# Stellar Scintillation
## What will this Book Cover

* The basics of Stellar Scintillation
* Review what Stars are and their formation
* This book will focus on stars and answer the questions: What causes stars to twinkle and Do planets twinkle?

## Who is this Book for

This book is for the general audience. It will be directed towards anyone whoever wondered, How do stars twinkle.

## So What is Stellar Scintillation

It is the scientific name for the twinkling of stars.
Scintillation consists of rapid changes in the apparent brightness of a star and the changes of certain color, position, and so on.

## What stars are and their formation

Stars are building blocks of the Universe. Stars are formed from Nebula. Gravity condense Nebula into stars. A star is a huge ball of fiery gas, where Nuclear Fusion takes place. A star can also be defined as a massive, luminous ball of plasma that is held together by gravity.

## What causes stars to twinkle

Stars twinkle when we see them from the night sky because we are viewing them through thick layers of turbulent air in the atmosphere. Stars look like tiny dots in the sky as their light travel through the layers of atmosphere. The light of the star is bent(refracted) many times and in random directions. The random refraction results in the star winking out. The star movement makes our eye interpret this as twinkling.
Stars closer to the horizon twinkle more than stars that are higher. Stars near the horizon have to travel through more air and is open to more refraction.

## Do Planets Twinkle

The answer is No. Planets do not twinkle because planets have a limited size. It "averages out" the turbulent effect making the planet stable to the eye.

## Expanded Knowledge

Plan a time to take a "Star Census". Make these observations in different locations (near a city or out in the country) and at different times (when there's a bright moon and when there's no moon). Just remember that each observation represents 1/144th of the sky. If you make only 6 observations, then you would multiply the total number of stars observed by 24 (which is 144 divided by 6).
PROCEDURE Try this experiment (at night at the agreed upon time) to measure the number of stars you can see.
Make an "Observing Device" from a bathroom tissue or paper towel tube. Measure the diameter of your tube. Cut its length to be three times its diameter. Through the tube, you will see only a small portion of the sky. It would take 144 tubes to cover the whole sky. One by one, face in each of the 4 compass directions (North, South, East and West).
Hold the tube 3/4 of the way up from the horizon in each direction and count the number of stars seen through the tube. Hold the tube half-way up from the horizon and repeat the count. Repeat the procedure again with the tube pointed a third of the way up. Repeat observations for the other directions. (To determine 3/4, 1/2 and 1/3, students can either use a protractor or they can simply estimate the angle)
Add up the number of stars for all 12 sightings. If it takes 144 tubes to cover the sky, then you have observed 1/12th of the sky. Multiply your sub-total by 12 to estimate the total number of stars in the sky. Estimated total number of stars: (includes the stars above and below the horizon)
Add up and compare the three measurements in each direction. Why do you see more stars in certain directions?
Make these predictions about twinkling:
a. Do stars lower in the sky or higher, twinkle more? b. Do stars twinkle more on a windy night, or a still night? c. Do stars twinkle more at sea level or on a mountain top? d. Do stars also change color as they twinkle?
http://www.super-science-fair-projects.com/astronomy/science-fair-project-on-stars.html

## Self Assessment

1. What is the scientific name for the twinkling of stars?
2. Scintillation consists of rapid change in?
3. Stars are the building blocks of the Universe.
4. A star is a huge ball of gas that Nuclear Fission takes place. True or False
5. Stars twinkle through small layers of turbulent air in the atmosphere. True or False
6. The light of the star is straight. True or False
7. The star movement makes our eye interpret this as twinkling.
8. Stars closer to the horizon twinkles more than stars that are lower. True or False
9. Planets (do or do not) twinkle the same way as stars.
10. Planets (finite or infinite)size.

## Self Assessment Answers

1. Stellar Scintillation 2. Brightness, color, position 3. True 4. False 5. False 6. False 7. True 8. False 9. Do not 10. Finite