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The International Year of Astronomy has begun

The year 2009 was declared as the International Year of Astronomy to mark the four hundredth anniversary of Galileo Galilei's discoveries. What did Galileo see and what do astronomers want to see today?

Galileo Galilei
Galileo Galilei

August 25, 2009: exactly 400 years since the first telescope observation by Galileo

About 400 years ago, Professor Galileo Galilei from the University of Padua in Italy decided to aim A small monocular telescope towards the sky. What he saw there changed our worldview forever. The Big Bang, black holes, dark matter, dark energy, extrasolar planets, brown dwarfs, quasars, pulsars, cosmic rays, space-time, galaxies - Galileo started it all.

Four hundred years after Galileo, telescopes are one of the greatest achievements of human civilization. Every day they reveal to us how big, strange and violent the universe is. 2009 is going to be a big year in the history of telescopes - and not just because it was declared the International Year of Astronomy.

In March 2009, the US will launch a new space telescope, named Kepler, with the aim of discovering Earth-like planets hidden in the bright light of distant suns. In May, astronauts embarked on a final repair mission to repair the 20-year-old Hubble Space Telescope. They are about to install a new camera and additional equipment to once again upgrade the most important telescope in history.

But what is expected next? Scientists have a lot more ideas than money. Future telescopes will be bigger and more expensive, and the governments that fund them have more pressing concerns than black holes and white dwarfs. Every decade the International Astronomical Council conducts a survey among its members to recommend the telescopes of the next generation: will they be ground or space telescopes? Will they pick up waves in the infrared or radio waves? Or maybe X-rays and gamma rays?

What is certain is that future telescopes will be huge. The largest visible-light telescopes operating today contain mirrors about 10 meters in diameter. But American scientists aspire to build a telescope with a large P-3 diameter, aptly named the "Thirty Meter Telescope". In contrast, the Americans hope to build a monster with a diameter of 42 meters that will bear the name "The Very Large European Telescope".

In the field of radio, where the electromagnetic waves are longer, the telescopes are also larger. One of them, the "square kilometer array" will connect an array of small dish antennas to create a universal reception area of ​​one million square meters.

In 2013, the American space agency, NASA, is scheduled to launch Hubble's replacement: the James Web Space Telescope, or JWST. This floating observatory will be able to pick up the first rays of light that were emitted even before the first galaxies were born, right after the universe became transparent and light could freely pass through it.

Galileo's legacy

If Galileo were alive today he would undoubtedly be shocked. Galileo's first telescope had a magnification of 8 times. Galileo saw for the first time that the moon was not smooth as they thought before him, this was a real world: with mountains and craters. Later, using more sophisticated equipment, Galileo saw the appearances of the planet Venus, sunspots and his most important discovery: four moons orbiting Jupiter.

Galileo was not the one who invented the telescope. There were others before him, such as the Dutch lens polisher Hans Liprehy (photo on the left), to whom some attribute the invention. And he may not have been the first to decide to aim the device at the sky either. But Galileo was the first to publish them and grasp the deep philosophical significance of what he saw.

Galileo's observations confirmed the theory of Nicolaus Copernicus who died in 1543. The Copernican model stated that the earth is not the center of the universe around it but a body around its axis and around the sun. The Vatican forbade Galileo to teach the Copernican model, but he got away with it and was eventually prosecuted for heresy. Although Galileo was not executed, he was forced to deny his discoveries and spent the rest of his days under house arrest.

And what's next?
An illustration of a huge and innovative ground telescope that the Europeans hope to start building in about three years.
The universe is a big encyclopedia of information that comes to us as light waves. Today's astronomers are interested in extracting answers to several questions from this encyclopedia. Telescope and B, for example, will try to answer what-before-why? Did the black hole at the center of the Milky Way give birth to our galaxy or vice versa, the Milky Way created the black hole. Recent information examining the first galaxies suggests that the black holes served as galaxy seeds and therefore preceded them.

An even more fundamental question is how big is the universe, and are there other universes?

And the most interesting thing - is there life outside the earth. So far, telescopes have discovered huge, hot planets orbiting distant suns. These planets are larger than Jupiter and apparently incapable of supporting life as we know it. But future telescopes will discover planets more and more similar to Earth, and eventually maybe even ones that contain life.

Then the revolution of Copernicus will be completed - from the center of the universe we will become just another place with life on it...

2 תגובות

  1. Galileo Galilei - the man and the legend is something that always fascinates me especially in light of the fact that Galileo was a groundbreaking figure in so many ways and yet Galileo's discoveries were so shamefully rejected by the church. It amazes me because the story of Galileo Galilei is an example of how blind and terrible ignorance and fanaticism can be.

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