The Chilean President Sebastian Pinera will speak later on Tuesday to the 33 men who have been trapped in the San Jose mine for almost three weeks.
Rescue workers have now set up two lifelines to the men - one for communication and one for food supplies.
They've lowered small sachets of soup to the miners who'd been surviving on a strictly-rationed diet.
They've yet to be told it could take up to four months to rescue them.
The scientists at the University of Geneva say the planets are from 13 to 25 times the size of Earth and covered with rock and ice.