John Webb, Australia, Robert Macnaughton discussed on Space Nuts
Nine hundred to building flared the first fiber optic system for the Schmidt Telescope. One of my colleagues. Call it what sins folly because nobody believed that it would do anything useful when it would just it was just be. Quirky is like is a bit like back in the postwar period the the then director of the Mount Strong Observatory which was Australia's Australia National Observatory at that time amounts from knowing camera the Commonwealth Observatory Sir. Richard Woolley. Somebody said to him. So why do you think radio astronomy will. We'll now ten years time he said forgotten and I think people thought that about the fiber optics. Where do you think fiber optic million ten years time forgotten? It's not going to be used on. The biggest telescope is already being used on the biggest telescopes in the world. It is absolutely revolutionized the science because what it lets she do as I said we didn't carry through the conversation that lets you look at many objects at a time. Four hundred eighty four thousand on the on the Vista Telescope which is in Chile operated by the Europeans that then allows you to gather enormous data sets of the most intimate statistics of stars and galaxies and quasars all these objects in the in the wider universe. And by doing that you can first of all you can. New Population Census Studies. You can look at the trends. You can start discovering a lot about the evolution of the universe. It's how we know for example old the the the Big Bang model of the origin of the universe how that is almost certainly the the the correct model because we can see its imprint. All over all over the millions of galaxies that we now have three dimensional positions for thanks to the fiber optic technique so it's kind of revolutionized that study but he also shows up the real oddballs. Tell if you're looking at you know four thousand stars at a time. You're going to find things that are very very unusual. And they're the ones that point the way to things like new physics the the understanding that relativity and quantum theory might not be all that there is these. Are Things things that we know the best models of reality we've got that we still but we still find gaps in the what we're looking for is what might be hidden hidden underneath which could lead to all kinds of things like teleportation travel all US grace and it actually leads me into the other question ahead. His real basic one but what is the speed of light. The speed of light is talking about Einstein's we know from him so yes. Is that going back to nine. Thousand Nine hundred five when Arnstein published his special theory of relativity which these who got words. But that's a theory of the way objects move and it sort of built on what Newton wrote in sixteen eighty seven in his book. Doc Principia the PRINCIPIA. He wrote his laws of motion. which which fine and work well until you get near the speed of light? The speed of light was already the well known at that time. Three hundred thousand kilometers per second. How by actually? It was first measured by a Danish astronomer in sixteen eighty seven by looking at the moons of Jupiter a man called Roma he Worked I think he'd Copenhagen studied the moons of Jupiter and realize is the way they behaved as he could see them in. The Sky meant that there was a time lag in the travel. Time of the light from the backside of Jupiter due to the front side of Jupiter analyzed. All that cracking good answer for the for the speed of light is actually French. Physicists in the late nineteenth century really kind of tidy down but what was curious and this is what fed into on Stein's thinking was that everybody expected expected. The speed of light would be something variable so that if you think about the speed of sound earth the speed the sound is carried through and if you're on a moving object like a car and the speed of sound changes for you because it's your station when you have a cargo past you can hear. Well that's the doppler effect. That's going back to what we're talking about earlier but the everybody everybody expected that if you if you say if you were looking at a source of light and that light is reaching you at three hundred thousand kilometers per second if if you're stationary yeah that's fine but the thinking was if in fact you're moving towards that light at one hundred thousand kilometers per second then then you should see speed as being less than or more than what it actually was. It turns out that the speed of light is. He's fixed in a vacuum. Does not how you moving. How the light source is moving? It is always three hundred thousand kilometers per second and one went. Once he realized is that was actually confirmed. By two Americans Mickelson Morley in the eighteen eighty S. The speed of light is in variant and announced. I'm I'm fed into his work and realized that actually the speed of light is almost mystical. It's it because space can vary space can change shape it depending on your motion and time can change depending on your motion but the speed of light doesn't is the is the thing that's constant absolutely constant. Yeah there is. There is a group of small group of scientists. One of whom is based here in Australia. John Webb who's Nelia Leo was somewhere else in the world. Which is why it's called the worldwide web? John Webb is a he believes he has evidence that the speed of light was different in the early universe Looking back thirty point five thirty point six billion years the beginning of the universe was thirteen. Point eight billion years ago to the best of our knowledge and he looks back nearly all that way and thinks he can see evidence that the speed of light has changed. It's a very speculative result nominee. Astronomers believe in but John Webb is convinced without from the University of New South Wales. We'll keep an interesting an eye on that. To see how it progresses. Yeah so when. When was the last time you looked at the night sky last night? Did you look to the stars. And so yeah. There's a bit of cirrus around. It's as long a brilliant night. Yeah look the best time you looked at what. What's the most memorable experience you've had in the nighttime environment? It's because my a life has been in astronomy and it goes back a long way. There are many many That I could that I could talk about one of them was in the mid to early. Two thousand two thousand six two thousand seven late in two thousand and six a colleague of Mine Robert macnaughton in siding spring discovered a comet. That was his job. He discovered comets but This one turned out to be incredibly bright and in the early months of two thousand seven it was just dazzling in a in western evening sky. Not where I lived at that time was totally crews are particular does. Yeah not all of them do some some go around the Sun Many of them are in orbit around the Sun but comics actually come from the depths of the solar system. In fact almost halfway to the next nearest star there's Sort of shallow of these icy objects called the ORT cloud named after a man called Yan art who was a Dutch stronger. In the Mid Twentieth Century must be a cloud of icy objects out there which fall inwards towards the solar system and when they get near the Sun the ice evaporates and they become luminous right. Yeah he was. That's right and that's how we that's how we know about comets but comment one of these. That came out of the Blue Egg. Robert detected it when it was quite faint but it turned out to be probably the most spectacular comet of the century so far it may be the most spectacular for the whole century. It was just so that's one but I I always have very fond memory of a night light. which would have been in the early nineteen eighty s and it was when I was building? The first of these fiber optic systems the flare thing that I mentioned that was a device that as I said used optical fibers to pick the light of stars from the focus of the telescope and brought them the fibers brought them out of the telescope to a basically a little thing that just line them all up in a straight line now we straight line was about half an inch long thirty millimeters or something AH thirty nine optical fibers in it each of them a about a tenth of meter in diameter and it was a crystal clear Leeann. I and I got the telescope all set up until this was right at the beginning of these experiments and I picked up this little fiber AIBA unit from the floor which I knew had the light of stars coming down in the end and I just saw a line of little lights. It'll all different colors because stars are different colors. Color is dependent on the temperature and it was magical. These are standing there withholding style in my hand with with these these. These thirty nine five lit up shining away and it was the real reason why it was. A buzz is because actually quite hard to get light down fibers become very very precisely at that point. I knew I could do it. And I knew the instrument was going to work. Did mazing so just to finish shop like to ask you if you had your soapbox and three minutes if time what do you want people to know about light and light pollution Russian. Okay so this is where I become. Well an advocate. It's not quite activists activism. It's very gentle activist. uh-huh why do we want moderate change. When do we want it in due course? So that's my soap box and what I would tell people will is that he asked them to think about whether light is going. Light basically goes on forever. I mean it does the dwindling away to very faint levels but if you're sending a beam of light upwards into the sky what am I going to do is going to light up the molecules of the atmosphere via and spoil that view of the sky for somebody else. And it's a death by a thousand cuts so individually our contribution to light pollution is very low but collectively when you've got a city like Sydney with more than four million people living there. Nobody thinks about where the light is going. Then you've got a city in which it is impossible to see the stars house so it's just to think about lighting up only what you want to light up. Keep the light below the horizontal plane. So none of it's going going up into the sky and there's a subtlety here. We now know that like that is rich in blue and that's really Dazzling white light that we getting used bright white light emission dial diodes light-emitting diodes. Led that light we now know is not good for human health at night because it fools circadian rhythms into thinking. It's still daylight screws up everything so think about Light Posi answer. Thanks for you time to great pleasure. Anytime thank you. Well that's it docks guy conversations this week. We hope you enjoyed it. We'd love to hear feedback thoughts. Were if you've got any questions.