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

ASTR 151 Chapter 8 Part 1

by: Wesley Fowler

ASTR 151 Chapter 8 Part 1 ASTR 151 001

Marketplace > Astronomy > ASTR 151 001 > ASTR 151 Chapter 8 Part 1
Wesley Fowler

GPA 3.97

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

These notes cover the Earth's moon, elaborating on its structure, orbit, interior, and composition.
Journey Thr Solar Sys Lecture
Dr. Sean Lindsay
Class Notes
moon, orbit, lunar, tide, Maria, highlands, crater, ejecta, regolith
25 ?




Popular in Journey Thr Solar Sys Lecture

Popular in Astronomy

This 5 page Class Notes was uploaded by Wesley Fowler on Tuesday April 5, 2016. The Class Notes belongs to ASTR 151 001 at a university taught by Dr. Sean Lindsay in Spring 2016. Since its upload, it has received 18 views.

Similar to ASTR 151 001 at University


Reviews for ASTR 151 Chapter 8 Part 1


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: 04/05/16
Wesley Fowler ASTR Chapter 8 The Moon Distance from Earth: 384,000 km Radius: 1,738 km (0.27 Earth radii) Mass: 7.3 x 10 22kg (~1/8 Earth Masses) Orbital Period: 27.3 days Rotational Period 27.3 days - The moon has no atmosphere and no global magnetic field The side of the moon that can be seen from Earth is called the Lunar near side, while the face that cannot be seen is the Lunar far side. We can see about 59% of the moon due to its slightly elliptical orbit, which causes a lunar libration. - Lunar libration: The oscillation of the moon, or its rocking back and forth. The moon’s rotational period is equal to its orbital period around Earth, both being 27.3 days. This is why only the lunar near side is visible from earth. The moon is in synchronous orbit. Tidal locking: When an orbiting moon is in synchronous orbit with its associated planet. - Most moons in the solar system are tidally locked. The Moon’s Surface Two dominate surface features: 1. The Lunar Maria: The younger, smoother surface that has fewer craters. Darker in color due to high amount of iron in rock. 2. The Cratered Highlands: Elevated above maria by several kilometers. Older surface with much more craters, a lighter color. The region is filled with mountains. The Lunar near side is mostly maria with highlands at the southern tip, while the far side is mostly highlands with some scattered maria. Impact craters: Ring-like impressions on the moon created from meteor impacts. Simple craters: Clear and singular bowl shape. Simple physics. Complex craters: Large craters that have a central peak. Complex physics. Ejecta: The material ejected from the moon due to a meteor strike. - Ejecta blanket: White surrounding material around crater. - Ejecta rays: White streaks from craters that stretch across the moon. The older surfaces of the moon have more craters than younger surfaces. Superposition: What is on top is younger. If there is a crater in a mare or a larger crater, the crater is obviously younger. Radioactive dating of lunar samples is a more accurate method than crater observation. • End of Late Heavy Bombardment: 3.9 billion years ago • Formation of Maria: 4.1 – 3.9 billion years ago • Cratered Highlands: 4.4 billion years ago Regolith: The fine dust that covers the moon, caused by the breakup of the moon’s surface. - Can be over 100m deep, this is why the astronauts left footprints on the moon. - The steady buildup of regolith creates an erosion rate of 5 meters per billion years. Permanently shadowed craters provide evidence of once-existing water ice at the poles of the moon. These regions, that have never seen sunlight, contain hydrogen and water ice molecules. - Less water in these regions than the driest place on Earth. Lunar Volcanism Crater-chains: Craters that were not created by impact, but by the collapsed of lava domes Volcanic Rilles: Long ditches where lava once flowed. These cover the surface of the moon. Wesley Fowler ASTR Chapter 8 The Moon’s Interior 3 Average Density: 3300kg/m - Lower than Earth’s, but higher than the Moon’s surface. Thus an iron core. Total Radius: 1,738 km Layers: Solid iron inner core: 240km (small) Fluid outer core: 330Km Molten inner mantle Large, rocky outer mantle: Out to 1600Km Thin rocky crust No plate tectonics No electromagnetic field Maria is believed to be made of lunar mantle material mixed with the crust Origins of the Moon Earth’s mantle and crust are very compositionally similar to the Moon. They are all made up of similar rocky and metallic materials. - The Moon lacks a substantial metal core Co-formation (sister) Theory: Earth and Moon formed separately, but at the same time, out of the same material. - The moon’s deficiency of iron refutes this theory. Capture Theory: Earth and Moon formed separately apart from each other, with the Moon being captured by the Earth’s gravitational force, causing it to orbit. - The physics required for the Earth to capture the Moon in its orbit are not possible. Fission (Daughter) Theory: Earth and Moon form as single object, and the Earth and moon split up due to a very high rotation rate. - The physics required for this split are not possible Giant Impact Theory: When the Earth was mostly molten and young, a grazing collision happened with a “Mars-sized” protoplanet caused a chunk to separate from Earth. - This physics required are possible, and the theory explains compositional similarities Evolution of the Moon Oldest rocks dated: 4.4 billion years ago (age of highlands) - Crust must have formed by this time Shortly after formation, the Moon’s surface was entirely molten, it was covered by what is called the lunar magma ocean. Lunar Magma Ocean Sequence: 1) Formation result of hot accretion 2) Light material (anorthosite) floats -> Crust, such that thinner crust formed on near-side 3) Dense materials sink 4) Large impacts form huge basins during Late Heavy Bombardment – Precursors to maria 5) Volcanism over next several hundred million years (3.9 – 3.2 Gya) filled impact basins to form maria with mantle compositions 6) No significant geologic activity after 3.2 Gya; Surface evolution dominated by the steady of impacts (generating new craters and regolith) Near-side crust is thinner than the far-side, and thus can flood with lava.


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

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."

Allison Fischer University of Alabama

"I signed up to be an Elite Notetaker with 2 of my sorority sisters this semester. We just posted our notes weekly and were each making over $600 per month. I LOVE StudySoup!"

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.