It's pretty well accepted in the sci-fi world that whenever you've got twins, one of them is bound to turn evil. Unless both are pretty evil. So NASA's decision to send astronaut Scott Kelly to the ISS for a year, then compare him to earthbound twin Mark, can only be interpreted as one thing: a study to determine which twin turns to the dark side. Ain't science grand?
Honestly, it's hard to believe it's taken NASA this long to embark on such vital research. Former Navy test pilots, the Kelly brothers joined NASA in 1996. Mark, the six-minute older brother, flew four space shuttle missions before retiring in 2011 to spend more time with his wife, Congresswoman Gabrielle Giffords. Scott has two space shuttle missions under his belt, and lived on the ISS for five months in 2010-2011.
When NASA decided to send Scott to the ISS for a year alongside Russian cosmonaut Mikhail Kornienko, the brothers mentioned that a twin study was bound to come up in press conferences. NASA decided it might as well run some tests, and called for study topic submissions from the scientific community. The space agency will decide which studies to conduct in January.
Of course, most of the studies will focus on the standard stuff: blood, saliva, and (euugh) stool samples, cheek swabs (to compare any DNA changes), and physical and psychological testing. Scientists will monitor how radiation and a zero-gravity environment affect the body's gene expression, metabolism, and mental state. Identical twin studies are the gold standard in determining genetic versus environmental influence on health and disease -- since both twins have identical DNA, differences between them can be attributed to outside factors.
But you can't help thinking NASA will watch to see if either Kelly brother starts turning evil. Will it be the one locked in a space capsule for an entire year, cut off from everything he cherishes on earth? Or the one trapped on his home planet, denied the chance to fly again, playing second fiddle to his space superstar brother? After all, earth-bound Mark, on the right in the image above, sports a mustache, and if we've learned anything from Star Trek, it's that facial hair = evil twin.