The term "the red planet" is of course synonymous with Mars, but the prevailing theory that the distinctive colour was a result of rusting causing by water flowing over the surface now has a challenger. Results from the Spirit and Opportunity rovers perplexingly revealed the presence of minerals that should not have survived contact with water, which set researchers at Aarhus University in Denmark on the trail of an alternative process that could explain the red colour. The solution they have proposed is that regular sand, when combined with magnetite (found in black basalt present on Mars) could have produced a red dust. The researchers found evidence for their theory after tumbling pure quartz in a hermetically sealed flask for seven months, eventually flipping it 10 million times. At the end of the process, some 10% of the sand had turned to dust, which when combined with magnetite developed a red hue. Wind action on Mars could have certainly produced a similar effect over millions of years. The chemical process is not yet fully understood, but if this is the explanation, we’ve got a lot to be thankful for. The black planet just doesn't have the same ring to it.