I hope you got a chance over the summer to see one of the grandest sights in the night sky, the Milky Way galaxy, our home in the cosmos arching across the heavens. But what if there were two? What if the second one was even bigger and brighter and intersecting our own Milky Way in a huge V up in the sky? Would that not be a sight to behold? That is just the view that will be seen from earth in the deep future, if anyone is still around to see it.
Since long before the earth existed, even before our sun was just a twinkle in the Milky Way’s eye, we have been falling. Our entire galaxy of 300,000,000,000 suns has been falling, in what is probably one of the longest falls in the history of the universe, into the Andromeda galaxy. Andromeda is bigger than us with hundreds of billions more stars. which means it has more mass. More mass means more gravity so the Milky Way is getting sucked in and there is nothing anybody can do to stop it.
Having trouble visualizing all this? Try this simple demonstration in the comfort of your own living room, and amaze your family and friends with your knowledge of celestial mechanics: Get two footballs, one to represent the Milky Way, the other for the Andromeda galaxy. Place them 30 feet apart on the floor. Believe it or not, this is just about the scale in size and distance apart that the two galaxies lie from one another in real life. Now simply sit on the couch and watch closely. In 9,722,222 years the two footballs will move one inch closer to each other! Wow! That is gravity at work. The same force that is irrefutably proved every morning when you get out of bed and your feet hit the floor, not the ceiling.
Check out Andromeda
Want to see our inevitability coming for yourself? You can actually see the Andromeda galaxy with your naked eye. No telescope is needed, but a pair of binoculars might come in handy. I pointed it out with my laser pointer to a few friends not long ago down in the Nevada desert. Pick a clear moonless night and get away from any distracting lights. Up in the northeast look for the constellation Cassiopeia, the queen. It looks like a W and will be kind of standing up on end. A W is composed of two Vs and using the sharper of the Vs point in a southerly direction about the length of the entire W. If you spot it, it will look like a faint smudge and binoculars will show it as an oblong smudge.
If you do manage to find it, the distant galaxy will be the most far-flung thing you have ever seen as well as the biggest. Also you will be looking downhill in the largest sense of the word imaginable. That laser beam I pointed out Andromeda with a few nights ago is on its way across the cosmos right now traveling at the speed of light, 186, 242.4 miles per second. It will arrive at Andromeda in the year 2,502,019 A.D. give or take a few thousand years.
While you are out there under the night sky, take one last look at Jupiter and Saturn, two planets hanging low in the southwestern sky that are much closer to home. They will not be around with us much longer as they fade into the sunset glow. By the way, if you are worried about our impending crash with Andromeda, you do not have to rush out and buy collision insurance tomorrow. It will be three and a half billion years before we get there.