Across
- 2. A natural satellite that orbits a planet.
- 6. These are also known as "shooting stars'.
- 9. A ______ eclipse occurs when Earth passes exactly between the Moon and the Sun.
- 10. A piece of a meteoroid that hits the ground.
- 12. A ______ planet is an object that orbits the Sun and is big enough to be round, but doesn't clear the neighborhood of objects near its orbit.
- 13. A layer of gases that surround an object held in place by gravity.
- 15. This mission's destination was Jupiter, and it was sent to collect data on the magnetosphere of the planet and to study its moons (see Space Missions).
- 16. Part of the Mars ______ mission's goal was to investigate the structure of Mars' atmosphere, surface meteorology and geology, as well as the form, structure, and elemental composition of rocks and soil (see Space Missions).
- 17. A ______ eclipse occurs when the Moon passes exactly between Earth and the Sun.
- 18. ______ craters often have central peaks and ejecta thrown out in long rays.
- 19. The path and length of time it takes for one object to travel around another.
- 22. On these two days, Earth's axis is tilted neither away from nor toward the Sun.
- 23. Traveling around something is called ______.
- 26. Eratosthenes was the first to accurately estimate the ______ of the Earth.
- 28. To give off.
- 30. A ______ crater is the result of a large impact that releases magma from beneath the surface.
- 32. ______ lines are bright lines show the visible wavelength of emitted light.
- 36. Astronomers calculate that the ______ ______ happened about 13.73 billion years ago. (2 words)
- 37. The different shapes the Moon takes as it orbits the Earth.
- 38. A large, hot ball of gas, made up mostly of hydrogen and helium.
- 40. ______ lines are dark areas that show that the light at certain wavelengths is being absorbed, so it is not seen.
- 42. An enormous collection of tens of millions to hundreds of billions of stars, interstellar gas, and dust.
- 43. A chunk of ice, dust, and rock material a few kilometers in size.
- 44. One ______-year (ly) is the distance light travels in 1 year, at the speed of about 300,000 km/second.
Down
- 1. Colors with longer wavelengths have ______ energy.
- 3. A ______ occurs when either the North or South Pole are "leaning" toward the Sun.
- 4. The ______ Space Telescope's goals are to provide deep and clear views of the universe, from the solar system to extremely remote young galaxies (see Space Missions).
- 5. If a planet passes directly in front of its star, the event is called a ______.
- 7. Earth spins on an imaginary axle called an ______.
- 8. A small or medium-sized piece of rock or metal that orbits the Sun.
- 11. We can use a planet's orbital period and orbit ______ and the temperature of the star to calculate a planet's probable temperature.
- 13. We measure huge distances in the cosmos in ______ units (abbreviated AU).
- 14. A tool used to study the spectrum of colors coming from a light source.
- 15. A ______ Moon is nearly round on the side facing the Sun, with a bulge on the other side.
- 20. Halfway between the full Moon and the new Moon is the ______-quarter Moon.
- 21. A change in the land created by an impact.
- 24. A ______ is a cloud of gas and dust in space between stars.
- 25. This planet has a dense atmosphere of carbon dioxide, with many volcanoes on its surface.
- 27. Planets circling stars outside our solar system are called ______.
- 29. The ______ Belt is a region of the solar system beyond the orbit of Neptune made up of millions of small icy bodies.
- 30. Halfway between the new Moon and the full Moon is the ______-quarter Moon.
- 31. Colors with shorter wavelengths have ______ energy.
- 33. This planet is sometimes called "the Red Planet" because of its oxidized (rusty) soil.
- 34. This planet is the smallest of the gas giant planets, but is still the fourth largest planet in the solar system.
- 35. When the illuminated portion of the Moon grows larger from day to day, the Moon is ______.
- 39. When the illuminated portion of the Moon grows smaller from day to day, the Moon is ______.
- 41. Small bowl-shaped craters with a fairly uniform blanket of ejecta distributed around the rim are ______ craters.