The argument about how the dinosaurs (and more than 70 percent of Earth's species) were wiped out of existence has taken a clear step in the direction of a massive asteroid or comet strike 65 million years ago.  In new images released this week by NASA, a new radar image of the Yucatan Peninsula taken from space clearly shows a 180-kilometer-wide (112-mile-wide) impact crater — evidence of a geologically devastating event.

The release of the new topological radar image taken by the space shuttle Endeavour three years ago has significantly bolstered the theory of a devastating cosmic impact that brought about the extinction of the dinosaurs and significant numbers of other species.

In the new image, the crater itself is still difficult to see due to the limestone sediments which has settled over it during the past 65 million years.  Despite being visually difficult to identify, the crater is easily identified by the elevation readings returned by the radar imaging.  It is in these radar images that the crater becomes obvious.

The idea of a cosmological event being the catalyst for extinction of massive numbers of Earth's species at the time was first offered up in 1980 by physicist Luis Alvarez and his son Walter Alvarez, a geologist.  Since then, mounting proof has driven the scientific community in that direction with increasing speed.

The Chicxulub crater is now the the focus of intense scientific study as evidence continues to mount which points to this being the flashpoint of the dinosaurs' demise.

As with all things scientific, however, there is no guarantee that a meteoric event is truly to blame for wiping out the dinosaurs and paving the way for humans.  Until we're certain, we're never sure, and even then we keep our minds open to the possibility that we're still not sure.