Space probe Cassini has been in orbit around Saturn since 2004 making hundreds of flybys of the giant planet and its dozens of moons
INTRODUCTION The Solar System is vast 4 6 trillion miles from the Sun to the outer reaches Its eight planets with their moons are tiny specks spread far apart in the great emptiness Our exploration of space which began over 50 years ago has mainly focused on these planets and moons We have overcome such gigantic distances by using unmanned probes They are programmed to fly close to planets and even land on them gather data record images and transmit the information back to Earth Knowledge of other planets is vital It helps us to understand how our own planet came to be how it is changing now and what might be waiting in the future Mobile probes like NASA’s Mars explorer Curiosity are called rovers Partly remote controlled and partly robotic they can explore a distant and hostile environment without the risk and expense of human spaceflight
SOLAR PROBES Categorized a yellow dwarf our Sun is a medium-sized star halfway through its 10-billion-year lifecycle This huge body makes up almost 99 percent of the total mass of the Solar System that spins around it 2 1 5 3 INSIDE THE SUN 1 CORE Thermonuclear reactor 2 RADIATIVE ZONE Heat spreads outward 3 CONVECTION ZONE Columns of heat rise and fall 4 PHOTOSPHERE Visible surface of the atmosphere 5 CHROMOSPHERE Thin layer of wispy hydrogen 6 CORONA Wide area of hot plasma radiating outward In the 1970s 80s two Helios probes circled the Sun slightly within the orbit of planet Mercury at record speeds of 157,000 mph 252,000 km h began s y tor va r e ield and i t Obs f ic t r s Dynamic magne 2010 s Sola the Sun ay r s NASA SDO s probing ious v a r 6 4 EMPIRE OF THE SUN Like all stars the Sun began as a vast intensely cold cloud of dust and hydrogen atoms This collapsed inward under its own gravity clumped together and ignited The Sun is made of 74 percent hydrogen 24 percent helium and 2 percent heavy elements Its core pressure and temperature of 23 million ºF 13 million ºC are high enough to rip apart hydrogen atoms and reform them as helium a process called nuclear fusion The incredible energy radiates in columns to blaze on the photosphere as light and heat The Sun’s charged particles meet Earth’s magnetic field and cause polar lights or auroras above Plasma eruptions from its surface right can cause magnetic storms on Earth 06
For the very first time we'll be able to touch taste and smell our Sun Lika Guhathakurta Solar Probe Plus program scientist The SUN is mainly PLASMA neither a gas liquid nor solid but more like PURE ENERGY SOLAR PROBE PLUS 1 THERMAL SHIELD Carbon composites 2 PRIMARY SOLAR ARRAYS For use early in the mission and then stowed behind the heat shield 3 COMMUNICATIONS ANTENNA 4 SECONDARY SOLAR ARRAY Liquid cooled deployed on final approach to the Sun’s surface Solar Probe Plus will speed around the Sun three times faster than the Helios craft PROBING THE INFERNO Probes have analyzed the interior of the Sun and on its surface observed sunspots magnetic storms larger than Earth The surface of the Sun is 10,300 ºF 5,700 ºC cool enough to be approached by robot spacecraft In 2018 Solar Probe Plus will become the most intrepid solar explorer yet To study the outer corona up close its instruments are protected by the shadow of a special carbon heat shield 2 Since 1995 NASA’s Solar and Heliospheric Observatory SOHO has been sending real-time data on space weather variations in the solar wind from the Sun 3 1 2 4 The Sun throws out a huge arc of energy or prominence big enough to engulf all the planets Surprisingly the Sun’s visible surface the photosphere is hundreds of times cooler than the invisible corona that surrounds it The SUN’s energy particles spend an average of 200,000 YEARS traveling around inside their star then after RELEASE they reach Earth in just EIGHT MINUTES 07
