Astronaut Takes Picture of UFO from ISS [Proof of Aliens?]

An astronaut on the ISS took a picture of what some people are calling a UFO and posted it to Twitter. The astronaut, Scott Kelly, recently achieved the world record for the longest time spent in space by a US astronaut. The most rational explanation for the strange object in the top-right portion of the picture is that it is simply a reflection of lights from inside the International Space Station. However, conspiracy theorists are insisting that this UFO is proof of alien life. What do you think?