Prologue: Oumuamua
He had a dizzying glimpse of those mysteries at the edge of existence that he had successfully ignored for most of his life.
— Arthur C. Clarke, Rendezvous with Rama
Approach
Riding in from above the plane of the ecliptic, the stranger arrived, unseen and unnamed, in our solar system. At almost three times the speed of a typical asteroid, it flashed around the sun before anyone even saw it. We didn’t see it coming until it was leaving.
Discovery
Astronomers first spotted the rogue asteroid on Oct. 19, 2017 — more than a month past its perihelion. The Pan-STARRS telescope atop Haleakala in Maui, its mission to spot Near Earth Objects (NEOs), was first to do so and so got naming rights. The object was dubbed “Oumuamua”, which means “scout”, or “a messenger from afar arriving first”.
Controversy
It’s an asteroid. No, it’s a comet. Is it a spaceship? Everyone agreed it was the first interstellar object discovered in the solar system. Everyone agreed it was traveling like a bat out of Hell. Not everyone agreed what it was. No one got a clear view of it, the only thing anyone could really tell is that it was long and narrow, as inferred from observations of its albedo.
Was it an exceptionally long rocky asteroid? Was it a dense comet? Was Arthur C. Clarke right once again and it was a “Rama”-style spaceship? A leading astronomer at Harvard said it was — he even wrote a book about it. For years, the controversy bubbled, albeit primarily in the small community of astronomers and astrophysicists.
Gone
And just like that, it was gone. Where, we do not know.