1 / 23

ASTRONOMY

ASTRONOMY. Chapter 23 Solar Activity and the Earth. Sunspots. The most obvious features. Appear as dark spots on the photosphere. Give off less radiation than surroundings . Number varies in an 11 year cycle – the solar activity cycle . Sunspot Cycle. Sunspot Cycle.

holden
Download Presentation

ASTRONOMY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ASTRONOMY Chapter 23 Solar Activity and the Earth

  2. Sunspots • The most obvious features. • Appear as dark spots on the photosphere. • Give off less radiation than surroundings. • Number varies in an 11 year cycle – the solar activity cycle.

  3. Sunspot Cycle

  4. Sunspot Cycle SUN GAZING These photos show sunspots near solar maximum on July 19, 2000, and near solar minimum on March 18, 2009. Some global warming skeptics speculate that the Sun may be on the verge of an extended slumber. http://www.nytimes.com/2009/07/21/science/space/21sunspot.html

  5. Sunspots • Umbra – dark central region. • Penumbra – lighter area surrounding the penumbra. • Formation of sunspots not completely understood. • Caused by the magnetic field and the differential rotation of the sun.

  6. Sunspots http://www.oneminuteastronomer.com/wp-content/uploads/2009/09/Sunspot-group_l.jpg

  7. Maunder Minimum • Between 1645 and 1715, apparently no sunspots appeared on the sun. • This time period is known as the Maunder minimum. • The corona was very weak during this period. • The Little Ice Age occurred in Europe and a drought in the SW United States. • No evidence of a direct relation between these events.

  8. Solar Flares • A flare is defined as a sudden, rapid, and intense variation in brightness. A solar flare occurs when magnetic energy that has built up in the solar atmosphere is suddenly released. Radiation is emitted across virtually the entire electromagnetic spectrum, from radio waves at the long wavelength end, through optical emission to x-rays and gamma rays at the short wavelength end.

  9. Solar Flares • The amount of energy released is the equivalent of millions of 100-megaton hydrogen bombs exploding at the same time! The first solar flare recorded in astronomical literature was on September 1, 1859. Two scientists, Richard C. Carrington and Richard Hodgson, were independently observing sunspots at the time, when they viewed a large flare in white light.

  10. Solar Flares http://hardgeek.org/wp-content/uploads/2009/11/solar-flare.jpg

  11. Filaments & Prominences • Filaments are dark, irregular lines across the surface of the sun. • Filaments can be 100,000 km in length.

  12. Filaments & Prominences http://www.oneminuteastronomer.com/wp-content/uploads/2010/05/Solar-Filament.gif

  13. Filaments and Prominences • When a filament occurs on the limb of the sun, it is called a prominence. • Prominences can be observed from Earth with the naked eye during an eclipse. • Prominences and filaments may last for weeks or months, but most are shorter-lived.

  14. Prominences • Prominences are dense clouds of material suspended above the surface of the Sun by loops of magnetic field. Prominences and filaments are actually the same things except that prominences are seen projecting out above the limb, or edge, of the Sun.

  15. Prominences http://apod.nasa.gov/apod/image/9909/equinoxprom_eit.jpg

  16. Prominences http://www.csmonitor.com/var/ezflow_site/storage/images/media/images/2010/0512/0512-solar-prominence/7883793-1-eng-US/0512-solar-prominence_full_600.jpg

  17. Prominences

  18. The Difference • The differences between Prominences and Flares: • Flares are hotter • Prominences may have temperatures of a few tens of thousands of thousands of degrees. • Flares are millions of degrees in their centers. • Event is different • Flares are explosive. • Prominences change much more slowly.

  19. Coronal Mass Ejections • Sometimes, prominences will eject matter into space. • This blob of high-energy particles can kill astronauts or produce incredible aurorae. • CMEs happen from once to several times per day.

  20. Coronal Mass Ejections http://www.nustar.caltech.edu/uploads/images/site/coronal_mass_ejection.jpg

  21. Coronal Mass Ejection The photo shows the effects of a coronal mass ejection — large clouds of plasma and magnetic field that erupt from the sun – striking Earth’s magnetic field. http://blog.chron.com/sciguy/2012/10/the-most-awesomest-picture-youll-see-today/?fb_action_ids=10151186581359764&fb_action_types=og.recommends&fb_source=timeline_og&action_object_map=%7B%2210151186581359764%22%3A114966428660942%7D&action_type_map=%7B%2210151186581359764%22%3A%22og.recommends%22%7D&action_ref_map=%5B%5D&replytocom=158296

  22. Solar Wind • The corona is expanding into space, causing the solar wind. • Two types of solar wind; • Fast: about 800 km/s; takes 10 days to reach Earth • Slow: about half the speed of the fast • Consists of about 5 particles/cm3at 1 AU. • Solar wind consists of ions and electrons.

  23. The Solar Constant • The Solar Constant is the amount of energy per square meter at 1 AU. • This is significant in determining weather on Earth. • At the top of Earth’s atmosphere, this value is 1368 watts/m2. • About half of this energy is absorbed as it passes through the atmosphere.

More Related