A total lunar eclipse, called the “blood Moon,” will be visible in North America, East Asia, the Pacific, Australia and New Zealand on Saturday, April 4, 2015.
The ”blood Moon” is a rare form of lunar eclipse that happens when the Earth casts its shadow on the moon and also blocks the sunlight. The light emitted by the Sun still light up the surface of the Moon in spite of the blockage, but gives Earth’s natural satellite a strange color, varying from bright red to brown.
The lunar eclipse is expected to last for about three hours and 29 minutes while the total eclipse will be visible for five minutes, according to Time and Date. The Moon is in the middle of a lunar tetrad, which happens when four total lunar eclipses occur in a row. The lunar eclipse that will occur on April 4, 2015 is the third eclipse of this event. The lunar tetrad also had two prior eclipses on April 14-15, 2014 and October 7-8 2014, while a fourth eclipse is expected to occur on September 8, 2015.
The schedule of this lunar is as follows. Penumbra, which happens when the Moon enters the outer fringe of the Earth’s shadow, is the start of the lunar eclipse. Since the shade is still weak, penumbra cannot be seen with the naked eye. When the Moon advances inwards, the shading becomes much stronger. This marks the beginning of the umbra second stage or the partial eclipse.
The third stage is the total eclipse where the Moon is completely covered by Earth’s shadow. The Moon will then glow in red, orange or brown color. Two factors influence the color of the eclipse. The first is the state of the Earth’s atmosphere. The second is the amount of the surface of the Moon that enters the umbra phase as it passes through. The last two stages, the fourth and fifth, respectively, of the lunar eclipse are next, and refer to the period in which the moon re-emerges into the sunlight, ending the eclipse.
Unlike a total solar eclipse, which can only be observed from a small path across the Earth, the lunar eclipse can be seen by half of the world. Also, compared to the solar eclipse, for the lunar eclipse you don’t need special protection for the eyes to safely observe it.
Image Source: Sky and Telescope