WEBVTT 00:00:05.506 --> 00:00:09.193 🎵 [music] 🎵 00:00:11.965 --> 00:00:15.048 KIDS: Our World! 00:00:15.050 --> 00:00:18.651 EVAN: Today on Our World we’re going to learn about... 00:00:18.653 --> 00:00:21.935 Globey, what are you wearing? 00:00:21.936 --> 00:00:26.258 X-ray glasses? You know those things don’t actually work, right? 00:00:26.260 --> 00:00:29.728 I know, I know, I’d like to have X-ray vision, too. 00:00:29.730 --> 00:00:33.031 But there is a space telescope that actually DOES 00:00:33.033 --> 00:00:36.803 have X-ray vision...the Chandra X-Ray Observatory. 00:00:36.805 --> 00:00:39.838 This state-of-the-art space telescope observes X-rays to 00:00:39.840 --> 00:00:42.508 help us learn new things about our universe. 00:00:42.510 --> 00:00:47.713 So what is an X-ray? It’s a type of light that has a really short wavelength. 00:00:47.715 --> 00:00:52.218 Visible light, or the light we can see, has a wavelength that looks like this. 00:00:52.220 --> 00:00:55.455 X-ray wavelengths are much shorter. 00:00:55.456 --> 00:00:59.191 This short wave length allows the x-ray to pass through many objects. 00:00:59.193 --> 00:01:02.828 That’s why doctors use X-rays to look at broken bones. 00:01:02.830 --> 00:01:05.698 X-rays pass through our skin. 00:01:05.700 --> 00:01:08.568 The x-rays, however, are stopped by the bone. 00:01:08.570 --> 00:01:11.905 X-ray film can be used to detect the x-rays and the 00:01:11.906 --> 00:01:15.275 shadow of the things the x-rays cannot pass through. 00:01:15.276 --> 00:01:18.345 When you go to the dentist, X-ray pictures are taken so 00:01:18.346 --> 00:01:21.546 the dentist can see what’s happening INSIDE your teeth. 00:01:21.548 --> 00:01:24.850 X-ray telescopes can be used in a similar way to look at 00:01:24.851 --> 00:01:27.820 shadows caused by clouds of dust and gas in space, 00:01:27.821 --> 00:01:31.623 but usually they are used to look at "x-ray machines" 00:01:31.625 --> 00:01:35.228 in the universe such as hot gas produced by the explosion of a star, 00:01:35.230 --> 00:01:39.098 to see a kind of light that isn’t visible with a regular camera. 00:01:39.100 --> 00:01:42.801 The Chandra X-ray Observatory is named after a astrophysicist, 00:01:42.803 --> 00:01:47.273 Subrahmanyan Chandrasekhar, or Chandra for short. 00:01:47.275 --> 00:01:51.483 Chandra made new discoveries on how and why stars change. 00:01:51.485 --> 00:01:54.213 He was one of the first scientists to combine physics 00:01:54.215 --> 00:01:57.183 (the study of matter and how it moves) with astronomy 00:01:57.185 --> 00:01:59.651 (the study of objects in the universe). He was awarded the 00:01:59.653 --> 00:02:02.455 Nobel prize for his study of stars. 00:02:02.456 --> 00:02:06.325 The Chandra X-ray Observatory was launched in 1999. 00:02:06.326 --> 00:02:10.296 It allows NASA scientists to get a whole new view of the universe, 00:02:10.298 --> 00:02:13.833 kind of like looking out into space with a pair of "X-ray glasses". 00:02:13.835 --> 00:02:17.003 Stars and other matter in space give off X-rays under 00:02:17.005 --> 00:02:20.306 certain violent conditions. Scientists can now observe 00:02:20.308 --> 00:02:24.010 what it looks like when galaxies collide or supernovas explode. 00:02:24.011 --> 00:02:27.046 Seeing these hot spots in the universe gives scientists 00:02:27.048 --> 00:02:30.083 information they could never get from taking regular pictures. 00:02:30.085 --> 00:02:34.286 So why can the Chandra X-ray telescope capture such brilliant images? 00:02:34.288 --> 00:02:38.958 Chandra is the best X-ray imaging telescope ever built. 00:02:38.960 --> 00:02:44.463 Its power is like being able to read a stop sign at a distance of 19 kilometers. 00:02:44.465 --> 00:02:47.900 But this special telescope wouldn’t work here on Earth. 00:02:47.901 --> 00:02:51.036 It had to be placed high in outer space. You see, 00:02:51.038 --> 00:02:53.573 Earth’s atmosphere is thick enough that X-rays are not 00:02:53.575 --> 00:02:56.375 able to reach Earth’s surface. Chandra’s orbit 00:02:56.376 --> 00:02:59.311 around Earth is so big that the farthest points of the 00:02:59.313 --> 00:03:02.781 oval shaped orbit are about one third the way to the moon. 00:03:02.783 --> 00:03:06.686 Even at is closest approach to Earth, Chandra’s orbit is more than 00:03:06.688 --> 00:03:10.256 200 times higher than the circular orbit of Hubble. 00:03:10.258 --> 00:03:13.091 This gives the Chandra telescope an ability to look 00:03:13.093 --> 00:03:16.261 for X-rays that are being produced by faraway objects in space 00:03:16.263 --> 00:03:20.233 in a large region of the sky without the Earth blocking its view. 00:03:20.235 --> 00:03:23.903 With the help of special mirrors and a high-resolution camera, 00:03:23.905 --> 00:03:27.073 Chandra is able to "see" x-rays in action! 00:03:27.075 --> 00:03:30.443 Whoa! That’s some incredible X-ray vision, huh Globey? 00:03:30.445 --> 00:03:33.546 Chandra’s observations have led to important discoveries 00:03:33.548 --> 00:03:36.148 that are accumulating at a rapid rate as Chandra 00:03:36.150 --> 00:03:38.951 observes hundreds of objects each year. 00:03:38.953 --> 00:03:42.055 Observations of the collision of two huge clusters of 00:03:42.056 --> 00:03:45.025 galaxies has helped to provide the best evidence yet 00:03:45.026 --> 00:03:47.726 for the existence of dark matter, a mysterious form of 00:03:47.728 --> 00:03:50.296 matter that gives off no detectable light, but is 00:03:50.365 --> 00:03:53.366 apparently the dominant form of matter in the universe. 00:03:53.435 --> 00:03:57.303 Chandra has also been used to probe the geometry of space around black holes, 00:03:57.371 --> 00:04:01.808 and revealed that supermassive black holes can affect an entire galaxy. 00:04:01.810 --> 00:04:04.776 If Chandra was still alive today, I’m sure he’d be 00:04:04.778 --> 00:04:09.348 thrilled to see all the amazing information the X-ray telescope is providing us. 00:04:09.350 --> 00:04:12.185 So the next time you’re at the dentist getting teeth X-rays, 00:04:12.186 --> 00:04:15.621 think about the Chandra X-ray Observatory...giving us an 00:04:15.623 --> 00:04:19.773 inside look at the “X-ray machines” of the universe! 00:04:21.815 --> 00:04:25.968 ? [music] ? 00:04:28.966 --> 00:04:32.768 KIDS: Our World!