Mercury Transit November 8, 2006 When Worlds Align Michael Portuesi & Ken Frank· San Francisco Amateur Astronomers San Francisco Sidewalk Astronomers

The Sun is our Closest Star ● The Sun is 93 million miles away from Earth. ● If you could drive a car to the Sun, it would take 163 years to get there!

Other Stars are Very Far Away If the Sun and Earth were only an inch apart, the nearest star would still be over four miles away…about as far from here to the beach! SunEarth Other Stars Over 4 miles to drive! One inch apart

The Sun is Very Big ● 109 Earths will fit across the Sun's surface ● Over 1 million Earths will fit inside the Sun

The Sun is Bright and Hot Center of Sun: 27 million degrees Surface of Sun: 10,000 degrees SOHO (ESA & NASA) -

Solar Corona at Eclipse – Paul Mortfield – Sun's Corona: 2 million degrees!

What is a Planet? What’s the problem with Pluto? Pluto is now known as a “dwarf planet” The new definition of planet: 1 Round (not potato-shaped) 2 Orbits the Sun 3 Doesn't “share its lane” with other objects (planets, asteroids, etc) ● New mnemonic: Mother Very Easily Makes Cucumber-Jalapeno Sandwiches Using No Pleasant Condiments Usually

Mercury 101 Mercury can be seen as a morning or evening star Mercury is a small, rocky planet, much like our Moon It is covered with craters…lots more than the Moon Distance from Sun = 28,580,000 to 43,380,000 miles Distance from Earth = 48,000,000 miles (closest approach) Orbital Period = Earth days Length of day = 176 Earth days Atmosphere = none Magnetosphere = yes (weak) Moons = none In and Out/McDonalds = none

Mercury rotates slooowly

Solar System: Wed 2006 Nov 8 19:12 UT

Orbit of Earth & Mercury Earth Orbit Mercury Orbit AscendingNode DescendingNode Line of Nodes Fred Espenak, NASA’s GSFC Mercury Orbit Inclination = 7.0° Orbit Inclination = 7.0° Orbit Eccentricity = 0.21 Distance = AU 16

2006 Transit of Mercury 21

A 23 year old Parisian, Charles Messier observed the 1753 transit- It was his first recorded observation!

The Mercury Transit Where can you see it?

Solar Eclipses Solar Eclipse, seen from the Mir Space Station, 1999

Sunspots & Mercury ● Sunspots are large storms on the Sun's surface ● They look small, but are bigger than the Earth! Mercury will look even smaller ● They move as the Sun rotates, in 27 days

Mercury Transit May 7, 2003

Fe XII line, 195 Fe IX/X line, 171 Fe XV line, 284He II line, 304 SOHO (ESA & NASA) -

The false-color TRACE images were made in ultraviolet light and show the hot gas just above the Sun's visible surface

View the Sun Safely! So we can all easily see the Transit, please don’t touch the telescopes. When viewing the Sun use only safe filters. Never look directly at the Sun

To find out more interesting stuff Join the Membership benefits include: Star parties X 3/month Mt. Tam, Fremont Peak, Yosemite trips and more

Thanks ● Johannes Schedler ● Paul Mortfield ● SOHO ● Fred Espenak ● Thierry Legault ● Transition Region and Coronal Explorer ● Museum of the History of Science, University of Oxford ● Astronomical Society of the Pacific

Copyright Copyright © 2006 Michael Portuesi & Kenneth Frank. This work is licensed under the Creative Commons Attribution- NoDerivs-NonCommercial License. To view a copy of this license, visit or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305

Credits ● Photos are owned by and copyright the original photographers as listed. They are used here with permisssion, and licensed under the same terms. ● SOHO images are courtesy of SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA.