Shop Windows to the Universe

Arches National Park Geology Tour provides an extensive, visually rich description of the geology of Arches, by Deborah Ragland, Ph.D. See our DVD collection.

Some Useful Definitions

There are a few terms which we use a lot when trying to understand the sky:

Latitude is a way of describing where you are on the Earth between the equator and the poles. If you're latitude is 45° North, then you are halfway between the equator (latitude = 0°) and the north pole (latitude=90°).

The horizon is the plane which defines the half of the sky that you can see.

Altitude is the angle between the object you are looking at and your horizon.

The ecliptic can refer to many slightly different ideas which all relate to the Earth's orbit. The plane in which the Earth goes around the Sun is called the ecliptic. The ecliptic is also an imaginary line in the sky along which the Sun appears to travel as the Earth goes around the Sun. The path of the ecliptic determines the zodiacal constellations; they are all constellations through which the Sun appears to move as the Earth goes around the Sun.

Shop Windows to the Universe Science Store!

The Fall 2009 issue of The Earth Scientist, which includes articles on student research into building design for earthquakes and a classroom lab on the composition of the Earth’s ancient atmosphere, is available in our online store.

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Cool It! Game

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

Native American Astronomy

People have been living in North America for a long, long time. The first people to live there were the Native Americans. They didn't have clocks or calendars so they watched tides, the Sun, the Moon,...more

Archeoastronomy

Man has always observed the sky. By watching the Sun and Moon, early man could tell what season was coming next. They had to know this to be able to farm and hunt. Archeoastronomy started in the 1960's...more

The Stones of Carnac

The stones of Carnac, France, are very famous because there are a lot of them and because they are so old! The oldest stones found in Carnac are from about 4,500 B.C. That's older than the stones at Stonehenge!...more

The Cairns of Clava

You may have heard of the lake called Loch Ness, where people think they've seen the Loch Ness monster. Near Loch Ness there are three giant stone tombs you may not have heard of...they are called the...more

Cuzco

Cuzco is a city in Peru. It was the capital of the ancient Inca Empire. In ancient times, Cuzco was the center of the Inca road network which was made up of about 40,000 kilometers (25,000 miles) of roads...more

The Stones of Fossa

The stone rings and tombs of England and France are very famous. But, there are also stone structures in Italy. There are some neat stones in Fossa, Italy. They are standing stones. These stones form circles...more

Kepler's 2nd Law: The Speeds of Planets

Kepler realized that the line connecting the planet and the Sun sweeps out equal area in equal time. Look at the diagram to the left. What Kepler found is that it takes the same amount of time for the...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