Female Announcer:
From the Library of Congress in Washington, D.C.

Jennifer Harpster:
I'm Jennifer Harpster, a digital reference specialist for the Science, Technology and Business Division at the Library of Congress.  I'd like to welcome you to today's program, "Our Sun -- Its Influence on Climate and Life."  This program is part of a series of programs -- uh-oh, is that okay?  I'm moving along [laughs].

[laughter]

Our speaker today -- oh wait, that was too far along.  This program is part of a series of programs in 2009 that is presented through a partnership between my division and NASA's Goddard Space Flight Center.  So what do nine planets with their moons, tens of thousands of asteroids and trillions of comets all have in common?  Anyone?

[laughter]

The answer is the sun, which is the star of today's program [laughs].

[laughter]

I couldn't resist that [laughs].  Our speaker today is Villanova University professor of astronomy and astrophysics, Dr. Edward Guinan.  Dr. Guinan has been the principal investigator for over 40 NASA-sponsored research programs that explore the behavior of the sun and stars like the sun to determine the effects of their radiation, magnetic activity and ejected plasmas on planets and life.  He has published more than 500 papers, edited three books and has been the recipient of the Outstanding Research Award and Alumni Award from Villanova University.  

In addition, Guinan has served as president of the International Astronomical Union's Commission 42 on Close Binary Stars and on Division 5 Variable Stars.  Since 2006, he has served as co-chair of the Astronomy, Education and Outreach Program for the International Astronomical Union.  

Today's lecture will begin by looking back at the young sun, and how its high energy emissions have played a major role in the loss of water on Venus and much of Mars's original atmosphere, and how the Earth survived the sun's early ravages.  In addition, we will learn about the effects of the sun's magnetic generated energy on the Earth's climate, possibly playing a major role in the Little Ice Age, which was from 1500 to 1850.  Also, Dr. Guinan will discuss, oops,  the sun's possible role in global warming over the past 150 years.  

The lecture will conclude with a discussion of the sun's future, and how the sun's ever increasing luminosity affects the Earth's long-term climate.  So please join me in welcoming Dr. Edward Guinan.

[applause]

Edward Guinan:
Thank you for inviting me, and thank you for that very gracious introduction.  We'll start with this one because this is the outline, and it's called a tasting menu for good reason, because some of the topics I'm going to cover will be a taste.  Some of them you may not -- we may not even finish that topic because of time constraints.  So I'll take you through the properties of the sun and its climate, the second part the magnetic sun, which NASA has many satellites on board or in space, and then our program that I was pundit for was the Sun-in-Time Program.  It's a look back on the sun, what it was four billion years -- three billion years and actually into the future even, and then a lot of interest has developed in the last, well, the last 50 years on global warming.  So we'll take you through that.  The sun has often been blamed for global warming, mainly by the oil companies [laughs].  And there's  still some people who believe that it is playing a role, and then I'll take you into the future.  This is the flambˇ of the talk, a flambˇ dessert because of what the sun does in the future.

So let me start this rolling, and so here comes the sun.  We had, if you came in earlier, you heard the Beatles song "Here Comes the Sun."  So we found some pictures.  So this is the sun.  The planets are drawn to scale, but not their distances, and of course, Pluto is no longer a planet.  But I left it on there for old time's sake because of Clyde Tombaugh.  I knew him, and he was the one that discovered that one.  So you see the distances are wrong, because you can't do everything, but the size of the sun and the planets are correct.  The Earth is about 100th the diameter of the sun, and the largest planet in our solar system, Jupiter, is about 10 percent of the sun's diameter.  

This is a little "fun facts" on the sun.  I don't know if they are fun or not, but its mass, and who cares about grams.  That's a lot of grams, 1033, 33 zeros following.  But it has -- it takes about 330 Earth masses [sic], 330,000 Earth masses to equal the mass of the sun.  

The diameter of the sun is almost a million miles across.  The Earth would take 109 Earths to straddle the sun.  The distance varies.  It's about 93 million miles on average.  

Temperature, I put in Fahrenheit for you, we don't work Fahrenheit, but we use Kelvin or Celsius; but about 10,000 degrees on its surface.  

The luminosity is how much it puts out, how much energy, and to put it into terms that you might because that's a large number, 1026 watts, one second of that is enough to power us for the next hundred years, but it's hard to harness that energy safely.  But it's equal to 90 billion megaton TNT device that's going off per second, which is a lot of energy.  But it's all taking place in the core of the sun, down in the deep in the center of the sun there's hydrogen fusion taking place.  

Its age is pinned down very precisely.  It's the star that has the best determined properties because it's on top of us.  It has the best mass, the best radius and best temperature.  And its age is precise because we use radioactive dating, isotopic dating, it's called, from meteorites, and you can get it within a hundred million years, which is very nice.  Most stars you can only guess their age to about 10 percent.

Chemical composition, you wondered what it is, it's about what the universe is made of when the Big Bang took place.  It was mostly hydrogen produced and helium, the sun reflects that, 74 percent, 24 percent helium.  Metals, astronomers use metals in a very loose term.  Anything heavier than helium is a metal.  So you wouldn't consider, you know,  neon a metal, but astronomers do.  And chlorine and things like that we consider metals.  

Energy source, as you know, is thermonuclear.  It's the fusion of four protons, hydrogens into helium, gives off the energy and gives off neutrinos which I'm not mentioning. And the bottom equation is the Einstein equation [E=mc2 ] what's going on, is that four and a -- what's happening is that energy -- mass is transmuting into energy, and the way I figured it out, if you take that luminosity you see on the top, luminosity, I'm moving out of camera range but who cares-take that, put it with the speed of lightening and you do the speed of light squared, and you get what it is; it's four million tons of matter is producing the energy.  Now, you think that's a lot of matter, and it is, but the sun is hundreds of millions of times more massive than that, so the sun loses very little energy, very little mass in going through its burning.  

This is a quick primer, and it's very quick.  Climate is very complex, but this is the simple version of it.  The sun, of course, is the major source of our energy, 99.4 percent of our energy comes from the sun.  The rest is thermal nuclear winds and things like that.  So the sun is the major energy source.  Photosynthesis is what most of the energy goes to.  It goes to heating.  The distance of the sun is a -- plays a role because if you're -- the energy -- the flux you receive from the sun falls off as one over the distance squared, so for example, if you moved the sun out double, moved it twice as far away, you see that equation there, one over distance squared, you receive 1/4 as much energy.  Thus, the outer planets are cold the inner planets are warm because they are nearer to the sun and getting more energy.  It's the same thing with sound, too.  If I weren't using this microphone, the people in the back would be hearing me in that same lull, one over the distance squared.

Now, the other factors that come in are called albedo, and that's just a fancy name, or an Arabic name, for reflection.  So you have that energy impinging on the Earth.  The Earth is clouded.  It has ice caps.  So 30 percent of what comes in from the sun gets reflected right back into space like a mirror and has no effect on raising, or changing the temperature of the Earth.  Most of that is due to clouds.  There's a picture of the Earth over there, ice caps, dust in our atmosphere, particles in our atmosphere.  The blue sky you see is scattering.  It's the sun's light that's been scattered.  And a lot of it is scattered back into space.  Some is scattered back to you.  

The other effects -- or the emphasis is a greenhouse effect.  So you have the energy going in, and that reaches the 70 percent that makes it to the Earth's atmosphere and surface, and that energy gets trapped temporarily.  The light that the energy emits get through the atmosphere, but when it hits the ground, it produces heat, which is infrared energy, and that interacts with molecules such as water vapor, carbon dioxide, methane, things like that, and we have a 54 -- I put it in Fahrenheit again -- a greenhouse effect of 54 degrees Fahrenheit.  Without a greenhouse effect, we would be below the freezing point of water.  We'd be zero degrees Fahrenheit global temperature.  

So a greenhouse effect is good.  It can be bad, because then you look at Venus.  Venus has what's called a runaway greenhouse effect.  The surface on Venus is 800 degrees Fahrenheit.  You go to your pizza place, you know, pizza.  That's what's about the temperature of the pizza ovens are.  

[laughter]

So Venus is very good for making pizzas, but not much else.  So what happened with Venus is it has a runaway greenhouse effect.  Its atmosphere is very thick and contains copious amounts of carbon dioxide.  It could have happened to the Earth.  It didn't.  Mars I didn't put on there.  Mars has a very weak greenhouse effect.  

The other factors that play a role are the energy on the Earth has to be redistributed.  The equator gets most of the energy because the sun's rays come in directly.  The poles the sun comes in and you get short days and nights and stuff like that, so you don't get as much energy at the poles.  You get five times more solar radiation at the equator compared to the polar regions.  So there's  exchanges of ocean currents like the Gulf Stream.  There's  things like El Ni–o, La Ni–a that play roles in determining small changes in the Earth's climate and the North Atlantic oscillation also plays a role, but these are internal changes.  

That's a quick and easy picture of what's happening.  You have the sun.  You have the 30 percent being reflected.  And I put on the other side of the greenhouse.  This is simple.  It is not anywhere near as simple as this.  It's very complex.

This is a picture of the sun.  I thought you might want to see an X-ray of the sun, of sorts.  This is the internal structure.  The sun is a star.  It's made of gas, hydrogen gas, as you saw and helium.  It is in thermodynamic equilibrium.  That means the energy source inside where you see the core of the sun, that's where the nuclear energy.  It's causing the sun to almost blow apart, but the gravity of the sun keeps it from doing so.  So the forces out are balanced by the forces in.  It isn't going to be that way in the future.  The forces in are going to overwhelm the gravity and the sun is going to expand.  Unfortunately, expand to include the Earth.  That would make really solar astronomers very happy because they'll be inside the sun [laughs], but it's not going to be good for us. It happens in a few weeks.  This will -- no --

[laughter]

-- it happens in about four or five billion years, so don't worry about it too much.  

And then you see in the sun, you see the inside is about two-thirds of the way out you reach a zone called the convective zone.  And actually, I have a pointer if I can figure it out.  I'm not supposed to leave this spot here, but I hate staying in one position, so about two-thirds of the way out, the sun begins to convect, which is a nice way of saying bubbles.  So it bubbles and starts to convect here, so you get up and down motions.  And when you get to the surface, that's where you see sunspots.  That's called the photosphere is the surface.  And then there's  magnetic effects that take place.  

You see filaments.  The coronal region is two to three million degrees Kelvin.  That would be about double that, four to five million degrees Fahrenheit, and this is all the stuff out here.  These prominent sunspots, chromospheres filaments, they're all due to magnetic effects.  That's produced by the fact that the sun has this convective plasma.  The sun is spinning.  Once in 25 days it spins, and that creates a dynamo, like a magnetic dynamo like you would have on a generator.  And that produces all of the magnetic phenomena that we're going to see.  That is very important for us and for climate.  

This is a neat picture.  They use a method called helioseismology, it's like when they use seismology for the Earth, when you have an earthquake you can probe inside the Earth and see it has a mantle and a core.  You can do the same thing with the sun.  For about 20 years, a series of telescopes around the world had been looking at the sun, and the sun vibrates in thousands of modes.  Remember, it's a fluid.  It's not a solid, so it vibrates in seconds, tens of seconds up to minutes.  By analyzing the vibrations, you can actually determine that the sun has like an atmosphere like our own with circulation.  The sun spins faster at the equator -- that's by the red -- and slower at the poles; ywenty-five days here and 30 days up there.  It's called differential rotation.  

You can map inside the sun by using helioseismology.  You can look deep into the sun's core to see how it's structured.  That plays a major role in the generation of magnetic fields.

This is a picture of the Sun - of a sunspot, but what it's showing you is I was talking about the convective zone, and these little things you're seeing here, this is sped up, it's going very fast.  These little guys, first of all, this is the size of Texas [laughs].   Anybody from Texas?  I had to pick a large state, and the Earth would be about the size of the center part of that spot.  This is a sunspot.  

So these bubbles, these are rising columns of hot gas, and they have lifetimes of five minutes.  They rise up and then the dark part you see is them subsiding, so the temperature of the bright areas are about two or 300 degrees hotter than the parts that are falling down, and you can see and hear that the magnetic field of the sun underneath is disturbing the flow of heat out, so the sun is transferring heat from its center by this convective, boiling, and when you block it, this is about 2,000 degrees cooler in that spot than out here.  So what's happened in here is that magnetic field has blocked or partially blocked the flow of heat out.  And so this is the sunspot.  

This is a picture of a solar eclipse.  Has anybody seen a total solar eclipse?  Nobody?  Oh, you have.  They're fantastic as these people will tell you, and this is a picture of when the moon moves in front of the sun, which is this black, it blocks out the photosphere, allowing you to view this corona.  This coronal region is two million degrees in the Kelvin scale, four million degrees in the Fahrenheit scale, and extends out even much longer than this, probably ten times further out.  

Here you see prominences, storms on the sun's surface that are taking place in red, and these are great.  If you have a chance to see a solar eclipse you should do it.  And China, next year, there's one in August.  I think it's in Shanghai.  You get two or three of these a year, but you have to travel a long way, usually, to see one.  So what astronomers do or what solar physicists do here is they study this during the solar eclipse.  It allows you to see the corona.  They discover the temperatures, the two million degrees.  It's hot.  Why is it heated?  It's magnetic energy, the bubbling the sun undergoes the magnetic effects of the sun goes pinch.  The gas will cause it to be extremely hot.  

This is a brief history of the sun.  This is one minute tour of the life of the sun.  The sun is born as a gas cloud, huge.  It's a thousand times the size of our solar system today.  This collapses down.  The center part will be the sun; the out part in here is going to be the planets.  So this is where the planets would form out in there.  It becomes this -- before it burns hydrogen, it's up at this stage.  This is the sun now two billion years in the future, the giant face, and then this huge where it becomes 150 times bigger than today.  This is where we have serious problems right in here because it comes out to near the Earth's orbit or even beyond the Earth's orbit.  

These are actual pictures of the stages.  These are star-forming regions.  These are places were stars are being born.  They are stellar incubators.  You can see a Judy Garland movie, "A Star is Born," over there [laughs].  And you can come back, you know, 50 years, and you can see things changing here.  Here's one it's a young star.  This star hasn't been born yet.  There's  stars inside these columns.  Here there is a star forming region where many stars are being born.  So the sun did that four and a half billion years ago.  If you want to find the nearest star-forming region, it's in Orion; the belt of Orion is where they are.

The next stage, this is an artist's conception.  This is the sun -- the cloud has collapsed down, has now flattened into a pancake.  The central thing will end up as the star.  It's called a protosun.  And this has happened in the first million years of the sun's life.  If things are lucky and we were lucky, planets will form in this debri disk.  Ninety-eight percent of the mass of the solar system is in the sun.  The 2 percent is in the planets.  Most of this gets blown away, and what remains behind are the planets.  

Here's the sun today.  The sun will stay similar to this.  It will burn hydrogen from 10 million years ago up to nine-and-a-half billion years.  So we're at four and a half.  The sun is a middle-aged star.  We hope it doesn't have a middle-aged crisis. 

[laughter]

That would be bad for us.  And this shows the sun now, and this shows the sun I the future.  It becomes a red giant.  And I have pictures of that.  So my minute is almost up here.  

And the final stage before that, the sun will actually convulse.  When it becomes this giant star, it starts to throw out.  It becomes unstable.  It doesn't become a supernova or a nova.  It just blows out material in a gentle way.  This is a planetary nebula, because in the old days they thought these maybe were planets, but they're not.  This is the core of the previous star.  This was a star like the sun.  It went through the red giant phase.  And this is called a planetary -- it's called the Cat's Eye as you can see, and you can see the molable times that it had ejections, and the ejections sometimes are very complex.  Sometimes you have ejections from the pull of the star.  So there's tens of thousands of these planetary nebula that again, it had nothing to do with planets but this is near the edge, the sun -- this is near the time of the sun's death for about ten billion, well, five billion years from now when the sun's 10 billion years old.

Now, the central object here, what will happen is this stuff will blow away, leaving behind that object there is the core of the sun.  That's the ash.  That's the hydrogen converting into helium. That's the helium.  That's the helium core.  It's what's left behind of unspent nuclear fuel.  That will collapse and form the final eight.  So this is the death of the sun.  It forms what is called a White Dwarf, and I put the movie up.  Some of you may be fans of "White Dwarf" series.  I doubt it.

[laughter]

If I had an audience who were 18, teenagers, they would know who this character was, but at one of our brightest stars, Sirius is the second brightest star in the sky.  Of course, the sun is the brightest, a trick question that we use in our classes.  

This star is -- so this is the star you see in the south.  It's called the Dog Star.  This -- it has a companion that was discovered over 150 years ago.  And its mass is half the sun, and its radius is the size of the Earth.  This guy here has a radius of two times the size of the sun, and it's as dense as 100 million tons of water.  So even I couldn't lift one of those.  I mean, I would have trouble holding that 100 million year piece of the white dwarf.  So the White Dwarf is the skeletal remain.  It has no energy left.  For those who enjoy diamonds, our sun someday in the future when it goes to the White Dwarf stage.  These are made of carbon -- carbon and helium will solidify and form a diamond.  This is a gazillion carat diamond [laughs].  

So now the next part is the magnetic sun, the magnetic sun, and these are pictures.  These are not true except for that.  These are false colors, because these are all taken in ultraviolet or X-ray where we have no vision.  These are all taken from above space because the ultraviolet and X-rays don't reach us, fortunately.  The only one that's actually from the ground in real color is this guy.  So here's the sun taking an X-ray.  You see the storms.  These are called the McDonald arches, and these are magnetic fields that emerge from the sun and then they trace out gas.  This is a flare.  This is an eruption on the sun, having an energy of about 100 million megaton bombs.  These happen quite frequently, and this is a sunspot.  So this is the only one from the ground.  This is actually the real colors.  The dark is what actually if you could look carefully would be orange.

So these are the NASA missions.  SOHO, as it's called, the Solar and Heliospheric Observatory's been in orbit for over 15 years.  And it has a whole suite of instruments on board that study the ultraviolet.  Ultraviolet is produced by hot plasma.  X-rays are produced by even hotter plasmas, millions of degrees.  So this is a way of studying the energetics of the sun.  All this stuff here, everything you see here is produced by magnetic effects.  The spinning sun, the convection generates these huge magnetic fields; they pinch the gas and heat it.  And that's what makes it hot.  

So SOHO, this is YOHKOH.  Because of the cost of these missions, the costs are shared.  This is shared by the U.S. and Japan.  The previous one was U.S. and ESA, the European Space Agency.  And this has made a nice collage of the sun changing the time.  The sun has an 11-year magnetic cycle.  It becomes very strong like it did in 2001.  We're right in here.  We're at the weakest phase.  But in four years it will be back here.  This will create storms, aurora, geomagnetic disturbances, even could black out or destroy your cell phone communications.  Wouldn't that be a waste?

Here's another one showing trace close-ups of these magnetic structures.  These have about 100,000 degrees, these cooled down.  And these are on the sun all the time.  So the sun, when you look at it, you don't know it's doing all these things.  Here is a -- this means -- Hinindo [spelled phonetically] means sunrise in Japanese, and this is also to study, the sun.  

And there's a stereo, which is just about a year ago, these are two satellites that are a pair.  Here's the Earth, and they are separated by now tens of millions of miles from the Earth.  One drifted ahead, one drifted behind, and the idea here is to take a stereoscopic image of a flare, so you can 3-D - so you can image these things in three dimensions and determine the structure or cross-sections of them.  This has some nice pictures and I have handouts that give you resources if you want to look at this.  If you would just look at, you would do NASA stereo and you would find beautiful pictures of these.  It was just in the news last week getting this picture.

And a mission that's being planned for the fall is the Solar Dynamics Observatory, which has been tuned in to study what happens during the 11 year magnetic cycle.  Sunspots, and now I have the how sunspots form, if this works.  I have to find.  This is an animation showing you what happens.  These are above the sun.  Now, we're going to go below the sun.  And what happens when you get a sunspot is the magnetic field comes up and pierces the surface, blocks the convective flow, and there you see it above, seeing the sunspots, and then you see those McDonald arch type things rising above.  This is an animation.  It's not real, but based on physics.  And then you have explosions, you just saw something fly off.  So that's how sunspots -- I didn't want to send that a second time, let's just go on. 

This shows you a piece of the 11-year cycle.  This is the solar cycle.  It's approximately 11 years between here.  The sunspots are the blue.  So if you track it you see that it's approximately 11 years.  We're having a low one now, and actually it's expected even to be lower in 2011.  Right now, for the last 60 days, the sun has been spotless.  For those who are Catholics, it's called immaculate. [Laughs] Immaculate is without spots.  So the sun has been that way for six days, very unusual.  So the sun seems to be slowing -- dimming down.  Notice these aren't all the same.  Some are higher; some are lower.  

What it also tracks is this thing here.  Irradiance is the amount of energy that reaches the Earth, so when the sun is heavily spotted, the irradiance, which is the black curve, is highest.  That's because of all the other things.  The spot's block some of the energy but they're overwhelmed by the magnetic energy, the things you saw -- the flares, the X-rays, and all the other heating that take place.  So that was a surprise, discovered in the 1970s and '80s, and now we have tracked three of these, and everybody, all the solar physicists are trying to guess what's going to happen in 2011.  You know, is it going to be -- there's a game you play whether it's going to be a low, high or whatever.  The game looks like the people who guessed low are going to win, because the sun has been very, very quiet over the last year.  And that is actually good for us.  It's good for communications because it won't -- when the sun's very active, it knocks out flares, it knocks out telecommunication, it can harm astronauts.  But you'll lose on aurora.  You won't see as many aurora.  

So this is a picture of the sun on X-ray.  And we're up to 2007.  It would look like this.  So this is taking you right around.  Again, this is not optical light, but this would have a lot of spots.  These are showing the storms on X-ray, and we're right about here.  What will happen in the future is that in 2012, we'll be -- the sun's not changing size here.  It's just done to show you the perspective.  So in 2011 or '12 it should be like that again.

Now, just a brief -- because this is a tasting -- can't go into all the -- this is a whole talk on its own. This solar weather is -- it used to be "solar terrestrial relations," it used to be called.  That isn't very sexy, so they changed it to "solar weather, storms & dangers," and I have a handout if you want to know. Every day you can get a weather forecast on what the sun's doing, which might be useful to you.  Usually, it isn't.  But it shows you what the sunspots are doing, what the winds are, what the flares are.  

And why it affects us, solar weather affects us we're not this near the sun, thank God.  We're 93 million miles away.  But these eruptions, and the sun has winds that flow out, we're basically protected from most of that because the Earth has a magnetic field which acts as a screen.  It deflects the plasma around it, or it moves it into the north and to the south magnetic polar regions, which are not at geographic pole.  The north magnetic pole is in Greenland.  It isn't where Santa Claus lives.  It's in another area.  But this is what protects us.  This is probably what saved us from when the sun was young.  

Here's an aurora, aurora borealis, northern lights, but this is taken from the International Space Station.  So the Earth's body is down here.  Usually, you see these looking up.  And you can -- these are city lights being smeared.  And this is when there was a plasma that reached the sun and it's interacting -- it's hitting a hundred, 200 miles up, and causing the nitrogen and oxygen, like you have in fluorescent lights, to fluoresce, and this gives you these beautiful colors.  It's a very unusual way of looking at an aurora.  

Now, we'll see what the sun does.  This is a -- from SOHO, what they've done is -- this is called a coronagraph.  They've blocked out the bright sun, which is here, allowing you to see what the sun's doing in a week.  These are stars.  You can see the sun is pretty active.  These things that shoot out here, if they're shot in the direction of the Earth, can cause problems with communications.  They can cause beautiful things, too, like aurora.  But they can call dangerous things, and they have.  

One thing happened is a geomagnetic storm in March 1989 knocked out power in the northeast and Canada in nine hours.  It baked these transformers.  It can still do that.  And so in 2012 or so, 2011, it can actually knock out our whole grid system, because we're so interrelated.  If something fails, then there's a whole cascade, and the sun can do this.  So this shows you the Northeast, and when this happened, all these lights went out here.  

It also, and again, this is a whole other talk.  I just wanted to give you a tasting.  This is a tasting menu.  Communication satellites are extremely vulnerable to solar plasma.  Military satellites are protected.  They have some protection.  But they can be wiped out.  And communication satellite means your cell phone.  So a couple years ago, I think it was December two years ago, many of you lost cell phone communication because two of the communication satellites were knocked out.  They're solid state, and any little bit of plasma or geomagnetic energy from the sun can destroy them, can knock out these satellites.

Astronauts in space, and they are in space all the time now in the international space mission, have to go to a safe room, which isn't so safe. It's better than nothing.  And a major storm would actually be lethal.  And so this is a problem, too.  This is why they've invested money into developing predictions. And when an eruption takes place, you can tell.  It usually takes a day to get here, a day and a half.  You can see if it is getting here or not whether you take protection.  Military satellites are shielded but they are also affected.  

And you have then -- what also happens is when the sun is very active, it causes the ionosphere -- this is the atmosphere that's a hundred, 300 miles up -- to puff out because it's receiving solar energy, become more dense, and the satellites flying through there get drag on them, and it causes the satellite to lose orbit, some have lost orbit.  They were worried about this with Hubble during 2001, 2002, because it was -- the drag on the satellite -- Hubble's a pretty big satellite -- would bring it down.  So they brought -- they had a repair mission, not a repair mission, but they boosted it up into a higher orbit.  And, of course, the Halloween flare a couple years ago interrupted satellite and cell phone service, which maybe isn't a bad thing.

This is the project that I've been working on.  Again, it's a tasting menu, so I didn't go to all the way in changing 3:00, but this is called the Sun-in-Time project.  I had so many -- I don't have that many resources.  This program uses solar proxies.  So this is a program to study the sun by using stars like the sun, but younger.  So we find stars that are matched the sun, but young, and we can use these stars to see what the sun was like one billion, two billion, three billion, four billion years ago.  This is the only way you're able to do this.  There's no -- models for the sun are not good enough to extrapolate them back.  So we gave this name the Sun-in-Time -- actually there's books outside called the "Sun in Time" because I got my idea for the title for this project from the book.  And I went to a conference in 1989.  

So we selected these -- the sun is G-2 star.  We selected 25 stars that have no rotation periods.  We observed these with every satellite we could.  These are X-ray, X-ray is the corona.  This is the two million degree plasma that the sun emits.  These guys are working.  Chandra is the equivalent, the X-ray equivalent to Hubble.  It does X-ray observations.  XMM is the European Space Agency large X-ray satellite.  These were two small ones.  So we got time on those.  The one that's working -- the only thing that's working right here is HST, Hubble Space Telescope, has been used to study these stars, like we do with the sun, like the satellites you saw, like SOHO and the Japanese satellites are studying the sun in ultraviolet X-rays.  We're studying these stars.  Of course, only a tiny fraction of these satellites are being used for this purpose.  

And this is the only graph I'll show.  This is the analog of -- analog is an easy way to show this is a factor of analog 10, analog one is ten times so from 27 to 30 is 1,000 times, okay?  This is a proxy for the present sun, and you see the young sun, and the young sun has approximately 1,000 more X-rays than the present sun because the sun is spinning fast. So this is the way that the sun is dying down with time because the sun is spinning so fast -- one rotation in two days.  Stars in here, one rotation in nine days, one rotation in 25 days.  And this is the future sun.  And over here is actually showing the rotation.  So here you have the age in million years, billion years.  And you have the young sun two days rotations, five days, and they you can go on. There's a lot more that you don't want to see, because this is my whole project, and we're trying to keep this short, so I made a pretty picture of it.  

This is the present sun, and going back in time, the young sun was spinning fast, two days versus 25 days, and produced giant sunspots, huge X-ray coronae, and as time goes on, these are millions of years, billions of years. This gives the X-ray luminosity.  The X-ray is the amount of coronal emission, and my student made this up for me.  So this is the easy picture.  This is the graph showing almost the same thing. This is the hard X-rays. This is the factor of the sun has decreased by a thousand times in X-rays, about a hundred times -- this, too -- a hundred times in ultraviolet, and far ultraviolet, about 50 times or so.

So when the sun was young, it was some star you wouldn't want to be around. And there wasn't life for the first half billion years because the sun was having flares and had huge amounts of X-rays coming out of it that would be lethal to us now.  This is a summary, then, of the young sun.  I just summarized everything and that the X-rays and ultraviolet and all that were 300 to a thousand times stronger.  The sun was dimmer because the nuclear reactions were a little bit slower then, 70 percent of what it is today.  Far ultraviolet was a little less. The winds of the young sun - we actually measured using proxies were 1,000 times today, 500 to a thousand times.  And the flares were huge, like two to five big nasty killing, what would be nasty to us today, flares per day.  But as time went on, the sun slowed down.  The sun had what's called angular momentum breaking.  

And this is now taking you to what it did with the planets.  So this is a -- I'm going to take you on to the next topic. Okay, I'm moving pretty fast, because this is a tasting menu, and there are some areas that I run out of time here, I have to skip.  So this is a [inaudible].  Notice how the magnetic field is protecting the Earth, and so let's stop that movie. And we had two papers with using our data on the young sun for Mercury and Venus, and as you see the top here, the sun was not nice to either one of those two planets, and Mercury, it was -- because Mercury's very close to the sun, very, very close.  Forty -- 38 million miles that it actually got its atmosphere swept away, completely gone.  Perhaps it even ate into the surface of the planet, removing the outer 20 or 30 percent of Mercury's surface.  Mercury's an unusual planet because it has a large iron core.  But what may have happened is it may have been the size of the Earth and got widdled down.  So Mercury's called the iron planet because it has this huge iron core.  Earth has an iron core.

Venus, further away, 70 percent the distance that the Earth is, but the sun, it was no match for the sun.  It had no magnetic field protection.  The early X-rays and ultraviolet radiation of the sun broke up the water molecule and the winds swept it off into space, leaving Venus an inhabitable planet.  The water was gone almost immediately, and then as the volcanoes took place on Venus, it just built up a huge, carbon dioxide atmosphere a hundred times our own, and an enormous greenhouse effect.

Earth fared better, and because it's further away than Venus.  Venus and Earth are about the same size.  I remember that Earth has the magnetic protection here, but it doesn't protect you from the radiation, so the X-rays, the far ultraviolet and ultraviolet radiation get to the atmosphere, and they cause photochemical reactions.  They break up carbon dioxide.  They can break up water and do things like that.  And they can cause the ionosphere to puff out.  One of the things that -- and the winds are very strong, but for the most part, the magnetic field of the Earth, which is stronger than today, protected its atmosphere from being blown away.  These reactions are good, and they're bad.  They sterilized -- if any life was there four billion years ago, it was sterilized.  But three and a half billion years ago is the first evidence of life, continuous life of the Earth.  

One of the things it can do is down here.  Is that these photochemical reactions that are quite complex, that break up molecules and allow new molecules to form.  One example of it is this nasty thing, formaldehyde, which is the carcinogenic material.  Maybe if you're older you remember frogs were put in there, and we played with them, and we didn't know it was not a good thing to play with.  And formaldehyde is actually a useful thing in the building block of life.  Formaldehyde is made from the -- can be made in our Earth's early atmosphere by breaking up carbon dioxide into carbon monoxide, breaking up water into hydroxyl and oxygen, and then these two come together forming HCO.  Two of those go together forming formaldehyde.  So it could have played a role in the development of life, and the reason for that is the key ingredient of formaldehyde, when  you put eight of them together, forms ribose, which is one of the key ingredients -- it's a sugar, and one of the key ingredients of RNA.  So it could have aided in the production of life on Earth by giving the energies for these chemical reactions to take place, and of course, life.I gave this talk at Halloween.  I never took it out because I like Frankenstein.  

What I don't have a lot of time for is Mars.  Mars did all right.  Mars is further away.  It's one and a half times further than the sun, so it receives half as much radiation, but Mars is a little planet.  It's 1/10 the mass of our own, so its gravity is weaker.  It has a harder time retaining an atmosphere.  Mars has water.  It's 100 percent.  It used to be an argument 20 years ago whether Mars had water or didn't have water.  It has water.  It's frozen.  But the arguments were, you see evidences of dried up river beds, each things, these kinds of sedimentary rock.  So I used to have a whole song and dance 10 years ago where I would do five minutes trying to convince people it has water, but it's, of course, frozen water.  Although once in a while, it bubbles out, so I no longer have to worry about that.  And this is the most convincing thing.  This has not been released yet.

[laughter]

So if you didn't believe it.  Now, this is -- and, again, I'm giving myself just two minutes to do this.  This is one of my pet projects.  We received some money from NASA to study, to use our solar data, and then we modeled it.  We took an early model of Mars, and we saw what happened.  This is Mars presently.  Mars is not a nice place.  Its atmosphere is 1/90 as thick as here and you have to be 20 miles up.  Twenty miles up is hard to breathe.  You know, there's not much air up there.  It's cold and dry.  It's minus 50 degrees Fahrenheit.  It has some ice caps.  Carbon dioxide, for example, exists there because it's so cold.  It's made up of mostly carbon dioxide, but it's very thin.  It has iron in its soil, iron oxide soil.  But the bottom line here is tectonically dead.  That means it doesn't have active volcanoes or plate tectonics.  And it has a solid iron core.  The liquid iron core is what produces magnetic fields, so it has no magnetic field to speak of.  

Old Mars, Mars in the past, three and a half, three billion years ago, gigayear, three billion years ago, appears to have an atmosphere about our own.  Our atmosphere is one bar, so it's what we have.  It was warm and moist, because that's what gave you the rivers and the lakes and things like that, and the sediments.  So it had liquid water oceans.  We've computed the oceans.  It could be 50 to 100 feet deep.  It had these gases, even oxygen.  It had a strong greenhouse effect, because it had water vapor, and it had a liquid iron core.  It had a magnetic field because it has ghost relics of magnetic fields, and it had, therefore, a magnetosphere.  That's that protection the Earth has.  

Unfortunately, Mars was a smaller planet.  It cooled off.  The magnetic core solidified after about a billion years, leaving Mars open to the ravages of the sun.  So the sun's gases, the plasma, swept away.  It broke up the water molecule and took away much of its water.  This is how Mars may have looked in the past with the oceans.  Leaving behind the oxygen got blown away or taken -- dragged off into space by the solar plasma.  The oxygen heavier got incorporated in the Martian soil.  And fortunately, it didn't all go.  As Mars lost its water, water is a very strong greenhouse effect.  Mars' temperature cooled down, water froze out, and this process slowed down immensely, leaving Mars with water, ice water, but still water.  

So this is Mars three and a half billion years ago when it had a magnetic field.  It was protected.  But what happened when that went away is that -- the magnetic field went away -- the ultraviolet radiation doesn't care about magnetic fields.  That got in and broke the water molecule up, and the winds of the sun dragged off the hydrogens into space, leaving it the way it is today.

The last 1,000 years, so we're taking you up to the present.  This is an old painting by Brueghel in 1565.  This is about the Little Ice Age and beyond, and did the sun do it or not do it.  There's a lot of -- we go back to this picture again, and here I put in that these gases here, since the last 150 years, have actually increased.  So this is the same, the sun is the same, but in here these gases, the greenhouse gases, have gone up 30 percent for this guy, and 100 percent for that one.  

So sunspots, the first sunspots were seen by -- or plotted by Galileo.  In 1609, he had a telescope.  There was a nice exhibit in Philadelphia if you want to see it.  His telescope is there.  And sunspots are a measurement of activity.  So if you plot 400 years of sunspots, you see that Galileo was doing work here, and then there was this period were there were no sunspots for a long time, and then you see the sunspot cycle.  This is what we have today, this 11-year cycle, lots of spots.  So every 11 years you get -- notice they're not the same.  That's why it's called a cycle.  Sometimes you get higher ones.  Sometimes you get little ones.  Sometimes you get none.  

This has a name, it's called the Dalton Minimum, and coincidentally, or maybe because this happened, it ends up that the Little Ice Age occurs at that time.  But we also had a period of no aurora. You have records of aurora.  There weren't any in the 1700s.  

And then I plagiarized this.  The Little Ice Age this is called from about 1450 to 1850.  The Earth did cool down.  There's lots of evidence from a, direct evidence.  There's this -- the ice pack began to -- 1250 the Atlantic ice pack began to grow southward, glaciers began to grow in groups.  So this is getting colder, so the 1300s, you had rains, famines.  You have glacial expansions.  All this is indirect evidence of -- even these things -- the Swiss Alps glaciers advance.  People used to go skating on the Thames.  You would never do that today.  You'd fall through; Alps getting bigger.  Some people even claim the Norsemen, they found Iceland and Greenland.  Well, what happened in here is that these colonies in Greenland had to be abandoned because it got colder.  Pictures you can go to [unintelligible] made of art in this time.  Art scenes are like this: you see people skating on rivers and art scenes that show snow and ice.

Now, beer, why you drink beer?  In the 1500s, the major drink in Europe, you couldn't drink water because it was all contaminated.  People used to throw their garbage out.  So grape is very sensitive to climate but barley isn't, so they -- because the wine prices got so high, they switched over to beer, and that still stays the same.  Bottom line, this is the picture.  These various little colors and everything are different methods are used to get the climate.

So here you see the present.  The present is -- this is a thousand years ago.  And this is taking you up -- it's 2,000 years ago.  You see it was warm; it got colder.  So this is Little Ice Age. The black graph in here is instrumental.  This is actually using thermometers.  Notice the steep rise here from 1850 or so.  This is a movie that shows from 1500, and I have to skip around because I want to get this done.  

So blue is cold, so this is 1660.  This is Little Ice Age, and now it will start to warm up.  As you see, orange, and then you have the present.  And a lot of the present has nothing to do with the sun, though.  Let me get out of that scheme.  

So, bottom line, Little Ice Age happened.  It was probably played some result, but volcanoes were also taking place at the same time, and the North Atlantic Ocean had a cool current coming down.  I'll jump to the -- and this is global warming in the last 150 years.  So I'm covering a lot of turf here, so this is a recent issue of "Sky & Telescope," where, "Should we blame the sun?"  Twenty years ago, half the people did blame the sun, including me, but I had to change my mind because the sun is actually not getting brighter.  It's actually cooling down.  

So that will be the answer here, and these are evidences of global warming, or everywhere.  Here's  glaciers, 1920.  This is where it is now.  So the glaciers are all retreating.  This is the Arctic Ocean.  This is  2000, 1979.  It used to be that extent.  Now, it's 2007.  Soon you're going to have a nice free Arctic Ocean, which will be great for commerce, but not great for climate.  And you have these pictures of polar bears, you know, endanger.  I just saw that lady last week who jumped in -- they're not nice -- she jumped in, in Germany, to hug a polar bear.  It didn't hug her back [laughs].

[laughter]

So the -- as you know, the Industrial Revolution was the 1850s.  It got really in full swing by 1900, so you have carbon dioxide, cattle producing methane. And you see then this is the increase in carbon dioxide, the little whips, the little things you see are seasons.  This is taken from Hawaii.  This is the temperature rise, 1860.  It actually tracked the sun for a little while right in here, but then the sun kind of leveled off.  We'll see that picture in a second.  

Notice what happened.  Look at these rises.  This is a carbon -- how do you get this data from ice cores?  You go into the Arctic and bring up ice, little bubbles, you can analyze how much carbon dioxide, how much methane or how much nitrogen there is, and these are like -- this is 30 percent change since 1880, and you plot it all on this -- here's a blowup of that last -- and methane, which comes from cattle or rice farming, really rose up, like double, and these are all greenhouse gases.  This is from the Intergovernmental Panel [on Climate Change] report.  

And I'm going to skip that one and give you the bottom line here.  This is taking all the data that there was, 1900 onward, where you get the different contributions of each element to climate, to temperature change, so here you see temperature change and degree centigrade difference, a Fahrenheit just multiplied by two, and you'll get the Fahrenheit difference.  This is the amount of watts, the forcing.  Forcing is when you make something happen.  It's like when you force.  When you make the sun warmer, it will force the climate to be warmer.  So what they've done here is that, since 1900, the sun has gotten a little brighter, which was true, but notice what happened here.  The sun has leveled off.  

And that kind of tracked, what you see here, is the observed, and yeah, there was a little correlation between the sun and the climate, but look what -- and the sulfates here are from volcanoes.  That makes it cooler.  Anything below this line makes it cooler.  So our pollutions that produce carbon dioxide also produce dust and things like that; so that actually compensated -- the soot and things like that -- compensated to some extent mitigating the temperature rise.  You have volcanoes in green. That's [unintelligible] over here, right there, and ozone changing.  

So bottom line here when you put in all the effects, and this is due to carbon dioxide and methane, is this blue one, when you add all those curves together, you -- this is the model, that gray or mustard looking curve, fits, and fits extremely well, and notice the sun.  If you just put the sun there, it has a little influence two-tenths, one-tenth of a degree.  The sun did cause the Earth's temperature to go up a tenth of a degree.  If you're from Sun Oil, you would be very -- you'd be very happy about that, but that isn't enough because this is a rise of almost two degrees.  So the models fit, and they're getting better and better.  These are super computer models.  

And here's the , here's the smoking gun.  I plot here -- now, again, if you were doing this work long ago, you would have then the solar variability.  This is the Maunder Minimum -- where the sun was then, and this is the scale is what the temperatures could be.  The black is instrumental.  That's using thermometers.  So back here you have to use Polan [spelled phonetically] and glaciers and stuff like that so there's uncertainty.  But notice what happened here.  The sun is actually not as active.  It's leveling off and getting dimmer, slightly, but notice the temperature rise.  And if I went up to 2008, that would be here.  The sun would be there.  So this is the smoking gun and its reliable sources using everybody's data, and that's from the report.  

If you wanted to see the future, and if we had -- if we wanted to see the future, these are the projections if you keep things going the way they are, carbon dioxide, or, you know, depends on China, India, you have to play games here whether we put caps on carbon dioxide, you get this picture here.  This is the 2020 to '29.  Again, the coding is down here in degrees.  Black is seven-and-a-half degrees centigrade.  That's 14 degrees Fahrenheit.  So here you see the best model -- not the best, the best case scenario.  The middle one is the most likely.  But here you see in 2090 to 2100, notice the purple.  It's seven to eight degrees, 10 degree rise in temperature at the poles, which melts the ice caps.  We don't fare so well either.  The Earth is much warmer everywhere, except in a few places it's not as bad.  So this is the worst case scenario in terms of what can happen, and this is the most likely.  

And just if you want to see what can happen to the U.S., hot temperatures in July, so here's 1993.  These were modeled, and they worked.  They give you scales here. Yellow is 90.  This is a high temperature in these places in July.  So this is what you get like nowadays I would say.  Here is Washington right here in 2085.  Some of us may be here, not many.  You notice that the red that you would -- you think it's hot now, as you would have many, many days between 100 and 107.  And these poor people down in here are having temperatures like you get in Phoenix, a 107 if the models are correct.  

And I'm going to do sea levels.  Sea levels -- black is like one foot.  A meter is three feet.  So this gets extreme, but the bad part is New Orleans.  Mississippi has very little chance if global -- if that ocean -- ocean level goes up because the glaciers run off and the heat of the oceans make the oceans expand, so ocean level rises because of two reasons.  Hot water expands and also the run off of the glaciers.  So where you see red won't happen for a hundred years because that's -- you're talking like 10 feet, but you noticed that the coastal - southern California [sic], southern Florida is affected, and where you see black, that's affected immediately almost.  And I had a blowup.  You see Washington.  I hope they don't have land properties too close to the ocean because the Chesapeake floods.  There's two little islands in the Chesapeake already going underwater.  They go underwater in about 20 years.  I forget those two islands.  Don't buy land there.  They have very good crabs.  

And this is Florida.  Well, those who are fans of Disneyworld, you're okay, but this is what Florida was.  This is extreme.  Sixteen feet is not going to happen in maybe 300 years from now if everything continues, but this is Miami, so maybe a few places might be above sea level there.  So it's pretty dire for -- with the highest point in Florida is 150 feet above sea level, and now we're all looking forward -- this is the end.  No, this is the flambˇ.  In one minute, you're going to see the future of the sun.  

So here's the Earth now.  We're in the habitable zone, 93 million miles.  That doesn't change.  We have a friendly sun sort of, but the sun is getting more luminous as time goes on because the nuclear reactions are getting faster, the sun's interior is getting hotter and the sun is expanding.  So two billion years from now, it's already the end, because what happens in two billion years, the sun is 25 percent more luminous and makes the Earth 15 degrees warmer.  But that's not what happens.  It triggers a runaway greenhouse effect.  The warmer Earth produces more water vapor.  Water vapor is a strong greenhouse gas.  Carbon dioxide comes out of the oceans and makes the Earth run away.  It gets hotter and hotter until the oceans begin to evaporate even.  So life on Earth as we know it is about a billion years.  

Now, again, a billion years is a long time.  It's not tomorrow.  But this is -- it isn't five billion years.  This is what happens in about a billion years.  Things become uncomfortable here.  Forgetting what we're doing, it may happen sooner.  This is natural.  This is the sun.  This is the normal course of the sun's life.  The sun is becoming a red giant.  

Here it is four billion years from now.  This is how the sun will be.  You look up in the sky, and you'll see a beautiful red giant.  It will be beautiful, near, and it will fill up half of the sky in red.  But on that time, there's no one living; not even cockroaches will be living on the Earth.  The temperature of the Earth will be above the boiling point of water.  It will have no oceans.  It will be barren.  Maybe a cockroach can be here, but that's about it.  

And then we'll go a little bit ahead.  This is a depressing end.  This is showing you at that stage about five billion years from now.  This is the sun looking down from above.  Here's Mercury, here's Venus; here's Earth.  Notice the sun is here.  So we're in it.  That's great for a solar physicist.  

[laughter]

You get to actually see inside the sun.  And this is the sun five billion years from now.  The Earth incinerates.  So here's a picture a student made up of the Earth incinerating, and then I have a picture in Vietnam, I think this was taken, and this you'll be very happy, this is the last slide [laughs].

[laughter]

Thank you, okay.

[applause]

Female Announcer:
This has been a presentation of the Library of Congress.  Visit us at loc.gov.

[end of transcript]