Many people question the need for Nasa to send a probe into a comet. There are plenty of problems that need solving here on earth, the cynics say.
But this mission was vital to securing the future of the planet. There is a school of thought that comets aren't solid hunks of rock, but floating clouds of smaller rocks held together by loose bonds.
If that's the case it doesn't matter if Bruce Willis can pilot a shuttle with physically impossible skills; if something's heading our way it'll be down to the shelters if mankind hopes to survive.
We need to know this stuff. We've had five major extinction events in the world's history that we know about, and at least two of those were down to strikes by space objects.
In 1972 we dodged a bullet when a huge rock skimmed the atmosphere and appeared as a flaming ball above Yellowstone Park. Yes, we have problems on earth, but it makes sense to ensure we'll still be around to solve them.
'Whatever the causes of political polarisation today, it is not social media or the internet,' claims Dr Grant Blank
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'If someone were to venture into one of these relatively benign black holes, they could survive, but their past would be obliterated,' he claims
Captured by accident by an amateur astronomer in Argentina