Latest Mission News and Object of Interest
— How Many Supernovae Are There in the Milky Way?
It is a typical galaxy and our home: the Milky Way. How many supernovae have occurred here since it was formed?
Recent evidence collected by Suzaku suggests that several hundred million of the Type II variety of supernovae have occurred in the Milky Way. This startling result was published by a team of Japanese scientists led by Dr. Kosuke Sato of the Tokyo University of Science.
The team studied the AWM7 cluster, an area rich in galaxies, similar to our local group. (See Newsletter Volume 1 — Number 6 for more on AWM7 at http://suzaku-epo.gsfc.nasa.gov/docs/suzaku-epo/newsletter/25sep06.html ).
Type II supernovae occur when stars that are massive enough to become neutron stars -- or even black holes -- end their lives with a big explosion, giving off significant amounts of oxygen. Type Ia supernovae, on the other hand, are the endpoints of a particular type of binary system. These systems have a white dwarf, which is the nuclear "ash" of a star like our Sun, and another star. If the white dwarf pulls enough matter from the binary companion, the temperature and pressure become so high that the carbon and oxygen (the "ash") ignite and explode. This spews newly created elements, mainly iron, throughout the nearby region.
Knowing the amount of oxygen vs. iron present in a supernova, we can use data from galaxies like ours to determine an average frequency for each of these two types. More oxygen indicates more Type IIs; more iron indicates more Type Ia's.
This graph shows the total elemental mass of each of five heavy elements that are products of supernovae. In a cluster, knowing the relative amounts of each element produced by the two types (see graph) allows the number of these events to be determined. Note: This graph uses a log scale so that, for example, there are ~5.5 x 109 solar masses of iron from Type Ia's and ~2.5 x 109 solar masses of iron from Type IIs in AWM7.
From these studies, scientists estimate 2.8 x 1010 of the Type II supernovae in AWM7, about 3 times more than Type Ia's. Because our local group is similar to the AWM7 cluster, the team concluded that several hundred million Type II supernovae have most likely occurred in the Milky Way.
You can see the original press release at http://www.rs.kagu.tus.ac.jp/~ksato/gingadan-e.html. Image credit: Dr. Kosuke Sato, Tokyo University of Science
Resources for All
— Review of What We Have For You
It is easy to forget or overlook resources that lead to an "aha" moment of understanding for a student. At the Suzaku Learning Center website we provide many ways for you to deliver high quality educational experiences.
"Building the Coolest X-ray Satellite" is a Telly Award winning video that presents several dimensions of the Suzaku mission. It details what is being studied, how it is studied, the cultural aspects of collaboration between Japanese and Americans, how an instrument was built, and the challenges overcome to see it through launch. The video has an accompanying teacher's guide with explanations and lesson plans for various levels of students.
Also available is a selection of PDFs, short videos, and animations that allow you to present exciting concepts about the extreme universe. These visual and audio aids can find a place in your classroom if you teach astronomy, physics, or possibly even chemistry.
Stop by and test drive these and other resources, such as lesson plans and our newsletter archive, on the Suzaku Learning Center Education page (http://suzaku-epo.gsfc.nasa.gov/docs/suzaku-epo/education/education.html).
Modern Applications and A Brief History of X-Rays
— Making X-Rays Crystal Clear
X-rays are used in everything from theoretical physics to forensics, often to help us "see" the invisible, to detect what we normally could not.
One tool we can use is X-ray crystallography. If we wanted to find the shape of something we could not see, we may try bouncing things, like balls or rocks, off of it and noting the pattern formed. This is the basic, though much simplified, idea behind X-ray crystallography. The technique uses a beam of X-rays to determine the arrangement of atoms in a sample, based on the way the crystal's electrons scatter the beam. The method produces a three-dimensional map of the density of electrons within the crystal.
X-ray crystallography works for crystalline structures such as salts, metals, minerals, and semiconductors, as well as various inorganic, organic, and biological molecules. Max von Laue's (left) research lead to his Nobel Prize award in 1914 for the discovery of the diffraction of X-rays by crystals. (See the Nobel Prize website at http://nobelprize.org/nobel_prizes/physics/laureates/1914/laue-bio.html.)
In the photo on the right, NASA astronaut Bonnie Dunbar looks on at the University of Alabama at Birmingham X-ray Crystallography Facility. Engineer Lance Weise shows her the X-ray generator, a lightweight, compact device about the size of a suitcase, which will allow scientists to analyze crystals in orbit for the first time. It can be used to identify and determine the purity of substances. Previous X-ray crystallography equipment was about the size of an automobile, but this facility will fit in a single Space Station "wall" rack about the size of a household refrigerator.
This Tulane University site (http://www.tulane.edu/~sanelson/eens211/x-ray.htm) on the topic may be useful to you.
Trivia Question:
Von Laue worked at the University of Berlin for another Nobel Prize winner. Name the other Laureate and the year in which he was awarded his Nobel Prize.
The first person to answer correctly… will win educational materials from the Imagine the Universe! team.
From the last edition:
Last year the movie "The Prestige" was released, starring Hugh Jackman and Christian Bale. In the movie, a famous scientist was sought out and hired to create a machine that performed a real magic trick. In reality, this scientist did some early work on the production of X-rays. Name the scientist, the trick, and the former rock music star who portrayed him.
Answer: Rock star David Bowie portrayed Nikola Tesla, who, in the movie, was sought out to build a teleportation device.
Congratulations to the winner of the previous trivia question: B. Zhang
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