Programs for Astronomy 12: The Unseen Universe
The first program displays satellites in orbit about planets in our solar system. You can click on one of the menus to display the moons either in high-resolution (a close view) or low-resolution (a more distant view), for all the planets which have moons. The text window displays the data on where the orbit began, and the names of all the satellites. If you click on a Moon, the name, time, and position will be displayed. You can stop the simulation to make it easier to select a particular moon.
The next program contains data and a simulation of binary star orbits. Now instead of moons orbiting a much larger planet, you will see two nearly-equal mass stars orbiting their mutual center. Here again, you select a star system from the menu, and the data are displayed in the window to the right side. All are real star systems, observed by the Hipparcos satellite. You will see two "privileged" points of view: one where the system is face-on to you, so you see the full orbit, and one where the system is edge-on to you, so the stars appear to travel back and forth in a line. In the first view, you'll see not only the data for your star, but also a spectrum which identifies the type of star. In the second view you see the same spectrum, but also a "high-resolution" spectrum which displays a real-time doppler effect as the orbit progresses.
Finally, after you have become experts on orbits, you'll explore two protoplanetary disks, where there is a full distribution of matter, not just points in orbits. In these programs, you can click on the image, and positions and doppler velocities are displayed in the box.
Programs for Astronomy 25, "The Dark Matter Mystery"This program displays hypothetical (simulated) planets in orbit about nearby stars. You can click on one of the menus to view an animation of the planets in orbit, either in high-resolution (a close view) or low-resolution (a more distant view). The text window displays the data on where the orbit began, the distance to the system, and the luminosity of the star. Positions are given in arcseconds, with the distance in parsec, and luminosity in solar units. If you click on a planet, the name, time, and position will be displayed; in the windows below and to the right, broadband (blackbody) and narrowband spectra are displayed. You can stop the simulation to make it easier to select a particular planet.
With the experience gained in from working with planets around stars, we then: then/endif not found. then turn to images (negative photographs) and doppler velocities from spiral galaxies. If you click with the mouse on a position in the galaxy image, the projected coordinates (in kiloparsec) will be displayed in the box to the right. Please note, however, that these coordinates are not truly meaningful for positions that do not include some part of the galaxy. If you select one of the magenta squares, then a doppler velocity is also displayed.
Other Software for Astronomy
This program illustrates Orbits, the Doppler Effect, and the Rotation Curves of Galaxies.
- Orbits: (On a Windows PC this software requires the installation of Java 2 SDK 1.3 or later. On a Mac this version of Java requires Mac OS X, where it is preinstalled.)
The following two simulations were developed by Amherst College students in the summer of 2002 under the auspices of a grant from the Mellon Foundation.