New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Week 11 Discover the Universe

by: Jocelyn

Week 11 Discover the Universe AST 1002

Marketplace > University of Florida > Science > AST 1002 > Week 11 Discover the Universe

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

Sun, Nuclear Fusion and the Interstellar Medium – Properties of the Sun and the process of nuclear fusion are discussed. Learn properties of the material between the stars known as the ISM
Discover the Universe
Reyes, Francisco J
Class Notes
25 ?




Popular in Discover the Universe

Popular in Science

This 5 page Class Notes was uploaded by Jocelyn on Sunday November 8, 2015. The Class Notes belongs to AST 1002 at University of Florida taught by Reyes, Francisco J in Summer 2015. Since its upload, it has received 13 views. For similar materials see Discover the Universe in Science at University of Florida.


Reviews for Week 11 Discover the Universe


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 11/08/15
Tuesday, November 3, 2015 Discover the Universe Week 11 The Standard Solar Model - The temperature of the core must be at least 10 million K in order to be able to convert H too He. The Sun’s central core temperature is about 15 million K. - 1 g/cm3 = 1000 kg/m3 Energy transports within the Sun - Extremely hot core, 10-15 million K. All matter is completely ionized (plasma) - Radiation zone: The temperature is so high that no electrons are left on the atoms to be able to capture photons. Core/Interior is transparent to light and energy here is transported by radiation. Electromagnetic radiation off of gamma rays. - Convection zone: Temperature falls further away from the core-at lower temperatures, more atoms are not completely ionized. The electrons left in the atoms can capture photos. The gas becomes opaque to light. Solar Granulation - Evidence for Convection • Solar Granules are the tops of convection cells • Bright regions are where hot material is upwelling (1000 m across) • Dark regions are where cooler material is sinking. • Material rises/sinks at a rate about 1 km/sec (2200 mph) • Detected by Doppler Effect The Solar Atmosphere - The solar spectrum has thousands of absorption lines - The scale is wavelength in nanometers - More than 67 elements are present: Hydrogen is the most abundant element followed by Helium 1 Tuesday, November 3, 2015 The Chromosphere and the Photosphere - The chromosphere can only be seen in a total solar eclipse when the size of the disk of the moon is slightly larger than the disk of the Sun so it will block the light form the photosphere. - The chromosphere produces the absorption lines - The chromosphere has lower temperature (4500 K) and lower density - The photosphere is the layer of the Sun that we do see. The photosphere forms the continuous spectrum. It has higher temperature (5800 K) and higher density Transition Zone and Corona - The Corona has very low density but high temperature: 10^6 K - From the corona we see emission lines from highly ionized elements which indicates that the temperature there is very HOT - The hot coronal plasma escapes the Sun as solar wind Solar Wind - The radiation (light or electromagnetic waves) emitted by the Sun travel at the speed of light and take about 8 minutes to reach Earth - The plasma (electrons, protons, and ions) ejected from the Sun travel much slower and take a few days to reach Earth - Solar coronal plasma has enough temperature to escape the Sun’s gravity Sunspots - Typically about 10,000 km across - At any time, the Sun may have hundred (around solar sunspot maximum) or none - Dark color because they are cooler than photospheric plasma (4,500 K in darkest parts) - Each spot can last from a few days to a few weeks or a month - Galileo observed these spots and realized the Sun is rotating differentially (faster at the equator, slower at the poles)
 2 Thursday, November 5, 2015 - The charged particles in the plasma (electrons, protons, and ions) form the atmosphere interact with the magnetic field - The Sun’s differential rotation distorts the magnetic field lines Solar Cycle - Solar Cycle: 22 years long. The direction of the magnetic field polarity of the sunspots flip every 11 years (back to original orientation every 22 years) - Sunspot Cycle: 11 years, however it can occasionally disappear known as the Maunder Minimum: period of 70 years of minimum sunspot activity coincided with a period of cold temperatures called the Little Ice Age - A solar maximum occurs every 11 years Heating of the Corona - Charged particles (mostly protons and electrons) are accelerated along magnetic field “ lines” above sunspots. - This type of energy , NOT light energy, heats the corona. - Solar Prominences: is a large, bright, gaseous feature extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's corona. Typical size is 100,000 km or weeks. - When see against the bright solar surface, prominences appear as dark filaments - Solar Flares: Eruptions on the Solar surface from stresses applied to the magnetic field lines, usually near sun spots • Flares such as these emit enormous amounts of X. Ray and ultraviolet radiation as well as high energy particles both of which have important effects on the Earth • Those high energy particles produce aurora emission. • They compress the magnetic field of the Earth. When doing so, it induces a voltage (and current) in power lines. It is possible for it to activate the power lines protections disconnecting the aliens and may create a black out. • Flares can damage satellites which can disrupt communications, TV transmissions • The particles ejected in a flare are so energetic, the magnetic field cannot bring them back to the Sun because they escape the Sun’s gravity 3 Thursday, November 5, 2015 What makes the sun shine? Nuclear fission! - Nuclear fission: combining to light nuclei into heavier ones. Example: In the case of the Sun, conversion of H into He - Atomic nuclei are positively charged and repel one another via the electromagnetic force. - Nuclear fission requires temperatures of at least 10 million K because merging nuclei (protons in Hydrogen) require high speeds - Higher temperature = faster motion Proton-Proton Chain - Proton: nucleus of an H atom - Deuteron: nucleus of a deuterium (one proton, one neutron), and isotope of H - Positron: antiparticle, same mass of an electron but has a positive charge - Neutrino: elementary particle with virtually no mass or charge. It hardly interacts with mass - Helium 3: Isotope of Helium (two protons and one neutron) - Helium4: Stable nucleus of helium (two protons and two neutrons) The total mass decreased during a fusion reaction The sun has enough mass to fuel its current energy output for another 5 billion years - The energy output form the core of the Sun is in the form of gamma rays - These are transformed into visible and IR light by the time they reach the surface. - Detecting Solar Neutrinos: These light detectors measure photons emitted by rare electron-neutrino reactions in the fluid (which is purified by water) • Solar Neutrino Problem: neutrino detectors found only 30-50% of the predicted number that were expected from the Sun • A discrepancy between theory and experiments could mean either: 4 Thursday, November 5, 2015 - 1) standard solar model is incorrect - 2) standard particle theory is incorrect - The discrepancy appears to be resolved 5


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Anthony Lee UC Santa Barbara

"I bought an awesome study guide, which helped me get an A in my Math 34B class this quarter!"

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.