You WOULD know how awesome he is IF you went to his Hot Science/Cool Talks presentation a few weeks ago. IF you went to this, then you would be a more intelligent and cool person. I went, and I am infinitely cooler because of it.
Just to give you a taste of the coolness he oozes, here is an article about the research that Dr. Holt is conducting on Martian ice glaciers.
Dr. Holt works closely with the SHARAD project (ahem, in Rome!) to produce significant evidence that glaciers exist on Mars, albeit covered in dust. This radargram makes it possible to produce the image shown above.
Soooo, check out this article , it's made of awesome.