Tag Archives: physics

Perpetual Motion

Wikipedia says, ‘[a] perpetual motion machine of the first kind [is] a “hypothetical machine which, once activated, would continue to function and produce work” indefinitely with no input of energy. There is a scientific consensus that perpetual motion is impossible, as it would violate the first or second law of thermodynamics.’

Is the universe a perpetual motion machine? If not, then it will ‘run down’ eventually and it has not been ‘running’ forever. Who or what ‘activated’ the universe?


The nature of existence

Some people believe that in the beginning there was nothing except God. Then God created everything. Other people say God had nothing to do with it, that there was a big bang which resulted in the universe in which we live. But what was there before the Big Bang? Has matter existed forever? The people who say that God created everything believe that matter does not have the power of self-existence, matter cannot create itself. If matter can only exist as the result of a creative act of God, then could matter continue to exist if God ceased to exist? In response to my “It was an act of God” post, Perry said, “A creator can make something but then not be involved in what happens with the invention. For example, I could sew up some juggling bean bags, sell them and not be involved in their subsequent juggling.” But there is a crucial difference. Perry did not cause the materials to come into existence that the bean bags are made of. Perry can take preexisting items and cut, sew and glue them, but he cannot cause them to exist out of nothing. No one knows what it means to be able to create something out of nothing. The pyramids continue to exist even though the Pharoahs are long gone. But how do we know if matter would continue to exist if God could somehow cease to exist? On the other hand, if matter has always existed and never had a beginning and will never have an end, then it seems to me that there is no need for a creator.


Portal was a game released in 2007 by Valve Corporation and “received praise for its unique gameplay and darkly humorous story.”1 I like the way Ben Gelinas puts it, “In Portal, your ‘gun’ isn’t really a gun at all, it’s a tool used to create doors (portals) in walls to [other locations]. Shoot a wall and it makes a portal. Placing these portals at key points inside rooms that otherwise hold you captive is essential for your escape into the more difficult room ahead.” I’ve only played partially through the game, but so far I have been able to create an orange portal and a blue portal. When you go in the blue portal you come out the orange portal and vice versa. Depending on where you place the portals you can be transported around obstacles or from room to room.

If you fall into a portal from a high ledge your momentum carries you out the second portal at the same acceleration. If you place one portal on the floor and the other on a wall this will convert your vertical movement into horizontal movement and allow you to jump large gaps.

One side effect of being able to place portals almost anywhere is the creation of infinite loops. If you place two portals opposite each other in a hallway you will see an infinite regression of yourself as you look through one portal into the other. If you place a portal on the floor directly under a portal on the ceiling you have set up a similar kind of situation. When you step into the portal on the floor you fall out of the portal on the ceiling and back into the portal on the floor. This will continue until your computer dies or until you push your joystick to one side and cause yourself you miss hitting the portal as you fall.

Valve Corporation has announced that Portal 2 will be released in 2011. The new game features the ability to direct tractor beams, laser beams and liquids through portals. Watch the videos at ThinkWithPortals.com.