week 8 - planetarium & meteorites

Tuesday we had a tour of the meteorite gallery and learned that meteorites are extraterrestrial rocks that travel through interplanetary space. Described to traverse the atmosphere and land on the surface of the earth. Meteorites that are observed to fall are called "falls" during the atmospheric passage, they create bright fireballs and generally sonic booms. There are about 1300 observed falls in the world's collection. There are more than 60,000 finds, and the vast majority of meteorites come from asteroids; more than 400 come from the Moon or Mars. 

Furthermore, there are different types of meteorites including primitive meteorites consisting of materials that are formed in the solar nebula, known as chondrites or "primitive" meteorites. Many were heated on their parent asteroids, but the asteroids themselves did not undergo large-scale meltings. There are 11 major chondrite groups; each group contains distinctive abundances of chondrules and fine-grained matrix material. Some are related and have formed in adjacent regions in the nebula. The ordinary chondrites comprise of three groups (H, L, LL); R chondrites comprise one; carbonaceous chondrites comprise five (Cl, CM, CO, CR, CV-CK); and enstatite chondrites comprise two (EH, EL). 

Some regions of individual asteroids get hot enough to melt. The heat may have come from the decay of short-lived radioactive isotopes and/or the collisions of large bodies. When a chondrite asteroid melts, two immiscible liquids form - a dense metallic liquid that sinks to the center and a silicate-rich liquid that rises. The metallic melt crystallizes to form a core; the silicate melt crystallizes to form the mantle and crust called the "differentiated."

Achondrites resemble terrestrial volcanic rocks and formed as flows at or near the astroid surface or solidified in shallow magma chambers.

Parasites contain angular or rounded grains of the magnesian-silicate mineral olivine surrounded by metal. They are formed at the core-mantle boundary.

Mesosiderites typically consist of a small mix of dark basalt and bright metal particles with some larger dark, angular rock fragments.

Irons are metallic objects composed of an alloy of iron and nickel; they have a silvery color, are highly magnetic and very dense. Most come from the cores of melted and differentiated asteroids. 

Their texture are typically irregular in shape with rounded edges, but they are never spherical. Most weight between half a kilogram and a few kilograms. Typically 10-40cm in length. Many meteorites have dimples or "thumb prints" on their surfaces.

We also visited a planetarium where guest speaker Santiago Torres shared how the stars looked like without any light pollution. I found it fascinating how beautiful the stars were and the science behind them. Red stars compared to blue stars are a lot older, where one is able to tell their age by the color. 

Finally, my group have been working on finalizing our project. I plan to create the poster venn diagram and bake the bread Saturday so we are able to photograph the ingredients by Sunday. We decided to go with the font Sagona and for an "elevated science poster" that is modern, elegant, and clean, compared to the typical science poster/textbook diagram. To achieve this, I will be experimenting with brighter fun colors like pink, yellow, and blue.