NASA Office of Space Science Education and Public Outreach Conference 2002 ASP Conference Series, Vol. 319, 2004 Narasimhan, Beck-Winchatz, Hawkins & Runyon
Using Sloan Digital Sky Survey Data in the Classroom Robert Sparks and Chris Stoughton Fermi National Accelerator Laboratory, Wilson and Kirk Road, MS #127, Batavia, IL 60510,
[email protected] M. Jordan Raddick Department of Physics and Astronomy, The Johns Hopkins University, 10513 Demilo Pl. #301, Orlando, FL 32836 Abstract. The Sloan Digital Sky Survey (SDSS) will map 25% of the night sky down to 23rd magnitude, cataloging more than 100 million objects and taking spectra of over 1 million objects. All data from the SDSS will be publicly available on the Internet. These data include exact positions of stars, galaxies and quasars in the sky; magnitudes in five wavelengths; and spectra. From these data, astronomers will create a detailed map of the universe. With this map, they will better understand the universe’s large-scale structure, yielding information on its evolution and ultimate fate. SDSS data will give students a unique opportunity to conduct astronomical research using the same data that professional astronomers use. Students will create Hubble Diagrams to illustrate the expansion of the universe, and will create Hertzsprung-Russell diagrams, which will allow them to find the ages of and distances to stars and star clusters. Because these activities use real data, students will be led through some the difficulties that professional astronomers experience in analyzing data. All SDSS data will be available on the SkyServer web site, http://skyserver.sdss.org. The vast amount of data – 13 million objects so far – can be browsed and searched using a variety of tools. The data range from tri-color images and processed spectra to raw image files to magnitude data in 5 different wavelengths. Student lessons available on the SkyServer web site range from the elementary to the introductory college level. Each lesson is designed to meet national standards for science education. Each lesson also has an extensive section of teacher notes available, providing appropriate background information and ideas for student evaluation.
Introduction SkyServer is the education and outreach web site of the Sloan Digital Sky Survey (SDSS). The SDSS’s early data release contains images of approximately 13 million objects and spectra of over 50,000 objects. All data in the early data 394
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release are available online to astronomers. SkyServer makes exactly the same data available to students and to the general public. Student Projects Using SDSS Data SkyServer features a variety of projects suitable for students from elementary school through the college introductory level. All projects use SDSS data extensively, and all come with teacher’s notes that contain sample solutions and correlations to national education standards. Old Time Astronomy Old Time Astronomy (http://skyserver.sdss.org/en/proj/kids/oldtime/) is designed for younger students. The project teaches them about the history of astronomy, and about the importance of careful scientific observation. Until photographic plates were developed, the only way for astronomers to record what they saw through their telescopes was to make a sketch. Instead of looking through telescopes, students will practice sketching using images from SkyServer. After getting some advice from an amateur astronomer on how to sketch astronomical objects, the students make their own sketches and compare them to sketches made by other students. Students then try to identify which objects their partners sketched. From these exercises, students will gain an appreciation of how difficult astronomical research was before modern photography. They also will learn the importance of making good observations and recording them carefully. The Hubble Diagram In 1929, Edwin Hubble measured the distances to numerous galaxies, then used redshift measurements made by Vesto Slipher to create his famous “Hubble Diagram,” which suggested that the universe was expanding. In SkyServer’s Hubble Diagram project (http://skyserver.pha.jhu.edu/en/proj/advanced/hubble/), students use SDSS data to create their own version of this famous diagram, and to see the expansion of the universe. The SDSS will measure the spectra of hundreds of thousands of galaxies. All spectra in the SkyServer database have their important emission and absorption lines clearly marked. Students use these spectral lines to find redshifts of the galaxies. Finding accurate distances to galaxies has always been a challenge to astronomers. In the Hubble Diagram project, students estimate the distances to galaxies by analyzing galaxy clusters. Once they have estimated relative distances to several galaxies, they plot galaxies’ distances against their redshifts. Students will see an overall linear relationship, but they may also see some noise in the plot due to difficulties in estimating the distances to galaxies. Hertzsprung-Russell Diagram The Hertzsprung-Russell (or H-R) diagram is one of the fundamental tools for teaching stellar evolution. Making a plot of luminosity vs. temperature divides
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stars into several distinct groups, including main sequence stars, red giants, white dwarfs, and several types of variable stars. In SkyServer’s H-R diagram project (http://skyserver.pha.jhu.edu/en/proj/advanced/hr/), students make H-R diagrams using data from a variety of sources, including parallax data from the Hipparcos satellite. Hipparcos data only is available for relatively nearby stars. Students can make H-R diagrams for distant globular clusters using SDSS data. Using a simple search tool, students collect data for hundreds of stars in the globular cluster Palomar 5 and use this data to create an H-R diagram. Other Projects Using SDSS Data These three projects are just a sample of how SDSS data can be used in the classroom. Other projects include Spectral Types of Stars, Colors of Stars, Asteroid Searches, Quasars, Image Processing, and the Constellation Game. New projects are being created and will be added later this year.
