The same thread was started in the Science forum, I recommended this link:
http://www.talkorigins.org/faqs/po-halos/gentry.html
My viewpoint at the minute is that although halos can be interpreted to show a Young Earth [and even this is open for debate], there are still many other possible interpretations which would fit with the vast majority of other scientific evidence, that is evidence for an ancient earth.
Also, on the subject of Christian scientists, many say that Gentry has been non-objective in his works because of his burning desire to fit them to his religious views. This may or may not be the case, I don't know. What I do know is how amazing it would be if an ardent non-religious scientist discovered something which lead to a Young Earth. Given the supposedly vast ratio of non-religious to religious scientists, one would think there'd have been at least one objective chap or chappette finding some Young Earth science. Particularly since it should be so obvious.
Nick