Category: How Big Is the Universe?

Let’s take a little trip from Earth to the outer reaches of our Universe. We are going to looking back at the Earth all the time so we’ll be traveling backwards. Don’t worry—I’ll make sure we don’t run into anything! DIGITAL EFFECT: Powers of 10 Style If possible on your system, run a “Powers of […]

Optional ControlsDuring the tour, some separate optional digital effects may be useful to give a frame of reference to the audience. Note also that at each stop in the tour, the presenter is encouraged to orbit manually to bring up the best view for the audience. The tour should be set up only to move […]

This program is about how big our Universe is.Before tackling something that big, let’s look at a few things that are a bit smaller and see if we can guess what they are and how big they are. DIGITAL EFFECT: Go to NightFast forward time until about 90 minutes past sunset. For each of images […]

But the Universe is still larger than just our own galaxy. Our Milky Way is but one of many millions of galaxies. Here are some of the many beautiful shapes that galaxies come in. Remember that each of these galaxies is made of many billions of stars and the size of each galaxy is many […]

Measuring distances by parallax depends on noting how the position an object seems to change when you change your point of view.  Hand out mini-stars.  Pretend that the little ball you are holding is star. Notice it is shaped like a ball—it doesn’t have points on it! Like our sun, stars are ball-shaped and they […]

BackgroundAbsolute magnitude is the intrinsic brightness of a star rather than its observed brightness from Earth. The absolute magnitude of a star is the magnitude it would appear from a standard distance of 10 parsecs (32.5 light-years). What’s a parsec? It’s a unit of distance based on parallax measurements: a parsec is the distance at which […]

For really faraway stars, yet another clever distance finding method had to be found. The next trick to determine star distances was to compare their brightnesses. If you observe two stars that put out the same amount of light and are equal distances away from you, the two stars appear to have the same brightness. […]

Radar is used on spacecraft to map the surfaces of other planets. Superb maps of the planet Venus were made with the Magellan spacecraft using radar waves which could penetrate through the dense clouds that completely obscure the surface of Venus.  Radar mapping works by measuring the distance of the spacecraft to the planet’s surface. […]

For relatively nearby things, like airplanes, we can use radar waves to measure how far away they are. Radar waves are invisible waves that are created and detected by electronic equipment. They are like the radio waves that your radio or TV at home can receive. You cannot hear radio waves directly; but a radio […]