Tracking the Shadow of the Moon
03 June 2012

Fig. 1
This is a natural-color image by NASA’s Terra satellite, showing the shadow of the Moon darkening part of Earth during the annular solar eclipse of 20 May 2012.
Credit: NASA

When a solar eclipse occurs, the shadow of the Moon falls on Earth, and moves rapidly on its surface. On 20 May 2012, an annular eclipse of the Sun was visible in eastern Asia, the northern Pacific Ocean and western North America. NASA’s Terra satellite has relayed a natural color image (Fig. 1) of the lunar shadow darkening part of Earth, during this eclipse.
An annular solar eclipse is one of the most wonderful natural phenomena. It takes place if the Moon’s apparent size is smaller than the Sun’s. Thus, during maximum eclipse, the Sun is not totally blocked by the Moon, and a brilliant ring of the Sun, known as the ring of fire, remains visible, for a few minutes.

On 20 May, the lunar shadow started its journey across our planet in southern China, at 22:06 GMT. After traversing the Pacific, its path ended in the western United States, around 01:30 GMT, on 21 May. The maximum duration of the annular phase was 5 minutes 46 seconds, over the ocean.

In Fig. 1, the color of Earth’s surface is black, in the area covered by the inner part of the lunar shadow (left of image), but it is yellowish brown in the pale outer part of the lunar shadow.


NASA Earth Observatory
NASA Eclipse Web Site

Aymen Mohamed Ibrahem
Senior Astronomy Specialist
News Center

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