last quarter earth in space

  •  To survive and reproduce, four key resources required  for animals✅

    • Food 

    • Shelter

    • Resources to help reproduction

    • Water

  • For plants: ✅

    • Water

    • Gas from the air

    • Light

    • Shelter

    • A source of mineral salts

    • Warmth

    • Resources to help reproduction

  • Three examples of invasive species✅

    • Brown Tree Snake: Invasive in Guam, likely arrived accidentally. Eats native birds and lizards due to lack of predators, harming Guam's ecosystem.

    • Kudzu Vine: Invasive in southeastern US, introduced for decoration and erosion control. Grows uncontrollably, smothering native plants and trees.

    • Zebra Mussel: Invasive in North American Great Lakes, likely arrived in ship ballast water. Disrupts food chain by filtering out plankton, harming native fish populations.

  • Human eyes are only sensitive enough to see abt 5000 stars ✅ as separate points of light

  • The Earth is just under 150M km away from the Sun, but since our solar system is so vast, we say that one ASTRONOMICAL UNIT is that distance (~150KM) ✅

  • The scale of the Milyk Way is so much larger that we need even bigger measurements - tte light year, how much light can travel in one human year. The milky way is 105,000 lightyears wide. 9.4607E+12 Kilometer = one lightyear ✅

  • A significant percentage of teh stars in the Milky Way have their own planetary systems. Event tho many stars and many planet systems, the main part of a galaxies mass is interstellar gas gas gas and dust dust dust. Interstellar means between the stars.

  • Most o/ the gas is HydroGen, the simplest element.✅Hydrogen was the main part of te gas that formed our system, used as a fuel for nuke reactions in most stars. The rest of the gas is HeliUm, the next simplest Element. ✅Forms as part of the nuke reactions in stars.

  • Dust contains tiny pits of carbon, silicon, oxygen, and scientists believe that these are produced and scattered through space when an aging star explodez.

  • We can detect these ones that are closer to stars because they reflect energy. This clouds are =imoprtant because new stars form from them.

  • Hydrogen gas and  other simple particles like electrons and protons formed really early on. When stars collapse or explode as substances to fuel nukes run out. Even larger atoms are formed: ✅

    • S\imple gas + dust gather together, forming: ✅

      • Clumps of rock some metals

      • Planets with some gas

      • Large clumps of gas 

      • Very large gas clumps that start nuke reaction

    • When nukje fuel runs oujt, produce clouds of gas gas gas!

  • There are many shapes✅

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  • Num stars in Milky Way = 250B +- 150 billion ✅

  • Astronomers examine other galaxies to compare them with our galaxy and learn more about it. Exoplanets orbit stars other than our sun. Plus we’re also lookin back in time.