diagram of parallax
* Put your thumb out in front of you, then close one eye and focus on your thumb. Then you open other eye and close the one you just had open. Now as you can see it looks like your thumb moved right? well thats how parallax works.
- Star's pulsate
- "Cepheid variables change in brightness due to changes in temperature and also by a change in the radius." - Red Vee
- caused by pulsations in the outer layers of the stars.
- m-M=5 log(d/10)=5logd-5 Where d is distance in parsecs.
- "In terms of what scientists means when they say "a star is x light years away," they are generally getting that number by calculating the red shift of the body in question. Redshift refers to the lengthening of electromagnetic waves as they travel through the universe. Since the universe is expanding at a known rate, scientists can work background and see how much the light from distant star has shifted toward red in order to determine how long that wavelength has traveling through expanding space. The more shifted the light is, the farther away the object is." - M.L.
A.U. (astronomical unit)
- "The astronomical unit is the average distance between the sun and the earth. Its value is between the sun and earth. Its value is 149,597,870 km.(about 93 million miles) Using these laws, you can determine the distance from earth to the planet in A.U. By sending radio signals (which travel at the speed of light) to a space craft, and measuring how long it takes for the space craft to return those signals, you can determine how far away a space craft is in kilometers." - David Palmer
- "Take a rubber band...hold it between your thumb and forefinger with your other hand, pull one side of the rubber band out until you have a skinny triangle. If the distance between your thumb and finger is 1 A.U....and the distance between your hands is 3.3 light years, then that skinny triangle would be one second of arc. or 1/3600th of a degree." - Fasson