This two-toned image shows an illustration of the protoplanetary disk around the young star FU Orionis, which was imaged multiple times by the Hubble Space Telescope but years apart. The disk has changed, indicating that it’s entering a more advanced stage of evolution, as planets form and the material available for forming and growing them evaporates, sublimates, and is otherwise blown away. Planets and the central star are all expected to orbit and rotate in the same direction; only collisions and interactions should change that story. Our own Solar System likely had a similar history to the protoplanetary system illustrated here. (Credit: NASA/JPL-Caltech)

Astronomers near a complete picture for how planets form

Newborn stars are surrounded only by a featureless disk. Debris disks persist for hundreds of millions of years. So when do planets form?

For a species that grew up on life-giving planet Earth, it’s a wonder that we still don’t have an end-to-end scientific picture for how…