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.

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

In order to study and explain space weather, scientists need to use some pretty complex math. So if you would like to study space weather when you grow up, keep plugging away in your math class! For example,...more

Starting Points for Science

There are some basic ideas that you find in many kinds of science. We have grouped these "starting points for science" into three areas: space, time, and matter. On one hand, "space" is the term we use...more

What is a Supercomputer?

Some science problems are so complicated that you need SUPERCOMPUTING power to tackle them! Just what is a supercomputer? A supercomputer is a computer that is one of the fastest or most powerful computers...more

Using Computers for Science

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 crunch the latest baseball stats and deliver phone calls to the right...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. Here's another picture of how this works. This picture shows where the magnetic poles of the Earth are to...more

Planetary Magnets

The Earth has a dipole magnetic field. This is when magnetic field lines point in a direction out of the South Pole and into the North Pole. Planets can also have quadrupoles (4 poles) and octupoles (8-poles)....more

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