As young stars form, they hoover up dust and gas around them, and the remaining material spins into a flat, rotating disk. Planets start out as small clumps in that disk, and those clumps collide with other small clumps, eventually adding to their masses. As a result, baby star systems often appear as a dot in the middle, surrounded by a dark gap and then a dusty disk. But somehow, as this process unfolds, the stars continue to grow too. This is hard to explain--how, if the planets are gathering up the stuff around them, is any of the stuff getting to the star?