1 00:00:12,769 --> 00:00:16,420 In order to undersand our position in the universe, 2 00:00:16,420 --> 00:00:26,919 I am going to show you something that has elaborated the ESA, specially to understand 3 00:00:26,919 --> 00:00:31,509 a little bit the distances. We are going to star by placing our position on Earth, 4 00:00:31,509 --> 00:00:38,260 the Himalayas and we raise over the Earth and move away from it. 5 00:00:38,260 --> 00:00:41,379 When we move above the surface of the Earth some kilometres we can see that it is not flat. 6 00:00:41,379 --> 00:00:48,180 We know it is spheric and not flat. 7 00:00:48,180 --> 00:00:53,880 In fact, it is a tiny part of universe, because it is so small and the universe is very cold and dark. 8 00:00:53,880 --> 00:01:00,230 Here we are going over the flatland of Tibet and now 9 00:01:00,230 --> 00:01:03,780 we start to see the whole Earth with its plendour. 10 00:01:03,780 --> 00:01:11,320 The Rosetta spacecraft, which is now a lot of millions of kilometres far away from the Earth and 11 00:01:11,320 --> 00:01:16,880 observed the Earth in this way many years ago and it observed that the Earth 12 00:01:16,880 --> 00:01:21,609 is not alone in the universe. It has a lot of elements around it that 13 00:01:21,609 --> 00:01:27,100 human beings have placed there, for instance satellites. These satellites 14 00:01:27,100 --> 00:01:32,029 allow us to know what is happening on Earth and it helps us for example 15 00:01:32,029 --> 00:01:39,299 landing in national airports with that GPS, but they also 16 00:01:39,299 --> 00:01:41,980 conform a problem for traffic. 17 00:01:41,980 --> 00:01:49,630 If in the future we had to move in the space, to go to other planets 18 00:01:49,630 --> 00:01:53,310 corssing that barrier of satellites could be 19 00:01:53,310 --> 00:01:58,080 a problem. Well, with a distance of a second, 20 00:01:58,080 --> 00:02:03,280 light will last one second to arrive the orbit of the Moon. The orbits of 21 00:02:03,280 --> 00:02:05,050 inner planets we can see here 22 00:02:05,050 --> 00:02:11,530 Venus, Mercury...are just a few minutes away. 23 00:02:11,530 --> 00:02:18,000 We can move away from the external orbits in approximately some hours 24 00:02:18,090 --> 00:02:23,840 Here light would have travelled for a day and we find Oort cloud, which is 25 00:02:23,840 --> 00:02:30,410 the origin of those comets that now are being oberved by Rosetta spacecraft. As we move 26 00:02:30,410 --> 00:02:32,650 approximatelly a year, we can see the first stars. 27 00:02:32,650 --> 00:02:37,690 So the first stars are a year light. 28 00:02:37,690 --> 00:02:42,520 The quantity of emissions in electromagnetic waves 29 00:02:42,520 --> 00:02:49,400 by human beings has reached distances of some tens of years light from us. 30 00:02:49,410 --> 00:02:53,530 The size of the Milky Way has around 100.000 years light of distance 31 00:02:53,530 --> 00:02:55,980 and we can move away as we can see very quicky using the 32 00:02:55,980 --> 00:03:04,500 speed of light to distances that are millions years light from the Earth and they conform our group. 33 00:03:04,580 --> 00:03:07,580 Now we have moved away from our galaxy and we start to see a group of galaxies 34 00:03:07,580 --> 00:03:13,690 until distances of the order of thousands of millions of light, comparable to the 35 00:03:13,690 --> 00:03:19,400 age of the own Earth 5.000 millions of years light, in English a thousand millions. 36 00:03:19,400 --> 00:03:23,959 Well, the structure we can see here is formed by 37 00:03:23,959 --> 00:03:28,720 the galaxies we can measure. It is done by the catalogue of the Sloan Digital 38 00:03:28,720 --> 00:03:33,570 Sky Survey and it allows us to know and set in the space 39 00:03:33,570 --> 00:03:42,000 these galaxies. All of this is the sphere of far universe with a background of radiation of 13,700 millions of years. 40 00:03:42,069 --> 00:03:47,939 And now we return again to the Earth. 41 00:03:47,939 --> 00:03:51,950 You have seen the visible horizon and there was a question "what is beyond 42 00:03:51,950 --> 00:04:02,750 that visible horizon?" and I am going to try to describe it in this lecture.