Across
- 3. The most abundant element in the Universe.
- 5. The spiral galaxy that contains our Solar System.
- 6. The collection of planets and other celestial bodies orbiting the Sun.
- 7. The remnant heat from the Big Bang, serving as evidence for the Universe's origin.
- 10. A region of space with a gravitational field so strong that nothing, not even light, can escape from it.
- 11. The process by which the Sun and other stars generate energy, fusing hydrogen into helium.
- 13. A phenomenon where light from distant galaxies shifts towards the red end of the spectrum, indicating that the Universe is expanding.
- 15. The theory that the Solar System formed from a cloud of gas and dust that collapsed under gravity.
- 16. A system of millions or billions of stars, along with gas and dust, bound together by gravity.
- 19. The prevailing theory for the origin of the Universe, suggesting it began expanding from a hot, dense state.
- 20. A massive, luminous sphere of plasma held together by gravity, producing energy through nuclear fusion.
Down
- 1. A stable star in the main part of its lifecycle, like the Sun.
- 2. All of space, time, matter, and energy.
- 4. Large planets like Jupiter and Saturn with thick atmospheres of hydrogen and helium.
- 8. The force that pulls particles and gases together, playing a key role in the formation of stars and planets.
- 9. Rocky planets, including Mercury, Venus, Earth, and Mars, that are smaller and closer to the Sun.
- 12. A massive explosion that occurs at the end of a massive star's life, ejecting its outer layers.
- 14. A cloud of gas and dust in space where stars are born.
- 17. The element produced by nuclear fusion in stars.
- 18. A natural satellite formed by a large object colliding with Earth, according to the leading theory of Moon formation.