It's definitely not Nibiru, nor planet X! It's the BIG GREEN COMET! The icy nucleus of comet 103P/Hartley 2 measures no more than a couple of kilometers across. That tiny nugget, however, is surrounded by an vast atmosphere of gas more than 150,000 km in diameter–about the same size as the planet Jupiter! And it's coming our way. And that means what? At present, the comet is a 7th-magnitude object best seen through telescope. The comet glides by Earth only 11 million miles away on Oct. 20th. Two weeks after Comet Hartley has its close encounter with Earth, NASA will have a close encounter with the comet. The Deep Impact/EPOXI spacecraft is hurtling toward Comet Hartley now, and on Nov. 4th it will fly 435 miles from the comet's active icy nucleus. The encounter will mark only the fifth time in history that a spacecraft has been close enough to image a comet's core. For astronomers this is an exciting visit. Typically during the course of a year about a dozen comets will come within the range of amateur telescopes. Most quietly come and go with little fanfare, but during the upcoming weeks one rather small comet will be making an unusually close approach to the Earth. On March 15, 1986, astronomer Malcolm Hartley discovered a new comet on photographic images taken at the U.K. Schmidt Telescope Unit at Siding Spring, Australia. At the time Hartley discovered it, the new found comet was an exceedingly faint object, with just a hint of a tail; it was about 25,000 times dimmer than the faintest stars that can be seen with the naked eye. After further images were obtained over the next several days, Hartley announced his discovery to the Central Bureau for Astronomical Telegrams in Cambridge, Mass. This fall, Comet Hartley 2 will again be passing through the inner solar system, reaching its closest point to the sun (called perihelion) on Oct. 28 at a distance of 98.4 million miles. And while en route to the sun, it will also make a very close approach to the Earth. In fact, on Oct. 20, the comet will be at its closest point to our planet at a distance of 11.2 million miles. It's quite unusual for any comet to approach this close to Earth. Such an event only happens on average perhaps three or four times a century. So, we should have an exciting show, but that's about all…………..unless!