英语听力：2013-10-16 地平线：黑洞吞噬—12（在线收听） |
If there's a black hole at the center of our galaxy, that's gonna force these objects that are really close to the black hole to move much faster than they would move if there were no black holes. So the first thing you wanted to see is there are very fast moving objects where you think the black hole was. So with our pictures that we took what you can measure is how these stars move on the plain of the sky. You take one picture. You come back a year later. You take another picture. You see where they've moved to. And what we're seeing in this box are that there are stars that are moving incredibly quickly. That was the first evidence of, for the black hole. Once everything had been plotted out, this is the map of the galactic center they were able to produce. It showed that stars were hurtling around in very fast and tight orbits. But what Ghez was interested in was what they were circling around.
If there is a black hole, there is a further prediction you can make about what these stars are gonna do. They are gonna move around the black hole on very short periods. In another words, you are gonna be able to see them move on more than just straight lines as part of their travel around the black hole. These stars are gonna move around the black hole because of the gravity just like planets move around the sun.
There is only one thing that has the shear force of gravity to compel such huge stars to veer round on such tight trajectories.
So what we see is that indeed you can, you see these stars were vibrant. In fact, in these images you can actually tell where the black hole was. The black hole was at the center of the focus of these orbits. |
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