ASTRONOMERS AND OUR CHANGING IDEAS ABOUT THE SOLAR SYSTEM

Improved technology New ideas and experiments More information becomes available Curious minds OUR UNDERSTANDING OF THE SOLAR SYSTEM CHANGES DUE TO:

A LONG TIME AGO PEOPLE BELIEVED THE S. SYS. WAS GEOCENTRIC. THIS MEANS THE EARTH IS AT THE CENTER OF THE UNIVERSE AND EVERYTHING ORBITS IT.

Ptolemy suggested the model in 140.

THEN IN 1543, COPERNICUS CAME UP WITH ANOTHER THEORY. He did this because it was simpler and better explained planetary motion. This was called the Copernican or HELIOCENTRIC model.

HELIOCENTRIC MEANS THE SUN IS THE CENTER OF THE SOLAR SYSTEM

IN THE LATE 1500’S TYCHO BRAHE CAME UP W/ ANOTHER THEORY. IT WAS NOT ACCEPTED. HIS MAIN CONTRIBUTION WAS TAKING REALLY DETAILED NOTES ON THE MOVEMENT OF OBJECTS IN THE NIGHT SKY. Just a note of interest: He lost the end of his nose in a duel and wore a prosthetic one and he was very protective of his notes and did not want to share them with his assistant even after his death. wheatoncollege.edu mentalfloss.com

Brahe’s assistant, JOHANNES KEPLER, later used Brahe’s notes to figure out that the orbits of the planets are ELLIPTICAL not circles like previously thought and the sun is not perfectly centered. Myhero.com

If there is time at the end of the notes, come back to watch the video on Brahe and Kepler

Still there was no proof of the heliocentric model and most people didn’t even know about it or believe in it.

Then came Galileo in He used the telescope to find proof of the heliocentric model

EVIDENCE # 1: Venus goes through phases (like the moon) Evidence # 2: Jupiter has moons orbiting it.

While Galileo was correct, the church, who was in charge at the time, did not like him saying this and he was put on trial and under house arrest for the rest of his life. That’s how strongly he believed in his theory.

Even later in 1687 Isaac Newton was finally able to explain how planets stay in orbit around the sun. GRAVITY (a force that pulls objects together) and INERTIA hold the planets in orbit. Gravity depends on distance and the mass b/t objects.

Edwin Hubble, saw for the first time that the Milky Way was NOT the only galaxy, in fact there are lots of galaxies out there. IN MORE MODERN TIMES... Powell-Hubble.jpg

SINCE THEN WE HAVE DISCOVERED LOTS OF NEW THINGS ABOUT THE SOLAR SYSTEM More planets, moons around most planets, the asteroid belt, comets are made of ice and rock, tectonic plates are shifting, there is water on the moon and Mars, their might have been life on Mars or the moon that is covered in giant oceans, Jupiter has a really large storm, we are not the only galaxy, the big bang and evidence for it, our solar system is much larger than we thought, there are lots of planets out there going around other stars, dark matter and black holes exist, just to name a few. And it’s all due to technological advances and curious people P.S. You don’t have to copy this slide