Solar Brightness Variability and the Evolution of Life on Earth

1. Solar Brightness Variability and the Evolution of Life on Earth Tanisha V. Taylor, G. Henry, T. Gary, S.Henry Center of Excellence in Information Systems Tennessee State University April 7, 2004

2. Objectives • Describe the purpose of the Automatic Photometric Telescopes • Discuss how the data is collected and analysis • Discuss the information in the geological timeline • Compare the data of the sun like-stars to the timeline and discuss the importance of both

3. Automatic Photometric Telescope • Located at Fairborn Observatory • Used to monitor stellar brightness changes in a variety of stars • Operates automatically without human oversight • Has site controlled computer that is interfaced to a weather station • Receives observing instruction via internet

4. Telescopes • Measure the brightness variability of 350 sun like stars • Analyze data that is collected to help understand the life cycle of our sun • Used to understand the effects that stellar activity had on earth in the past as well as now

5. BRIGHTNESS VARIABILITY CHART

6. Geological timeline of Earth • Compiles the records of the progression of life on earth • Depicts the main events that occurred in each stage • Divided into 4 eras and a number of periods according to the radioactivity of rocks and fossils found

7. The Geological Timeline of Earth

8. The Geological Timeline of Earthcontinued

10. Conclusion • Life did not form on Earth until our Sun’s brightness decreased to about 0.5% • Cambrian Explosion did not occur until our sun shed about 99% of its brightness and attained its stability of 0.1% • This suggests that the decrease in brightness variability of our sun may have been an important factor for the emergence of advanced species

11. Acknowledgements