Last updated on December 20, 2013 at 12:57 EST  It Doesn’t Take
a Planet to Make Some Rings  July 12, 2013  Watch the changing
dust density and the growth of structure in this simulated
debris disk. Dust quickly collects into clumps and then forms
arcs and rings, structures similar to what astronomers observe
in actual debris disks. As the dust heats the gas, the gas
pressure increases and changes the drag force experienced by the
dust. This essentially herds the dust into clumps that grow into
larger patterns. The panel at left shows the disk from an angle
of 24 degrees; at right, the disk is face-on. Lighter colors
indicate higher dust density. For clarity, the animation does
not show light from the central star. The disk extends about 100
times the average distance between Earth and the sun (100 AU, or
9.3 billion miles), which is comparable to the outer edge of our
solar system’s Kuiper Belt.  Many young stars known to host
planets also possess disks containing dust and icy grains,
particles produced by c