Space part 1 Science

Galaxy

A huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity A large assemblage of stars (and often gas and dust), typically containing millions to hundreds of billions of member stars Star - a large hot ball of gas which generates energy in its core by nuclear reactions Around 100 billion in the universe Held together by the gravitational attraction of all its member stars on one another Formed around 200 million years after the "Big Bang" Most large ones seem to have supermassive black holes at their centers Sometimes contain very bright centers called quasars 3 major types: Spiral Elliptical Irregular

Properties of Irregular Galaxies

Chaotic mix of stars, gas and dust Usually found near large spiral galaxies who may be distorting their shape.Chaotic mix of stars, gas and dust. Usually found near large spiral galaxies who may be distorting their shape.

Describe the Milky Way Galaxy

Flattened Disk Bulge in Middle Fried Egg Not solid from edge to edge Huge 1000-3000 Light Years Thick 100,000 Light Years across (Diameter)

universe

In astronomy, the sum total of all things which can be directly observed or whose physical effects on other things can be detected In simpler terms, space and all the matter and energy in it Major components: galaxies solar systems planets

Estimating the age of the Universe

Looking for the oldest stars Nebula (gas and dust) exist in space and are remnants from the formation of the universe. Stars undergo a life cycle based on the composition of the gases within them. As stars age the amount of hydrogen in the star changes, therefore changing the color and brightness of the star.Measuring the rate of expansion of the universe The galaxy is expanding based on the color of the light emitted from galaxies and stars. As the universe expands and galaxies move apart, the wavelength of light emitted from those galaxies is stretched. Shifting the light toward the red end of the spectrum and is called "red-shift". The more distance or faint a galaxy the more it is moving away from Earth.

What is the name of our galaxy?

Milky Way

Properties of Elliptical Galaxies

Round or elliptical in shape. Contain very little gas or dust. Because of little gas, no new stars are forming. The largest and smallest galaxies are elliptical galaxies. About 1/3 of all galaxies. Simply massive blobs of stars.

Properties of Spiral Galaxies

Shaped like flattened disks with one or more spiral arms.Our galaxy, Milky Way, is a spiral galaxy. Our solar system is located in one of the spiral arms.

3 Types of Galaxies

Spiral have arms of stars, gas , and dust that curve away from the center of the galaxy in a spiral pattern Ex. - Milky Way Irregular faint galaxies without a definite shape; smaller than the other types of galaxies; contain fewer stars Elliptical shaped like spheres or eggs; have almost no dust or gas between stars; contain old stars

Where is our Solar System?

The Sun and our solar system is located in one of the outer arms (Orion's Arm) of the galaxy. The distance from the Sun to the center of the galaxy is about 30,000 light years. All objects in the galaxy revolve around its center. The sun and our solar system take about 240 million years to make one trip around the center of our galaxy.

parallax

The apparent shift in position of an object when viewed from different locations Used by astronomers to measure distance

Light Year

The distance that light travels in one year in a vacuum, which is about 9.5 trillion kilometers (6 trillion miles) The Milky Way Galaxy is about 100,000 light years in diameter The speed at which light travels this distance is about 300,000 km/sec (186,000 mi/sec)

The big bang Theory

The primeval explosion of space, time, matter and energy that most astronomers think gave rise to the universe as we see it today. Occurred about 13.7 billion years ago Thought to have expanded within a second from something the size of a speck of dust to the size of our solar system

Astronomical Unit (AU)

Unit of distance equal to the average spacing between the Earth and the Sun Equal to about 150 million kilometers (93 million miles) Light takes about eight minutes to cover this distance