This is not a statement of advocacy of the claim...

The position of the earth 1000 years in the future will be very different from the position of the earth now, relative to almost every object outside our solar system. Similarly, if you could go directly back in time right now by even 1 hour, you would be floating in space, only to have the earth crash into you slightly less than an hour later.

That's why there's a remark about movement in time also being in space. If you want to go back to the earth 1000 years ago, you have to travel a very great distance in space, otherwise you'll just be floating around in the spot where the earth will arrive in 1000 years. (And you might get sucked into the sun in the meantime.)