Characteristics Of Stars Galaxy: A collection of stars, gases and dust. Universe: Contains billions of galaxies.
Feb 23, 2016
Characteristics Of Stars
Galaxy: A collection of stars, gases and dust.
Universe: Contains billions of
galaxies.
The Milky Way galaxy has a whopping circumference of
roughly 250-300 thousand light years! Within the main body
of the Milky Way there are estimated to be between
200 and 400 billion stars.
Types of Galaxies1. Spiral2. Elliptical3. Irregular
Spiral Galaxies:Arms spiral outward like a pinwheel
Our galaxy, The Milky Way, is a spiral galaxy
Elliptical Galaxies:Look like flattened football.
Have billions of stars, but little gas and dust.
Contain the oldest galaxies
Irregular GalaxiesNo definite shapeExample: Large Magellanic Cloud
( Light will travel 10 trillionkilometers in one year!)
Scientists use LIGHT YEARS to measure distances in space. A light year is the distance light travels in one year.
Light travels at the speed of 300,000,000 meters/second.
Classifying StarsStars are classified by 3 Main Characteristics:
1. Size2. Temperature3. Brightness
Hottest (20,000-50,000*C)
: (10,000*C) (6,000*C) (4,000-5,000*C) (3000*C)
Color reveals the temperature of a star.
Brightness of StarsApparent Magnitude: Brightness as seen from earth
Absolute Magnitude: Brightness of a star from a standard distance
Hertzsprung-Russell Diagram
A graph plotting brightness and temperature.
90% of stars are Main Sequence
Solar flare
Overview of Star Life Cycle
Lifetimes of Stars
A star’s life depends on its mass. Stars smaller than the sun live up to 200
billion years. Medium sized stars like the sun live around
10 billion years. Stars 15 times more massive than the sun
live about 10 million years.
·Clouds of gas – made up of elements and compounds·As they spin and condense, heat energy is transformed, forming stars
NEBULA
·Medium sized star·By speed of light, only takes 8.3 minutes to get to Earth from the Sun·Located on the edge of a spiral of the Milky Way galaxy·Center of Solar System
SUN
·Dense gravity well in space·Light cannot escape the gravitational pull of a black hole·Observed because astronomers can see light and energy being given off by objects being pulled into them·No volume, infinite density·Could be a result of a Supernova explosion
BLACK HOLE
http://chandra.harvard.edu/resources/flash/bh_truth.html