Wormholes occur when spacetime becomes warped; wormholes are hypothetical and may not actually exist, but they are allowed for under the theory of general relativity.

Time travelers could conceivably travel through a wormhole if it were traversable.

The practical details of such travel have not been worked out.

But would you be able to pass in and out safely?

I once read that you could create a wormhole by putting a very high voltage between two metal plates. And when you move one to another place, there is still a connection in space. If you stand in the field you could see the plates closer to another than when you look from outside the field.
Maybe you need more volt the further they're apart.
And it would make travel in space possible, but not in time.

Yes you could with what you have stated....has to be as close as an atom :( but nothing says its reasonable to radio back to the past...LOL

They tend to fall apart dont they...LOL mass = suck factor!

Before talking about things "allowed by relativity" perhaps you should read it.

Special relativity (1905 paper) is actually entitled:-

"On the Electrodynamics of Moving Bodies" and is available at:-

http://www.fourmilab.ch/etexts/einstein/specrel/www/

An English translation of General relativity is available at:-

http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf