The Sun and Space Weather

1. The Sun and Space Weather

2. Objectives: • Identify and describe the parts of the sun. • Explain how solar activity affects Earth. • Explain how astronomers study the sun.

3. The Milky Way galaxy • Our galaxy, the Milky Way, is just one of perhaps billions of galaxies in the universe. • • The closest star to Earth is about four light years away • A light year is the distance that light travels in 1 year. It’s speed is about 186,000 miles/second or 300,000 km/second. That adds up to 9.5 trillion km. • There are more stars than grains of sand on Earth

4. The Dynamic Sun • The Sun, like all stars, is a dynamic star, always active, always changing. The more we learn about it, the more we learn about all stars.

5. Where the action is • Nuclear fusion occurs in the Sun’s core • Hydrogen atoms combine to form helium and release huge amounts of energy, radiation and light • It takes over 10,000 years for the light to get to the Sun’s surface

6. Solar influence • We live in the atmosphere of the Sun, basking in its light and warmth, protected by our magnetic shield, the magnetosphere • We are also struck constantly by the flow of its solar wind.

7. The Sun is also the source of radiation and storms that we call SPACE WEATHER

8. First recorded sunspots • Galileo in 1610, using one of the first (just invented) telescopes, was the first person to observe and record the path of sunspots across the Sun for several weeks.

9. Solar Cycles • Since 1610 people have kept written records of sunspots, so that we know of the solar cycle, which is the rise and fall of sunspot numbers (and solar activity) about every 11 years. This is due to the Sun’s changing magnetic structure.

10. The last solar cycle • Was near its peak level or “solar maximum” in 2013. • The next solar maximum will be in 2024.

11. Zooming in for a closer look • From far away sunspots appear like dark blobs on the Sun, but up close, they reveal incredible complexity. In the most close-up view, each little cell-like gray area you see is about the size of Texas.

12. Sunspots • A sunspot is a kind of whirlpool controlled by intense magnetic forces where hot gases from inside the Sun are blocked from reaching the surface. Therefore they are cooler than the rest of the Sun and appear darker.

13. Solar Rotation • The Sun rotates every 27 days or so. This causes magnetic field lines to become twisted and stretched to the breaking point. These eventually break and reconnect, creating heat, intense active regions, and solar blasts of charged particles.

14. Differential Solar Rotation • It must be noted that since the Sun is made of a gaseous plasma and is not a solid body, it does not rotate at the same speed at all places. Specifically, near the poles the surface rotates in around 35 days, but near its equator the Sun rotates about every 25 days. This is called differential rotation. This process leads to stretching and stressing of the Sun’s magnetic field, which does cause solar storms.

15. Sunspots from down under • Sunspots are magnetic structures that emerge from beneath the surface • The white lines represent magnetic field lines • When the lines tangle and break apart, they are the creators of solar storms

16. The average sunspot is about the size of Earth, though the largest can be 20 times the size of Earth.

17. Underlying magnetism • Sunspots are magnetic features of the Sun. Magnetic field lines get tangled up in sunspots, block energy, and make the area cooler and darker.

18. It’s all in the magnetism! • The Sun is strongly affected by magnetic forces.

19. Storms at their source • When the magnetic forces above sunspots become tangled and break apart, violent storms can burst from the Sun. This is the main source of our strongest space weather events, either coronal mass ejections or solar flares.

20. Coronal mass ejections (CMEs) • CMEs are large solar storms that can blast out a cloud of billions of tons of particles at over two million Km per hour. Smaller ones can occur almost any day. • The clouds reach Earth’s orbit in 1 to 3 days but only a few of them actually head our way.

21. Solar flares • Flares are quick, intense but smaller explosions than CMEs • They appear as bright flashes sometimes followed by a burst of high energy particles that can travel at half the speed of light. Large flares can occur several times a year when the Sun is near its peak activity.

22. Loops after a storm

23. Earth’s magnetic shield • The Earth has a magnetic field with north and south poles. The Earth's magnetic field reaches 36,000 miles (57,000 km) into space. Earth is surrounded by a region called the magnetosphere. This prevents most of the particles from the Sun, carried in solar wind and storms, from hitting the Earth. Some particles can enter the magnetosphere. Particles that enter from the tail end travel toward the Earth and create the aurora light shows.

25. Space weather upsets • There are less pleasant space weather effects. Energy pumped into our atmosphere upsets modern technology. Radio signals and communications become disrupted. Satellites orbiting around Earth can suffer damage. On the ground, magnetic field changes can damage electrical equipment on Earth.

26. Power outage • In 1989 Quebec, Canada lost power for 9 hours and others for days due to power equipment damage caused by a large solar storm. This kind of event could happen again.

27. Astronaut safety • Astronauts can get high doses of radiation from solar storms and cosmic radiation when out in space. For humans to travel to the Moon and Mars, better storm forecasting and shielding will be needed.

28. Global Warming • It is important to understand the long-term changes in the Sun and their potential effects on climate. These changes include general activity level, UV radiation, and total energy output. Solar general activity may influence cloud formation which can, in turn, trap heat in Earth’s atmosphere. Man-made factors seem to play an important role in global warming.

29. The Sun’s role • Is the Sun's variability tied to Earth's climate? Some scientists cite a correlation with droughts, small ice ages, and large-scale weather patterns on Earth. Many scientists are researching this topic today. The latest research suggests that a small variability of the Sun can drive large-scale changes in weather. The small increase in solar radiation over the past 200 years may account for a part of our global warming. The general consensus is that man-made causes are the major driving force in global warming.

30. Little Ice Age

31. Solar exploration in space • NASA is actively involved in exploration of the Sun and space weather. SOHO (the Solar and Heliospheric Observatory) has been the main solar watchdog for over 11 years. Another, TRACE, is learning more about solar storms. And there are others too!

32. SOHO (Solar & Heliospheric Observatory) • a joint mission of NASA and the European Space Agency (ESA) studying the Sun since 1996 • 12 instruments to study the Sun’s interior, atmosphere, and solar wind all day every day • a major tool for monitoring space weather • weighs 2 tons; its solar panels span 25 feet • SOHO is 1 million miles (1.6 million Km) towards the Sun

33. TRACE • Studies the Sun and solar events at a much smaller scale than SOHO • Launched in 1998 • Worked closely with SOHO • Retired in 2010

34. STEREO • Another mission, STEREO, launched in Oct. 2006, is unique. A pair of nearly identical NASA spacecraft are studying the Sun from positions ahead of and trailing Earth. They are identifying particle data and providing 3-D views of solar storms for the first time ever

35. Solar Dynamics Observatory (SDO) • A “supercharged” SOHO on steroids • Launched in 2010• With images 4 times more detailed and 10 times more often than SOHO