The mathematicians still objected. It was no longer a question of force. But the theory of probability, they said, made it almost unreasonable to suppose that a collision or near collision could actually have happened within the lifetime of the sun. So astronomers set to work again, some of them to lengthen the past life of the sun, others to bring the stars in general closer together so as to increase the risks of collision. Both parties succeeded admirably. Jeans himself published a calculation which made the sun a million million years of age--seven thousand times older than any other calculation had ever made it. There were now seven thousand times more chances of a collision having taken place than there had been when he started. Others (you may read an account of their observations in an article on the Spiral Nebulæ, by C. Wirtz, in _Scientia_, November, 1925), discovered that when you look long enough and deep enough into the gulf of space (about three hundred thousand light-years is as far as you need to go), it looks as if all matter were outward bound, and moving faster and faster all the time. Therefore the stars used to be much more thickly placed here around home than they are now. A collision becomes easy to imagine. But why is matter going away from here? Apparently for the same reason that rats leave a sinking ship. Our own galaxy, the Milky Way, ought to be five times more thickly settled with stars. As things stand, it is much too light for its size. It cannot hold itself together and is being deserted by its outer fringe of suns all the time. Nor is this the worst of it. The very matter of our solar system is fifty-two times less dense than it should be. Its critical point--that is, the point where it will fly to pieces at the slightest provocation--has long since been passed. Some day, a few million years hence, when you get up in the morning the morning is likely not to be there. This is not such a good story to tell to the children. Nor is the situation any better if you turn your back to the stars, and look at those little stars within things which we call atoms. Very much to the contrary. Some meteorologists created considerable consternation a few years ago by prophesying that one of the glacial epochs, probably the last one, was coming back to play a return engagement--decidedly not by request. But what is a glacial epoch or two compared with atoms in the state ours are in?