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The Spring 2011 issue of The Earth Scientist is focused on modernizing seismology education. Thanks to IRIS, you can download this issue for free as a pdf. Print copies are available in our online store.

The Orbit of Mars

This animation shows how Earth and Mars move around the Sun in their orbits.

Click the "Play Fast" button in the lower left corner to make the planets move. For every second that goes by, the planets will move ahead one week's worth of time.

(Note: If you cannot see the animation below, or it is not working properly, you may need to download the latest Flash player.)

The other buttons make the planets move faster or slower, move backwards, or stop. The date in this simulation is shown above the buttons.

The "telescope view" in the upper left corner shows how big Mars looks from Earth through a telescope at a given time. The view only shows the size of Mars as viewed from Earth. It does not show how Mars changes in other ways over time, such as Mars spinning on its axis or the changing seasons on Mars.

Beneath the "telescope view" is a readout of the distance between Earth and Mars. Each time Earth passes close to Mars the event is called an "opposition". Notice how the size of Mars as seen through the telescope is not the same at every opposition. The orbit of Mars is not a circle; it is more of an oval in shape. Because an opposition can happen when Mars is at different points in its orbit, the distance at opposition changes, and so does the size of Mars as viewed from Earth. During the opposition in August 2003, Earth and Mars were closer together than they had been in thousands of years!

The red dot is Mars. Earth is blue, and the Sun is yellow. The locations of the planets are shown to scale, but their sizes are not (the planets are actually much, much smaller than the Sun).

Last modified February 18, 2004 by Randy Russell.

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Our online store includes issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, ranging from seismology, rocks and minerals, oceanography, and Earth system science to astronomy!

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA