But there is a way to counter the increasing brightness of the Sun, the scientists believe - just increase the radius of the Earth's orbit!

BBC: Blue Marble Nasa

We call these stars supergiants and they are 20 times more massive than our own sun and so when these stars go supernova they expand to a radius of up to a billion miles, becoming the biggest and brightest star in the universe.

BBC: NASA's Swift satellite observes massive supernova stars