Across
- 3. when objects in the night sky seem to change position due to the Earth's rotation on its axis
- 5. the spinning of our planet on its axis
- 6. the period of time it takes for earth to make a complete rotation on its axis; 24 hours
- 8. the star at the center of the solar system around which Earth and other matter orbit
- 9. the daily disappearance of the Sun below the horizon in the west as a result of Earth's rotation
- 11. how much energy is coming from the star per square meter per second
- 13. the instant at which the upper edge of the sun appears above the horizon in the east
- 14. the energy needed to drive photosynthesis
- 16. the form of energy that makes it possible to see things
- 18. the elliptical orbit of the Earth around the sun
- 20. the measured value (always positive) from one point to another
- 21. a natural satellite that orbits a planet or smaller body
- 22. an area where sunlight cannot reach because it is blocked by an object
- 23. the portion of the electromagnetic spectrum that human eyes can detect
Down
- 1. the third planet from the sun
- 2. the Sun and the celestial objects bound to it by gravity
- 4. an obvious regularity in the natural world or in a manmade design
- 7. all the matter and energy, including Earth, the galaxies, and the contents of intergalactic space
- 8. a massive ball of plasma that shines because of thermonuclear fusion in its core
- 10. the intensity of light
- 12. the image obtained by plotting dots, bars or lines to show scientific data
- 13. occurs twice a year, when the Earth's axis is most oriented toward or away from the sun
- 14. one of four major divisions of the year based on the Earth's tilt and the light from the sun
- 15. an imaginary line around which Earth rotates
- 17. a pattern in the sky formed by stars
- 19. the period of darkness between sunset and sunrise