Extremely rare but incredibly powerful gamma radiation explosions would be strong enough to wipe out all life on the planet, say researchers.
Scientists say dinosaur population was already under stress from other global calamities when the big rock hit.
Climate change and habitat encroachment is causing plant and animal species to become extinct 1,000 times faster than before humans arrived.
Democratic strategist and former Clinton adviser James Carville said the Republican Party knows the stakes against “presumptive” Democratic nominee Hillary Clinton, declaring that if the GOP loses the 2016 presidential election the party will be pushed into extinction.
Bringing back the woolly mammoth, passenger pigeon or other extinct species is the subject of a conference in Washington.