Observerare

• 

  Debbra Greig

  https://sciencealert.co.uk/eos%ED%8C%8C%EC%9B%8C%EB%B3%BC-%EB%B6%84%EC%84%9D%EA%B3%BC-%EC%8B%A0%EB%A2%B0%ED%95%A0-%EC%88%98-%EC%9E%88%EB%8A%94-%EC%BB%A4%EB%AE%A4%EB%8B%88%ED%8B%B0-%EB%B2%A0%ED%94%BD/