Many of us associate the conservation of energy with perpetual motion machines. Actually, we were all wrong. Perpetual machine is perpetual machine, and eternal energy is energy conservation. They're all different. We can't be together. As long as it is a perpetual motion machine, it is called a perpetual motion machine. Perpetual motion machine definitely needs energy, but our understanding of energy is different.
Our universe is full of all kinds of energy, both known and unknown. Just because we don't know it doesn't mean it doesn't need energy. For example, the waterwheel by the river is a perpetual motion machine. If we don't know its energy source, but if you think about it carefully, you will find that it is really a perpetual motion machine. )
In the near future, a person invented a thermal battery, which needs a very low temperature and can still generate electricity at MINUS 200 degrees. Is it a perpetual motion machine?
So there must be a perpetual motion machine, but we have to use other unknown energy to complete it.
For example, if we pry a big stone off a cliff, we only need to do a little work, but the stone that rolled off the cliff has done a lot of work. If we pry it up with an unknown upward force, then the stone flies from cliff to cliff and does a lot of work. At this time, the perpetual motion machine appeared. Newton's gravitation and unknown repulsion. It is a perpetual motion machine, but it also needs energy, because permanent magnets also need energy, without energy and magnetism.