Through photosynthesis, green plants and cyanobacteria are able to transfer sunlight energy to molecular reaction centers for conversion into chemical energy with nearly 100-percent efficiency. Speed is the key – the transfer of the solar energy takes place almost instantaneously so little energy is wasted as heat. How photosynthesis achieves this near instantaneous energy transfer is a long-standing mystery that may have finally been solved.

A study led by researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) at Berkeley reports that the answer lies in quantum mechanical effects. Results of the study are presented in the April 12, 2007 issue of the journal Nature.

“We have obtained the first direct evidence that remarkably long-lived wavelike electronic quantum coherence plays an important part in energy transfer processes during photosynthesis,” said Graham Fleming, the principal investigator for the study. “This wavelike characteristic can explain the extreme efficiency of the energy transfer because it enables the system to simultaneously sample all the potential energy pathways and choose the most efficient one.”

This composite photo provided by NASA shows A powerful jet from a super massive black hole is blasting a nearby galaxy in the system known as 3C321, according to new results from NASA. This galactic violence, never seen before, could have a profound effect on any planets in the path of the jet and trigger a burst of star formation in the wake of its destruction.

لينک مطلب                                                         

لینک دانلود سمینار درس فیزیک جدید؛ با عنوان «آشنایی با نسبیت عام ...... مفاهیم، آزمون ها و پیشگویی هـــا» که در تاریخ 20 آذر مـاه در دانشگـاه  بوعلی ارائـــه شد.

 A black hole is a region of space whose attractive gravitational force is so intense that no matter, light, or communication of any kind can escape. A black hole would thus appear black from the outside. (However, gas around a black hole can be very bright.) It is believed that black holes form from the collapse of stars. As long as they are emitting heat and light into space, stars are able to support themselves against their own inward gravity with the outward pressure generated by heat from nuclear reactions in their deep interiors. Every star, however, must eventually exhaust its nuclear fuel. When it does so, its unbalanced self gravitational attraction causes it to collapse.

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ایمان به جهان بیرونی و مستقل از شخص ناظر، پایه تمام علوم طبیعی را تشکیل می دهد. اما از آنجا که درک حسی، اطلاعات مربوط به این جهان یا «واقعیت فیزیکی» را تنها به شکل غیز مستقیم به دست می دهد؛ واقعیت جهان بیرونی را صرفا با ابزارهای ذهنی می توانیم درک کنیم.

در نتیجه تصورات مـا از واقعیت فیزیکی هرگـز نمی تواند نهایی باشند. ما همیشه باید آمـاده باشیم کـه این تصورات (یعنی پایه های بدیهی علم فیزیک) را تغییر دهیم تا به لحاظ منطقی حقایق دریافت شده را به کامل ترین و بهترین وجه ممکن ارائه کنیم.

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