On “Star Trek, the aliens often look so human that crew members fall in love with them. But in real life, scientists in the field known as astrobiology can’t be sure alien life would even be carbon-based like us, or use DNA to carry a genetic code.

Some insight now is coming from earthly labs, where scientists are building alternative kinds of genetic codes, and showing how they can evolve.

Whether life could be built with an alien biochemistry was among the more interesting questions that came up during a public event with famed biologist Richard Dawkins and physicist Lawrence Krauss, author of the book “The Physics of Star Trek.”