英语听力：自然百科 穿越银河系的旅行 Through Milky Way—14

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Going to the heart of a galaxy² might not be the similar to going to an amusement park. The rides are some similar to how the stars orbit/ some of the galaxies³, 10 million miles per hour compared to, say, our sun, is about a factor of 50 times faster. So something has to be going on at the center of our galaxy to make that happen.

 

The heart of our galaxy lies 26,000 light years away. It’s difficult to observe through the vast amount of stars, gas and dust. And there is something else which obscures the view, the earth’s atmosphere. 

 

By measuring how a laser beam may be distorted in /moving air, it’s possible to compensate⁴ for the atmosphere’s blurring⁵ effect, a process called adaptive optics. 

 

So let me show you an example of how powerful adaptive optics is. The stars that we want to see are the ones at the very center, we think the heart of the galaxy is right within the center. This box which is pointed⁶ out here, without / adaptive optics, this region looks completely blurry⁷, you don’t see the individual stars; with / adaptive optics, you see the individual stars.

 

For 15 years, Andrea has been taking infrared⁸ images of the stars at the center of the galaxy to produce an extraordinary time-lapse film. 

 

So if we zoom⁹ in to the very heart of the galaxy, we can actually see the data that we’ve taken over the last 15 years, and you can see the stars, you can see the tremendous motions that they’ve gone through. Particular, SO2 which is my favorite star, every astronomer¹⁰ has a favorite one. You can see SO2 goes around, and particularly you can see as it gets to the center of the frame, it moves much more quickly. So something is interesting as it goes through that region. So putting everything together, all the measurements that we’ve made, we’ve been able to make an animation¹¹ that shows how the stars have moved toward the course of 15 years.

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