December 2016

Financials:

November 1 beginning balance $1806.27

Nov 7 renewal dues $291.67

Nov 7 new member $20.00

Ending balance Nov. 30 $2117.94

Attendance tonight: 40. This may be a new record, at least for the past several years!

Daryl’s monthly update and recent images:

What is the original name of Earth Shine? Da Vinci Shine! He believed that the moon had lots of water.

Daryl showed fabulous images he put together of the Moon before the SuperMoon on the night of November 13/morning November 14, and five days either side. Some images were side-by-side so you could see the waxing and waning Moon and others were superimposed so you could see just how much the Moon was larger by just before dawn (for those of us in Bartlesville) on November 14. Perigee on November 13 was at 11:58 pm and on November 14 at 7:52 am.

He also showed images taken near Hulah Lake of Orion, including the Great Nebula, Auriga and the Pleiades. Also pictures of the Flame and Horsehead Nebulae. The Winter Milky Way passes through Auriga. He took these images with a 3 minute exposure time and then stacked and processed them. (There was some discussion about whether or not you could see the Horsehead Nebula visually; you can’t with the naked eye.)

Solar update: We are in a time of decreasing sunspot activity; there was one sunspot Nov. 26, the first in some weeks.

Main presentation--Meteorites: Tour Guides of the Asteroid Belt and More by Dr. Kathryn Gardner-Vandy

Dr. Kat Gardner-Vandy is a planetary scientist who studies meteorites. She has a PhD in Planetary Sciences from the University of Arizona and a BS in Geology from the University of Oklahoma. She is self-employed as an Earth and Space Science consultant and is also a Research Associate at The University of Tulsa. In January, she will be starting as an adjunct professor in the Aviation and Space program at Oklahoma State University.

This was a fabulous presentation accompanied by images and real meteorites. I will forward the PowerPoint presentation itself when I get it. These minutes are not so much in order as she spoke them, but by topic.

First off, what is the difference between a meteorite and a meteor? Answer: A meteorite lands on Earth (or another celestial body), a meteor does not!

She described her background as being in geology and her PhD in meteorites. How asteroids melted early on in the development of our solar system.

The earth is constantly gaining weight, a little at a time, through meteorites striking the planet; most of this weight gain is in dust particles. 80000 gram gain/yr.

The earth gets hydrogen from meteorites in parts per billion.

She showed an image of Nina Lanza (whom she knows) and other members of a team of 8 doing meteorite research in Antarctica. Why there? Because anything you see there that is black (on top of the white snow) is very likely a meterorite! They really stand out against sparkling white snow.

There are 2 basic types of meteors: chondrite and achondrite.

Chondrites:

These are made up of chondrils, which are small particles or crystals that have stuck together. As they hit the atmosphere they are ablated and a fusion crust (black) develops, about 1 mm thick around the outside. Chondrites are the oldest things in our solar system, about 4.56-4.57 billion years in age. 85% of meteors are the chondrite type, what are called “ordinary” meteors. Chondrils are the building blocks of our planet. You can think of chondrils as being kind of like sand; you can think of them as being sediments, little particles from dust. They aggregate to form chondrites.

Some meteors have a lot of iron in them, some a little, some in between. Most meteeors are magnetic (one thing you can try if you are out exploring and think you may have found one; test for magnetism if it’s large enough to tell anything).

They often have calcium and aluminum inclusions. We really don’t know how chondrils form, although they form freely in nebulae. Other materials in chondrils include nickel, silicates, oxygen, magnesium, aluminum, potassium and sodium. Meteorites with lots of carbon are called carbonaceous meteorites.

The largest meteorite ever found is the Hoba meteorirte in Namibia. A small shrine has been built around it. This meteorite weighs 60 tons!

Achondrites:

These form from hard bodies with a melted core in the middle.

There are meteorites on Mars and Mercury. Chondrils are not found on Mars. Mars has a specific geochemistry. Shergottites are from Mars. An image of an iron meteorite on Mars was taken from the Opportunity rover.

The Moon was probably formed by a meterorite hitting the developing Earth and then the Moon was spun off. The Earth and Moon share the same oxygen isotopes.

Meteorites travel tens of thousands of kilometers an hour.

The most well studied meteorite is Allende, weight two metric tons, which hit February 1969 in Mexico. This one is carbonaceous.

Meterorites have coding. For example a CV3.2 is unaltered. A CV6 is metamorphosed. A CV is an aqueous meteorite alteration.

She showed us some actual meterorites which we handled only with surgical gloved hands so we wouldn’t damage them. One had a beautifully etched plaid pattern of crystallized iron; another was an achondrite containing basalt. One meteorite was from the Moon and another is a piece of Allende. She also showed us some “meteor-wrongs”, rocks which you might think were meteorites but they were not.

She had a large image of a meteorite that hit Morocco. The image was taken with an optical scope and showed many different, colorful minerals.

Another example she showed us is a type of meteorite called a pallasite, which contains greenish olivine. Olivene is found in the earth’s mantle.

The asteroid Vesta has a core, a mantle and a crust—and on the surface, a “Snowman” crater.

Most meteorites come from the asteroid belt.

A meteorite that hit Earth about 65 million years ago is responsible for killing off the earth’s large dinosaurs.

Meteorites deliver lots of organics and water to the earth.

Who does a meterorite belong to? That is a good question. Best practice is to report one when you find one and not keep it for yourself. The Smithsonian tends to be a keeper of meteorites.

Meteorites often have play-doh like bumps called regmaglypts. This is another distinguishing feature to look for if you are trying to figure out if a rock is a meteorite or not.

Have meteorites actually hit people? A lady was hit by a meteorite in her home. The couch where she was sitting is in the Smithsonian. Another one hit a dentist’s office at 5:15 in the afternoon. (Fortunately no one’s teeth were hurt!)

Another meteorite hit a car. There is a rumor that a meteorite from Mars killed a dog.