NASA researchers have developed a revolutionary process to generate incredibly accurate eclipse maps, challenging traditional methods and providing unprecedented insights into the true shape of the moon’s shadow as it crosses the Earth.
Shattering the Smooth Sphere Myth
Ever since then calculations of eclipses have assumed that the moon is a uniformly colored sphere, carried out to whatever degree of precision was available and enabled; this included spherical trigonometry approximations of umbral paths. But a new study by NASA has finally blown this assumption out of space, so to speak.
This is only approximately true, however to model the appearance of a shadow traversing the limb of the Moon with data from the Lunar Reconnaissance Orbiter (LRO), in Justin Cowart and Ernie Wright have created two examples as well as one showing an eclipse over Boston. Such a novel method has shown that seconds of totality can be gained or lost due to the mountains and valleys along the edge profile of the moon.
In addition to that, Wright has added Earth elevation data such that observer locations on the globe would be shown at their correct altitude. The result was a movie that procedurally shows us the real, form varying moon’s shadow, with accurate lunar limb and Earth’s terrain effects.
The Potato-shaped Umbra
Perhaps the single most intriguing element of the new eclipse maps is the profile of the moon’s central shadow, or umbra. It was generally assumed that the umbra would be a nice, smooth oval but this is what scientists think it actually looks like: more of a potato-shaped shadow.
That distinctive shape is the result of the valleys & ‘mountains’ bordering the edge of the moon. This features acts like tiny pin holes that project the images of sun to the surface of earth. The small hole in the center of these projected sun images called the umbra, no sun images will reach here.
At the edges of the umbra distribute small arcs from sun images projected to the screen. That surprise find reflects only one of many results that have been unearthed as part of NASA’s new method for mapping solar eclipses — a significant departure from the traditional approach invented 200 years ago.
Conclusion
The technique of mapping the eclipse pioneered by NASA has put our comprehension of how the moon’s shadow shapes and influences the time and duration of an eclipse into another gear. Using both a highly detail lunar topography map and high resolution elevation maps of the Earth, NASA has produced the most accurate models to date validateing what fairdale said roads before our very eyes: eclipses are not uniform and how they turn out depends greatly on exactly where you are. It improves our scientific knowledge, but also opens the door to more accurate eclipse predictions and observations Copyright 2018.
