No, its not a joke. Einstein proved that energy can neither be created nor destroyed, only transfromed from one form to another... Our brain, our mind, our body, our conciousness, are stock full of massive amounts of energy. When we die... BAM... its all gone. But it can't actually be "gone", scientifically speaking, it had to simply change to another form. So while it doesn't necessarily mean that we are ghosts walking around, or get zapped up to heaven, or anything like that... but it means that SOMEthing happens with all that energy when we die, as it cannot just cease to exist. So there is SOME form of life after death. What it is, nobody on this side will ever know.
I studied Einstein a long time ago and remember reading all about it. I can't articulate it all that well I'm afraid... but im sure you can find information about it if you look.
Cpt.