Astrophysicist who has attempted to bring science to the mainstream with shows like NOVA ScienceNow, an educational science program he hosted on PBS from 2006 to 2011. He played a major role in dismissing Pluto's classification as a planet.
He earned a PhD in astrophysics from Columbia University in 1991 and during his collegiate years he was on the rowing and the wrestling team.
He got married to Alice Young in 1988 and the couple has two children together.
He has made numerous guest appearances on HBO's Real Time with Bill Maher.
In 2001, US President George W. Bush appointed him to serve on the Commission on the Future of the United States Aerospace Industry and in 2004 he earned the NASA Distinguished Public Service Medal.