IT’S planet Earth, but not as we know it. Looking ahead more than 7 billion years, scientists have taken a stab at what our vulnerable little world will look like when the sun has swollen into a monster red giant star. The oceans of today will have been replaced by frothing seas of molten rock, and puffy rain clouds by a burning haze of iron, silicon and magnesium (see “Hell on Earth”).
This prediction of our planet’s awesome future raises two questions. First, is it science? A lot of it might look like mere guesswork, yet much of the reasoning is, in principle, testable – through astronomical observations of other solar systems, for example. So, yes, this is science. The second question is whether anybody cares what the Earth will be like 7 billion years hence. Rising temperatures will have made complex animals like ourselves extinct long before that. And with climate change over the