Transcription
The edges of the solar system. So what I have first of all, thank you very much for all of you being here. You know, in my eight years of supporting the summer school, this is the first time I'm actually giving a talk. I am NOT a teacher. The last time I taught was probably 30 years ago, so bear with me. All the questions that you might have, of course, you have all the professors and teachers here; save it for them. What I want to do is sort of give you a tour, a motivation for why heliophysics—heliophysics is a concocted word; it didn't exist as a discipline just a few years ago—and now we have written textbooks. You've been attending, you know, diligently the summer school; you are learning, going back, doing postdoc, becoming teachers. So just to provide a framework, a motivation, and what the next three years of the summer school is trying to do, which is to develop, take heliophysics and apply it in different environments: the comparative astrophysics, the comparative planetology, the world of exoplanets, which has—which has—just emerged from observations of Kepler data.
So what—what I'm doing here is I recently gave a talk on celebrating 40 years of Skylab, and of course, many of you might not even know what Skylab is. Skylab was the first NASA-tended sort of observatory; it did a lot of solar physics and astrophysics, I would say both remote sensing and in-place observations. And so there I gave this talk, really how this particular orbiter, you know, a small space station if we may say so, really prepared sort of solar physics into heliophysics, the integrated big picture, and then from there into interplanetary space weather, which is, I think, the next frontier. And—and that's why I'll give you kind of a tour of that. And so this is a picture—I think this is a two-minute picture—just pay attention to that while I say some other stuff, but this gives you the importance of what's happening on the Sun and its impact throughout society. This is a talk, separate talk by Bill Mortor.
So why are we doing this? I think, you know, human society's vulnerability to solar flares and CMEs as our environment continues to expand is very evident when you look at what's going on with the impact that we have in today's technological society. We have a permanent presence of humans in Earth orbit and eventually human voyages beyond Earth. Solar variability can affect human spaceflight, satellite operations, smart power grids, GPS navigation, emergency radio communications, air travel, financial services, and even terrestrial climate. If you can think it, it's as if it can be affected. Anything that has a sort of electromagnetic switch in it has the potential to be affected by heliophysics or solar storms. And this all actually started with Skylab, as you will see. This, I think, particular picture ends, and these are showing you all the technological impacts—essentially, you know, precision equipment during farming or on the ocean—these all can be affected by space weather. And the motivation for space weather, the science, is really heliophysics. Going to go onto the next slide.
And—and so what you see here, you know, space weather very simply defined refers to magnetic disturbances and high radiation levels that result from solar activity. Aurora, power outages, and radio blackouts are some of the many manifestations of these activities. Human civilization has now extended from the physical domain of the Earth where we live to the neighboring domain of the heliosphere, which is really controlled by the Sun's gravity and magnetic field. Space-based commerce and government infrastructure has grown so explosively in the past half-century, I would say that satellites are actually beginning to run into each other, and we have some examples of that. Furthermore, humans have been living continuously in the heliosphere on the International Space Station for the past decade and more now, and this human presence will only increase. So in some ways, we are no longer simply observing some domain beyond our reach; we must now gain that level of understanding, I think, required to develop and inhabit a new environment. That's what heliophysics teaches.
This is a daunting graph; don't be scared. I think your professors will show more of these; I just illustrate this almost like a cartoon, you know. This is a prototype picture for studying, you know, the Sun-Earth, the Sun-planet, or stellar-exoplanet system. The picture is not to scale; it is 93 million miles—I mean, there—that—that's huge, mind-bogglingly huge for us. And in this, if you can see, you know, the Earth, that little pale blue dot, actually is enveloped in the Sun's expanding outer atmosphere, which is the solar corona. In that sense, the name of the program that I oversee, Living with a Star, is literally true; we are actually living in the outer atmosphere of our star. The Sun is coupled to a planetary system by radiation, charged particles, and magnetic fields, and these are modulated over, you know, many different scales, the most common being the 11-year solar cycle that you are very—familiar with. You know, it goes up and down, you know, the Sun peak, trough, and—and you can see that the effects that we feel because of that much modulation are becoming more severe or known in the way of space weather today, simply because technology is beginning to be affected by this.
The study of heliophysics involves three forces, you know, two are very familiar to us, you know, when we deal with terrestrial weather, which is pressure and gravity. What makes heliophysics really unique is the third force: magnetic field. You can't see it, you can't touch it, but you know it exists. Imaginary lines—that's how we study them, right, when we are doing electromagnetic forces. And the combination of these three forces makes heliophysics into something that is a bit exotic for a discipline. It is a combination of meteorology and astrophysics together. So meteorology is terrestrial weather; astrophysics is the Sun as a star. The combination of the two is heliophysics. So the science is rich, complicated, and the effects are really vast, but very interesting. And I'll probably come back to this theme again, just to drive this point home, because what you're going to learn here is a very broad interdisciplinary sign; you have to learn many different aspects of physics in order to make sense or start solving problems. So but you can, of course, choose certain areas within this broad field. Heliophysics is a systems approach, you know, if I hadn't already said that enough number of times; it does not focus on any region of space, but rather on our Sun-planet region as one system. So you start with the solar dynamo, and, you know, if you read the chapters in Volume one and two, you'll get the basic physics that's entailed in heliophysics—not going to talk about that—and then from that is generated various solar outputs that are modulated by the 11-year solar cycle and other relevant time scales. And—and the various solar outputs are broken up into various spectral ranges of radiation: you know, near ultraviolet, visible, infrared, x-rays, extreme ultraviolet, energetic particles, which are these solar wind particles, you know, which has both a charge as well as mass, and then solar wind as I mentioned there. And you can see how those lines that have been drawn kind of show you which radiation affects which layers of our planetary environment. Now remember, this is—this cartoon is for Earth, but every planet will have its own planetary environment, and this will change accordingly. What you see out there on the far right-hand corner: galactic cosmic rays—that's not of solar energy, but it is the Sun's magnetic bubble that allows the penetration of galactic cosmic rays, which are produced during, you know, inhalation of stellar systems. These particles come through the Milky Way galaxy, interstellar medium, and they penetrate the magnetic bubble of the heliosphere, and they are very—higher charged particles that can have more effect on—so anyway, the important point to remember is that the study is about the connection between the regions and how one sort of drives our response in another; it's a system study.
So how did all this get started? You know, heliophysics is not starting as brand new in some sense; it's one of the oldest of disciplines; it's just that we are making this connection and presenting it in a very coherent manner. So this is sort of Sun-or-system science growth from consuming science to producing science. And what do we mean by that? It's not just curiosity-driven science, but it is also science that has relevance to life and society, and that makes it stand apart from other kinds of science. And this started a long time ago, you know, the First International Polar Year in 1982, and which went after synoptic observations, a network of polar stations, you know, as technology became available. Scientists started doing more and more experiments; you know, map phenomena came into existence. The Second International Polar Year, 1932, added a third dimension: explore the upper atmosphere. Then you go into the International Geophysical Year, 1957—the year of the Sputnik launch—also, you know, added Antarctica and space, explore space. You can see how this phenomenon is developing. International Quiet Sun Year in 1984 at solar minimum, complementary IGY, complement IGY, which is the International Geophysical Year, International Magnetospheric Study, 1976, year study system complexity, Solar-Terrestrial Energy Program, 1990, add numerical modeling; we are systematically—we were developing this, it seems like—study integrated interactive system, National Space Weather Program. This is the first time the word "space weather" was used; it came into existence in 1995, applications-directed science. This is the first time we started using that word, relevant to life and society. This was largely an effort started by the National Science Foundation, community coordination. Living with a Star program started in 2000 as a NASA initiative, again applications-directed science, the same science, and this was a NASA community coordination. And finally, the International Heliophysical Year in the year 2007, following in the footsteps of IGY, at comparative heliospheric studies, universalize heliospheric structure and processes, fundamental science. Okay, that, and this was a two-year program sanctioned by the United Nations. So this is about the evolution of system studies, and what you can see there is really growth from the International Polar Year to the very large bubble on the right-hand corner, which is the entire solar system. Okay.
So heliophysics, a broadening of the concept geophysical, which is our planet, geo-space, extending the connections from the Earth to the Sun and interplanetary space. Our understanding began with a very local view, and as technology developed and international coordination grew, we began to view the Earth as more of a system, and that's where we are, you know, our science is very much like that, right, then does to restore whether very system-driven; that's where heliophysics is going.
Why heliophysics? So heliophysics is the study of the physical domain defined by the Sun, the heliosphere, just like astrophysics is the study of the physical domain—physics—physical domain defined by stars. This physical domain includes the Sun itself, the solar wind, and stretches out to the start of the interstellar medium, where we have the Voyager spacecraft, and I'm sure somebody here will talk to you about the exciting science going on there. So in principle, heliophysics studies everything inside the Sun's domain of influence, as I already mentioned. Heliophysics is an environmental science and a unique hybrid between meteorology and astrophysics, and I am repeating this because these are really important concepts. It has an applied branch, which is space weather, started in 1995, and Living with a Star that started in 2000, and a pure branch, just the plasma physics processes that most of you are interested in, that was kind of propelled into existence during the International Geophysical Year.
So how did Skylab really contribute to heliophysics? What—where were some of those game changers that Skylab introduced back in 1973, 1974? The corona is hot and controlled by magnetic fields, and you're going to learn a lot more about that. And—and what were they measuring? They were measuring x-ray and extreme ultraviolet rays and their variability on Earth. High-speed solar wind originates from coronal holes. Solar particles impact Earth. These were the concepts that were being driven home from the Skylab observations and its impact on Earth. Mass from the corona is ejected into interplanetary space; these are the coronal mass ejections, right, more both mass and momentum at a tremendous speed. So solar catastrophic events can impact Earth's magnetosphere. Three very important points from Skylab. I'll give you another concept of—yes, absolutely, I am a graduate student of helio—as a matter of fact, and my thesis, for a big chunk of it, was utilizing Skylab observations. Thank you. And yes, some of those films are here. It is—yes, it is—it's history today that would be—and in fact, if Gong is here, maybe she can organize something; she's the director—acting director—of the High Altitude Observatory. So I kind of want to still go on on the theme of heliophysics and kind of tie it also to the organization of the universe, and—and—and that—that kind of—it—it's—it's—it's given in a sense, kind of showing, you know, phenomena that are sort of affected by gravity, phenomena that are affected by magnetic fields. You have astro and solar below; you have gravitational organization where you see the universe, galaxies, stars, solar systems, planetary systems, questions of origins, life on planets. And then you go to the plasma astrophysics where heliophysics falls, you know, magnetic organizations, solar connections. And that branch actually talks more about destinies of life around and between planets, habitability of planets. You know, the universe is filled with electrically conducting gas, right, ionized gas called plasma; exceptions are what they are. Planetary atmospheres, you know, we reside on one, and some dense interstellar clouds. So in—in that sense, we also live in a magnetic universe. Now we may presume that most stars are magnetically active like the Sun, but the Sun is the only star available for direct study here. And—and so examples of gravitationally organized matter we have already given: planets, stars, galaxies. And magnetically organized matter are sunspots, magnetosphere, stellar and galactic spiral fields, galactic plumes. So knowledge of heliophysics, in that sense, can be applied to this—to this organization right here. Another—and I'm not going to dwell very long on these—are things that you are going to learn here: really exploiting parallels between helio, astro, planetary, and Earth science. In fact, there are, you know, undergraduate teachers here; we've been having questions about solar-stellar connections or comparative planetology. You know, we know quite a bit about the Sun and its impact on our planet; what happens if we look at Venus, Mars, Jupiter? Those are the comparative planetology. And, you know, it wouldn't be fair for me to say that it is easy; it is not easy; it's—it's hard work; you have to study hard; you have to take really difficult classes for many of these because this is a very complex system with many different temporal and spatial scales. This is a multi-scale system, and these couplings between scales—a very—you know—interesting graph that Professor Campos, he actually drew up a long time ago to illustrate his point to his students, really. And you can see, you know, the scale there, that a temporal scale going from one second to 100 AU. One second is a solar flare phenomenon or a zone phenomenon; 100 AU is what we are beginning to see at the Voyager time scale. And—and so what are we looking for from this sort of study? We are—we are really after a quantitative, predictive understanding of this complex system; its quantitative, predictive—so you know that it has to be absolutely rigorous. So I just leave you with that, but these are the kind of processes we are trying to study, create models, and continue on.
Very simple picture: the sum of the phenomena happening on the Sun: solar flares, coronal mass ejections, high-speed streams, and what are their impacts on the space weather phenomena on Earth? Then you can see solar flares cause radio blackouts, or it can cause radiation storms, which are high-energy particles which can affect human health and satellites. Coronal mass ejections actually have effects on radiation storms as well as geomagnetic storms, which are all the phenomena that we feel in terms of power grid outages, scintillations in the ionosphere, loss of communication, navigation satellites, etcetera. And high-speed solar beams, which happen pretty much continuously, sometimes gusty as high-speed solar beams and sometimes just low solar beams, and they also have their effects, you know, in generating radiation storms and geomagnetic storms. And you're going to hear more about this from Bill Martyr, who is at NOAA's Space Weather Prediction Center, who will really tie in the impact of heliophysics.
A quick overview of heliophysics observatories. This is not complete; it's a little dated; we have more satellites there, but this gives you a picture of all the different kinds of satellites observing, you know, really in different orbits, different vantage points; some are remote sensing, some are in-place situations that essentially provide the observational foundation that then dictates—dictates—theoretical validation of our models. And I'll show you a—sincerely—well, let's—you can see this picture because if you even—surely sort of give you the envelope, the magnetosphere, and—and in that context where these satellites are located. Now remember, some of these satellites are actually observing the Sun; these are remote sensing observations. Some day—some day—but why Jupiter? We are not going to live there. See, this is what happens. And—and so this is—this is—this is sort of a schematic of the various satellites you saw there. I think the missions that we say in development, which are yellow, have actually launched, except for MMS, which will be launching next year. And then the missions in development are Solar Orbiter, Solar Probe Plus, and I see that I'm missing ICON and GOLD; those are our two brand new missions that are really looking at the ionosphere-thermosphere region. And remember, you have to study each of this region with observations in order to really create that system science. The next four or five charts, I have them, but I'm not going to talk to them, as I said, because you're going to have someone else talk about the impact, so I'm just going to scroll through it. You know, you can see, you know, how heliophysics affects all of these areas.
So let me go now to where we are with the solar cycle. You know, solar activity is so low that solar max looks a lot like solar min—I mean, really—and if you plot it over a very long time field, you see how low. So you may think that because this is a low solar cycle that perhaps we don't need to kind of worry about our technology, that it is safe, and let's see if that's true or not. But before I go there, I kind of—also, we've talked about the space weather phenomena but did not really address the Sun-climate connection. Climate is just as important a phenomenon that is driven by the Sun. Now climate, in the NASA domain, is something that Earth science practices, but we absolutely interact in terms of climate variability. Climate also is now being utilized more and more when we look at other planets; it's a longer-term phenomenon as opposed to the shorter-term space weather activity. And what you find here is on this left-hand side, the plot there shows total solar irradiance, ultraviolet, extreme ultraviolet, and you can see that in cycle 24 these are phenomenally reduced, and this must have an impact on our planetary environment as well as climate. What is really more interesting is the—the ratio of spectral solar irradiance from solar max to solar min. If you look at that little green straight line there, that is the ratio of visible light, which is kind of comes out during total solar irradiance measurements; that variability is only 0.1%, one-tenth, very small. But if you look at the blue, in the UV, that is huge, and that variability can be up to 100, and sometimes it is not just a ratio between solar mean and solar max; sometimes it can happen within a day if there is a big solar flare going on, and that—those are the radiations that are absorbed in our ionosphere, mesosphere, thermosphere, various different layers. So it's very important. Okay. So we are so used to seeing solar cycle plots, right, as sort of an x-axis plot modulating maximum/minimum, and we always think solar max is a time when all hell is breaking loose; that's really not true. And in order to drive that point, what we have done here is we have actually changed the orientation of the solar cycle, so you have no bearing on max and minimum; all you have are two extremes of the solar cycle. So the rate there is high sunspot number; the blue is low sunspot number. To be cute, you know, we've kind of compared it with La Niña and El Niño, but what you're seeing that on the—on the red side there are—what do we have? We have super solar flares going on; we have extreme solar cosmic rays; these are the solar energetic particles phenomena that happen; are radio blackouts, extreme geomagnetic storms, melted power grids, etc. Now during the low phase of the solar cycle, it's not quiet; there are other things going on: extreme galactic cosmic rays, rapid accumulation of space junk because the ionosphere configuration has changed, short contraction of the heliosphere, collapse of the upper atmosphere, and total solar irradiance changes going down has an effect on climate. And so those are the big phenomena out.
There, during a solar max event—right? We are talking about a melted power grid from an extreme geomagnetic storm. Talking about that again—is this a phenomenon only during large cycles, during the peak of the solar cycle? Let's investigate that. So there was a very extreme event called the Carrington event in 1859. We believe we haven't seen anything like this, at least not on this planet. And sometimes, you know, especially in 1859 where we didn't have the wealth of observations we have today, what we had were ground-based magnetometers, or we had the sighting of a rural over the further south the auroral oval is observed, or the overall display, right—the aurora borealis. The stronger is the geomagnetic storm. So in this particular case, you can see latitude, and if you can see that lower graph there, you will find that there was a magnetometer that's in red in Bombay, and a latitude of—I don't know—barely above the equator, you know, where there was where we had actually measured the magnetic field, ground-based magnetometer from this Carrington event. So this is one of the largest events in history for which we have enough observations that we are beginning to piece this together.
So when did this particular event take place? The largest dramatic storms on record occurred during the peak of solar cycle or large solar cycles, but during lower than average solar cycles. And the two red bubbles, if you can see them, are the 1859 storm and the 1921 storm. They were they were pretty significant. And guess what? We are actually in one of those rare weak cycles. I'm not drawing any correlation, but just to make the point that these things can happen anytime, any cycle. So this solar cycle is even smaller. Where is our Carrington event? Yeah, I knew you'd ask that question. Even that said, you know, it doesn't mean that we have to have one. Well, the question is, did we actually have a Carrington event? Maybe there is no way to clearly prove it because this particular event was not Earth-directed. This was the July 23rd event of a coronal mass ejection that really was traveling at a speed of about 3,500 kilometers per second. This was absorbed by not Sun-Earth line satellites, but by the STEREO satellite, which is actually at a different vantage point from the Sun or Cline. And this particular semi-affected the STEREO-A satellite, but also STEREO-A satellite was able to take observations. So is it possible that Sewell or a solar superstorm just narrowly missed Earth? A lot of very interesting work that has gone on which are telling us perhaps we had something very big that we escaped. These are just some of the pictures from the STEREO observations. You know, these are the coronagraph images, and the white speckles there are essentially the telescope detectors are getting overwhelmed by energetic particles. And what you see here is essentially computer models that use these observations and then generate propagating CM into the interplanetary medium. That's it. That's what you're looking at. This gives you a picture of where STEREO-A was, where all these, and how huge this particular coronal mass ejection was.
Okay, so let's now go back to extreme galactic cosmic rays. It's it's the essentially linear phase, the low sunspot number phase, which is where we are today. Let's look at the heliosphere. So just as Earth is protected from solar energetic particles by its magnetosphere, similarly, and and that's right up there on that corner, the heliosphere is protected—where the solar system is protected from galactic cosmic rays by this magnetic bubble called the heliosphere. And that's what you're looking at essentially. And and so how does that work? During solar minimum, what we have—I think I had another plot, but it's somehow not here—during solar minimum, the heliosphere contracts, the magnetic field is simpler, and during solar maximum, the heliosphere expands. It's like the heliosphere as if it's breathing. And and so the galactic cosmic rays have easier time penetrating the heliosphere during a weak, low solar cycle, solar cycle, or during solar minimum, then it does during a strong solar cycle or solar maximum. Now why should we care about that? What happens? It's because, you know, as I mentioned, when solar activity is low, cosmic rays are able to invade the inner solar system. It not only gets to the inner solar system—if there are satellites, or someday even human astronauts, they'll be affected by this. And and this is a plot I believe from one of our satellites, ACE, that's showing you—blue dotted plot, huh—cosmic rays have really gone off the scale during the solar cycle because of the weakening solar cycle. And remember that cosmic rays are not a product of the solar system, but of the interstellar medium.
Why is this important? Why do we need to know? I think this is this is really a very interesting plot. So what you're seeing there is that radiation exposure for human exploration—it is not a question of if, but when—that we will see human astronauts leave low-Earth orbit and venture out into the solar system. It will happen in my lifetime. I don't know. I think that in your lifetime, definitely. So as demonstrated by MSL—this is this is a Mars Science Laboratory experiment—what you are looking at, this is the plot that you have to look at that is really important. So here is an integrated dose equivalent in some particular, you know, unit, and what you're finding is what the MSL RAD instrument has. So during the cruise phase, space solar energetic particle is pretty high—the dark blue—but if you look at the galactic cosmic ray during the cruise phase, it's much higher—a factor of 10. If you look at what happens on the surface of Mars, for example, you see it now. Is it the law on this one? No. So this is this is during the cruise phase, this is the surface. Solar energetic particle effect on the surface—minuscule—but if you look at what happens to galactic cosmic rays on the surface, for whether it is a satellite or whether it's astronauts, it's huge. These are the kind of things we have to keep in mind, and the fact that galactic cosmic rays are modulated by the solar cycles—the solar minimum in some ways is a safer time to travel beyond our low Earth orbit. Yes, it's actually going up—still going up—that that's what I think I will look up and show you. Yes.
And finally, you know, during periods of low solar activity, cosmic rays pose a threat not only to astronauts, but also to ordinary air travelers. And this must resonate with all of us, right? A 100,000-mile frequent flyer receives a dose equivalent of 20 chest x-rays. One chest x-ray is something that we here on Earth receive over 20 days from natural stuff, you know—radon gas in buildings, secondary effect of neutrons, etc., etc. So we are getting a lot more—you know, 200 days' worth—you know, if you are a 100,000-mile flyer. And this is happening, you know, at mid-latitude. If you are going over the poles, from Chicago to say Beijing, a 13-hour flight during a low activity period, you could potentially get a lot more—you can get sort of two days of chest x-rays in 13 hours. And you might ask the question, you know, so why should we care? I mean, you know, we don't feel it immediately, but we also know that exposure to x-rays has its effect on, you know, cataract risk, other cancers, etc. But this is this is an area of study. So what about people in space or interplanetary space? You know, so this is again an active field of research that you will participate in and inform the rest of the world, I think, someday.
So let's start with now the whole concept of interplanetary space weather. Would someone tell me how much time I have? So okay. So the fact that we are able to actually predict, in some sense, or inform interplanetary space weather, you know, space prediction of space weather itself was a challenge, you know, a decade or two ago. We didn't have sufficient observations, our model. Now we are talking about interplanetary space weather is simply because we have really surrounded the Sun with our satellites—STEREO A and B, launched in 2006, you know, which are drifting away from the Sun's hotline at a rate of about 22.5 degrees, and they are actually almost close to being behind the Sun as we are talking, and of course, the Solar Dynamics Observatory and solar and SOHO. These are the spacecraft that allow us to view the Sun continuously, really, three-dimensionally. We can see the far side of the Sun. If you have an iPhone or Android, you can download an app called 3D Sun, and you can get what the Sun is doing, even on the far side, in the form of your hand. And this is—these observations have made interplanetary space weather possible, a new concept. And this is essentially a picture from the Solar Dynamics Observatory. I'd be remiss if I didn't show you the fabulous observations that we are getting from the Solar Dynamics Observatory. Of course, we are showing here just one quarter of the Sun—that's a filament eruption—but we are getting these at a rapid cadence per minute, at very, very high resolution—I mean, IMAX resolution—that is changing our physics and also exactly what is going out into the interplanetary medium. So that's kind of the beginning, I would say, of the interplanetary space weather concept, which we call a new Herod.
I'm so if you look at this—probes are now orbiting—or in transit to—Mercury, Venus, the Moon, Mars, Ceres, Saturn, and Pluto. And it is only a matter of time before astronauts are allowed—the actual—this is—and this is—we sort of came home during a phenomenal event in March 2012, which we call the St. Patrick's Day one, that took place over a two-week period. This is that active region that really produced this effect. There were some 50 flares, the history of which were of the highest measure x-rays, and then we were able to take essentially these observations, put it into our model through a supercomputer, and you can see what the CME is doing here. And again, these are—this is Earth, which is right here, various satellites—to do AV Spitzer, various planets. So you can see if a particular planet is going to be affected by these events or not. There were about 15 NASA satellites that were affected by this phenomenon. So what did we learn from there? I think we are at a stage of development that—you saw the computer model, for example—observations are very similar to some of the—for satellite images of hurricanes that we took in terrestrial weather—and also hurricane forecasting, which is really modeling that effort. So tropospheric weather, you know, storm tracking is essential for midterm forecasting. And and this picture here essentially showing you that weather in the Midwest is Washington's weather tomorrow—Washington, our nation's capital. It's important we know what's going on there, whether or not—and and so what's the equivalent of space weather in that? You know, it's that coronal mass ejection, you know, tracking is essential for midterm forecasting. That's what we are seeing. And this is a coronal mass ejection plot that you're looking at. And this kind of observation then allows us to create the models which can go out throughout the solar system.
This is very interesting. So this is the STEREO mission and the Heliospheric Imagers in the STEREO mission. And what what STEREO HI images are trying to do is really measure something that is so faint that it is almost imperceptibly important. And they have done that, you know—this is actually measuring something at a magnitude of the Sun—right? 27 magnitude to minus 27, 13th magnitude star. What this set of imagers are doing is measuring a bright solar flare to something like an asteroid, which is charcoal black. It's sort of the order of magnitude. In this image, compared to the human eye, is of the order of ten billion. You know, there is nothing—no observatory that is capable of doing that. And so you're seeing the Sun's surface and all the way down here is Earth, and even the Earth is imaged by these imagers. And so the next frontier in space weather forecasting involves the uninterrupted tracking of strong clouds from the Sun to the planet. So the same picture that you saw in a different coordinate—they have been squished, essentially. You're seeing a coronal mass ejection here, is again, or you can almost begin to see the tangled magnetic field that we want to understand in an interplanetary coronal mass ejection. These are very important developments. Very quickly, for NASA reasons for developing this predictive capability may be divided into three pressing areas: reasons—human safety—talked about it—it's interplanetary travel, spacecraft operations, but scientific research I think is probably the greatest beneficiary. Since I'm running out of time, I'm not going to talk a lot about this, but there is lunar space weather that we have absorbed and now understand. You know, these are again phenomena that essentially the lunar dust interacting with solar wind particles as well as radiation. Why? Why would a predictive capability help any orbiting mission? It's simply because that if we knew that a coronal mass ejection or a big storm is coming in a particular direction, whether it's the Moon, Mars, or any other place, then perhaps the instruments there have a capability to adjust their rates of measurement, you know—burst mode or viewing angle or any number of things—so you can collect the maximum amount of data during this timeframe. Same thing here, you know, these are important in support of Mars missions. Mars's magnetic field is not global like Earth's; it it's actually in pockets of umbrella right here and quite dominant in the South. So our CME interaction with Mars actually gives rise to order all ovals in these umbrellas. Our new mission, MAVEN, is going to benefit significantly from getting this feedback—predictive feedback—of when a coronal mass ejection, you know, is traveling in there, a space where the red Mercury—Mercury actually has a much higher rate of magnetic reconnection than we have—than we have observed on our planet. CME interaction with Mercury's magnetosphere can be lethal. These are the areas essentially of comparative planetology that others will talk to you about. I just show you some plots here, you know. This gives you essentially schematics of magnetospheres on in different environments, and I know Professor Bacchanal has much better pictures, and she will show you those pictures. And these are essentially, you know, comparative magnetized spheres—magnetospheres—from different sets of satellites, going back to Skylab.
Now I want to end my talk with Skylab—Skylab and Venus. So suppose we were able to put a Skylab-like orbiter—it has to be better, you know, retrofitted, technologically advanced, etc.—what what would Skylab really find? I mean, what's happening in Venus is phenomenal, you know—reverse shocks called hot flow anomalies above the atmosphere of Venus now can suck the planet's ionosphere into space and locally reverse the direction of the solar wind, sending material back to—what—the Sun. This is what some scientists are theorizing. You know, if you put a Skylab-like orbiting observatory there, then these—the orbiter could actually sample these events locally. I'll give you another example. And if you know—Pluto is very much on everyone's mind these days because New Horizons will be being there shortly. And so what would be learned if there was a Skylab at Pluto? You know, Pluto is very far from the Sun, and it is—it still experiences CMEs. We know that even though the Sun's Bates kind of reduces significantly, but it's still going to be perceptible. And we know that—how do we know that? Because Voyagers are actually experiencing CMEs. So what would Skylab experience at Pluto? Would it see a darkening of Pluto's surface as solar energetic particles interact with goop on the ground to produce organic material? Would it detect blue-toned auroras? I mean, we'll know that next year, we hope. At present, we don't even know if Pluto has a magnetic field. And I don't know—Professor Bacon L might have some ideas that haven't been published yet. New Horizons will give us a glimpse of space weather at Pluto next year. So you can see how you can take space weather, heliophysics, and apply it in entirely different environments. And then you have Professor Cohen, who will give you a really solar system—exoplanet connection. And this is just fascinating—this is extreme space weather on closing exoplanets, our simulation. And this is for Living With a Red Dwarf program, as it has been called. And what you're looking there, you know, in red—red dwarf—a planet can be much closer to the parent star, unlike our own star. And what happens is these red dwarfs can have very large sunspots, and if you kind of really begin to model this environment, what a coronal mass ejection would look like—what you're seeing is that that poor exoplanet, you know, outer atmosphere is annihilated essentially through this CME interaction. So the habitable zone of an exoplanet in a given environment is again something that this community of scientists can begin to address. This is sort of the same model, but showing sort of eggs or magnetic impact. This is—these are, I believe, or all ovals, which is just not at the poles, but all over the surface. So it's really phenomenal that we can take our physics and apply it to different conditions and begin to create realistic enough images which someday we might be able to observe.
Now, talking about exoplanets—we haven't even been to a star yet. You know, we have been to all the planets, the extreme reaches of the solar system, but we haven't visited a star. Oh, we are going to change that very soon. In 2018, NASA will launch a mission called Solar Probe Plus that will actually be humanity's first mission to a star. And it is going to go to within a distance of 10 solar radii of the Sun. This is where you see the coronal mass ejections, you know, blowing out the solar beam from being slow speed to high speed, becoming asymptotic. And I'm, you know, I'll be happy to talk to all of you about this mission later on. I can't dwell on it very much, but this is going to launch in 2018. It's going to have 24 orbits, get multiple Venus gravity assists to get to its closest distance after at the end of seven years, which is 10 solar radii, to address two of the fundamental mysteries in heliophysics: why is the corona so hot, and you know, what provides the momentum for solar wind to accelerate on? And then, since all of you are students and dreamers, I'm sure I will end this talk with, you know, think of a Skylab in another stellar system, and that might not be, you know, such a far-off idea. I mean, in such a context, would Skylab even need a coronagraph to detect a bright red dwarf semi from the close range of the system's Goldilocks zone? We don't know. Thank you. [Applause]