NASA's New Horizons spacecraft is about to visit the most distant object ever explored by humans. Though NASA scientists know the approximate size of Ultima Thule, on Dec. 31, 2018, the object’s shape, color, and albedo (how much light it reflects)—and whether the flyby will be a success—is still a mystery.
Days Before Flyby, Ultima Thule Still Mysterious
Published: January 2, 2019
Onscreen: NASA’s New Horizons spacecraft is getting closer to its historic flyby of Ultima Thule 4 billion miles from Earth.
Anne Verbiscer: The anticipation is certainly building. We're having images come in regularly every day looking at them.
Onscreen: This close to the flyby, the team was expecting each new picture to reveal more of Ultima’s secrets.
Verbiscer: I think everyone would have said, “Oh three days before you'll know how fast it's rotating, how bright it is, and get an idea of what the shape is like.”
Onscreen: But so far, answers remain out of reach.
John Spencer: We still how fast it's rotating. We expected to see variations in its brightness as it rotates.
Hal Weaver: Imagine an oblong object rotating and reflecting sunlight depending on how much of the area of the surface is facing you, you would expect to see brightness variations but we haven't seen that.
Spencer: We've got lots of measurements of its brightness and they're all pretty much the same. So, we’re very intrigued to see what that means.
Onscreen: As of December 30th, Ultima Thule still appears as just a few pixels.
Verbiscer: It is holding its secrets to the last possible minute. I mean we keep saying, “Well, we’re gonna know eventually, right?” But right now it's still a mystery. This this object is proving to be the ultimate mystery.
Pluto and Beyond
Written, Produced, and Directed by: Terri Randall
Edited by: Jedd Ehrmann
Digital Producer: Arlo Perez
© WGBH Educational Foundation 2018