Between Mars and Jupiter lies the Asteroid Belt, where large chunks of the 170 km wide Baptistina asteroid had strayed to our side of the Solar System and hit the Moon and the Earth. One of the galactic boulders that hit our world may be the one that caused a mass extinction 65 million years ago and had wiped out the dinosaurs.

Scientists from Southwest Research Institute (SwRI) and Charles University in Prague believe that the Baptistina asteroid was hit by another asteroid measuring 60 km in diameter, causing it to spew out about 140,000 smaller pieces measuring 1 km each, and 300 more measuring 10 km each. Some of the fragments eventually broke out of orbit from the main body, with 2% of them hitting the Earth.

Scientists put the huge galactic drama within Earth's timeline, and found that the Baptistina collision may have caused the huge amount of craters whose ages go back 100 to 150 million years ago. They surmise that 20% of asteroid impact may have been caused by asteroids that broke off from the larger Baptistina family.

The event also ties up with a 85 km crater (called Tycho) on the moon, which was formed 108 million years ago. Scientists are excited at the prospects of connecting up the Baptistina collision to events on the Earth, the Moon and even on other planets. They hope to find out the implications the impact had on the geological and biological history of Earth. Maybe even how it affected human evolution.

Recently, one of our staff writers urged a "grassroots" movement to save Pluto, which was recently stripped of its planetary status.  For those of you who agree that Pluto should remain a planet, here's some good news.

It seems as if the the astronomical  community is not about to let Pluto go down without a fight. 300 researchers recently signed a statement denouncing the IAU's recent definition demoting the ninth rock from the sun. A conference is planned next year where they hope to come up with an alternative definition of "planet." Alan Stern, who heads the New Horizons Mission to Pluto at NASA is helping to organize the conference.

"Teachers are writing me saying, 'We don't know how to teach this,'" Stern says. "We've got to help them out of this jam that the IAU has put them in," says Stern.

Another organizer, Owen Gingerich of Harvard University, believes Pluto's planet label could stick despite the IAU decision if most textbook authors choose to use it. "If the conference is broadly enough representative with the key players, then it may well be that it establishes a different nomenclature than what has been officially voted on by the IAU," he told New Scientist. "It might achieve a more satisfactory consensus," Gingerich says.

For many people it was inevitable, but we still didn't think it would have happened...now it has. 2,500 astronomers who met in Prague for the International Astronomical Union's (IAU) general assembly have demoted Pluto's planet status. Who would have thought that in your science lessons that in the future our solar system would have less planets?

Rather than vote that our solar system contained 12 planets (including the discovery of 2003 UB313 by Professor Mike Brown), the IAU voted that Pluto should be demoted and that our solar system contains 8 planets. "The eight planets are Mercury, Earth, Venus, Mars, Jupiter, Saturn, Uranus and Neptune," said the IAU resolution, which was passed following a week of intense debate.

Pluto has been considered a planet since its discovery in 1930 by the American Clyde Tombaugh, but now it appears that Pluto will have to be ripped out from school textbooks after the IAU resolution. In remembrance of the planet Pluto, here are a few facts that BBC News put together:

• Named after the underworld god
• Average Sun distance: 5.9bn km
• Orbits Sun every 248 years
• Has at least three moons
• Rotates every 6.8 days
• Gravity about 6% of Earth's
• Surface temperature -233C
• NASA probe visits in 2015

The ongoing debate as to what exactly constitutes a "planet" has aroused some ire among astronomers at the meeting of the International Astronomical Union in Prague. The planet definition committee offered three new definitions in an attempt to mollify the scientists that had rejected the first proposal. However, most of the scientists in attendance rejected these as well.

The latest proposal continues to define planets as round objects that orbit the Sun, but adds the following: "In our solar system, we distinguish between the eight 'classical' planets as the dominant objects in their local population zones, and 'dwarf' planets, which are not." This is an attempt to find common ground with the astronomers who had come up their own definition last week.

"They have presented practically the same resolution as before," says Julio Fernandez of the University of the Republic in Montevideo, Uruguay. Fernandez was one of the authors of last week's  proposal.  He added, "Most of the people here think it makes no sense."

It seems like hair-splitting. Everyone agrees that objects in Solar orbit fall into one of three categories: – the big planets from Mercury to Neptune; a number of "dwarf" planets (i.e. Pluto, Ceres, et.al.); and asteroids.  What subject of just what constitutes a "dwarf planet" seem to be the problem. Fernandez says they aren't planets at all, while the Committee says they are.  It's a small thing until you have to answer the question of exactly how many "official" planets actually orbit the Sun. 

A lunchtime meeting turned hostile when Fernandez tried to read his alternative definition.  He was cut off by Ron Ekers, the IAU president.  "I think it was disgraceful treatment," says Brian Marsden, formerly head of the Minor Planet Center in Cambridge, Massachusetts. As more questions were prevented, one astronomer cried out: "If there is democracy, listen to the questions. Let the people speak!" More of the scientists became angered when a  member of planet committee, MIT's Richard Binzel, said: "You can vote based on physics, or maybe you have some preconceived idea of what a planet should be."

Irish astronomer Mike Bailey said "With the present state of knowledge, it's impossible to draw the line between dwarf planets and asteroids." A final resolution declaring that a planetary companion can be a full-fledged planet  if its center of gravity of the system is out in space was rejected by most of those in attendance. That resolution would have made Charon a planet, leaving other planetary companions as moons.

Now there is an attempt to reconcile the warring parties' views in preparation of a vote on the subject coming up this Thursday.

And the rollercoaster ride at the International Astronomical Union (IAU) meeting in Prague continues. After delving on the possibility that Pluto might be demoted to a dwarf-planet, which actually means it is a non-planet, the convention has gone deeper into the issue by putting up a new proposal for Resolution 5, specifically on the definition of a planet.

"A planet is a celestial body that (a) is by far the largest object in its local population, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) does not produce energy by any nuclear fusion mechanism."

It would seem that the debate largely is founded on the question of just how much size, and what shape does a planet really have, as well as the presence of self-determined gravity.

According to the new proposal, if the definition is to be strictly followed, "Pluto, Ceres and other large Trans-Neptunian objects in quasi-hydrostatic equilibrium should not be considered as planets, since they never were the dominant bodies in their accretion zones."

The members of the IAU is set to vote on August 24 on whether to stick with the original proposal, to modify it, or accept the new one.

You may have heard of the hype about Pluto becoming a "pluton" together with its moon. Then there's the proposed 12-planet set-up for our solar system. Now, some astronomers are considering the moon a planet, along with 53 other planet candidates.

According to the new definition of planet proposed by the International Astronomical Union, any round object orbiting the sun is a planet, unless it already has a planet of its own to orbit around. However, there's this thing called the barycenter, which is the center of all gravity. If the barycenter is "outside the larger object, then the smaller object is a planet." That's the reason why Pluto's moon Charon is being considered a planet by some astronomers.

But back to the barycenter. At the moment, the system's barycenter is the earth. But in a couple of a few billion years, the barycenter will "move outside the Earth as the Moon recedes." That this, if the Earth or Moon still exists.

Whether our moon, Pluto, or various asteroids will be considered as planets will be discussed soon as authorities will vote on the new definition of planet on the 24th at the IAU meeting in Prague.