Space Exploration — Martin Rees

even as ik Newton probably thought about space travel there's a wonderful picture in his book rink appear showing cannonballs being fired from a mountaintop and they fall down to earth but if the cannonball is fired fast enough then it's tragic she curves downwards no more steeply the new earth curves away underneath it it goes into orbit and he calculated that in order to go into that kind of orbit it would have to be fired at 18,000 miles an hour that's 25,000 kilometers / far beyond of course what could be achieved by cannon in his time and of course it wasn't until 1957 that the Soviet Sputnik was the first orbiting objects to be actually sent artificially into space and that was followed by some dogs and then by Yuri Gagarin and then by the space race between the United States and the Soviet Union and the Apollo program which landed men on the moon in the late 1960s and early 1970s since that time manned spaceflight has rather languished it's more than 40 years since people landed on the moon you've got to a middle-aged to remember when that happened to young people today it's ancient history the people walked on the Mars they know that the Americans landed men on the moon they know the Egyptians built pyramids but he's in both cases seem rather ancient history motivated by rather arcane goals and of course what drove the space race at that time was superpower rivalry between the Soviet Union and the United States had that momentum been maintained had the huge expenditure be maintained to be footprints on Mars by now but of course since that time no humans have been further than low-earth orbit in many cases in the space station the reason for that is partly that the case for sending people into space is getting weaker all the time as miniaturization gets more advanced and as robotics get better and of course is far cheaper to send robots you don't need to bring them back and that is the way in which we have learnt a great deal about our solar system of course we depend on space every day for sat-nav communications and environmental monitoring and telecommunications and also we depend in astronomy on telescopes up in space above the blurring and absorption effect of the Earth's atmosphere so we've learnt a great deal about our universe from being able to go into space and of course robotic space probes have gone to all the planets and major bodies of our solar system many have gone to Mars as the Curiosity rover which is an American probe about the size of a small car which has been trending across the surface of Mars about four years studying its geology and probes have been to Saturn and Jupiter and famously in the last two years an American probe has sent back pictures of Pluto 10,000 times further away than the moon and a European probe has landed on a comet the Rosato probe and this indicates the advance in robotics and we could do much better now because the frustration for the people involved in the Pluto and comet probes is that the technology they were using was 15 years out of date it took ten years to get to Pluto ten years to get to the comet and of course you have to settle a design of a spacecraft five years before launch so if we think how smartphones have developed in the last 15 years we realize how much better robotic probes could be now and so I fully expect that in the next decades we will have hugely advanced robotic probes exploring all the borders of our solar system in far more detail than today another thing that'll happen is that we have very large robots fabricating things in space the limit now is that there's a limit to the size of an object that you could put in the nose kind of a rocket to send it to space but if you can fabricate things up there may be mining materials from the moon or from an asteroid you could build huge lightweight structures huge telescopes huge solar energy collectors in space and I think that won't happen but what about people going into space as I said the case for people is getting weaker as robots get more advanced and will certainly have in 10 or 20 years robots able to build structures in space without humans being there at all but I think nonetheless that humans will still want to go into space as an adventure and the first people on Mars I think will be going as an adventure raft for practical purposes because it could be that the Chinese decide to have a big spectacular program percent people to Mars and they'd have to go to Mars because if China wants to asserted superpower parity with the United States it wouldn't be very sensible to do something United States did 50 years earlier they'd have to do something new they'd have to go to Mars but if they don't decide then I think the future of manned spaceflight lies with private companies and there are some of these in the United States already because they can accept higher risks than NASA or ISA can impose on civilians publicly funded and so my scenario is that companies like those already existing in the space in in the United States SpaceX run by L on musk and Blue Origin run by Jeff Bezos these are two billionaires in the US I think they will be launching people into space they are already planning to launch people into low-earth orbit and then there's a plan to launch people on an orbit going around the backside of the moon but not landing coming back that takes about five days I'm told they sell the ticket of the second flight but not the first flight and that perhaps tell you something about the risks involved but maybe in 20 or 30 years people will go on ma to Mars maybe even Bombay tickets and they'll be volunteers and their own mask himself who is the pioneer of space fact he says he wants to die on Mars but not on impact and 40 years from now he might be able to do that he's only 44 years old now so he might be able to end his days on Mars and so I think there will be by the end of a century certainly a community of people living away from the earth probably on Mars but they will be sort of pioneers they've been the same kind of crazy people who dragged sledges across the Antarctic or fall from a supersonic balloon or the Russian who went around the world in a in a high-altitude balloon and does many other things they be people like that who are prepared to take high risks adventurers and libertarians who want to get away from the earth maybe the kind of people who we living on Mars and I think this will have an important consequences for the future of humanity because we know that what's happening now is a technology's advancing in that we can do genetic modification on humans and we can have cyborg technology where we link ourselves to machines and maybe download two machines and I think there'll be some ethical constraints on using these techniques here on earth but if we imagine these people away from the earth there be away from any legal restrictions on the earth and moreover they would have a very strong incentive to adapt themselves or their progeny to this very alien environment to which humans ill adapted so they will use these technologies to modify their descendants and perhaps use cyborgs techniques and they will be the first post humans they will change it to new species within a few centuries then the future of evolution will depend on descendants of those pioneers and let's bear in mind that that evolution technological evolution will be far faster than Darwinian selection that's led to us the winning selection is such that it takes millions of years for new species to evolve and then become extinct but on the technological timescale we can imagine in future that these aliens will develop from human beings because they will have a huge incentive if they're in space to modify themselves and adapt to this alien environment so I see that there will be people living on Mars by the end of a century and they will be first people who will use these techniques to adapt themselves so drastically to these very different environments that eventually they will need to post humans within just a few centuries one of the problems with of course space exploration is we depend on chemical fuel and this is intrinsically rather inefficient and limits the speed which a rocket can achieve and if we really wanted to extend range beyond our solar system then we've got to develop some kind of fuel more efficient than chemical fuel so that we can get up to higher speeds because it would take tens of thousands of years to get to the nearest star using chemical fuel you need to develop some kind of nuclear engine or even something far better than that in order to get further so until we can get a new kind of fuel for our Rockets then certainly manned space flight is going to be restricted to the inner part of our solar system but if we can add new kinds of fuel then it may be possible for humans to go to the star as the other possibility of course is that we will have post humans who were never far longer life time than human beings have and of course if your life is measured in thousands of years then a very long journey is less daunting than it if we have human lifetimes limited to less than 100 years so I think the future of exploration by humans beyond our solar system will have to await either the evolution of creatures with a far longer lifespan or the development of some kind of space technology which allows rockets to go as a good fraction speed of lights which would be a huge advance on chemical rockets which could only barely escape from the Earth's atmosphere

Channel: Serious Science

Views: 3,237

Keywords: science, lecture, Serious Science, cosmology, space, astrophysics

Id: jQbFdugIOD4

Length: 11min 35sec (695 seconds)

Published: Fri Feb 24 2017