Published: 2014-10-06 18:54:00
Updated: 2014-10-08 08:02:12
Posted October 6, 2014
Updated October 8, 2014
By Tony Rice
On Wednesday, a total lunar eclipse will be visible before sunrise. Total lunar eclipses occur when the moon passes completely through the shadow cast by the Earth.
But what if the roles were reversed? What does a lunar eclipse look like when viewed from the moon? The short answer is: a solar eclipse.
According to astronaut Alan Bean, it’s a “marvelous sight, our home planet [eclipsed] our own star.” Bean and the rest of the Apollo 12 crew photographed the Nov. 24, 1969, lunar eclipse on their return trip the moon.
An astronaut standing on the lunar surface on Wednesday morning would see Earth move from the upper right to lower left in front of the sun, high in the lunar sky. The Earth (despite actually being about 1/100th the size of the sun) appears three times bigger than the sun in the lunar sky, a featureless black disk covering the bright sun. You might also expect the sun to disappear behind Earth during an eclipse viewed from the moon, but Earth’s atmosphere refracts sunlight around it creating a brilliant ring around the Earth. The lack of atmosphere on the moon helps brighten up the effect as well.
From the lunar surface, you'll see the complete eclipse from start to finish. The Earth never sets in the lunar sky. The moon’s rotation is gravitationally locked to the Earth, ensuring that the same side faces Earth throughout its orbit.
You can see Wednesday’s eclipse here in central North Carolina near the western horizon at 5:15 a.m. as the partial eclipse begins. 30 minutes later the upper left half of the moon should have a noticeably reddish tint while the lower right remains a slightly darkened silvery gray. Totality begins at 6:26 a.m., and the moon will be at its darkest and hopefully most colorful just before 7 a.m. The color of the eclipse depends on atmospheric conditions at the time.
Our view of the eclipse will end as the moon sets, the total eclipse ends and the sun rises all within a few minutes of 7:15 a.m.
The forecast looks promising, with cloud cover decreasing throughout the eclipse. The earlier you set your alarm, the higher the moon will be in the sky, but if you aren't a morning person, try getting out between 6 and 6:30 a.m. to see the end of partial going into the total eclipse.
Don't forget to give your eyes a few minutes to adjust for the best viewing.
If clouds spoil this week’s show, we have two more chances next year. This week’s eclipse is the second of four total eclipses in a row. The next opportunities are April 4, 2015, and on Sept. 28, 2015.
Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on twitter @rtphokie.