The longest total lunar eclipse of the 21st century will take place on Friday, July 27, 2018 and will be visible into the morning of July 28.
A lunar eclipse takes place when the moon lines up perfectly with the Earth and sun such that the moon is cast into the Earth’s shadow.
During a total lunar eclipse, the sunlight reaching the moon’s surface has first been refracted by the Earth’s atmosphere. A phenomenon known as the Rayleigh scattering of bluer light causes sunlight to bend towards the red part of the light spectrum and results in the moon appearing as reddish-orange in color. Due to this rusty red color, a totally eclipsed moon is sometimes referred to as a “blood moon”.
According to scientists, this lunar eclipse will be particularly long because the moon will be passing through the central part of the Earth’s umbral shadow. In addition, the moon will be apogee, the furthest point from the earth in its elliptical orbit, so it will look less bright and smaller than usual. It will also take the moon longer to move out of the Earth’s shadow and travel across the sky — stretching out the length of the lunar eclipse.
The National Aeronautics and Space Administration (NASA) in the United States says that the “totality” period of the lunar eclipse, when light from the moon is completely obscured, will last for one hour and 43 minutes in Central Asia and Eastern Africa.
Residents in other parts of Africa and Asia as well those in Europe, Australia and South America will be able to catch a glimpse of a partial lunar eclipse. However, the spectacle will not be visible in North America which will have to wait until 2020 to see a total lunar eclipse.
Sky-watchers around the world will also be get a view of Mars tonight as the red planet approaches the closest it has come to Earth in the last 15 years. The planet will be visible as a “bright red star” in the night sky.
On the night of July 27, the sun, Earth and Mars will be aligned in a straight path so that Mars appears to rise in the east just as the sun sets in the west, making them appear in “opposition” to each other.