Recently there’s been a lot of buzz about the James Webb Space Telescope that was launched late last year and has recently sent back images that boggle the mind when it comes to conceiving of the vast distances of space and time that it seems to reveal. As a star lore historian, what I’ve been contemplating is not the images or the deep space, but the math that was used to determine where to put the James Webb ~ a place that was realized over 250 ago by French mathematician and astronomer Joseph-Louis LaGrange.
LaGrange lived in late 18th century France and spent part of his life’s work wrestling with what is known in celestial mechanics as the “three body problem,” which seeks to determine whether there is any stable configuration in which three bodies can orbit each other while remaining in the same position relative to each other.
LaGrange worked on a solution to this problem during the eight years from 1764 to 1772. In the midst of his research, the planet Venus transited the Sun, in 1769, a rare event that occurs in pairs that are eight years apart, and which only recur every 120 years. In every eight-year cycle, Venus will come to inferior conjunction with the Sun five times.
And as it turns out, LaGrange was able to determine that there are five solutions to the three-body problem, now known as the LaGrange Points. These are five places where the gravitational pull of two large masses precisely equal the centripetal force required for a third object to move with them. The Webb Space Telescope is positioned at LaGrange 2, which allows it to move with Earth around the Sun and not lose its relationship to either body.
I’m always seeking a way to center the science of astronomy in the human experience, so this inspired me to look for an idea or cultural expression of this “three body problem” as a human encounter, as two human beings coming into relationship with one another such that their forces are so balanced that this third element can arise, because it seems right to me that the macrocosm is fully reflected in the microcosm.
What I find is a description in the New Testament Gospel of Matthew, where the Christ Being says: For where two or three are gathered together in my name, I am there in the midst of them.
The Webb Space Telescope is a million miles away, moving with us around Sun looking and into a region of the sky over the southern hemisphere.
~Mary Stewart Adams
Image of the five LaGrange points that are present in the Earth/Sun relationship, where the force of gravity between the two bodies is such that a third object can orbit in harmony with them. The James Webb Space Telescope is at LaGrange 2. Image from NASA.