Let's suppose it is, just for argument's sake.

But as the man says, space and time are inextricably linked, not just for obscure relativistic Einsteinian reasons, but because everything is moving. The earth rotates at roughly 1000 miles per hour at the equator, it revolves around the sun at 18.5 miles per second, the sun revolves around the galactic nucleus, dragging the earth with it, at tens, if not hundreds of miles per second. The Galaxy is moving within the Local Group of galaxies, and so on and so on.

A time machine would not only have to allow time travel, it would also have to keep track of all these motions and move you in space as well, so the traveler wouldn't rematerialize thousands of miles below the earth's crust or way out in deep space when he arrived at his temporal destination. Not only that, it would have to speed you up or slow you down so that you not only arrived at the new frame of reference, but with zero velocity relative to it. But this would violate all sorts of energy, momentum and angular momentum laws.

Because of these considerations, it would be very difficult to practically accomplish time travel, even if you had the basic technology and science worked out. So let's make the basic problem a little easier. Instead of sending a solid object back and forth through time, let's send something like a radio signal. Transmit a message with a time tick, say a recorded voice, or even Morse Code, through time using your time machine. Because radio waves propagate omnidirctionally at the speed of light, there's a chance an antenna placed in the past will pick up the message.

So you set up the experiment this way, turn on your radio receiver, at say, midnight (0000). Wait for a ten minutes (0010)and then turn on your transmitter. You should immediately pick up the message since the receiver is right next to the transmitter. Then turn on your time machine and send your message through it five minutes into the past (0005).

However, you turned on your receiver at 0000, remember? You should have picked up your time-traveled message a full five minutes before you started transmitting it at 0010! Give or take a few minutes for the time lag due to travel time in space. However, if you do pick up your message from the future, what's to stop you from pulling the plug on your transmitter as soon as you hear the message, so it never gets sent? But if you do that, where did the message you hear come from in the first place? This is the time travel paradox you often hear about (it's a variation of "what if you go back into the past and murder your grandparents before they have a chance to meet?").

The short answer to your question is "no".