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Find government information on education including primary, secondary, and higher education.

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Educational Games, Worksheets, and More for Kids

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An Educational platform for parents and teachers of pre-k through 7th grade kids. Support your kids learning journey with games, worksheets and more that help children practice key skills. Download, print & watch your kids learn today!

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Ever wonder what you might weigh on Mars or The Moon? Here's your chance to find out.

This Page requires a Javascript capable browser

TO DO & NOTICE:

Fill in your weight below in the space indicated. You can enter your weight in any unit you wish.

Click on the "Calculate" button.

Notice that the weights on other worlds will automatically fill in. Notice that your weight is different on the different worlds.

You can click on the images of the planets to get more information about them from Bill Arnett's incredible Nine Planets web site.

WHAT'S GOING ON?

Mass and Weight

Before we get into the subject of gravity and how it acts, it's important to understand the difference between weight and mass.

We often use the terms "mass" and "weight" interchangeably in our daily speech, but to an astronomer or a physicist they are completely different things. The mass of a body is a measure of how much matter it contains. An object with mass has a quality called inertia. If you shake an object like a stone in your hand, you would notice that it takes a push to get it moving, and another push to stop it again. If the stone is at rest, it wants to remain at rest. Once you've got it moving, it wants to stay moving. This quality or "sluggishness" of matter is its inertia. Mass is a measure of how much inertia an object displays.

Weight is an entirely different thing. Every object in the universe with mass attracts every other object with mass. The amount of attraction depends on the size of the masses and how far apart they are. For everyday-sized objects, this gravitational pull is vanishingly small, but the pull between a very large object, like the Earth, and another object, like you, can be easily measured. How? All you have to do is stand on a scale! Scales measure the force of attraction between you and the Earth. This force of attraction between you and the Earth (or any other planet) is called your weight.

If you are in a spaceship far between the stars and you put a scale underneath you, the scale would read zero. Your weight is zero. You are weightless. There is an anvil floating next to you. It's also weightless. Are you or the anvil mass-less? Absolutely not. If you grabbed the anvil and tried to shake it, you would have to push it to get it going and pull it to get it to stop. It still has inertia, and hence mass, yet it has no weight. See the difference?

The Relationship Between Gravity and Mass and Distance

As stated above, your weight is a measure of the pull of gravity between you and the body you are standing on. This force of gravity depends on a few things. First, it depends on your mass and the mass of the planet you are standing on. If you double your mass, gravity pulls on you twice as hard. If the planet you are standing on is twice as massive, gravity also pulls on you twice as hard. On the other hand, the farther you are from the center of the planet, the weaker the pull between the planet and your body. The force gets weaker quite rapidly. If you double your distance from the planet, the force is one-fourth. If you triple your separation, the force drops to one-ninth. Ten times the distance, one-hundredth the force. See the pattern? The force drops off with the square of the distance. If we put this into an equation it would look like this:

The two "M's" on top are your mass and the planet's mass. The "r" below is the distance from the center of the planet. The masses are in the numerator because the force gets bigger if they get bigger. The distance is in the denominator because the force gets smaller when the distance gets bigger. Note that the force never becomes zero no matter how far you travel. Perhaps this was the inspiration for the poem by Francis Thompson:

All things
by immortal power
near or far
to each other
hiddenly linked are.
That thou cans't not stir a flower
without troubling a star.

Isaac Newton

This equation, first derived by Sir Isaac Newton, tells us a lot. For instance, you may suspect that because Jupiter is 318 times as massive as the Earth, you should weigh 318 times what you weigh at home. This would be true if Jupiter was the same size as the Earth. But, Jupiter is 11 times the radius of the Earth, so you are 11 times further from the center. This reduces the pull by a factor of 11 ² resulting in about 2.53 times the pull of Earth on you. Standing on a neutron star makes you unimaginably weighty. Not only is the star very massive to start with (about the same as the Sun), but it is also incredibly small (about the size of San Francisco), so you are very close to the center and r is a very small number. Small numbers in the denominator of a fraction lead to very large results!

LINKS

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Your Weight on Other Worlds | Exploratorium

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Ever wonder what you might weigh on Mars or The Moon? Here's your chance to find out. This Page requires a Javascript capable browser Fill in your weight below in the space indicated. You can enter your weight in any unit you wish. Click on the "Calculate" button.

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Explore the Earth and space sciences and related arts and humanities connections with Windows to the Universe! Earth, planets, moons, the Sun, and the stars. Astronomy, Mythology, images, video, interactives, teacher resources, and classroom activities. Spanish and English, differentiated learning.

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This is a collection of many of the best images from NASA's planetary exploration program. The collection has been extracted from the interactive program "Welcome to the Planets" which was distributed on the Planetary Data System Educational CD-ROM Version 1.5 in December 1995. It has also been updated with the addition of more recent images.

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What Exists Within the Reaches of Our Solar System?

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Learn more about the celestial bodies that exist within our solar system.

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Free elementary, middle and high school teacher resources, including puzzlemaker, student games and activities and lesson plans.

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StarChild: A Learning Center for Young Astronomers

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This site is intended for students in grades K through 8.

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Sky at a Glance | Recent Astronomy News & Night Sky Events

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See this week's sky at a glance with observing tips and maps to guide you to the night sky. Don't miss out on comets, meteors, eclipses, and more!

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national oceanic and atmospheric administration

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This arcade is a portal to games and interactive activities focused on ocean and air themes. It highlights the science and the activities of the National Ocean and Atmospheric Administration (NOAA) and other agencies and organizations promoting environmental stewardship.

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"Our loyalties are to the species and the planet. We speak for Earth. Our obligation to survive is owed not just to ourselves but also to that Cosmos, ancient and vast, from which we spring."

- Carl Sagan, Astronomer

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The Sky - Discover Space Exploration and Astronomy on Sea and Sky

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"Our loyalties are to the species and the planet. We speak for Earth. Our obligation to survive is owed not just to ourselves but also to that Cosmos, ancient and vast, from which we spring." - Carl Sagan, Astronomer

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A live look at humanity's attempts to understand and experience the cosmos. Find space articles from Popular Science.

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NASA.gov brings you the latest images, videos and news from America's space agency. Get the latest updates on NASA missions, watch NASA TV live, and learn about our quest to reveal the unknown and benefit all humankind.

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Earth from Space provides several ways to search the selected images. Each image is available in three resolutions and includes cataloging data and a caption. However, this site contains only a small selection of the best of our Earth photography. The complete database of NASA's Earth imagery is available at the Gateway to Astronaut Photography of Earth.

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Welcome to Earth and Moon Viewer and Solar System Explorer.

Viewing the Earth

You can view either a map of the Earth showing the day and night regions at this moment, or view the Earth from the Sun, the Moon, the night side of the Earth, above any location on the planet specified by latitude, longitude and altitude, from a satellite in Earth orbit, or above various cities around the globe.

Images can be generated based on a full-colour image of the Earth by day and night, a topographical map of the Earth, up-to-date weather satellite imagery, or a composite image of cloud cover superimposed on a map of the Earth, a colour composite which shows clouds, land and sea temperatures, and ice, or the global distribution of water vapour. Expert mode allows you additional control over the generation of the image. You can compose a custom request with frequently-used parameters and save it as a bookmark item in your browser. Please consult the for additional information and answers to frequently-asked questions.

Viewing the Moon

In addition to the Earth, you can also view the Moon from the Earth, Sun, night side, above named formations on the lunar surface. or as a map showing day and night. You can also make expert and custom images of the Moon. A related document compares the appearance of the Moon at perigee and apogee, including an interactive Perigee and Apogee Calculator.

Viewing Solar System Bodies

You can view a variety of solar system objects whose surfaces have been imaged by spacecraft. For some objects, a variety of imagery is available and can be selected from the control panel. Day and night are not shown for solar system bodies because the ability to calculate the Sun's apparent position from them is not implemented.

You can view Mercury; Venus; Mars and its moons Phobos and Deimos; the asteroids Ceres and Vesta; and Pluto and its moon Charon.

You can view named features on any of the bodies named above.

The Earth and Moon Viewer would have been enormously more difficult to implement without the help of the software and imagery mentioned in the credits.

Related Software on this Site

Windows users can create images like this in real time, on their own machines, as well as view the sky, stars at the horizon, the solar system, orbits of asteroids and comets, and more with Home Planet, my public domain Earth/Space/Sky simulator available for your downloading pleasure. Other public domain astronomy and space software available from the same site includes:

On the Web:

Eclipse 2010 - Aku Aku Eclipse,Eclipse 2008 - Nuclear Ninety North,Eclipse 2001 - In Darkness: Africa, andEclipse 1999 - Expedition to Iran.

Moon at Perigee and Apogee.

Solar System Live: interactive orrery.

Switzerland from Space.

Terranova: a new terraformed planet every day.

makes custom star maps for any location on Earth at any date and time.

For Windows:

Home Planet,Earth screen saver,Sky screen saver,Moontool, andCraters screen saver.

All of these packages and more can be located from my home page.

by John Walker

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Welcome to Earth and Moon Viewer and Solar System Explorer. You can view either a map of the Earth showing the day and night regions at this moment, or view the Earth from the Sun, the Moon, the night side of the Earth, above any location on the planet specified by latitude, longitude and altitude, from a satellite in Earth orbit, or above various cities around the globe.

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Free elementary, middle and high school teacher resources, including puzzlemaker, student games and activities and lesson plans.

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A landing page for the decommissioned and retired Amazing Space website (amazingspace.org) where you can find select Amazing Space resources.