Gaia's mission: solving the celestial puzzle

the heavens are alive do not be deceived by their parent peace and tranquility of the night sky above you the celestial ballet of stars the dance and flicker gently to the human eye a raging and burning in a near vacuum of space living and dying with a beauty ferocity and magnificence that is almost impossible to comprehend stars explode into life then explode in death we are all produced from the hearts of these dying stars charting these dark heavens is an essential part of astronomy but in order to investigate a celestial body astronomers must know where to find it without this knowledge astronomers would wander blindly in what Galileo once termed a dark labyrinth in 2013 a rocket were blast into the sky from a launch site in French Guiana and travels some 1.5 million kilometers to reach its destination in orbit around the Sun the spacecraft is called Gaia its mission is to make the largest most precise three-dimensional map of the Milky Way ever attempted science behind Gaia was recognized by everybody right from the start something that mankind must do daya is going to be revolution in fundamentals for me it's going to be a mission that's going to affect everything astronomy guy is going to produce tomorrow's version of all the great star catalogs that gone back in history to the very dawn of astronomy the answer is just one and there's one Milky Way and we'll find out what it's all about Jerry Gilmore professor of experimental philosophy at the University of Cambridge is the UK's principal investigator and has been involved in the evolution of Gaia since 1990 the way astronomy works is really very simple the first thing you have to do is look at the sky and say can I see anything yes or no and so you see something and so you can measure it you can count stars and the ancient Greeks made these catalogues of stars the Babylonians a Mesopotamian some very sophisticated astronomers they have these very very elaborate clay tablets thousands of them the British Museum detailing star charts and so on there are ancient Chinese star maps so every culture had that model of the universe and distances and scales and times and astronomy are so vast compared to a human lifetime you can't see anything changing over a lifetime or even over centuries even over the lifetime of a culture without the sort of technology that's become available only since the electronic age in the last half a century so every culture had a view of the Milky Way which was a static background sort of thing is he painted on cathedral roofs and we're going to turn that into something vibrant in 1989 the European Space Agency launched the first space-based mission Hipparchus which charted some 100,000 stars so Hipparcos did make significant discoveries that showed us immediately that even our little tiny local neighborhood their tiny patch around the Sun was attempts the way stars move then people had realized that her Bacchus was really a proof of principle and fire as the real coin the Milky Way the galaxy in which planet Earth soars around the Sun at 67,000 miles per hour is so vast that it takes a beam of light 100,000 years to travel across it it is home to more than 100 billion stars and maybe as many planets it includes such exotic phenomena as star clusters supernova gas clouds supermassive black holes and an elusive substance believed to be the fabric of our universe called dark matter it's also we believe perfectly typical of all the big galaxies to dominate the light in the universe and so it's a perfect thing to study because it's it's a good average everyday galaxy and once we can understand this we'll understand the general principles that underlie all of the way galaxies formally evolved but also it's the only one that's close enough that we can actually do it in 3d and so we'll be able to or at least we hope we will be able to distinguish between the many many many different complex processes and events that happen in the lifetime of something as complex and big and old as a Milky Way both most of the galaxies that are like the Milky Way but also the ones that are different find out why they're different so it's our chance to understand how nature actually put together our night sky the gaia spacecraft is an extremely complex and sophisticated satellite it consists of three major functional modules the payload module providing astrometry photometry and spectroscopic data the mechanical service module featuring the thermal control system and an intricate micro propulsion system to help guide the satellite finally the electrical service module which manages the power contains the most powerful computer to be housed in an astronomy satellite to date the payload consists of a single integrated instrument the design of which is characterized by a dual telescope concept a small beam combiner and the largest focal plane ever sent into space designing Gaia has been a major European collaboration with UK companies Astrium an e2 V providing pivotal technological advances in electronics particularly here in the UK on on Gaia focused on what we'd call the the electrical platform that's all the aspects which are to do with the power the control the computing aspects of Gaia that will support the mission the the attitude control of Gaia has been a very particular focus and it's it's very specialized in the case of this mission it actually uses one of the main instruments main scientific instruments to help perform the very precise guidance that's required because this is over and above what we would normally have to do on our spacecraft the the sensors are called CC DS charge-coupled devices and these silicon sensors their job is to receive photons of light and convert them into electrical charge which the sensor stores in a two-dimensional array of pixels if you've got a mobile phone or even a digital camera the sensor will normally just be millimeters or centimeters across whereas because Gaia requires a very large area at sensing area or large focal plane the chips are about 50 millimeter square so that they're really large by camera standards the Gaia focal plane has 106 of these sensors each about 10 megapixel which adds up to a gigapixel of image area when I started working the infrared astronomy I was using single pixel sensors which is laughable now because you can get multi megapixels it's very interesting to see that evolution and be part of it the distances the stars are really hard to measure and the number that we know accurately is tiny and we know it only in the immediate neighborhood of the Sun for almost everything in the universe we've actually got a very crude indirect idea of their real distances so the unique special feature the guy is going to do it's going to be a distance machine it's going to be the first time ever we're actually going to be able to get real distances for a very very large number of stars on going on for a billion and we'll be able to walk in 3d at least mentally through the fields of scars guy does this by measuring parallaxes imagine us he'll guy of the earth star here distant stuff miles away as we move around the star appears to move it's not star moving as us moving but fortunately we know exactly how we're moving because that's that's us around the Sun and so by converting how we are moving into the way the star appears to move we can determine the distance if that apparent motion is very large the things close if that parent motion is tiny the things very far away it's as simple as that so guy will just measure just huh it will just measure with exquisite precision how everything is moving a billion times there's two telescopes on guys are taking two different snapshots of the sky but what guy does is measure at an instant all the stars and some direction of the sky and from that we measure very very accurately the relative positions all stars one relative to another and the satellite moves a little bit takes another picture we repeat that process moves a bit quite quickly you build up a whole picture of the sky in which you know the exact relative positions - very high accuracy one star relative or another but that's still not much use what you really need to know is well what's the absolute measurement which way is up so what we have to do is lock Geyer in some way into the universe and that turns out to be quite an interesting challenge because they've been done at this level of precision before so what we do is from our own measurements we will identify roughly 1 million quasars these are supermassive black holes at huge distances across the universe at vast distances such vast distances they don't move as seen by us and we will use these to define the reference grid so guy will measure the positions of all the stars relative to the other stars relative to a million supermassive black holes 3/4 of the way across the complexities of measuring the distances and motions of a billion stars across our galaxy with such finite precision has a number of fundamental challenges the technologies keep going what you have to do to measure the distance to a typically interesting staff is measure the parallax angle in units of a few micro arc seconds now that's a number that doesn't mean anything to anybody but just to put it in perspective a micro arc second is the thickness of a human hair has seen across the earth it's the size of my thumbnail as seen on the moon and so one's measuring precision measurements it's exquisite precision measurements so the level of precision that Gaia is measuring stuff the whole space-time is just quivering as the earth goes around the Sun so warping and morphing and so we have to do these amazing calculations in which we actually have to correct everything begin a relatively if it's an equally we can test in relativity to match much higher precision than ever been tested before so that's the level at which we're doing is real precision measurements one of the key challenges for a mission like guy in in fact a whole enabler for the mission itself is to find a technology that is especially lightweight and stable to be used for the optical benches and for the optical components so the package that we developed uses a modern sort of high-tech ceramic material it's called silicon carbide which is almost a magic material for this application it's perfect because it's very strong it's very lightweight which is really important for space applications and the other important parameter is that it's a very low expansion material in order to ensure that Gaia can measure things with exquisite precision the satellite itself has to be exquisitely stable satellite is the size of a couple three meter size of a typical office it's not huge but it's got this ginormous 1/2 a tennis court sized Sun shield underneath it so it's a huge great screen and Geyer itself will sit in the shadow and be super cold and the reason it's doing that is because heat distorts things and so the distortions distortions that would be caused by Gaia changing temperature will be so large compared to the precision we need there'd be a real problem to get rid of so Gaia will be sitting there no it doesn't have any coolers on and it just sits there passively but it will be temperature stable such that the temperature difference from one side of the room to the other will be less than one millionth of one degree in order for gaia to measure with such exquisite precision it has to be positioned in an orbit in which radiation and gravity a stay there are five naturally occurring orbits in our solar system in which the gravity of the earth and the gravity of the Sun exactly cancel each other out these genuinely weightless spots are known as lagrangians named after the Italian astronomer Joseph Lewin a Grunch Gaia will sit in a second of these orbits termed LaGrant number two was simply l/2 you can put a satellite there and takes almost no fuel to keep it there and so this is a critical thing for Gaia because we don't want to be tuning a motor on and off and shaking it because takes a long time to stop shaking misses the measurements you want something is going to sit there and will almost know if it it'll just keep smoothly careering on and so this is the space called l2 one and a half million kilometres beyond the earth and the outside you look you'll be able to see it actually you'll need a moderate sized telescope to see it but it'll tire itself will be a star in the sky once securely locked into the l2 orbit Gaia will begin transmitting vast quantities of data across the dark oceans of space data which over its five-year mission will help to unravel the secrets of our galaxy though currently a normal sort of serious movie that you download in a few minutes or something's few gigabytes a few billion bytes the next scale up after that sort of terabytes a thousand of those now guy goes a thousand times bigger again and so the Gaia data scale is more than exists in all the libraries of the world today there's a gigantic supercomputer over the road is going to be processing this stuff it's a petabyte on a Jagan annuity to him scale also it's a typical example of the next generation of big data projects the data product will be very complex but we're designing a system to make them accessible to it to everyone and not only to research astronomers but we will also have data and open data to interested members of the public to amateur astronomers and and so forth we're going to announce here from Cambridge in real time these new discoveries and we're setting up a scheme with school kids where they can go off and look at robot telescopes and look at them so we'll have an adopter supernova for a class your local class can guarantee Tuesday of two years from now we'll find you a supernova and it can be yours so I think that's a cool step but it's not just those stars ablaze with nuclear fusion at their burning heart that we're interested in Gaia is also looking for failed stars brown dwarves stars that never truly ignited and a left adrift across space as interstellar it will also provide an inventory of our solar systems asteroids and comets from the near-earth objects to those located in the farthest frozen reaches of the outer solar system revealing exoplanets as well as objects that could pose a threat to life here on earth for a mission so epic in this scale it's easy to forget the very personal and human stories behind the drama and excitement of Gaia's launch star clusters are a very element very basic element in the whole process of star formation and started evolution they gave us a lot of information on stellar structure studying for star evolution and things like that this mission allow allows me for the first time to look at the star cluster in a way that has never been possible from the ground it can observe the whole cluster it can observe velocities in the cluster it can observe faint stars in the cluster that all things that were very difficult from the ground because they required very long-term projects 50 to 100 year project and with Gaia we can do this over a period of five six years to an accuracy level and a complete list metal that has never been obtained from the ground will be able to discover who are our neighboring stars and perhaps which stars were the stars that emerged out of the same out of the same birthplace as our Sun did we can look for air as sons brothers and sisters we can look for perhaps their own planetary systems to find other Earth's like us I think psychologically and emotionally we are just about to enter the same era for our Milky Way as Western European to win the voyages to the New World and the great voyages of discovery of the earth happened an entire psychology changed people's view of who they were and where they were in the world was completely revolutionized there was no longer Western Europe and that's it you know we have our neighbors and tough we are part of this whole new approach and there was this burst of intellectual achievement cultural achievement it just revolutionized people's view and I think we're going to do the same thing here we're going to be able to walk through the universe and we're going to realize just exactly what we are compared to other people we're going to find tens of thousands if not hundreds of thousands of other planetary systems some of which we like our own quite close we'll be able to take pictures of those planets we're going to discover the things we can't see the dark measure we will go beyond what we can see to be able to understand reality and I think this is exactly the same transition the Captain Cook made we go beyond our preconceptions to see hey this is what the world is like guys and we'll be able to just walk through it we will see the remnants the debris streams of the first shards that became what is today the Milky Way we can run the process right back to the first things that ever happened we will see the entire history of the Milky Way unfolding before our eyes we're going to discover completely new things we're going to discover that stars are moving in ways that we think are impossible and so we're going to learn completely new things about what happens we're going to discover that there's actually an awful lot of matter there and hardly any there and we'll be able to say well what is it then how is that possible so we'll learn a lot about elementary particle physics and possibly even about theories of gravity so I think there's going to be the real dramatic change the stuff that's going to kind of come out of Gaia is not the spectacular science that we know it's going to do it's the stuff that we don't the questions we don't know how to answer [Music] [Music] [Music] you

Channel: Cambridge University

Views: 385,305

Rating: 4.6893497 out of 5

Keywords: Gaia, mapping the Milky Way, survey of a billion stars, Hipparcos, University Of Cambridge (Organization), Cambridge research, The Milky Way, Space, The Universe, Sean Pertwee, 3D map of the Milky Way, The European Space Agency, ESA, European Southern Observatory (Organization), NASA, satellite, Prof. Gerry Gilmore, Institute of Astronomy, Dark Matter, Super Novae, super massive black hole, black hole, star clusters, big bang, evolution of the Milky Way

Id: oGri4YNggoc

Length: 19min 58sec (1198 seconds)

Published: Thu Dec 19 2013

Reddit Comments

[u/jayjr]

This is a good clip. Thanks.

I am still a bit in the dark how the indexing method is being set as, and how that is going to be working with the IAU so that we now have a monster database to apply things like exoplanet research on (instead of the hodgepodge method done today).

What i'm meaning is shown here. As you can see, we've got 100,000 stars which have IDs which the IAU isn't really using, which is sort of silly. We need to have IDs for everything and this will be as easy of a way as possible.