Accidently formated my external 1TB hard drive! Is there any way to recover the data off of my 1TB hard drive once it has been erased? From my mac I just selected that external drive and clicked on erase and both the partions are gone now :(

PS: I havn't copied anything on it.
There are only 2 options at this point, #1 is to try a data recovery program and #2 is to have your hard drive sent in to a professional data recovery lab where they actually physically recover the data from the drive, but this can cost $1,000s. I have lost many many hard drives do to corruption and accidentally erasing and the best option for me has been to use Data Rescue. I actually just got done recovering over a TB worth of photos and videos from one of my hard drives and data rescue works wonderfully. I have tried many other data recovery applications and none of them work as well as this one. I hope this helps.