To get an idea of the scale of the thing, here is a picture of the comet relative to the size of London : http://www.esa.int/spaceinimages/Images/2014/11/Comet

To get an idea of the scale of the thing, here is a picture of the comet relative to the size of London : http://www.esa.int/spaceinimages/Images/2014/11/Comet_over_London http://www.esa.int/spaceinimages/Images/2014/11/Comet_over_L... I had no idea the thing was so small. To get something to intercept an object that size traveling at 1000's mph is an amazing feat!