Our Lone Star: Understanding the Vastness of Space | David Whelan | TEDxAustinCollege

[Music] [Applause] i moved to texas six years ago to take my job here at austin college and being an astronomer i was the butt of several jokes moving to the lone star state but i think my brother-in-law said it best when he said poor david with only that one lone star to study now here is that lone star the main subject of my talk tonight today and what you probably know better as the sun but what you may be wondering is why i call the sun lone what makes our sun so lonely but perhaps more vitally who cares so to answer the first question the reason our son is so lonely is because space is so big and i'm going to be describing that that's the point of my talk tonight but let me address the second question now who cares the people who care are people who have an interest in space they're the people who love to learn about space missions missions to mars missions to the moon the dragon capsule and who want more they're the people who create science fiction and of the people who devour science fiction they're the engineers who actually build the space capsules that our astronauts go up in and the young people who hope to one day help with that endeavor all of these people people the space people whether dreamers or doers have one thing in common a fascination with what lies beyond and i'm going to give you a look at that beyond i'm going to give you a cold hard look at the vastness of space but to start i think i want to begin with the popular view of the cosmos if you look at a video online youtube or you're watching a movie or a television show probably what you're going to see is something where everything is really close together you see a perspective with lots of planets nearby one another and of course there's always warp speed right so it doesn't take very long to get from place to place but the reality is quite a bit different from these imaginings to give you one example the distance between the earth where we are and the sun our lone star is 94 million miles 94 million miles you all know how long it takes you to run a mile right imagine running that mile okay now try imagine running for 94 million of them that would take longer than your life so there's no real way to conceive of that number you can think of that number but it really actually doesn't make a great deal of sense it's just a number and to give you a second example the nearest star outside of our solar system is 4.2 light years away but again we have a problem because what is a light year when light in our everyday life is instantaneous you turn on the lights the lights are on light moves too fast to understand that number two so we need some kind of context for understanding how big space is to put it in the form of a scientific question we could ask can we conceptualize the size of space so that's our question and this is my best answer to that question so here's what we're going to do we're going to shrink the sun down to the size of this basketball so now you know why it's finally here if the sun were the size of this basketball then where would the earth be and how big is it that 94 million miles shrinks down to a mere 25 meters which is outside this theater in the old art gallery beyond 25 meters away and on this scale the size of the earth is only the size of a nerd candy or the cross-section of a sprinkle on your ice cream earth is tiny it's absolutely tiny and really far away between this sun and earth there are of course two other little things mercury would be about the middle of the first section here and venus would be about the middle of the second section back there and for everything inside of earth's orbit that's it that's all there is in the inner solar system mars of course is a little further on but the biggest planet in the solar system is jupiter on this scale jupiter is about the size of a small marble located 120 meters away which is in the right campus center two buildings over saturn is twice as far away as jupiter we're still on campus uranus is twice as far away as saturn so now we're off campus and neptune is three times saturn's distance on this scale neptune would be a half a mile away and this red circle represents a radius of one half mile around this position right here one half mile in every direction and we have all eight planets a mile from end to end of that circle and we have a basketball a couple of marbles and some other things too small to otherwise be noticed suddenly social distancing doesn't seem too far away does it [Music] the solar system actually keeps on going this is not the edge of the solar system the edge is what's known as the heliopause which is an ill-defined region way way out there on this scale three kilometers or almost two miles that's this big circle and between neptune's orbit half a mile away and the heliopause almost two miles away there's a smattering of comets the size of dust grains very slightly larger dwarf planets and that's it so that's our solar system in a nutshell of course the real question before us though was why is our star lonely our lone star so let's talk about that next nearest star to the sun it has a name it's called proxima centauri and proxima centauri is 4.2 light years away as i've already said one thing you might be interested in knowing is if the sun is as big as a basketball proxima centauri is the size of this ping-pong ball because stars come in different sizes too so what do you think 4.2 light years away how far away is this ping-pong ball from this basketball it has to be outside the solar system so it has to be more than two miles right what do you think 10 miles 100 miles i can sense that you know where i'm going with this four thousand three hundred miles away if we tried to put this on a map of the earth we could choose a few places to put it for instance let's go west it would be in the pacific ocean halfway between the hawaiian islands and midway atoll if the basketball were here or going south we'd be in south america in northern chile the city of antofagosta which is on the tropic of capricorn or if we go eastward towards europe it would be almost all the way to the west coast of ireland and i wanted to sink in for you that between this basketball our sun with its planets and moons and asteroids and comets out to a distance of two miles and this next nearest star proxima centauri there's nothing empty black space devoid of life devoid of anything to look at think about that the next time you're on a long car ride or a flight because if you left your basketball son at home you'd be on an interstellar adventure of the most boring kind because unlike your car ride unlike your flight there would be nothing to see you've all heard of the milky way galaxy it's where we live along with about 100 billion other stars or so i've marked about where the sun is halfway between the center and the outer edge of the milky way galaxy but once again we've encountered this problem with numbers i've quoted a number 100 billion and again that is like no number that you have experience with in your everyday life and so let's even just try to understand it based on the analogy i've already used if every star is a basketball or a ping-pong ball or some other type of ball and each of them is separated and this is actually pretty accurate by a distance similar to us between between us and proxima centauri i can't conceive those kinds of distances 100 billion stars 100 billion basketballs each of them separated from one another by 4 000 miles or more space truly is incomprehensibly large so here we are on this tiny speck of rock called earth orbiting a really far distance from our sun and all the stars that we see at night they're all further away than proxima centauri is and i have to be brutally honest about this one we do not have the technology to visit those places space people everywhere that is one of your limits perhaps the most important limit and now that we have defined that limit we can begin to dream how to go past it how to conquer it creators of science fiction imagine your worlds with this science fact forget warp drive forget putting things closer together deal with space as it really is there's a compelling human story about crossing that about making that an endeavor and engineers present and future start planning for how we're going to have the energy to go these long distances and how we're going to sustain life for those long journeys because if we collectively believe that we can we will and those first people who go on a ship heading out into the stars to land on some other planet around some other star they will have been assisted by an army of scientists and engineers and they will be buoyed by the hopes and dreams of all of humanity left behind here on earth it will be a shared victory and i call that seeing beyond thank you you

Channel: TEDx Talks

Views: 3,437

Keywords: TEDxTalks, English, Science, Astronomy, Exploration, Future, Physics, Space

Id: pxWNWEZZ_zI

Length: 12min 42sec (762 seconds)

Published: Wed Oct 28 2020