Starting Friday evening and lasting for a few more evenings, humans will have the rare opportunity to view all seven non-Earth planets in the solar system at the same time. The next time such an opportunity will arise won’t be until 2040.
The planets will be formed in what is called a planetary alignment, or “planetary parade.” Normally, such a view is not possible because the orbital period of each planet is different.
“The eight planets in our solar system orbit the sun in roughly the same plane because they all originally formed from the same disc of debris around the sun,” New Scientist explains. “The line the sun traces across the daytime sky – called the ecliptic – aligns with this plane, so when the planets appear in the sky, they all appear roughly along the ecliptic. It isn’t a perfect line of planets, because their orbits are tilted slightly, but it is…
