http://www.eurekalert.org/pub_releases/2006-04/ns-wgo040506.php
Ok, this is ridiculous. We are hunting for another planet which
scientists believe are in between Mars and Jupiter.
Mars and Jupiter can be seen from Earth, if there are indeed
planets out there, why can't we see it, especially during the rare
occasion when the planets will align together?
Even if it is small, previous fly-bys should have caught something.
Besides, there exists an asteriod belt between Mars and Jupiter. It
would be rare that these asteriods would really collide and form
another planet. This scientist is truely mad.
Anyone can rebut me, I can be wrong. 