End of the World? In 5 Billion Years

I read this article today in Nature (pic from Nature website) about the possibility that Earth is on a collision course with Mercury, Venus, or Mars. Luckily, it's predicted to happen in about 5 billion years, so I think I'll sleep well tonight. The collison is predicted to happen due to the chaotic behavior of our solar system. Briefly, one simulation indicated that a change in the eccentricity of Mercury's orbit could cause a transfer of angular momentum from the larger planets resulting in a destabilization in the rest of the terrestrial planets leading to the collision.