A mystery came out of the ocean on South Carolina's Seabrook Island, and authorities haven't yet identified what some are calling "space junk." The Lowcountry Marine Mammal Network was the first to notice, posting a photo on Facebook of a "mysterious object that washed ashore" on Thursday. The island is about 24 miles south of Charleston. The object is big, taller than a woman standing nearby, and it's cylindrical. It also looks like it's made of concrete, but Marine Mammal network officials say that's deceiving. Touch it and it feels like "a soft foam," said the network, adding that it was quickly whisked away by town officials. The Lowcountry Marine Mammal Network asked for help identifying the object and the Kiawah Conservancy shared the plea on its Facebook page. Dozens of people have responded with guesses ranging from parts of an alien craft to refuse from a "government munition dumping site" in the Atlantic. "I saw it this morning on my walk," posted Jennifer Passantino on the Kiawah Conservancy Facebook page. "I assume it was a buoy, but could also be the remains of an alien spaceship." The most popular assumption is that the object is part of a NASA rocket, shuttle or "re-entry capsule." "Part of the space shuttle Challenger that blew up about thirty years ago. Looks like a rocket nozzle to me," wrote Jim Elrod on the Mammal Network Facebook page. "Notice the different insulating materials. Take a sample of the insulating material and try to burn it to see if it melts." "You may want to contact NASA," said Barry Dearborn in a Facebook post. "This could be part of the space shuttle Challenger's External Tank." Todd Mason disagreed, noting any part of the shuttle would by now be "covered in marine life." "This is either newly introduced to the ocean or was buried deep prior to being dislodged," Mason said. In June, the Charlotte Observer reported a similar mystery object -- made of metal -- washed ashore at Corolla. Its use and origin were never reported.