Why Asteroid 98943 Torifune Looks Like Two Space Rocks Glued Together
A recent flyby by Japan’s spacecraft Hayabusa2 has revealed an unexpected secret about the near-Earth asteroid 98943 Torifune: what once appeared to be a single elongated rock is actually a double-lobed asteroid, made of two separate bodies that merged together long ago.
The discovery has excited planetary scientists because it offers another glimpse into the chaotic and creative processes that shaped the early Solar System.
A Close-Up Surprise
For years, astronomers observing Torifune from Earth could tell that the asteroid had an unusual shape. Because of its distance and small size, however, telescopes could only show that it looked stretched or oblong.
When Hayabusa2 passed close to the asteroid earlier this month, the spacecraft captured detailed images that revealed a much more fascinating structure. Torifune is not merely elongated—it consists of two distinct lobes connected by a narrow neck, giving it the appearance of a cosmic peanut.
The asteroid is roughly the length of four soccer fields and belongs to the group of objects that periodically approach Earth during their journey around the Sun. Scientists emphasize that Torifune does not pose any known impact threat to our planet.
How Does an Asteroid Become a Double?
The most likely explanation is that Torifune began as two independent asteroids. Early in Solar System history, countless small rocky bodies drifted through space at relatively low speeds. Occasionally, some of them gently collided rather than shattering apart.
If the impact was slow enough, the objects could remain attached, creating what researchers call a contact binary asteroid—essentially two worlds that touched and never separated.
This idea is supported by observations of other similar objects, including Arrokoth, the distant Kuiper Belt object explored by NASA’s New Horizons spacecraft. Arrokoth also appears to have formed when two separate bodies slowly merged together.
A Rubble-Pile World
The images from Hayabusa2 show another intriguing feature: Torifune’s surface is covered with large boulders, yet it lacks obvious impact craters.
This suggests the asteroid may be a rubble pile, meaning it is composed of many fragments loosely held together by gravity rather than being a single solid rock. When impacts occur on such a surface, the material can shift and settle, gradually erasing clear crater shapes.
Rubble-pile asteroids are especially interesting because they preserve clues about the violent collisions that
