157 Miles Wide and Still Too Small to Be a Sphere

This particular asteroid, discovered on September 1st, 1804 by Karl Ludwig Harding, was the third asteroid ever found, right at the dawn of a wave of asteroid discoveries that began in that era. It is the second largest asteroid in the solar system, with a mean diameter of around 157 miles, and yet notice how distended and irregular its shape is. The reason comes down to a fairly straightforward physical principle. For a body to pull itself into a spherical shape, the gravitational attraction among its constituent material has to be strong enough to overcome the rigidity of the material itself, and at this size and mass, that threshold simply was not crossed. The image being shown is an artist's conception rather than an actual photograph, but given what is known about the body's mass and composition, it is likely a reasonably accurate depiction of just how irregular a 157 mile wide object can remain when gravity alone is not doing enough work to round it out.