Some people don't seem to quite understand what went on here so I'll just explain the confusing parts in detail.
At the beginning of the story, she was a billion lightyears away from Earth, which means whatever information of Earth she was seeing on her monitor was already a billion years past.
After that, she warped to Earth, note, warped. And it turned out humanity left a complete wreckage of it, a complete wreckage of themselves, and a poor alien girl heartbroken.
Oh, and, assuming she hadn't slept through her science class, she probably also had the technology to revive the scientist, just my guess.