How Quantum Mechanics Helps Birds Find Their Way

Some birds use Earth's magnetic field to navigate, but how they do this has been a mystery. Now, researchers have found a protein in bird eyes with a quantum mechanical sensitivity to magnetic fields.

An Economist Explains: This Is How To Tax Billionaires

Mehdi Hasan sits down with economist Gabriel Zucman, one of the world’s leading experts on tax avoidance and wealth inequality. “If you want to ensure that the super rich pay their fair share, you have to go after wealth itself.”