By Emily Levesque, University of Washington
Gerard Kuiper’s name sounds familiar because we associate him with the Kuiper belt. The Kuiper belt is a wide ring of small rock-and-ice objects orbiting our Sun. The ring begins just past Neptune and stretches to more than 90 billion miles away from the Sun.
Discovery of the Kuiper Belt
The Kuiper belt may be named for Kuiper, but he wasn’t the researcher who predicted it. That distinction goes to Julio Angel Fernandez Alves, an Uruguayan astronomer.
In 1980, Fernandez published a definitive paper studying the orbits of comets and noting that they must be coming from somewhere relatively nearby, in solar system terms. His data suggested a belt of comets and other rocky and icy objects, sitting precisely where the Kuiper belt lies today.
Other astronomers simulated the motion of planets and comets in our solar system and agreed—there must be a new collection of faint and distant objects waiting to be discovered at the outer edges of our solar system.
David Jewitt and Jane Luu’s Observation
Astronomers David Jewitt and Jane Luu hit pay dirt in August of 1992. Even then, the blinking technique was still the best method for finding moving objects. For Jewitt and Luu, this meant taking a series of four images and blinking between them, catching enough data to track any new object’s motion and determine conclusively whether it matched the predicted motion of a Kuiper belt object.
On one evening of observations, they blinked the first two images in a set and spotted a compelling candidate, a small new object moving slowly across the night sky. The slowness was key. Since orbital speed is determined by a combination of mass and distance, slow motion meant an object was likely pretty far away from the Sun. Something speeding through their blinked images was probably just a nearby asteroid, but a slow-moving object was almost certain to be further away.
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Albion: First Member of the Kuiper Belt
Jewitt and Luu kept watching their strange new candidate object, taking the third and fourth image and then continuing to track it for the rest of the night to gather as much data as possible.
In the end, they were able to confirm what they’d found: the first official member of the Kuiper belt, an object known today as Albion that’s about 70 miles across and four billion miles from the Sun.
After Jewitt and Luu’s discovery, the study of Kuiper belt objects exploded—today we estimate that there are at least 35,000 objects as big as Albion—or even bigger—in the belt.
In the following years, some of these searches became highly automated, with robotic telescopes automatically capturing repeat images of the sky and software that could simulate blinking images and pass along anything that looked enough like a moving object to a human expert.
Discovery of Eris and Pluto’s Position
In 2005, astronomer Mike Brown was examining one dataset when he came across a surprisingly bright and slow-moving object. He recognized that his survey had found a new Kuiper belt object, and that it was enormous.
The object, later dubbed Eris, was the largest Kuiper belt object ever found at the time, at least, officially.
Mike Brown’s discovery of Eris put Pluto in an awkward position. Eris was thought to be practically identical in size to Pluto.
This discovery raised many questions. Did this mean that Eris was now our tenth planet? What about Albion, and the heaps of other objects in the Kuiper belt? Were some of those planets too? Pluto certainly seemed to be a member of the Kuiper belt; did this preclude or damage its classification as a planet?
What the discovery of the Kuiper belt did was provide us with the knowledge of a fleet of dwarf planets, and a fascinating new region of our solar system to study and explore.
Common Questions about the Discovery of the Kuiper Belt and Its Members
Even though it is named after Gerard Kuiper, the Kuiper belt was first predicted by Julio Angel Fernandez Alves, an Uruguayan astronomer. In 1980, Fernandez published a definitive paper studying the orbits of comets and noting that they must be coming from somewhere relatively nearby, in solar system terms.
Astronomers David Jewitt and Jane Luu discovered the first official member of the Kuiper belt, an object known today as Albion that’s about 70 miles across and four billion miles from the Sun.
In 2005, astronomer Mike Brown was examining one dataset when he came across Eris the largest Kuiper Belt object ever found at the time. Mike Brown’s discovery of Eris put Pluto in an awkward position. Eris was thought to be practically identical in size to Pluto. This discovery raised many speculations not just on Eris being the tenth planet of the Solar System but on Pluto’s status as the ninth planet as well. However, it did provide us with the knowledge of a fleet of dwarf planets, and a fascinating new region of our solar system to study and explore
