Exoplanets and Space W4

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Across
  1. 2. The habitable zone is the region orbiting a star where there is liquid ________
  2. 5. The process where the cores of atoms are squeezed together under immense heat and pressure to form a heavier atom, releasing a massive amount of energy. This process powers stars.
  3. 7. Clues or signals that would indicate the presence of advanced alien technology or civilization, rather than simple biology. Examples include artificial radio signals or industrial atmospheric pollutants.
  4. 9. A region in space where the pull of gravity is so strong that nothing, not even light, can escape from it. They usually form after a very massive star collapses.
  5. 10. A change in the observed frequency of a wave (like light or sound) caused by the motion of the source. In space, this tells us if stars are moving toward or away from us.
  6. 12. A unit of measurement equal to the average distance between Earth and the Sun (about 150 million kilometers). It is used to measure distances within a star system.
  7. 14. The leading scientific theory about how the Universe began. It suggests the Universe started as a very hot, dense point and has been expanding and cooling ever since.
  8. 15. An advanced method of analyzing starlight that filters through a planet's atmosphere during a transit to identify the chemicals present, such as water or carbon dioxide.
  9. 17. A vast cloud of gas and dust in space. Some nebulae are "stellar nurseries" where new stars are being born; others are formed by exploding stars.
  10. 18. When a smaller object (like a planet) passes directly in front of a larger object (like its star). NASA uses the "Transit Method" to detect exoplanets.
Down
  1. 1. A late stage in a star's life when it has run out of hydrogen fuel in its core, expanded greatly, and cooled down, causing it to appear red. Our Sun will become a Red Giant in billions of years.
  2. 3. The effect and danger on the human circulatory system in deep space
  3. 4. Often called the "Goldilocks Zone," it is the orbital region around a star where temperatures are "just right" for liquid water to exist on a rocky planet's surface.
  4. 6. Any planet that orbits a star located outside of our Solar System. The name is short for "extrasolar planet."
  5. 8. The sun and deep space all full of this dangerous electromagnetic radiation
  6. 11. A system that includes a central star (like our Sun) and everything that orbits it, including planets, moons, and asteroids.
  7. 13. The natural force that pulls anything with mass or energy toward each other. It keeps planets in orbit around stars and moons in orbit around planets.
  8. 14. Chemical clues or atmospheric gases (like oxygen or methane found together) that strongly point toward the presence of active biological life rather than natural geologic processes.
  9. 16. A group of galaxies pulled together by gravity