Advertisement.

EnchantedLearning.com is a user-supported site.
As a bonus, site members have access to a banner-ad-free version of the site, with print-friendly pages.
Click here to learn more.

ad
(Already a member? Click here.)
Table of Contents Enchanted Learning
All About Astronomy
Site Index
Our Solar System Stars Glossary Printables, Worksheets, and Activities
The Sun The Planets The Moon Asteroids Kuiper Belt Comets Meteors Astronomers

THE SUN
Introduction to the Sun Solar Structure Size, Mass Flares, Solar Wind, Prominences Sun's Birth Solar Eclipses Activities,
Web Links
Solar Rotation Sunspots Sun's Death

THE BIRTH OF THE SUN

A Globule of Gas:
The Sun, like other stars, was formed in a nebula, an interstellar cloud of dust and gas (mostly hydrogen). These stellar nurseries are abundant in the arms of spiral galaxies (like our galaxy, the Milky Way).

In the stellar nursery, dense parts of the clouds undergo gravitational collapse and compress to form a rotating gas globule.


The globule is cooled by emitting radio waves and infrared radiation. It is compressed by gravitational forces and also by shock waves of pressure from supernova or the hot gas released from nearby bright stars. These forces cause the roughly-spherical globule to collapse and rotate. The process of collapse takes from between 10,000 to 1,000,000 years.

A Central Core and a Protoplanetary Disk:
As the collapse proceeds, the temperature and pressure within the globule increases, as the atoms are in closer proximity. Also, the globule rotates faster and faster. This spinning action causes an increase in centrifugal forces (a radial force on spinning objects) that causes the globule to have a central core and a surrounding flattened disk of dust (called a protoplanetary disk or accretion disk). The central core becomes the star; the protoplanetary disk may eventually coalesce into orbiting planets, asteroids, etc.


Protostar:
The contracting cloud heats up due to friction and forms a glowing protostar; this stage lasts for roughly 50 million years. If there is enough material in the protostar, the gravitational collapse and the heating continue.

A Newborn Star:
When a temperature of about 27,000,000°F is reached, nuclear fusion begins at the core of the Sun. This is the nuclear reaction in which hydrogen atoms are converted to helium atoms plus energy. This energy (radiation) production prevents further contraction of the Sun.

Young stars often emit jets of intense radiation that heat the surrounding matter to the point at which it glows brightly. These narrowly-focused jets can be trillions of miles long and can travel at 500,000 miles per hour. These jets may be focused by the star's magnetic field.

Later, the Sun stabilizes and becomes a yellow dwarf, a main sequence star which will remain in this state for about 10 billion years. After that, the hydrogen fuel is depleted and the Sun begins to die.

Star Birth Web Links:
Star birth from NASA




Enchanted Learning®
Over 35,000 Web Pages
Sample Pages for Prospective Subscribers, or click below

Overview of Site
What's New
Enchanted Learning Home
Monthly Activity Calendar
Books to Print
Site Index

K-3
Crafts
K-3 Themes
Little Explorers
Picture dictionary
PreK/K Activities
Rebus Rhymes
Stories
Writing
Cloze Activities
Essay Topics
Newspaper
Writing Activities
Parts of Speech

Fiction
The Test of Time
iPhone app
TapQuiz Maps - free iPhone Geography Game

Biology
Animal Printouts
Biology Label Printouts
Biomes
Birds
Butterflies
Dinosaurs
Food Chain
Human Anatomy
Mammals
Plants
Rainforests
Sharks
Whales
Physical Sciences: K-12
Astronomy
The Earth
Geology
Hurricanes
Landforms
Oceans
Tsunami
Volcano
Languages
Dutch
French
German
Italian
Japanese (Romaji)
Portuguese
Spanish
Swedish
Geography/History
Explorers
Flags
Geography
Inventors
US History

Other Topics
Art and Artists
Calendars
College Finder
Crafts
Graphic Organizers
Label Me! Printouts
Math
Music
Word Wheels

Click to read our Privacy Policy

E-mail


Enchanted Learning Search

Search the Enchanted Learning website for:



Advertisement.



Advertisement.



Advertisement.



Copyright ©1999 EnchantedLearning.com ------ How to cite a web page