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TEDx Talks
Published: 2017-09-07
Source: https://www.youtube.com/watch?v=jh9qtIIxiVA
well thank you so much and my name is Cynthia Chang and %HESITATION I guess I am all the other speakers were asked to talk about immigration and I am the odd ball outside Thomas I did not miss the memo home but they they did ask you physics so I'm going to tell you a story tonight but it's going to be very different from the other stories
you've heard mine is going to be about adventure and it's an adventure that we want in order to learn about in the universe in a this is a I'm so the study of the universe as a whole is known as and cosmologists in general are interested and understand so that is the on the history of the evolution sure of the universe on largest scales so the
sorts of questions that we like to think about include how and when did the universe again what is the fate of the universe and what is the universe made of things like that and of course these questions of humankind has thought about these questions for as long as we've existed and to illustrate how old and profound these questions are I'm showing an illustration from the eighteen
hundreds always shows a curious observer and he's peering into the heavens trying to understand what lies beyond of course there's a lot of artistic license in this picture a but actually on the spirit of this picture is very similar to what we do today and present modern day call quality %HESITATION but thanks to the advent of specialized telescopes that we've been able to build and precision
observations we can actually begin to address these grand questions in a precise scientific and quality about quantitative manner I'm so we fast forward from the eighteen hundreds to the present day this is a picture that shows a timeline or a map of the universe as we understand it today so we believe that the universe began its existence fourteen billion years ago and a lack of a
large explosion called the Big and since then the universe has been expanding and cooling off does the universe has evolved there's been a few significant milestones in its history that I've outlined here in the picture also starting up twenty four million years after the Big Bang the universe became cool enough for the first hydrogen atoms to form now at this point the oldest like that we
can observe in the universe which is known as the cosmic microwave background was released now after this point the universe was just filled with neutral hydrogen and it was a very dark and boring place for a very long time and the cosmic dark ages lasted until about a hundred million years after the Big Bang and at that point the first stars ignited in the universe and
dog appeared in the cosmos and after that the universe continue to evolve more structures appeared including the stars and galaxies that are familiar to us today and we use observer said at the very center of this picture looking out and we're trying to fill in the details of the strange and so for tonight's story I'm going to focus on one particular slice of the universe's history
and that is this period known as cosmic don so during this period the first stars ignited in the universe and we just cosmologists would like to understand in greater detail of what the universe look like during this part of its own development so we don't we we believe that because I don took place between one hundred and four hundred million years that may sound like a
large set of numbers to you %HESITATION but I want you to think about let's take the whole fourteen billion year existence of the universe and compress it down into a human's life span now if I were to do that then the period of cosmic dawn would actually correspond to the first few years of humans and so in other words if we take our telescopes and look
back at cosmic don we're essentially trying to study the universe when she was a toddler and you look very different by so that's that's sort of the science that we like to do and what we're interested in something so now that I've told you what kind of science I might like to do I'll have to tell you how we're going to do it and what we're
going to look for so locally %HESITATION %HESITATION for observational cosmologists are %HESITATION her tool of choice for understanding the universe is white telescopes and we look at life in various sorts and thankfully during the period of cosmic dawn the universe was filled with neutral hydrogen and hydrogen has a very special property and that a close with a very specific kind of low so it turns out
the hydrogen atoms emit radio frequency %HESITATION light and if we can tune in our telescopes to observe at frequencies between fifty and one hundred fifty megahertz we can literally listen and to the period of the first stars igniting in the so that's the game plan and so now you might be wondering how we actually going to do this in practice how do you catch a radio
waves well %HESITATION there's good and bad news here so the good news is that you may have read a megahertz numbers are much maybe a slight %HESITATION because FM radio stations all broadcast in this race and so that's great because if you wanted to measure a radio wave at a hundred megahertz all you do is go to your car stereo and turn it on and you're
to go but with all things that sound that easy there's always a catch and the catch here is that if you're trying to build a cosmic dawn telescope and put it on hold all you would pick up is your favorite radio stations all the popular music and all of that would drown out all of the cosmological I know that you're so you would never be able
to see the signal I'm so that that's very sad so then you might be wondering well what is a cosmologist to do %HESITATION given this dilemma so the solution in this case is to leave civilization behind so we want to get as far away as possible from the radio stations and find a very quiet place so that we can see the sky and out of the
contamination that we create and so this is where our adventure begins %HESITATION so it turns out that South Africa owns a research based on very an island a which is shown in the upper right hand picture over here and you can see that it is quite literally in the middle of nowhere it is two thousand kilometers away from the main and I can tell you you
don't pick up any radio station on their so the store have minutes hall tonight is about our research team at U. K.'s that and how we went on a voyage to marry an island this April and we set up a new radio telescope in order to try searching for the signature from the first stars igniting in the so I'm going to start off by showing the
final telescope that we set up number experiment is called prism which stands for probing radio intensity at highs that from and this is the instrument in its full glory %HESITATION I'm excited to share with you tonight that this is actually the first astronomy of any sort that's been done from Marion island and so we really are exploring uncharted territory here which is quite exciting so now
and science the story isn't just about the theory and the technology but it's also very much about the people and there is a significant and so I want to share a picture of our students who are the members of the deploying team to Marianne this a role no the instrument that you saw on the previous slide was designed built from scratch and feel that entirely by
students so they get all the credit for making this work and not only that %HESITATION but they %HESITATION they spent three weeks on Marion and it's three weeks is a very short period and so they had only that amount of time a set of a fully functional robust system that could be left behind for a full winter and during that three week period everyday they spent
two hours hiking through cold weather Myers lava fields ice palace you name it to get to our site work on the equipment and hike back but it is all worth it for the love of science and up but it is going to their hard work that I'm able to stand here today and sure the story with right so %HESITATION fielding a telescope to a remote location
as I was a pretty scary experience and so I'm going to share some photos just illustrate some of the challenges that faced %HESITATION and so this photo shows %HESITATION our Kerrville being delivered to our site which is located four kilometers away from them there were no cars on the island so yes we want those four kilometers everyday in order to deal with our instruments and what
easier these three tiny orange boxes and those contain all of the pieces of hardware that we struck a radio telescope and leave it fully functioning for a year and so what this picture doesn't capture is just how nerve wracking it is to tell the helicopter to yes we are okay to go you can dump us off in the middle of and so the best way the
best the best of it helps lift up the cancellation of the feeling that I could come up with for these lyrics from you the only baggage you can bring us all that you we've been really is a little bit nerve wracking %HESITATION but it's okay and so we started unpacking or not and everybody got to work and this is whatever to members assembling sure and the
things to a lot of careful preparation and hard work we're actually able to get everything set up within a few days and remarkably it all works the first time traded which was some kind of America all gone grateful for that %HESITATION what is even more remarkable is that when we look at the observations that are %HESITATION that our antennas took we could find no evidence of
contamination of radio %HESITATION radio interference that's created by humans on a radio stations of any sort always always clean sky but as far as we can tell Marion island is probably the most radio quietly we have ever observed from and now we have a new instrument in place of taking observations and we really hope that we'll have a clean shock of seeing the signature from the
first ours igniting so that's where my story for this evening and was actually just the beginning %HESITATION because we have this new telescope installed and now it's going to continue observing for the winter season and so even though our team has come and gone from area we have passed the torch on to committee so beloved who is shown in this photo and he is the super
hero of the next chapter of her story unbuttoned because he is the person who is spending the winter on where Karen are equipment so when all is said and done he will have been there for thirteen months I can tell you the internet primary was pretty about some sonas you could shout out so I hope would convince you tonight that with radio telescopes can really explorer
some the university if you are this period of because they should be pretty fun as one of the nice to see stars and and in our search for him exceptionally radio quiet %HESITATION location guys our adventures have taken us to marry an island %HESITATION which seems to be a wonderful new location for write a list we have our equipment up and and we're doing our observations
