5
Living in the Atmosphere of a Star
Deep beneath the surface of the Sun, enormous forces were gathering.
At any moment, the energies of a million hydrogen bombs might burst forth in the awesome explosion. . . . Climbing at millions of miles an hour, an invisible fireball many times the size of Earth would leap from the Sun and head out across space.
Arthur C. Clarke, “The Wind from the Sun”
Space weather starts inside the Sun and ends in the circuits of man-made technologies. Defined simply, space weather is a range of disturbances that are born on the Sun, rush across interplanetary space into Earth’s neighborhood, and disturb the environment around our planet and the various technologies— cell phones, satellites, electric power grids, radios—operating in that environment. The key to space weather is the transformation of energy, a transformation from magnetic energy and intense heat on the Sun to plasma energy in interplanetary space to magnetic and electrical energy around the Earth.
To the unaided human eye, the space between Sun and Earth appears to be a vast, dark void and the Sun is a static, unblemished
fireball. But centuries of scientific observations and theories, as well as four decades of space exploration, have revealed that the space between our home and our star is windier than a mountain peak and as electric as a city night. And the space carved out by the Sun is hardly empty. It is filled with invisible electric and magnetic fields, high-energy particles, and a substance that’s neither solid nor liquid nor gas. If a gas gets hot enough, the atoms— which are normally composed of a nucleus of positively charged protons and electrically neutral neutrons, surrounded by a cloud of negative electrons equal in number to the protons—start to lose electrons and become electrically charged. The electrons basically “boil” off the atoms, leaving a gas of free electrons and atomic nuclei that are positively charged. The result is an electrically conducting gas of disassociated electrons and nuclei called plasma—the fourth state of matter. Most of the universe, including our nearest star, is in the plasma state.
Gusty streams of this plasma continuously blow out from the Sun and rain down on Earth in a torrent of matter and energy; more energy escapes the Sun in some of its storms than humans have consumed in the entire history of civilization. In effect, we live inside the atmosphere of a stormy star, an atmosphere that stretches to the edge of the solar system and pushes against the interstellar plasmas of the Milky Way galaxy. That solar atmosphere has changeable weather and a dynamic climate, with the cosmic equivalent of winds, clouds, waves, hurricanes, and blizzards, all waxing and waning on cycles from minutes to months to millennia.
In astronomical terms, the Sun is a middle-sized, middle-aged gas ball that is just one of 100 billion stars in our Milky Way galaxy.1 But our star is by far the largest object in our neighborhood, making up nearly 99 percent of the mass of the solar system (333,000 times the mass of the Earth). It would take more than
100 Earths to span the width of the Sun and more than a million Earths could fit inside. Even though the Sun is 93 million miles away—and its light takes 8 minutes, 20 seconds to reach Earth—it dominates life on our planet.
The main component of the Sun is the most basic chemical element, hydrogen, which is composed of one proton and one electron. It accounts for 92 percent of the Sun’s atoms, though it is not quite precise to classify these most basic chemical constituents of a star as atoms. In the core of the Sun, the pressure is 250 billion times more intense than what we experience at the surface of the Earth, the density is 10 times the density of gold, and temperatures approach 16 million degrees Celsius (29 million degrees Fahrenheit). With conditions so extreme, the Sun’s hydrogen atoms are actually broken up into their constituent parts—protons and free electrons. These particles are so closely packed together and moving so fast (the very definition of heat is mass in motion) that they collide frequently and combine in fusion reactions, producing helium and releasing energy.
This process of nuclear fusion actually goes through a number of complicated steps that took many years to figure out. The bottom line is that the amount of hydrogen mass going into the reaction is greater than the amount of helium mass coming out. Where does the missing mass go? It gets converted directly into energy. Every second, 700 million tons of the Sun’s hydrogen is fused into 695 million tons of helium. About 5 million tons of mass is lost along the way, being converted to energy (principally gamma rays) that eventually reaches us as sunlight, solar wind flow, and other forms of solar radiation.
Currently, helium makes up about 7.8 percent of the Sun, a percentage that will grow over the next 5 billion years as the star slowly fuses all of the hydrogen. All the rest of the chemical elements, such as iron, carbon, and oxygen, make up less than 0.1 percent of the Sun, an astonishing figure when you consider that Earth and its atmosphere are made up almost entirely of those heavier elements. (Earth has very little hydrogen and helium in
pure form. Almost all of our hydrogen is tied up in water; traces of helium are found in the atmosphere, while the rest is trapped principally in methane gas wells.)
Just above the core of the Sun, the “radiation zone” allows this nuclear reactor to move energy and light from the center toward the surface (see the color Plate 2 for a diagram of the Sun). Somewhat cooler than the core (about 5 million degrees C, 9 million degrees F), the radiation zone is comprised of plasma that passes on the energy produced below. Energy passes from particle to particle, gradually working toward the outer edge of the radiation zone. As Michelle Beauvais Larson of Montana State University describes it, the process is similar to standing in a crowded room where each person holds an empty glass. Imagine there is a sink at one end of the room and the people at the opposite end want a drink, but the room is so packed that no one can move. If the room were like the inside of the Sun, the person nearest the sink would fill his glass with water (energy) and pour it into the glasses next to him. The people with water in their glasses would do the same thing. This process could continue until the water is passed across the room. Energy moves from atom to atom in the radiation zone in a similar way, though not as neatly or systematically. In fact, it takes nearly 170,000 years for radiation to bounce its way from the Sun’s core to the outer edge of the radiation zone (that figure is but one of many estimates of the time it takes for radiation to ping-pong its way out of the zone, as there are many different models of the activity inside the Sun).
Between the radiation zone and the visible surface of the Sun is the convection zone, where superheated gases rise from the interior like water boiling in a pot. Bubbles of hot plasma churn and circulate from the interior to the surface, release some of their energy, and descend back toward the radiation zone. The trip from the radiation zone to the photosphere—the yellowish-white sphere of light that we see—takes about one week. The Sun gives hints of this boiling action in the granulations or bubbles that percolate on the visible surface, where temperatures decline to about 6,000 degrees C (10,000 degrees F). The energy from the
interior is released in the many forms of electromagnetic energy: X rays, ultraviolet and infrared light, gamma rays, radio waves, and visible light.
While plasma and energy swirl and circulate from the core to the photosphere, the Sun is also spinning its entire gargantuan mass around an invisible axis, just as the Earth spins. One of the most intriguing and important quirks of the Sun is its differential rotation; that is, the Sun rotates with different periods from the poles to the equator and from the surface to the interior. By charting and measuring the motion of sunspots across the visible face of the Sun, British scientist Richard Carrington and others determined in the latter half of the 1800s that on average the Sun makes a complete rotation once every 27 days. But in fact, the surface of the Sun at the equator makes a full rotation in as little as 25 days, while the surface at the North and South Poles can take as long as 36 days to spin once around.
Similarly, the various layers of the solar interior (core, radiation zone, and convection zone) seem to move at different relative speeds, and the entire outer layer of the Sun is slowly but steadily flowing from the equator to the poles. In 1997, scientists using instruments on the Solar and Heliospheric Observatory, a joint satellite mission of the European Space Agency (ESA) and NASA, found that “rivers” of hot plasma flow beneath the surface of the Sun. Like the trade winds on Earth, these rivers of plasma transport gas beneath the Sun’s fiery surface. “We have detected motion similar to the weather patterns in the Earth’s atmosphere,” noted Jesper Schou, a solar scientist at Stanford University who was part of the team that discovered the flows. “And we have found a jet-like flow near the poles that is completely unexpected, and cannot be seen at the surface.” These 40,000-mile-wide belts in the northern and southern hemispheres of the Sun flow at different speeds relative to each other, and they all move slightly faster than the solar material surrounding them. The belts reach at least 19,000 kilometers (12,000 miles) below the Sun’s visible surface.
Like stripes on a barber’s pole, these river-like bands start in the Sun’s middle latitudes and gradually move toward the equator
during the 11-year solar cycle, according to Craig DeForest, a solar physicist at the Southwest Research Institute. “They appear to have a relationship to sunspot formation as sunspots tend to form at the edges of these zones,” DeForest says. “We speculate that the differences in speed of the plasma at the edge of these bands may be connected with the generation of the solar magnetic cycle which, in turn, generates periodic increases in solar activity.” The result of this swirling mess—of matter and energy moving from the core to the surface, from east to west, all at different speeds—is that the Sun generates a complex global magnetic field that might explain everything from sunspots and coronal mass ejections to the solar cycle. Solar physicists call that process the solar dynamo.
In nature, electric currents produce magnetic fields, and changing magnetic fields produce electric currents. Within the Sun all of this flowing plasma generates electric currents, since plasma is a natural electrical conductor. Though they cannot yet explain how, scientists suspect that the shearing action between the moving plasmas on the edges of the radiation and convection zones produces intense electric currents that induce a global magnetic field throughout the Sun that stretches out into space. The magnetic fields are a bit like rubber bands, consisting of continuous loops of lines of force that have both tension and pressure. Like rubber bands, magnetic fields can be strengthened by stretching them, twisting them, and folding them back on themselves. The fluid-like flows of plasma at different speeds inside and at the surface of the Sun do just that—they wind the Sun’s magnetic field into a tangled mess of loops and knots that poke out through the solar surface and stretch into its mysterious atmosphere (see Figure 8).
For the sake of space weather, the most important part of the Sun is its atmosphere, known as the corona. Starting just above the visible surface—the photosphere and the transitional “zone of color” or chromosphere—the corona stretches millions of miles away from the Sun. Typically, the corona is only visible from
FIGURE 8. Tightly wound magnetic coils snap into an intense flare during the Bastille Day space weather event of 2000. NASA’s Transition Region and Coronal Explorer (TRACE) spacecraft captured this close-up view. The area in these images is about 186,000 miles across, large enough to span 23 Earths. The Slinky-like formation of coronal loops was roiling at nearly 2.7 million degrees C. Courtesy of NASA.
Earth during eclipses, but the invention of the coronagraph and of space-based telescopes has allowed scientists to detect the faint light of the corona (about as bright as the full Moon). In those glimpses, they have spied magnetic loops and lines flowing with plasma and hanging above the surface of the Sun. They have also found gaping holes in the corona where the magnetic field lines from the Sun stretch out into space and high-speed solar wind gushes out.
The temperature of the Sun from core to surface makes a steep decline, such that the photosphere is about 6,000 degrees C. Despite its residence above the surface, the corona is actually hundreds of times hotter than the photosphere, reaching temperatures in the millions of degrees. How the corona can be so much hotter than the surface remains a grand mystery of solar physics. Most researchers surmise that it is related somehow to the dissipation of energy and the interaction of that energy with the complicated magnetic fields that burst from the interior and extend above the surface in great arches and loops. But no one in the field of solar physics has been able to offer an acceptable or understandable explanation because the causes of this unusual heating have been hard to detect. Deciphering the mystery of the heating of the corona is considered crucial to understanding why the Sun has weather.
Technically, the corona does not end: the high-pressure, million-degree plasma pushes the corona outward from the Sun to become the solar wind. Solar researchers have found that the electrified plasma of the solar wind flows out of the corona like water gushing through cracks in a dam. The solar wind essentially seeps out through the edges of honeycomb-shaped patterns in the surface of the Sun, escaping around the edges of large convection cells bubbling up from the interior. “If you think of these cells as paving stones in a patio, then the solar wind is breaking through like grass around the edges, concentrated in the corners where the paving stones meet,” said Dr. Helen Mason, of the University of Cambridge, England, during a 1999 press conference. “However, at speeds starting at 20,000 miles per hour at the surface and accelerating to over 2 million miles per hour, the solar wind grows much faster than grass.”
The expanding, speeding plasma of the solar wind races away from the Sun in all directions to fill the space between the planets. Each bubble of plasma rises from inside the Sun and carries an imprint of the magnetic field of the Sun embedded in a mix of ions and electrons and helium nuclei. Blowing at 800,000 to 5 million miles per hour, the solar wind carries 1 million tons of matter into
space every second (that’s the mass of Utah’s Great Salt Lake poured out every second). Yet the solar wind would not even ruffle the hair on your head. Given the vastness of space, all of the mass is quickly spread out to a point where it has fewer particles per cubic centimeter than the best vacuums scientists can produce on Earth. Our own air is millions of times denser than the solar wind, such that 1 cubic centimeter of earthly air has as many particles as one cube of solar wind measuring 10 kilometers on a side.
This solar wind flows past Earth like water past a cruising boat. Tenuous compared to air, the solar wind is still potent enough to confine Earth’s magnetic field, molding it into the shape of a comet or wind sock. Earth’s magnetic cavity or cocoon keeps almost all of the Sun’s harmful radiation and solar wind particles from reaching us (except for the ultraviolet rays that give you a sunburn). Less than 1 percent of the solar wind penetrates the magnetosphere, but that is enough to act as a cosmic generator, producing several million amps of electric current. This interaction supplies almost all of the energy in Earth’s magnetosphere.
In addition to the flow of the plasma, the solar wind carries with it the solar magnetic field. The amount of electrical energy transferred from the solar wind to the Earth’s magnetosphere depends on the north-south orientation of that solar wind magnetic field (known as the interplanetary magnetic field or IMF). If the magnetic field in the solar wind is directed southward, it can interconnect with the Earth’s northward-oriented magnetic field. This direct magnetic connection allows energy to flow more freely between Sun and Earth, powering up the cosmic generator around our planet. Even though a mere fraction of the solar wind energy penetrates the magnetosphere under the worst of conditions, it’s enough to cause global magnetic storms and auroras around Earth.
The most studied aspect of space weather is the sunspot, the first solar disturbance that was suspected to affect Earth. Appearing as dark patches against the bright background of the rest of
the Sun, sunspots are actually relatively cooler than the surface (3,800 degrees C compared to surrounding temperatures of 6,000 degrees C). Discovered thousands of years ago by observers in ancient China, sunspots are regions of intense, complicated magnetic activity on the Sun, with magnetic fields 1,000 times the strength of Earth’s field. Sunspots tend to appear in groups, and almost always in pairs of opposite magnetic polarity. They can last from several hours to several months, and they can be as large as 20 times the size of Earth (see Figure 9).
FIGURE 9. Caused by intense magnetic fields emerging from the interior of the Sun, a sunspot appears to be dark when contrasted against the rest of the solar surface because it is slightly cooler than the rest of the visible surface. Courtesy of SOHO/ESA and NASA.
Though sunspots have been considered the impetus for magnetic storms and other space weather effects around Earth, Space Age observations have shown that, as solar researcher Tom Bogdan of the High Altitude Observatory, Boulder, Colorado, puts it, “sunspots are more like symptoms than the disease itself.” The active regions above sunspots (in the corona) emit X rays and radio waves that can hinder radio communication from Earth. But mostly, the spots are warning signals telling scientists that the Sun is more or less turbulent and disturbed and where the next solar blast might lift off. Over longer timescales, some researchers believe that sunspots may be an indicator of climate change on Earth. Scientists are still figuring out the role of sunspots in space weather, but they do know that when a flare erupts, sunspots are often nearby.
From 1859—when Carrington made the first observation— until well into the 1990s, flares were considered to be a principal driver of space weather effects at Earth. The strongest flares occur just several times per year, while weaker flares are relatively common, with as many as a dozen a day occurring during the Sun’s most active periods. But as scientists have scrutinized these explosions, they have found that they are not necessarily the dominant factor in producing magnetic storms and auroras around Earth. That does not mean they are any less potent when it comes to raw power.
Solar flares appear as sudden, intense flashes in the chromosphere of the Sun. Flares occur when magnetic energy built up in the solar atmosphere is suddenly released in a burst equivalent to millions of hydrogen bombs. Scientists estimate that enough energy is released in one flare to power the United States for 20 years at its current level of consumption. On the other hand, the energy released is less than one-tenth of the total energy emitted by the Sun every second. The most commonly accepted model of solar flares suggests that the explosion creates high-energy electrons that funnel down toward the solar surface and produce X rays, microwaves, and a shock wave that heats the surface. The explosion also produces seismic waves in the Sun’s interior that resemble earthquake waves. The seismic energy released at the surface is estimated to
be 40,000 times the energy released in the great San Francisco earthquake of 1906.
Flares energize the particles in the corona—cooking them to tens of millions of degrees Celsius—and accelerate the particles in the outflowing solar wind to a point where radio waves, X rays, and gamma rays are shot out across the solar system, sometimes in the direction of Earth. Most of the particles are deflected by Earth’s magnetic field and the atmosphere absorbs nearly all the harmful radiation, but flares still can have a crippling effect on space-based activities. The intense X rays from a solar flare travel to Earth at the speed of light, giving space weather watchers little time to react. A corresponding blast of high-energy particles (known as a solar proton event) reaches the magnetosphere in as little as 20 or 30 minutes. The onslaught of radiation heats the gases in Earth’s upper atmosphere and causes the uppermost layers to swell, sometimes to a point where the increased friction can drag satellites down from their orbits prematurely. Long-distance radio signals can be disrupted and sometimes even blacked out by the resulting change in the Earth’s ionosphere. The sensitive electronics and microchips of satellites can be pierced by the high-energy particles. Finally, the energetic particles accelerated in solar flares are dangerous to astronauts and, at times, even to occupants in some high-flying airplanes.
The most important solar event from Earth’s perspective is the coronal mass ejection (CME), the solar equivalent of a hurricane. A CME is the eruption of a huge bubble of plasma from the Sun’s outer atmosphere. Essentially, the corona rips open and blasts as much as 100 billion tons of material into space—equivalent to 100,000 battleships (but less than 46 quintillionths (45.6 × 10–17) of the mass of the Sun). They are the largest structures that can erupt from the Sun and are one of the principal ways that the Sun ejects material and energy into the solar system. CMEs expand and fly away from the Sun at 1 million to 5 million miles per hour,
traveling as huge magnetic clouds across the solar system—and sometimes through our neighborhood in space.
The buildup and interaction of magnetic loops hanging in the Sun’s corona—which can stretch over, under, and around each other—seems to supply the energy to heat the corona and produce the violent explosion of a CME. Spiro Antiochos, a solar theorist at the U.S. Naval Research Laboratory in Washington, D.C., compares this process to that of filling helium balloons. If you inflate a balloon without holding it down, it will slowly drift upward. But if you hold the balloon down with a net, you can generate a lot of force when you fill it, causing it to push upward. Once you remove the net, the balloon shoots skyward. After observing how magnetic fields abut and interact, Antiochos and colleagues theorized that the Sun’s magnetic fields intertwine and overlap like a net, restraining each other and forcing the buildup of tremendous energy. As the stressed field continues to emerge from the solar interior, it builds up more potential energy, pushes harder against these magnetic ropes, and moves higher into the corona. Eventually, through a process known as “magnetic reconnection”—in which opposing magnetic lines of force merge and cancel, releasing the stored magnetic energy—the field is released from its bonds and escapes the Sun at great speed.
Just hours after blowing into space, a CME cloud grows to dimensions exceeding those of the Sun itself, often as wide as 30 million miles across. As it ploughs into the solar wind, a CME can create a shock wave that accelerates particles to dangerously high energies. Behind that shock wave, the CME cloud flies through the solar system bombarding planets, asteroids, and any other object in its path. If a CME erupts on the side of the Sun facing Earth, and if our orbit intersects the path of that cloud, the results can be spectacular and sometimes hazardous.
Coronal mass ejections occur at a rate of a few times a week to several times per day, depending on how active the Sun may be. And because of the size of the plasma clouds they produce, the odds say Earth is going to get hit by a CME from time to time. Like flares, the fastest CMEs can accelerate particles in inter-
planetary space to the point where they can harm spacecraft or astronauts. CMEs also can produce shock waves and disturbances as they push into slower-moving solar wind, piling particles and energy in front of them like snow on the front of a plow.
As those particles reach Earth, the magnetosphere deflects most of them back into space. “It’s like a never-ending football game,” says Philippe Escoubet, project scientist for the European Space Agency’s Cluster mission to study the magnetosphere. “The Sun is kicking particles like balls. The Earth is one of the goals and its magnetic field is the goalkeeper. The magnetosphere is always trying to push the balls away, but some get past. When particles score goals they disrupt the Earth.” Much of the time, those energetic particles trickle in through the rear flanks of Earth’s magnetic tail—on the nightside—and near the polar regions. Solar plasmas collect in the Earth’s magnetic tail, mingling with earthly plasmas that have escaped our upper atmosphere. High-energy electrons and protons spiral along the planet’s invisible magnetic field lines, suspended in space by magnetic and electric forces. They accumulate around the equator of Earth in the radiation belts and the tail of the magnetosphere in a dense region known as the plasma sheet.
However, it is not the particles from a CME that produce auroras and magnetic storms. The power of a CME lies in its ability to drive currents in Earth’s magnetosphere—just as Chapman and Ferraro had proposed in 1930—and to energize the plasma that already surrounds the Earth. When a CME is directed at Earth and the conditions are just right, the ramming pressure of the cloud and its shock wave can make Earth’s magnetosphere resonate like a bell struck by a hammer, exciting the electrons and ions trapped in the tail and radiation belts. Most importantly, if the magnetic field carried by the CME has a southward orientation (opposite Earth’s northward-flowing magnetic field lines), the magnetosphere gets a major jolt. The magnetic field of the CME merges with the magnetic field on the dayside of Earth, transferring enormous amounts of energy to the magnetosphere in the process.
This interconnection, or reconnection, between the magnetic field of the Sun and the magnetic field of Earth is what gives a CME “geoeffectiveness,” as scientists describe it, that is, a strong effect on Earth. Electrical current systems in space and in the ionosphere intensify, inciting the complex activity known as a magnetic storm. Much of the energy from the CME is pulled into the tail (nightside) of Earth’s magnetosphere, where it is briefly stored before it destabilizes the system and gets shot down magnetic field lines toward our atmosphere, producing auroras and other phenomena in the ionosphere. In essence, a CME knocks hard on the Earth’s front door but actually comes in through the back door.
This energy transfer can cause the radiation levels in near-Earth space to skyrocket. The high-energy ions and electrons of Earth’s Van Allen radiation belts become more numerous and more energetic. In fact, the whole magnetosphere becomes a hotter place as the energy of the CME increases plasma temperatures. The pressure gradients between the energized plasmas drive millions of amperes of electric current through the magnetosphere, currents that we detect as a worldwide decrease in the strength of Earth’s magnetic field (as measured at the equator). Some of the current is diverted along the Earth’s magnetic field lines toward the upper atmosphere (particularly the ionosphere). The flow of this current causes the atmosphere to warm and expand, increasing the density of gases at high altitudes. During big storms the amount of power dissipated by these currents in the northern hemisphere alone can exceed the electrical power generating capacity of the United States.
Though magnetospheric physicists have long puzzled over the mechanism that accelerates the particles inside Earth’s cavity, recent observations suggest that the Van Allen radiation belts act as a sort of cosmic particle accelerator. The two concentric rings of radiation have long been known to vary greatly but have often been represented for engineering purposes by average models (see Figure 10).
For decades, space physicists theorized that the Sun and its solar wind provided most of the high-energy particles found in Earth’s radiation belts. But observations from scientific and mili-
FIGURE 10. This cartoon of Earth’s radiation belts reveals how one belt resides underneath/inside the other. The outer belt is largely made up of electrons and protons caught up in Earth’s field by the interaction of solar wind and the magnetosphere. The inner belt is a product of cosmic radiation, which bombards the upper atmosphere and splashes energized particles into the space around the planet. Courtesy of Mike Henderson/Los Alamos National Laboratory.
tary satellites over the past 10 years show that the intensity of the belts can vary by 10, 100, or even 1,000 times in a matter of seconds to minutes. The radiation belts react to blasts from the Sun by boosting electrons to near light speed, to a state in which they are known as satellite-harming “killer electrons.” “The radiation belts are almost never in equilibrium,” says Geoff Reeves of Los Alamos National Laboratory. “We don’t really understand the process, but we do know that things are changing constantly.”
According to Reeves, there is no way that the solar wind or a CME alone could cause such a fluctuation in the particles trapped around Earth. “There are just not enough high-energy electrons in the solar wind to explain how many we observe near Earth,” said Reeves. Dan Baker of the University of Colorado adds, “It’s amazing that the system can take the chaotic energy of the solar wind and utilize it so quickly and coherently. We had thought the radiation belts were a slow, lumbering feature of Earth, but in fact they can change on a knife’s edge.”
Though scientists have not yet worked out the physics of the great particle accelerator in our sky, they believe the magnetosphere is an effective and efficient accelerator of particles that dwarfs any man-made supercollider or Tokamak.
There’s no need to run for cover from space weather. Storms from the Sun cannot harm life on the surface of the Earth. But they do affect the way we live. With the average CME dumping about 1,500 gigawatts of electricity into the upper atmosphere, big changes occur in the space around Earth and the upper atmosphere. Those changes can suddenly upset the daily commerce of a world that has come to depend on satellites, electric power, and radio communication—all of which are affected by electric and magnetic forces.
As the next five chapters will show, each of those effects has already made front-page news on Earth, and they are likely to have an impact on our efforts to explore worlds beyond our own. The magnetic storms caused by all of these swirling particles and electrical currents from space can distort the magnetic field of Earth enough to wreak havoc on electrical power and ground-based communications systems (Chapters 6 and 7). X rays and high-energy protons from solar blasts can completely wash out radio communications for hours to days and can disrupt signals sent to and from satellites (more about this in Chapters 7 and 8). Super-energized particles from the radiation belts and from auroral storms can damage the sensitive electronics of satellites (Chapter 8). They can even harm an unprotected astronaut working in space and occasionally penetrate far enough into the atmosphere to give a mild dose of radiation to passengers on high-flying jets (Chapter 9). And in the most controversial and least understood effect of space weather, the long-term variation of solar activity could influence the climate patterns of Earth on scales from decades to millions of years (Chapter 10).
