Galileo Galilei

• Galileo's telescope

Middle Finger of Galileo's Right Hand

Montage of Jupiter and the Galilean satellites: Io, Europa, Ganymede, and Callisto. Images acquired by Voyager 1 spacecraft.[http://nssdc.gsfc.nasa.gov/photo_gallery]

Voyager 1 Montage of Saturn and several of its satellites: Dione, Tethys, Mimas, Enceladus, Rhea, and Titan.[http://nssdc.gsfc.nasa.gov/photo_gallery]

A Solar Prominence EruptsCredit: SOHO - EIT Consortium, ESA, NASA

Last year, our Sun went though Solar Maximum, the time in its 11-yearcycle where the most sunspots and explosive activities occur. Sunspots,the Solar Cycle, and solar prominences are all caused by the Sun'schanging magnetic field. Pictured above is a solar prominence thaterupted on May 15, throwing electrons and ions out into the SolarSystem. The image was taken in the ultraviolet light emitted by aspecific type of ionized helium, a common element on the Sun.Particularly hot areas appear in white, while relatively cool areas appearin red. Our Sun should gradually quiet down until Solar Minimumoccurs in 2007.

2001 September 24

One of the images of the surface of Venus obtained by the Magellan spacecraft. Lava flows extend for hundreds of kilometers across the fractured plains shown in the foreground, to the base of Maat Mons, a 5 mile high volcano. [http://nssdc.gsfc.nasa.gov/photo_gallery]

Charles R. Munnerlyn changed the world’s concept of vision when he designed the first digital device for automatically determining refractive errors in the human eye. Known as one of the founding fathers of laser vision correction, he ushered in one of the fastest growing surgeries performed in the United States – used on more than 1.4 million eyes in 2001 alone. That first invention also ushered in Munnerlyn’s entrepreneurial spirit. After years of toil and millions of dollars in investments, he and a small group of engineering and medical colleagues founded VISX, a company that is now the world’s largest manufacturer of laser-based vision correction systems.

Textbook: Foundations of Astronomy (Paperback)by Michael A. Seeds

http://www.amazon.com:25 used & new available from $7.25

Paperback: 656 pagesPublisher: Thomson Brooks/Cole; 6th edition (July 2000)ISBN: 05343785520.8 x 8.2 x 10.5 inches, 3.2 poundsAverage Customer Review: 5 stars

Hubble Space Telescope (HST) being refurbished. Astronauts Story Musgrave and Jeffrey Hoffman are seen, with Australia's west coast in the background. [National Space Science Data Center, http://nssdc.gsfc.nasa.gov/image]

Hertzsprung-Russell diagram

Picture from ASTRONOMY: THE EVOLVING UNIVERSE sixth edition

Credit: Michael Zeilik

The horizontal axis is surface temperature; the vertical one, luminosity, in units of the Sun’s luminosity. The solid white lines show where stars of different luminosity classes fall on the diagram; supergiants at the very top; giants just below them; and finally main-sequence stars. The relative sizes of the stars are shown correctly within each luminosity class, but not between them. The colors are those as perceived by the eye looking at these stars through a telescope.

The Crab Nebula from VLTCredit: FORS Team, 8.2-meter VLT, ESO

The Crab Nebula, filled with mysterious filaments, is the result of astar that was seen to explode in 1054 AD. This spectacular supernovaexplosion was recorded by Chinese and (quite probably) AnasaziIndian astronomers. The color indicates what is happening to theelectrons in different parts of the Crab Nebula. Red indicates theelectrons are recombining with protons to form neutral hydrogen,while blue indicates the electrons are whirling around the magneticfield of the inner nebula. In the nebula's very center lies a pulsar: aneutron star rotating, in this case, 30 times a second.

November 22, 1999

M16: Stars from Eagle's EGGsCredit: J. Hester, P. Scowen (ASU), HST, NASA

Newborn stars are forming in the Eagle Nebula. This image, taken withthe Hubble Space Telescope in 1995, shows evaporating gaseousglobules (EGGs) emerging from pillars of molecular hydrogen gas anddust. The giant pillars are light years in length and are so dense thatinterior gas contracts gravitationally to form stars. At each pillars'end, the intense radiation of bright young stars causes low densitymaterial to boil away, leaving stellar nurseries of dense EGGs exposed.The Eagle Nebula, associated with the open star cluster M16, liesabout 7000 light years away.

2000 September 24