2009: International Year of Astronomy

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We could say that modern astronomy began in 1609.  That was the year when the telescope, invented by the Dutch in 1608, was first used to observe and describe celestial objects.  Until telescopes were used, astronomy was primarily about measuring the positions of the Sun, Moon, and planets in the sky.  This helped early astronomers make calendars and to plan their harvests, but people were unable to study the celestial bodies and learn their characteristics.  A recently discovered lunar map indicates that Thomas Harriot of England was the first to observe and draw a magnified image of the Moon in July 1609. 

Galileo Galilei, of course, is most well-known for building and using early telescopes.  He did his lunar observations in December 1609 while observing from Padua, Italy.   The prevailing idea at the time was that everything in the heavens had to be perfect and unblemished.  Drawings of mountains, valleys, and craters on the Moon contradicted this idea, showing the Moon to be an ‘imperfect’ world like Earth.  As Galileo published his drawings and Harriot did not, Galileo gets the credit for changing our concept of the universe, helping us realize that celestial bodies are worlds and not just sources of light.

On January 9, 1610, Galileo saw three ‘fixed stars’ next to Jupiter.  Four days later he discovered a fourth and realized that these ‘stars’ orbited Jupiter.  Today, those four moons– Io, Europa, Ganymede, and Callisto, are called the Galilean moons.  The direct observation of moons orbiting Jupiter disproved Claudius Ptolemy‘s model of the universe, already centuries old at the time, which held that all bodies in the universe orbited the Earth.

Moon n Venus played hide-and-seek
Creative Commons License photo credit: voobie

In December 1610, Galileo observed Venus and saw that Venus showed phases like the Moon’s when magnified in his telescope.  This meant that sometimes the sunlit side of Venus faces Earth, while at other times we see the night side, although Venus is never opposite the Sun in the sky.  This could happen only if Venus orbits the Sun rather than Earth.

By the way, Galileo did far more than just astronomy.  Rice University’s Galileo Project has more on his extraordinary life, including a timeline.

It was also in 1609 that Johannes Kepler published his New Astronomy, containing his first two laws.  The first law states that each planet’s orbit is an ellipse rather than a perfect circle.  The second law states that a planet sweeps out equal areas in equal times.  Kepler published his third law, which relates the square of a planets period (time for one orbit) to the cube of its average distance, in 1619. 

This makes 2009 the 400th year of modern astronomy.  Appropriately, the United Nations declared this year to be the International Year of Astronomy.  At that link, you can learn about events taking place all over the world promoted by the International Astronomical Union (IAU) and the United Nations Educational, Scientific, and Cultural Organization (UNESCO).  Their goal is for people all over the world to discover the wonders of the sky and to appreciate our place in the universe.

Star Cloud Over Saskatchewan.jpg
Creative Commons License photo credit: Space Ritual

You can participate in the International Year of Astronomy right here in Houston.  Several of the Fun Hundred events we’ve set up to celebrate our 100th anniversary are astronomy-related.  They include Sun-Earth Day at the vernal equinox, our annual viewing of the Perseid meteor shower in mid-August, members nights at the George Observatory, and a winter solstice event on our sundial. 

Also, you can observe the phases of Venus in the first three months of this year, just as Galileo did through his telescope.  Keep in mind that Galileo’s telescope looked like this; anyone with a good pair of binoculars has better observing equipment.  Go outside at dusk and look west southwest for the brightest point of light in the sky.  That is Venus.  Through a telescope, you’ll notice that Venus appears half-lit in mid-January 2009.  As you keep observing through March, you’ll see Venus become a more and more pronounced crescent.  This is because Venus is coming around to our side of the Sun and thus turning more and more of its night side to Earth.  The very skinny crescent of mid-March is so pronounced that it is noticeable in binoculars.

Remember, the great discoveries, or aha moments, as my co-blogger described, are not limited to great, historic scientists.  The beauty of science is that anyone who takes the time to observe can share in the act of discovery.

Looking back…

In case you were wondering about notable science events that occured the week following August 22…

On August 24, 79 A.D. Mount Vesuvius erupted, covering the cities of Pompeii (hopefully you had the chance to see the exhibit here in Houston at the Museum of Fine Arts), Herculaneum, and Stabiae under volcanic ash. The city was lost for 1,700 years – until it was accidentily rediscovered in 1748. The excavation of the city has given valuable insight into the city during the height of Roman Empire, acting as a time capsule, allowing scientists to study the buildings, food, and even people that were buried that fateful day.
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This is Mount Etna erupting in 2006 (there is no footage of the 79 explosion of Mount Vesuvius for obvios reasons.)

Also on August 24, in 2006, the International Astronomical Union (IAU) redefined the term “planet,” and Pluto was sent on its cosmic way (read the post about the controversy that ensued, by our astronomer James.) Pluto was “demoted” to the status of Dwarf Planet. There are currently eight planets and four dwarf planets in our solar system. The new definition of a planet is a celectial body that meets the following criteria:
    (a) is in orbit around the Sun, 
    (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and
    (c) has cleared the neighbourhood around its orbit.

Karoli looking foward
Creative Commons License photo credit: ckaroli

On August 25, 1609, Galileo Galilei demonstrated his first telescope to Venetian lawmakers. He was one of the first men to build a telescope, and did so without actually ever seeing one of the few that existed. He was the first to discover any of Jupiter’s moons (he found 4), now known as the Galilean satellites.

On August 27, 2003, Mars made its closest approach to Earth in nearly 60,000 years. The last time Mars was that close to Earth, man had just began to migrate out of Africa. Man wouldn’t start settling down, farming, and beginning to live in cities for another 48,000 years. Mars passed approximately 34,646,416 miles (55,758,006 kilometers) from Earth.

Looking Back…

In case you were wondering about notable science events that happened the week of June 20th…

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Creative Commons License photo credit: Neil Rickards

A far cry from Grand Theft Auto and Super Mario. On June 21st, 1948, the first stored-program was run on a computer. The Manchester Small-Scale Experimental Machine, nicknamed “Baby”, ran a program that held only 17 instructions. The computer program test was to find the highest proper factor of 218. It took 3.5 million operations and 52 minutes for the computer to produce an answer. And I thought my computer was slow.

Also on June 21st, 2002, Europe was declared to be free of polio (poliomyelitis,) a disease that targets infants and small children. The vaccine was created in April of 1955 by Jonas Salk.

The world doesn’t revolve around you. On June 22nd, 1638, Galileo Galilei was forced by the Catholic Church to recant his heliocentric theory that the sun, and not the earth, is the center of the universe. Of course, now we know that the sun is not the center of the universe either.

Minty Fresh. On June 26th, 1974, the first Universal Product Code was used in Ohio. The barcode was used at a supermarket; the first product scanned was a piece of Wrigley’s gum.

barcode
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