Thursday is a special day for Pluto. On July 12, this dwarf planet crossed the plane of the solar system for the second time since its discovery. It will be 161 years again. This opportunity provides scientists with a unique opportunity to observe Pluto using an Earth telescope.
All major planets have almost perfectly aligned orbits. They all run on the same plane, which astronomers call it the “eclipse.” Although all major planets operate on this ecliptic, Pluto is different and orbits the sun at an angle of 17 degrees.
This means that sometimes Pluto runs above other planets and sometimes runs below it. The moment when Pluto transitions on the ecliptic is called a node. In this case, Pluto passes from above the ecliptic to below it, making this particular point the descending node of Pluto.
The last time Pluto passed one of its nodes – its rising node – was in 1931, a year after the dwarf planet was first discovered by Clyde Tomb. It took 87 years to reach the lowland this week, which took 161 years to recover, and Pluto then coincides with other planets in 2179.
In addition to being a clever fact as the orbit of Pluto, this moment gives scientists the opportunity to see Pluto in a whole new way. When the Sun, Earth, and Pluto are perfectly aligned, Pluto reflects more of the light back to Earth through a process called opposition. Therefore, astronomers point many of our telescopes to dwarf planets to learn as much as possible about the cold world.