HOW MANY MOVES AHEAD DOES MAGNUS CARLSEN THINK AHEAD?

It's an old cliche that the best players plot long lines of future moves. In a 2010 profile,Time magazine described Carlson's 'beautiful mind' and how he"often calculates 20 moves ahead". A recent ESPN story about an 8 year old chess prodigy similarly marveled at his " ability to think 20 moves ahead".