ساينس الصف الثالث الاعدادي – الفصل الدراسي الاول ساينس تالتة اعدادي – ترم اول In This part we will study : The Solar system Solar nebula It is a sphere f gases and dust from which the planets of the solar system were originated. Most important theories 1 – Nebular theory 2 – Crossing star theory The modern theory 1 – the Nebula (glowing gaseous sphere) -Over the time, the nebula gradually lost its heat so its size contracted and its revolving speed around itself increased. Nebula: It is a glowing gaseous sphere revolving around itself, from which the solar system was originated. لمتابعة مستر احمد الباشا وكل ما يخص الساينس : جروب الفيس بوك http://bit.ly/2Of1mcN صفحة الفيس بوك http://bit.ly/2Gq5xMo بالتوفيق مستر احمد الباشا