Across
- 3. The path an object takes around another, often used to describe the path of planets around the Sun.
- 4. The average distance from the Earth to the Sun, approximately 93 million miles (150 million kilometers).
- 8. A region of spacetime exhibiting gravitational acceleration so strong that nothing—no particles or even electromagnetic radiation—can escape from it.
- 9. A Danish astronomer known for his accurate and comprehensive astronomical observations.
- 10. The increase in the illuminated part of the Moon or a planet.
- 11. A celestial object consisting of a nucleus of ice and dust that develops a bright, fuzzy tail when near the Sun.
- 15. A space telescope launched into low Earth orbit, providing clear images of distant galaxies and nebulae.
- 20. A small rocky body that orbits the Sun, typically found in the asteroid belt between Mars and Jupiter.
- 21. A meteoroid that survives its journey through Earth's atmosphere and lands on the Earth's surface.
- 22. An explosive event that occurs during the death throes of a massive star.
- 23. A hypothetical region of space containing a large number of comets, located far beyond the orbit of Pluto.
- 25. The prevailing cosmological model that explains the origin of the universe.
- 31. Pertaining to the sky or the heavens.
- 32. The change in frequency or wavelength of a wave in relation to an observer moving relative to the source of the wave.
- 33. The distance that light travels in one year, approximately 5.88 trillion miles (9.46 trillion kilometers).
- 34. A small rock or particle in space.
- 36. A planet that orbits a star outside our solar system.
- 37. When the Earth passes between the Sun and the Moon, causing the Earth's shadow to fall on the Moon.
- 41. A meteoroid that enters the Earth's atmosphere and burns up due to friction with the air, also known as a shooting star.
- 42. Three laws that describe the motion of planets around the Sun.
- 44. A vast system of stars, gas, and dust bound together by gravity.
- 45. The Moon phase where the entire face is visible from Earth.
- 46. A celestial body that orbits the Sun, is spherical in shape, and has cleared its orbit of other debris.
- 47. More than half but less than fully illuminated Moon or planet.
Down
- 1. A system comprising the Sun and the celestial bodies that orbit it, including planets, moons, and asteroids.
- 2. Rocky planets, including Mercury, Venus, Earth, and Mars.
- 5. The force that attracts objects with mass towards each other.
- 6. Having the Sun at the center, as in the heliocentric model of the solar system.
- 7. A hypothetical form of matter that is believed to make up approximately 85% of the matter in the universe.
- 10. A small, dense remnant of a star that has exhausted the nuclear fuel in its core.
- 12. A large, cool star in the later stages of its life cycle.
- 13. The Moon phase where the side facing Earth is not visible.
- 14. The different appearances of the Moon or a planet as seen from Earth during its orbit.
- 16. An optical instrument that gathers and magnifies light to observe distant objects.
- 17. A cloud of gas and dust in space, often the birthplace of stars.
- 18. Less than half illuminated Moon or planet.
- 19. The decrease in the illuminated part of the Moon or a planet.
- 24. When the Moon passes between the Earth and the Sun, blocking all or part of the Sun's light.
- 26. The process by which two atomic nuclei combine to form a heavier nucleus, releasing energy.
- 27. A group of stars forming a recognizable pattern in the sky.
- 28. The obscuring of one celestial body by another, such as a solar or lunar eclipse.
- 29. Planets composed mostly of gas, including Jupiter and Saturn.
- 30. The scientific study of celestial objects such as stars, planets, and galaxies.
- 35. The apparent shift in the position of an object when viewed from different angles.
- 38. A luminous celestial object consisting of a mass of gas that generates light and heat through nuclear reactions.
- 39. Having the Earth at the center, as in the geocentric model of the solar system.
- 40. A Renaissance mathematician and astronomer who formulated a model of the universe that placed the Sun rather than the Earth at the center.
- 43. An American astronomer who played a crucial role in the development of the Big Bang Theory and the concept of an expanding universe.