Sphere
by Michael Crichton
Because he wrote a government report on how to handle alien contact, psychologist Norman
Johnson is called to the scene when the Navy discovers a 300-year-old crashed space ship
on the Pacific floor. But it turns out to be an American space ship, just not from
today’s America.
And yet now we have proof that time travel is possible—and that
our own species will do it in the future!
Sphere by Michael Crichton (Alfred A. Knopf,
June 1987).