

The effects on Earth from a supermoon are minor, and according to the most detailed studies by terrestrial seismologists and volcanologists, the combination of the moon being at its closest to Earth in its orbit, and being in its 'full moon' configuration (relative to the Earth and sun), should not affect the internal energy balance of the Earth since there are lunar tides every day. The Earth has stored a tremendous amount of internal energy within its thin outer shell or crust, and the small differences in the tidal forces exerted by the moon (and sun) are not enough to fundamentally overcome the much larger forces within the planet due to convection (and other aspects of the internal energy balance that drives plate tectonics).