Most astronomers believe that the large concentration of mass at the galaxy's center is a black hole whose gravity is causing the gas to whirl.
大多数天文学家认为，星系中心的大量物质是一个黑洞，它的引力导致气体旋转。
2
Planets are believed to emerge from the accretion of particles in a disk of gas and dust as they whirl around the star.
行星被认为是由围绕恒星旋转的气体和尘埃组成的圆盘中的粒子累积而成。
3
When sucked up by a whirl of air, this unburned gas travels up the core until it reaches a region where there is enough fresh, heated oxygen to set it ablaze.