EAR - Earth OVERVIEW

Earth

Introduction

 You all are coming along in your Astronaut Training Program. In this module, you will learn about characteristics of Earth as it relates to space. Knowing how Earth orbits and rotates is essential for astronomical observations and future space travel.

Essential Questions

  • What effect does the Earth's orbit and rotation have on climate?
  • How does Earth's orbit and rotation affect astronomical observations such as constellations and other planets?

Key Terms

A.M. - anti meridian; before the Sun is in a position directly overhead

Asterism - unofficial constellations

Celestial Sphere - an imaginary sphere with the Earth at its center on which the stars appear to be located

Constellation - one of 88 groups of stars that have been given a name and a design

Day - the time required for the Earth to complete one revolution around its axis

Declination - angular distance north or south from the equatorial plane of the Earth measured toward the poles

Diurnal Cycle - a rhythmic pattern based on a 24 hour period

Equinox - the two days when the Sun crosses the celestial plane; when day and night are about equal in length

P.M. - post meridian; after the Sun is in a position directly overhead

Prime Meridian - zero degrees of latitude, described as a line from the north pole to the south pole that passes through the Royal Observatory in Greenwich, England

Right Ascension - the celestial equivalent of longitude; the angular distance of a point celestial sphere, measured east

Sidereal Day - the time required for one complete rotation of the Earth in reference to a star, 23 hours, 56 minutes, and 4.09 seconds

Solstice - one of two times of the year when the Sun is at its greatest distance from the celestial equator

Time Zone - any of 24 longitudinal divisions of the Earth in which a standard time is kept

Year - the time required for the earth to complete one revolution around the Sun

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