A new definition of planet could give our solar system a hundred worlds.
All the Makings of a Planet
Pluto looks like it has all the makings of a planet, and yet astronomers still see fit to place it outside the realm of planets.
Northern Lights on a Distant World
Brown dwarfs are like the Pluto of stars. New research published in Nature points to a more planetary nature by discovering bright aurora on a brown dwarf.
It’s Only a Model
When Johannes Kepler proposed a new model of the solar system in the early 1600s, it was a revolutionary idea. The model addressed many of the problems with earlier circular-orbit models, and greatly simplified the calculation of planetary motions. Still, the model was so radical that it wasn’t fully accepted until Newton was able to derive the model from his law of universal gravitation. What made Kepler’s model so powerful is that is required only three simple rules, which we now call Kepler’s laws.
Tis the Season
Today marks the Winter Solstice for those of us in the northern hemisphere, and Summer Solstice for those in the southern hemisphere. While the solstice is often assumed to be the shortest (or longest) day of the year, though the complexity of planetary motion means that isn’t quite the case. It does, however, mark the lowest (or highest) transit of …
Touchdown
This week the Rosetta probe will release Philae to land on the comet 67P/Churyumov-Gerasimenko. It will be the first soft landing on a comet, but not the first probe to land on another world. Besides our homeworld, humans have walked on the surface of one other body and landed probes on five. If successful Philae will mark the 6th solar system object we’ve landed upon.
Going Rogue
A rogue planet is a planet-sized object that doesn’t orbit a star. Instead these objects move through the galaxy just as stars do. They’ve long been thought to exist, but their small size and low temperatures made them difficult to observe.
Twist and Shout
Orbital dynamics, that is, the motion of planets and stars about each other, is deeply dependent on computational modeling. The basic motion of one planet or star about another (the so-called two body problem) is fairly simple, and can be summarized by Kepler’s laws of planetary motion, the motion of multiple planets and stars is extraordinarily complex. In fact while the two-body problem is almost trivial to solve, the three-body problem has no exact general solution. As soon as you have three or more masses in your system, the motion can be highly chaotic.
Alas, Poor Ceres
In 1801 a new planet was discovered in our solar system. Just twenty years earlier the planet Uranus was discovered beyond the orbit of Saturn, and was the first planet discovered since the dawn of civilization. This new planet was named after the Roman goddess of agriculture, Ceres.
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