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