Tuesday, August 22, 2006; Posted: 3:00 p.m.(CDT)

Updated: Thursday, August 24, 2006; Posted 10:00 a.m. (CDT)

Leading astronomers have declared that Pluto is no longer a planet, approving new guidelines that downsize the solar system from nine planets to eight. The International Astronomical Union stripped Pluto of the planetary status it has held since it was discovered in 1930.

According to the International Astronomical Union's website, the 2006 General Assembly has come to the conclusion "that a 'planet' is defined as a celestial body that is in orbit around the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and has cleared the neighborhood around its orbit."

According to the IAU the new definition keeps Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune as planets.  It also adds a new class of objects that will be known as "dwarf planets."  The IAU says Pluto, Ceres and 2003 UB313 (which is only a temporary name) are the first members of the "dwarf planet" category.

Meanwhile, a popular e-mail is claiming that Earth is "catching up with Mars."  The e-mail claims that Mars and Earth won't be this close again until 2287, and that this type of "encounter" hasn't happened in 5,000 years. KSBI-TV Chellie Mills has more.

Wayne Harris-Wyrick, Omniplex Planetarium Director, says the e-mail is not completely false, it's just bad timing. Wyrick tells us Mars actually was this close to Earth, this same month, three years ago.

He says for some reason this e-mail keeps resurfacing causing a headache for all astronomers.

As for the e-mails claims that Mars will be seen as big and bright as the moon, that too is false. 

Wyrick says, "Mars was never as big as the moon as seen from Earth."

In fact, if you were to look up in the night sky for Mars you could not see it anywhere. Wyrick tells us that's because currently Mars is hiding behind the sun.

Mars is not the only planet being talked about this week. Astronomers have met to determine a definition for what constitutes a planet.

Wyrick says there are at least three objects in our solar system which could potentially become planets.

He says astronomers decided to quit saying "I don't know," and develop an actual definition.

Wyrick tells us the new definition will be broad enough to cover current planets, but narrow enough to keep the total number of planets to a minimum.

Some worry that adding new planets will only mess up our children's text books, but Wyrick says that's already a problem. He tells us the text books have to be changed every time a new plant or bird is found, so why not change them for a new planet.