Plunging at 4.5 million mi/hr! Almost makes you think we should track it's progress. That is, until we consider the distance scale. A simple calculation, based on the data presented in the article, is that it will take "only" 150 million years for the collision (plunge) to take place. <br><br>Considering the collision is 3 billion light years distant, it is sobering to realize the actual collision already happened approximately 2.85 billion years ago. <br><br>Russ Schnitzer