Polar vortex puts American Midwest in a deep freeze. Gridlock: Why Australian politicians are seemingly powerless to act on energy policy. Siberian cave unlocks new clues to the life of Denisovans and Neanderthals. Trump to consider Herman Cain for Federal Reserve Board — World News with Matt Bevan. Murray-Darling Basin Authority 'totally ignored climate change', Royal Commission finds. Sport with Warwick Hadfield. Australia needs 'balance' of power sources to secure supply, Taylor says. Politics with Michelle Grattan. Should horses train on Victoria's beaches? Murray-Darling Royal Commission assessment 'a matter of legal opinion', Glyde says. New banks Xinja and Volt get green light as Hayne report looms. Labor promises increased transparency in judicial appointments system. Science with Jonathan Webb: The flying telescope.