Has the cosmos existed forever, or did something bring it into existence? Time to grapple with the universe's greatest mystery

As Big questions go, it's hard to beat. Has the universe existed forever? Over the years, some of the greatest minds in physics have argued that no matter how far back in time you go, the universe has always been here. Others have argued that the opposite must be true - something must have happened to bring the cosmos into existence. With both sides claiming that observations support their view, until recently an answer seemed as distant as ever.

However, earlier this year, cosmologists Alex Vilenkin and Audrey Mithani claimed to have settled the debate. They have uncovered reasons why the universe cannot have existed forever. Yet what nature grudgingly gives with one hand, it takes back with the other - even though the universe has a beginning, its origins may be lost in the mists of time.

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