TELEPORTATION
We see teleporters used all the time in Sci-Fi, who could forget the now famous phrase "Beam me up Scotty"? So, how realistic is it?
Suppose we have a man who weighs 60 kg (there are 2.2lbs to a 1kg in case you're not familiar with imperial measurements). Now, in order to teleport this man, first you need to know where every atom in his body is located and how that atom is connected to its neighbours in order to recreate the person. For this example let's assume that the man is made of carbon (this is a very poor assumption as we are made from lots of different types of atoms).We know from Avogadro's number that there are 1023 atoms of carbon for every 24g of material, so that totals 2.5 x 1026 atoms. We would need to know the (x,y,z) co-ordinates of each atom in relation to time and how they are located to every other atom at that time.
Even this simplistic approach illustrates the huge amount of data storage required.This illustration is assuming a very basic level of physics, if we go up a gear in complexity we require further information on the instantaneous configuration of the atoms themselves. At such small dimensions quantum effects become very significant and it becomes an impossible task to assign fixed positions for everything as both the position and state of the subatomic particles becomes unknown as it's impossible to know both at the same time in our currrent understanding of quantum mechanics.
Let's assume we fix that problem, we would still have a huge amount of data to store and this would require a hard disk bigger than our solar system and a phenomenal energy source to create the matter. Supposing even that were possible, it would mean that it would be possible to create an exact copy of yourself, complete with your own thoughts and memories. What would you do with the original copy? For a teleporter to work the original you would have to be destroyed (perhaps to aid the energy requirement) or there will be multiple copies.
In summary, we don't ever see a day when teleporters will be invented. The random quantum fluctuations would mean that it would be impossible to create an exact duplicate of an original person, even if you could generate the vast amount of energy required and use it to form matter. What about just using a wormhole to open a doorway and then "walking through". This is certainly much more feasible as it doesn't rely on breaking the individual down to their component parts. The question is just how simple would it be to create the wormhole in the first place. We know that space time is like a fabric and with sufficient mass impressions can be made into the surface. The more mass the deeper the impression. Theoretically, it is possible for two such impressions to be joined together to create a "tunnel" linking to locations which could be any distance apart, maybe even a different universe. We think it's more feasible than a teleporter but it's a very very long way off our basic understanding.