13. The Sun - The Sun Outline Our goals for this section:...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: The Sun Outline Our goals for this section: To summarize the overall properties of the Sun To explain the methods of energy production in the Sun To name the parts of the Sun To explore some of the unsolved mysteries of solar physics The Sun today! http://sohowww.nascom.nasa.gov/data/realtime/ realtime-update.html The Sun is BIG The Sun is a star , a hot ball of gas held together by its own gravity and powered by nuclear fusion occurring in its core In its composition, mass, size, and brightness, the Sun is a fairly typical star, although a bit bigger than the average Properties of Our Parent Star The Sun in UV light, as seen by SOHO, the SOlar and Heliospheric Observatory, which is a joint project of the ESA and NASA. SOHO watches the Sun continuously from space. Properties of the Sun Radius 6.96 x 10 8 m Radius 109 R earth Mass 1.99 x 10 30 kg Mass 333,000 M earth Average 1410 kg m-3 Average density 1.4 x density of water Rotation period 24.9 days @ equator 29.8 days @ poles Surface 5780 K Surface temperature lead melts at 601 K 3.86 x 10 26 W Luminosity 3.86 trillion trillion 100 W light bulbs The Sun has a highly active, layered atmosphere We divide the atmosphere into four main layers (bottom to top): the photosphere , the chromosphere , the transition zone , and the corona The Structure of the Sun The structure of the Sun (NOT to scale!!!) The Sun is incredibly massive, so it has a lot of gravity If its made of gas, why doesnt it just collapse until its a solid, like Earth? The Sun is in hydrostatic equilibrium , meaning that the outward force generated by its gas pressure (P=nkT) balances the inward force of its gravity at each radius within the Sun The fossil record and radioactive dating techniques tell us that the Earth has been warm for at least 4.5 Gyr, so the Sun has to have been around and hot for at least that long For a long time, people thought the Sun generated its energy through chemical reactions or by gravitational contraction, the latter is called the Kelvin-Helmholtz lifetime The Suns Energy Source Lets make an estimate......
View Full Document

This note was uploaded on 03/01/2011 for the course ASTRO 1a03 taught by Professor Samantha during the Spring '11 term at McMaster University.

Page1 / 32

13. The Sun - The Sun Outline Our goals for this section:...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online