Shop Windows to the Universe

With Explore the Planets, investigate the planets, their moons, and understand the processes that shape them. By G. Jeffrey Taylor, Ph.D. See our DVD collection.

Relativity - Simultaneity

This movie explains the concept of "simultaneity", which is part of Einstein's theory of relativity.
Image courtesy of Trent Schindler, National Science Foundation.

This movie explains an idea called "simultaneity". Simultaneity is an important part of Albert Einstein's theory of relativity. Imagine two people who are moving very, very fast relative to each other. Now imagine they see two flashes of lightning. The two people might disagree about when the lightning flashes happened. One person might say they happened at the same time. The other person might say that they happened at different times. According to Einstein, both people could be right!

(Note: If you cannot see the movie you may need to download the latest QuickTime player.)

Last modified May 29, 2008 by Randy Russell.

Shop Windows to the Universe Science Store!

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, as well as books on science education!

Windows to the Universe Community



You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Tools for Math and Science

Some ideas are used throughout the sciences. They are "tools" that can help us solve puzzles in different fields of science. These "tools" include units of measurement, mathematical formulas, and graphs....more

Starting Points for Science

Some ideas are used in many, many places throughout science. We have grouped these "starting points for science" into three clusters: space, time, and matter. "Space" is the word we use for everything...more

What is a Supercomputer?

Some scientific problems and processes are so complex that you need SUPERCOMPUTING power to tackle them! Just what is a supercomputer? A supercomputer is a computer that is among the largest, fastest or...more

Using Computers for Science

In the last decades, computers have become a normal part of life. They are used to send e-mail, write a school report or look up recipes. They are used to keep track of the balance in your bank account....more

Universal Time

When it is noon where you live, it is midnight on the opposite side of the world. Usually when we think of time, we mean "the time of day where I live". If we say something happened at 9 AM, we mean it...more

The Magnetic Field

The force of magnetism causes material to point along the direction the magnetic force points. As shown in the diagram to the left, the force of magnetism is illustrated by lines, which represent the force....more

Planetary Magnets

The Earth is a good example of a planetary dipole, where the lines of force point in a direction out of the South (magnetic) Pole and into the North (magnetic) Pole. Planets can also show evidence of quadrupoles...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF