The fourth state of matter -- plasma | Christine Charles | TEDxCanberra

have you ever sat on a beach at night and wondered at the Stars the galaxies the planets maybe you've even dreamed of being an astronaut of sailing through the Stars and on to Mars and beyond I have heard that TED audiences are adventurous I am looking for adventurous people today to ask you to imagine the adventure of a lifetime a round trip to Mars my early days were in Brittany a coastal area in France where I used to love sitting on a beach at night and watching the Stars I dreamed of stars I dreamed of traveling to the planets but I never ever thought that my life and passion would become one where I was helping to build the starships the Rockets that would reach for truly unchartered frontiers Mars and beyond my life and work now involves research on space travel and plasma rockets and many nations get together to develop the space missions of the future of course our sights are set on to Mars we are here on planet Earth which is surrounded by a gaseous atmosphere which contains mostly air which we breathe in and out outside this cocoon is space and deep space which contains the solar system our galaxy the Milky Way and other galaxies 99% of ordinary matter in the universe is in the plasma state most stars are made of plasma and we want to use these States to propel our rockets into space so plasma is the fourth fundamental state of matter starting from solid to liquid to gas to plasma by raising the temperature just imagine an ice cube which would melt in your hand to become water as a liquid you could then boil this water in a kettle and get water vapor and you could put more energy and heat into this water vapor to dissociate and ionize the water molecules so that it could reach the high temperatures of the plasma state so a plasma is a very hot ionized gas which contains light and photons and charged particles the negative electrons and the positive ions and sometimes negative ions these charged particles give the plasma very interesting conductive properties similar to those of metals so the Sun is a very very hot ionized plasma with the temperature of 15 million degrees Celsius in its core 6,000 degrees at the surface a little bit cooler but still very hot in the center you have fusion reactions of hydrogen atoms which releases an enormous amount of energy in the form of radiation and light and of charged particles the charged particles form the solar wind which expands and flows out of the sun's surface and start traveling into space and impacting on anything it will find on its way fortunately for us earth is also a big dipole magnet with the North and the South Pole and this creates a protective magnetic shield around the atmosphere which is called the magnetic maddoxes fear and this shield limits the impact of the solar wind onto earth and this interaction can be seen in the polar and polar regions in the North and South Poles and you can see this beautiful northern and southern lights from the from Norway or from Canada or from Antarctica but a naturally occurring plasma familiar to us all is lightning strikes these are very powerful with up to 1 billion volts of electricity in the air looking for a path to ground or to earth so when lightning strikes it heats and ionizes the air along its path and you get a plasma so how about we make a plasma or mini lightning strike now on stage I'm going to use this device which is called a Tesla coil this was invented by Nikola Tesla over a century ago he essentially gave us alternating current or electricity as we have it now so when I turn this on what happens is it produces very very fast oscillating signal here about ten oscillations per microsecond so very fast but it is what a large voltage this means that when I turn this on and I bring this closer to a metallic or grounded surface I can I can trigger a spark of plasma you see that light so the light are the photons which are emitted by the plasma you don't see the charged particles but they are here and they carry the current from the tip through the plasma and to ground another device you're very familiar with is the fluorescent tube so this contains neon gas so again if I turn this on I can radiate energy into it and ionize the neon gas which is in here so this is a lighting device a few dollars you know what this is this is a flipped packet of chip you may have noticed that you have a very very thin coating here also done with plasma technology this is this acts as a barrier against oxygen and water you don't want your chips to get soggy and to go off do you know talking about chips this is the really fabulous chip or many of them you know what this is this is a silicon wafer which is covered by millions and millions of transistors these transistors are the engine in your computer in your tablet in your digital camera in most electronic devices they are very small because they are manufactured using plasma technology and in particular the ions in the plasma in the 1960s to manufacture a computer as powerful as your mobile phone would have cost 1 million dollars to manufacture it would have been the size of this stage and now thanks to plasma technology you can hold it in your hand and it costs much less now let me take you to my world and passion plasma rockets there was a trigger in my life quite a few year ago where when I had the opportunity to spend considerable time with NASA crew of shuttle flight sts-114 Space Station for about ten days the crew was in its final stage of training in Houston and it is important to say that to access space we must use powerful chemical rockets which burn a huge amount of propellant to give us a fourth big enough to overcome gravity during takeoff but when we are on orbit in orbit around Earth we can deploy plasma rockets and you know what this is a simplest plasma rocket you can think of this is the fluorescent tube again we can radiate energy into it iein is the gas make a plasma if you chop one end off the plasma will expand into space a force will be created in the opposite direction this is the principle of your plasma rocket it will start traveling into space when the plasma exits this rocket it looks like this photo there why do we want to use plasma rockets because they are very fuel efficient you can actually go from Earth orbit to the moon orbit with just 80 kilos of gas like what you would have in your car tank and what we are trying to do we are trying to accelerate the plasma before it exits the rocket to further decrease this fuel consumption and increase the thrust so the prediction is that you could go for a round trip to Mars in about in less than a year as opposed to many years using conventional chemical rockets but what we need to do is we need to test these rockets here in the laboratory and we are very fortunate in Canberra because we have warm but Excel this is our brand-new space simulation chamber essentially it's a big vessel three metres in diameter six metres in length we attach big pumps and we pump the air out to create vacuum or conditions similar to space it is an absolute necessity to test the plasma rockets because access to space one is expensive space debris and pollution is already of great concern and mostly we want to get our astronauts back to earth at the end of their mission so in one but Excel we prepare for future manned travel to Mars what I would like to do now is to invite some space cadets rocket scientists and future astronauts on stage to carry out some more experiments on plasma rockets okay please come please come here this way I'd give you one tube give you one tube let just here hold it compete closer to me okay so we're going to try and see if you are if we can create a glow look at that so what's happening here it's called a skin effect the current is going through the plasma it's actually being carried at the surface of your skin and to ground but you all right right and if I put my hand here I get half of the current this is a radio frequency signal a bit like a radio antenna right your emitter so it travels at the surface of the skin called the skin effect we use this in our plasma rockets you can see that the plasma doesn't go past your hands so the current is going this way and I'm not getting anything if I put this here I'm getting both of the current you're getting a little bit let's try with you just like this there we go did you feel anything no that's good so yeah look at that we can get both going excellent so that's the first step but we said that we are adventurous aren't we where we need a special device whoops whoops this way Oh wrong one here we go that's a device here we go to feel the skin effect we use the spoon which is a conducting metal so you're going to hold the spoon like this do you feel the tingling the bit of heat yes okay how about you just hold this here now you hold it here and you can also hold all hold her hands like this and we're going to try this oh no it's we'll see what happens and what doesn't work oh we got one going yes big round of applause for space credits thank you very much we have dreamed of space travel we have landed man on the moon we have established the International Space Station we have explored Mars using unmanned vehicles now we are working on human travel to Mars and I know that somewhere in this audience it might be you who will be on that first round trip to Mars and maybe even beyond now when I sit on a beach at night and gaze at the Stars I look for the bright spot which is the International Space Station you can see it when you have a clear dark sky and it truly inspires me and my work to think that one day a plasma rocket will travel from that Space Station and the first humans will set foot on Mars

Channel: TEDx Talks

Views: 194,054

Keywords: Energy, Physics, English, tedx talks, ted x, ted, TEDxTalks, ted talk, United States, Astronomy/Space, tedx, tedx talk, Science (hard), ted talks

Id: n-17xqfF4FU

Length: 15min 30sec (930 seconds)

Published: Mon Nov 03 2014