Used Astroable to find position of the sun and stars. Also played a big role in earth discoveries.
Determined location of almost 850 stars, Created a system to explain how planets and stars move
First Greek to propose a sun centered or heliocentric universe.
A sun centered universe
discovered orbits. thought thats object moved in a perfect circular orbit around Earth. but was incorrect.
Concluded that the earth is a planet. Proposed a model of the solar system with the sun at the center.
Had a observatory built near copenhagen. Studied Mars.
Discoverd 3 laws of planetary motion. Discovered mars orbi was a oval shape.
Described behavior of moving objects.
Sir Isaac Newton
Proposed that a moving object will continue to move at a constant speed and in a straight line. Developed the concept of Inertia.
disked shaped galaxy with arms that make it resemble a pin wheel, makes up 20% of the galaxies.
round or oval shaped. no spiral arms. usually small galaxies but the largest known galaxy is elliptical (most common). makes up 60% of galaxies. contains old stars.
irregularly shaped with no apparent organized structure. they do not have the a center. make up 10% of galaxies. composed of young stars.
Big Bang Theory
the universe was condensed and then it exploded and spread out as the years went on
galaxies are moving further and further away from us.
How Stars are classified
Based upon information that we know about our own sun. Stars can be classified based on their mass, color,size, temperature, brightness, and many other ways.
How can you use Binary stars to determine the mass?
If the stars are equal mass, the center is halfway between them. And if one star is more massive, the center of the mass will be closer to the massive star.
Is a stars brightness as it appears from earth.
Measures how bright the star would be if all the stars were the same distance from earth.
The dark regions on the surface of the photosphere are sunspots.
Are brief outbursts that normally last about an hour and appear as a sudden brightening of the region above a sunspot cluster.
The outermost portion of the solar atmosphere. Temperature exceeds 1 million k.
Order of the 5 layers in the sun starting from the core.
1. The Core 2. The radiation zone 3. The convection zone 4. Photosphere 5. Chromosphere
How do you locate the north star?
Find the big dipper and it will be pointing to the brighter star which is the north star.
Barred Spiral Galaxy
Stars are arranged in the shape of a bar. The bar rotates and has a spiral arm attached