Groups of Stars Chapter 2C

Consider the Heavens Science is the study of God’s creation! The study of creation beyond our atmosphere is called astronomy! Astronomers study the motions of the heavenly bodies and the laws that govern those motions. Galaxy Centaurus

Galaxies: Giant Groups Andromeda Galaxy

Galaxies: Giant Groups The universe! - Contains every star, every planet, every satellite, every solar system, and every galaxy! We still don’t understand everything about the universe, but one thing we do know! God created it, and it tells of His glory!

Galaxies: Giant Groups Genesis 1:1 “In the beginning God created the heaven and the earth.” Psalm 19:1 “The heavens declare the glory of God; and the firmament shows His handiwork.”

Galaxies: Giant Groups The vast size of the universe argues strongly for a Creator who is not limited by space. A Galaxy is a star system containing from millions to billions of stars! Our Milky Way galaxy had over 400 billion stars!

Galaxies: Giant Groups The total number of galaxies is estimated to exceed 120 billion!

Super Structures Galaxies are not spread randomly in the universe… They are in groups called “clusters” Our milky way is in a cluster called the “Local Group” The two largest galaxies in the local group are us, the Milky Way, and a large galaxy called “Andromeda”.

Super Structures Two of the closest galaxies to ours is the Large Magellanic Cloud and the Small Magellanic Cloud. These are only 200,000 light years away from earth. They each contain several billion stars.

Superclusters It the current belief that our Local Group is part of an even larger grouping called a Supercluster. These superclusters join together to form the walls of ball-shaped structures which appear to be completely empty in the middle. Astronomers are amazed at the order in the universe.

Galactic Shapes We live inside the Milky Way! Because of this, we aren’t 100% sure what our galaxy looks like! We are fairly confident that it is a spiral galaxy.

Galactic Shapes There are four general shapes to galaxies! 1.Spiral 2.Barred Spiral 3.Elliptical 4.Irregular

Spiral Galaxies Spiral Galaxies have a central nucleus that resembles a flattened ball. Attached are long, curved arms.

M100

Barred Spiral These are spiral galaxies with unusual bar- shaped arms sticking out from their central nuclei.

Spiral Galaxies Spiral Galaxies are held together by the gravitational attraction between stars.

Nebulae within Spiral Galaxies Spiral Galaxies also contain many Nebulae. Nebulae are large clouds of gas and space dust. Whirlpool Galaxy which contains the Eagle Nebulae

Crab Nubulae

Butterfly Nebulae Taken September 2, 2009

Elliptical Galaxies Elliptical Galaxies resemble eggs or footballs! They are not as structured as spirals and do not contain much free gas. M87

Irregular Galaxies Composed of stars clumped together in no definite shape. Our two closest galaxies are irregular – The Large and Small Magellanic Cloud Large Magellanic Cloud

Small Magellanic Cloud

The Axis of Rotation In the Northern Hemisphere we have a star that appears to never rotate… That star is Polaris or the North Star. It does not rise or set because it is directly above the northern end of the earth’s Axis of Rotation. The Axis of Rotation is an imaginary line that goes from pole to pole through the earth.

The Axis of Rotation The ends of the axis are called the celestial poles. There are stars which appear to travel or rotate around the celestial poles and are called circumpolar stars. If you could stand at the North Pole, the north star would be directly above you. Below the equator, you cannot see the north star at all.

Constellations The constellations are even mentioned in the Bible! Job and Amos mention Arcturus, Orion, and Pleiades. Although the constellations may be given names as groups of stars, they may actually be far apart from each other.

Constellations There are currently 88 constellations recognized around the world. Canis Major

Constellations of the Northern Hemisphere The most commonly known are the Big Dipper, the Little Dipper, and Cassiopeia.

Constellations of the Northern Hemisphere The big Dipper is actually part of another constellation – The Great Bear The Great Bear – Ursa Major

The End of Chapter 2