Word: orbital
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...newly found planet has about half the mass of Saturn, but its orbit places it about 73 million miles (117 million km) from 55 Cancri, or 20 million miles (32 million km) closer to it than Earth is to the sun. That gives the planet a roughly Earthlike year of 260 days and, more important, puts it in what astronomers call the habitable zone, the distance from its sun at which liquid water can exist. The planet is too dense and gaseous to harbor life as we know it, but if it has any moons, they could be warm enough...
Rather than looking for a stellar wobble, Charbonneau and others are watching red dwarfs for signs of their light subtly dimming as an orbiting planet passes in front of them--a sort of mini-eclipse known as a transit. "If an Earth-size planet in an Earthlike orbit passes in front of a star like the sun," he says, "it dims the star by 1 part in 10,000 or even less." Since a habitable planet around an M-dwarf is much closer--about 7 million miles (11 million km) away--the transit lasts significantly longer. And since the star...
...wouldn't know it, but billions of comets are lurking right now at the outer edges of the Solar System waiting for their big moment onstage. Most will never get the chance: They're destined to orbit endlessly in the deep freeze of outer space - lonely chunks of dirty ice that will always be far too small to be seen, even with a powerful telescope...
Every so often, though, one is nudged out of orbit by a chance encounter with some other object; it plunges in toward the sun, heats up and releases gases and dust that form a halo and stream away in a long, magnificent tail...
...Jerome A. Orosz separately found an object they called M33 X-7, which is about 15.7 times more massive than the sun and researchers are confident is a black hole. In addition to its sheer size, M33 X-7 is unusual for having another star in an extremely close orbit around it, Orosz said. He added that the discovery meant current theory would have to be rethought, since it states that black holes near stars should be smaller than average, rather than larger, as M33 X-7 is. “The assumptions about how stars form black holes...