An Ancient Tomb: 5 Most Incredible Discoveries of Week Including the secret behind a baby's smile By Newser Editors, Newser Staff Posted Sep 26, 2015 5:00 AM CDT 1 comment Comments Undated handout photo issued by the British Musuem Thursday Sept. 20, 2012 of Pompeii. (AP Photo/The Trustees of the British Museum) (Newser) – Who needs fingerprints when an invisible bacteria cloud might do? It's among the week's notable discoveries: You Have an Invisible Cloud, and It's Gross: When someone says you're in their personal bubble, they aren't exactly speaking metaphorically. University of Oregon researchers say they've found people really are surrounded by a sort of cloud that's unique to them. The gross part? Let's put it this way: The lead author reveals that "the world is covered in a fine patina of feces." 'Exceptional' Pompeii Find Predates City's Destruction: The ancient city of Pompeii holds many treasures, but the most recent find hails to a time long before the city was destroyed. French archaeologists unexpectedly made an "exceptional" discovery that dates to the fourth century BC and involves the remains of an adult woman. Researchers Say They Know Why Babies Smile: Ever wonder what's going through a baby's mind when she smiles at you? Researchers think they do. A new study suggests that babies who are smiling are attempting to make whomever they're interacting with smile back—while using pretty sophisticated timing to manipulate the situation. Graves of Utah Victims From 1857 Massacre Found: An archaeologist believes he's found the true resting place of the victims of the Mountain Meadows Massacre—more than 150 years after the killings. Members of the Mormon church slaughtered the travelers in a wagon party during a time when hostility against non-Mormons in Utah was high. What Everett Bassett initially thought: "There's no way this could be the grave." Scientists Finally Know What Sound a Giraffe Makes: What does the giraffe say? For decades it’s been a simple answer: nothing, except for a snort or grunt every now and then. But University of Vienna researchers now say they've determined that giraffes do indeed "produce vocalizations"; here's what those vocalizations sound like. Click to read about more discoveries.