মহাবিশ্বের উৎপত্তি, বিবর্তন এবং চূড়ান্ত পরিণতি নিয়ে গবেষণাকে বিশ্বতত্ত্ব বলে। মহাবিশ্বের উৎপত্তি ও বিকাশ সম্বন্ধে যে। সব তত্ত্ব আছে, তার মধ্যে বহুল প্রচলিত হলো বিগ ব্যাঙ তত্ত্ব। কোটি কোটি বছর পূর্বে ছোট অথচ ভীষণ ভারী ও পরম বস্তুপিণ্ড বিস্ফোরিত হয়ে সকল দিকে ছড়িয়ে পড়তে শুরু করে। এই বিস্ফোরণকে মহাবিস্ফোরণ বলা হয়। মহাবিস্ফোরণ সংঘটিত হয়েছিল প্রায় ১৩.৭৫ বিলিয়ন বছর (১৩৭৫ কোটি বছর) পূর্বে এবং এটাই মহাবিশ্বের বয়স। মহাবিস্ফোরণের পর অতি ক্ষুদ্র পদার্থ কণা প্রথমে ছোট ছোট কণায় পরিণত হয়। তারপর ছোট ছোট কণাগুলো কিছুটা ঠাণ্ডা ও একত্রিত হয়ে জ্যোতিষ্কে পরিণত হয়। বেলজিয়ামের জ্যোতির্বিজ্ঞানী জি. লেমেটার (G. Lemaitre) বিগ ব্যাঙ তত্ত্বের প্রবক্তা। হাবল মহাবিশ্ব সম্পর্কে বলেন মহাবিশ্ব প্রতিনিয়তই সম্প্রসারিত হচ্ছে। পদার্থবিজ্ঞানী স্টিফেন হকিং তাঁর বিখ্যাত A Brief History of Time গ্রন্থে পদার্থবিজ্ঞানের দৃষ্টিকোণ থেকে বিগ ব্যাঙ তত্ত্বের ব্যাখ্যা উপস্থাপন করেন ।
আমাদের অল-ইন-ওয়ান মোবাইল অ্যাপের মাধ্যমে সীমাহীন শেখার সুযোগ উপভোগ করুন।
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