关于这张图
This animation shows the events that serve as the basis of an astrophysics technique called "echo mapping," also known as reverberation mapping. At center is a supermassive black hole surrounded by a disk of material called an accretion disk. As the disk gets brighter it sometimes even releases short flares of visible light. Blue arrows show the light from this flash traveling away from the black hole, both toward an observer on Earth and toward an enormous, doughnut-shaped structure (called a torus) made of dust. The light gets absorbed, causing the dust to heat up and release infrared light.…
