Astronomers think of comets as time capsules from the formation of the solar system. Comets are too small to have been affected by the chemical and physical processes that forced planets to evolve, said Weaver. Observations of comets therefore, although limited by their distance, tell scientists a lot about the evolution of our world, our solar system, and the universe.

In the past, comets have been characterized by the micro-movements of water molecules or hydrogen atoms. But the researchers in Japan used a new atomic measuring stick with LINEAR: how the atoms spin in molecules made with two hydrogen atoms and one nitrogen atom.

The spins of these atoms provide clues about where they originated relative to the Sun. These atoms were floating in the hot nuclear soup of the Sun's birth, and their movements were determined by how much radiation they received from the proto-Sun. By laws of subatomic physics, the spin of atoms once set never changes.

The scientists discovered that the atoms of LINEAR place its origin in a surprising location: between Saturn and Uranus. Most comets, said Weaver, are thought to have originated further out from the Sun, past Neptune.

Weaver is quick to point out that although this is interesting, it can't be used to turn any theories about comets upside down.

"This finding could be an important piece of information, but this kind of measurement was just used for the very first time," said Weaver. "Still, science has to start from somewhere. Now we have to just go out and apply this technique to a hundred more objects so that we have another tool in our arsenal of understanding."

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