Video Podcasts: The Incredible Two-Inch Universe

Going Further

You can use this 4-STEP SCALE MODEL to imagine some of the distances involved in NASA's explorations of the universe.

The Realm of the Earth and Moon:
NASA's three Great Observatories view the universe from their orbits near Earth: The Hubble Telescope orbits 550 km up from the Earth's surface. (2 mm at this scale) The Chandra X-ray Observatory orbits Earth as far as 1/3 the distance to the Moon. The Spitzer Infrared Telescope slowly drifts away from the Earth as it follows Earth's orbit around the Sun.

The Realm of our Sun:
At this scale, the farthest distance humans have traveled is from the salt-grain Earth to the dust-speck Moon half an inch away. NASA is working to send astronauts to Mars, another 30 feet (10 meters) away at this scale.

The Realm of our Solar System:
What is the farthest distance a NASA spacecraft has traveled? Voyager I, launched in 1977, is now just beyond the Solar System, more than twice the distance to Pluto.

The Realm of Galaxies:
The most distant light captured by a NASA satellite has traveled through space for so long-more than 13 billion years-that it shows us a picture of the universe before there were any galaxies. The blotchy blue, green, and yellow colorized image from NASA's WMAP probe shows us what the glowing universe looked like shortly after the Big Bang.