Greg Bear : I think the problem is that we have a lot of people who are not very good at math and science in general. Although geology was still reluctant to admit to any form of `` catastrophism , '' eschewing biblical explanations , many read and pondered ... seriously . Named after an evil Egyptian serpent god , Apophis swings by every seven years . Bear : We can never be 100 % sure how close it will come or if events might change its course . If Apophis hit Earth , he says , the blast would be the equivalent of over a billion tons of TNT .
Greg Bear : I think the problem is that we have a lot of people who are not very good at math and science in general. Named after an evil Egyptian serpent god , Apophis swings by every seven years . Bear : We can never be 100 % sure how close it will come or if events might change its course . If Apophis hit Earth , he says , the blast would be the equivalent of over a billion tons of TNT .