منذ هذا التاريخ أصبحت الارض صالحة للعيش

خلصت دراسة بريطانية حديثة، إلى أن الأكسجين الذي يعد سر الحياة على الأرض، يعتبر مكونا حديثا في الغلاف الجوي، وهو ما يعني أن الأرض باتت صالحة للحياة والسكن بعد فترة كبيرة من نشأتها.

ونشرت الدراسة التي أجراها فريق دولي بقيادة جامعة ليدز، وتضم باحثين من جامعة كاليفورنيا وريفرسايد وهارفارد بالولايات المتحدة وجامعة جنوب الدنمارك، في دورية “نيتشر”.

وقال الباحث الرئيسي بالدراسة وهو من جامعة ليدز، سيمون بولتون إن “حدث الاكسجة  العظيم غيّر بشكل أساسي بيئة الأرض وصلاحيتها للسكن، وكان يُعتقد أن هذه الفترة المبكرة من الأكسجة حدثت منذ حوالي 2.43 إلى 2.32 مليار سنة، لكن يُظهر بحثنا أن أكسجة الغلاف الجوي كانت غير مستقرة على مدار 200 مليون سنة”.

وكانت المرة الأولى التي تكون فيها الأكسجين بشكل كبير في الغلاف الجوي، منذ حوالي 2.43 مليار سنة، وهذا يمثل بداية حدث الأكسجة العظيم، وهي فترة محورية في تاريخ الأرض.

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