TEDxBrussels - Marc Millis - 11/23/09

get connected burn the Box well I'm going to be talking about starflight the um brochure says finding habitable worlds I'm talking about actually reaching them and for a number of reasons well it's just cool um but the survival of humanity depends on it it's a kind of a little detail that's sort of important it might be impossible I got to be about there and what's really the part that I like about it and this is where the cool comes in too when thinking about it it's a way of to use a cliche of burning the box and so I'll be saying a little bit more about that okay um when talking about it's so hard when you're just dealing our existing day and for right now kind of our concept unless you're uh cheating by doing phone calls right now or texting your your P perception of our existence is this room but you know all of humanity just lives on as Carl seum would say that that blue dot and I like that picture because it also has the moon in it and that was taken by the Voyager spacecraft uh back and and what's nice too is through astronomy we can find out about a lot of other uh worlds out there and even through the colors there you can tell whether or not there's life but one thing that you could not tell at that time even from that photograph which was taken in the 70s that leisure suits were considered fashionable um but the other thing to keep in mind is that in at least um you know Earth is not going to exist forever and about five billion years the sun will go supernova and maybe sure that there we go and it will cook the Earth or not Supernova it will go into a red giant and that's for sure what's uh less for sure are all these other doomsday predictions that might happen uh quite a bit sooner um and I even read one thing about an asteroid site that right now our first war warning might be the flash of light and the shaking of the ground after it hit U which is kind of a uh a bad thing so when it comes to what's an exit strategy from that two possibilities that uh I'll go into um are the idea of colony ships which I'll say a little bit something more or trying to find another Earth and so what are the prospects of that well other habit Awards just two imagine uh it hasn't happened yet um but imagine if we ever discover that there is another earthlike planet out there and it will just be like this inaccessible Jewel beckoning us uh what has been happened is over 400 exoplanets an exoplanet is a planet around another star rather than our sun over 400 have been discovered but they're the easy ones to discover they're big and none so far have been habitable they're harder to find they're smaller well the idea is is that um what do you look for instead well so far the idea and these are all kind of preliminary is these are other Suns that might be um the kind of thing where a habital earth could be around and the other column there is the number of light years that they are away the closest one being 27 light years away and the farthest of that five is 50 light years away and you know if you don't know what a lightyear is in space it's it's kind of hard to we think light is so fast but in space light is really really slow and light the fastest thing we know takes 50 years to go that far and this is only five possible areas of a habitable uh planet uh another uh colleague of mine started doing how many people know what the Drake equation is okay that's enough I'm not going to explain it um he he started doing a statistical version including the error bands and stuff and some in uh U initial inputs the closest possible intelligent life might be 500 light years away now this is very provisional estimates so don't take that as a a firm answer could drastically change so if a habitable planets that might be 50 light years away um and there's no intelligent life on them all the better for us um but now here's a comparison of getting there light like I said is the fastest thing we know and when I put the four up there our nearest neighboring star is like 4.3 4 point uh 4.4 light years away and the fastest human-made object The Helio spacecraft and that's the speed that it's at when it's its closest approach to the sun that's not its average speed that's an advantageous one if it was going that fast it would take 19,00 years to reach our nearest neighboring star now if we include the other range for the possible habital uh star systems we're talking Ang ages or time frames that are equal to about how long Homo sapiens have been on this planet so if you had Homer Sapien was able to launch something like The Helio spacecraft toward a star it might not be there yet um so that's what we're talking about just from uh normal travel now time is not the only issue spacecraft if you ever noticed use these Rockets where they spew things out in the back and the farther or more you want to carry the more propellant you need to carry an extra propellant to propell the prop and it adds up exponentially and I won't show you the equation but here's an example send something the size of the space shuttle to our nearest neighboring star with 50 light uh in within 50 years that's less than 10% the speed of light and use the best conceivable rockets that number is debatable so you want to guess how much propellant that's going to take and this is just for a flyby yes that's our Sun the entire mass of our sun um so you know the people on Earth are going to be really pissed off if you use our sun worse that's uh if you wanted to stop when you got there that's how much you would need as your braking propellant and that same ratio between the little shuttle and the sun you need that ratio from Sun to lots of other Suns to be your starting propellent so the mass issue is another one but there are ideas for space flight like Sals actually this is a hybrid that involved no propellant but that's not all there is to it there's energy now in this chart um what this is is this is uh and it's a logarithmic chart which is why it's in a straight line the power growth of our human ability our prowess for generating and consuming power um and both the low-end and the high-end predictions there so somewhere within that band is the likely trend of how much power uh prowess will have over the years and the question comes well how does that compare with an Interstellar Mission even something simple as a probe to our nearest um star system and uh by the way in this energy thing I I should be clear that this also includes the sub proportion of energy that's actually devoted to space missions using the space shuttle as a comparative example so um any one of these factors if you adjusted it by virtue of debate could shift it but according to Trends as they appear now uh the soonest that we could launch a probe to Alpha centari might be two to four centuries away um using conventional physics and uh with this there's a whole bunch of ideas that are brought forth all based on existing physics and the catch is is thank you um there's no best single method and that's because there's no best single reason for why to do the attempt now here's just a a simple comparison of some if your motivation is to be first whether to be first to launch or to be first to get there um then you want to find Optimum opportunities and then that's really hard to do because there's so many competing factors if the issue is survival of humanity then you want to start looking at the idea of colony ships of sending a self-contained segment of humanity out so that it's going to be far far away from our solar system when our sun dies um jumping down to the next one about another way of reaching habitable worlds is undiscovered physics and that's the stuff that I like to do um which is a challenge unto itself um if you just want to discover how habitable worlds or see if intelligent life is there well then you can just stay on Earth and look and listen um I mean presuming they're going to be near Enough by um and if it's just scientific curiosity well then we're in the realm of discretionary spending but the point is is depending upon why you want to do inter Cellar flight it will drastically change what approach you take and um just as one warning for those who want to be the first to reach the destination you have this that you need to worry about the incessant obsolescence postulate that no matter when you launch that first probe a more modern probe launch later is going to catch up pass it and reach a destination sooner um actually this is just a postulate this will fail under a number of conditions uh like if we uh uh really stagnate technologically for a long time and I will avoid the temptation to say something political um or if a closer destination is reached or uh any and also there's a case that you can reach an Optimum time when you consider nonlinearities of growth and and the relativistic things but that gets into a whole another issue um the idea of colony spaceships and I don't have any examples here to show you even there's been some the main point is is that even though technologically it's conceivable that we could start to think about building these things it's a a huge energy issue still but what these are really good for is trying to is understand ourselves better now I mean what is a sustainable size of a human Community is it 500 5,000 50,000 and how much do you need to have a closed loop life support in terms of continuous energy um we conveniently have our son a colony ship is going to have to have uh something that lasts indefinitely um and also that has infinite reliability but what about the form of governance and what is a meaningful life if you're trapped on this say a sheld out asteroid or whatever that uh you're going on so that these people in their future life we're so used to the idea of growth here as being a life motivation well if you're on a limited size and actually the Earth is a limited size which is one of the things to figure out here what is our ultimate population Beyond which we're in trouble um but taking a look at these things is a way of exploring even these issues now and now I come to the category which I lo like about burning the box and this is one uh quote that I like in dealing with it and one of the ways I go about thinking of it from Arthur C Clark um who by the way we got him to agree to do the forward on our book one month before he died um so Bert ran did the forward book inste but anyway um you know to find the limits of the possible go into the impossible and one of my favorite places for the impossibility is science fiction and this is a collage of a whole bunch of Science Fiction ideas of starflight and they make it look so easy and they make it so alluring too with Captain Kirk having sex with so many aliens um but um but the Undiscovered physics we're talking about space drives meaning some means of moving a spacecraft without using Rockets or beam power and you know and faster than light travel I'm not going to say that much about fast and light travel because it's actually more heavily in the literature and also is related some of s's uh work um but the space tribes will say a little bit more but the idea of is this impossible well I don't know but one thing is for sure we're not going to make progress by saying it can't be done and uh just to get you thinking now I have I could go on for this for hours and this is really fun stuff I'm just going to give you some examples of what it's like and what modes of thinking you get uh doing this so here we have some representation for our entire universe that circle and a hypothetical spacecraft a generic looking one that shouldn't remind you of anything and the question is well what if it reacts on the mass of the universe and propels itself uh spacecraft Moves In One Direction and The Universe moves in the other rela relative to what um this requires uh issues about um inertial frames and such as that and by doing these sort of thing you really get into some provocative questions of physics that aren't normally thought about when trying to figure out the age of the universe or something like that now how many of you have ever done the thing where you it's called a soap boat where you have put something in water and touch the back of it with detergent anyone okay some of you have and it might have been in your childhood back when leisure suits were popular um but I just say skip that um so here's our generic spacecraft and uh we put a small amount of soap behind it is floating on water changes the surface tension of the water which pushes it along the spacecraft had no propulsion you changed the space and in this case the water was the reaction Mass so if you try and think of analogies to that to what if you change SpaceTime then it gets into the question well was SpaceTime a reaction Mass again these are just one one of these uh mental tools start playing with these ideas and um here's yet another one uh the question is if you started the engines all those masses around there how are they going to move um evenly or as a unit and that gets you into a whole another realm of how you start converting these ideas into the math so you can do the calculations and uh hopefully find engineering Solutions and this is kind of a a wrap up on the the main points Stellar flight even though it seems so long now from fruition um at some point it's going to be necessary for the survival of humanity and if you want one thing as like an an earlier step in thinking and as a way of better understanding our limits to our life on Earth you can start thinking about Colony ships and if you like burning boxes or burning other things um the idea of pondering this undiscovered physics of space drives and warp drives and well by the way Transporters is in a whole another Arena by itself even much harder to talk about um but you know it opens up interesting lines of thinking that aren't within the normal realm of physics the age of the universe and such as that I mean just think about it if you could know the age of the universe to five decimal places that'd be kind of cool but would it help you compared to if we could discover means of actually getting out there I think that would be a lot more interesting and just as the closing slide here um yeah uh that's saying at Astra increment means uh two the stars in steps where each step is greater than before and at this stage you know to find out what are the next critical questions that we can begin to answer to step away at this is what myself and some of my colleagues are trying to do and not just for the ultimate gain but because of what you learn in the process even if this remains impossible possible and if this remains impossible we've got 5 billion years we may make better make good of it thank you

Channel: TEDx Talks

Views: 4,111

Keywords: ted talks, TEDx, TEDxBrussels, tedx, tedx talk, tedx talks, ted talk, ted x, ted

Id: 1s5tWSLsr1M

Length: 15min 13sec (913 seconds)

Published: Fri Dec 11 2009