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A Briefer History of Time - by Stephen Hawking and Leonard Mlodinow

Dimulai oleh reborn, Maret 09, 2007, 09:11:19 AM

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reborn

Barusan buka situs UC Berkeley, terus liat berita [pranala luar disembunyikan, sila masuk atau daftar.]. Baru tau ternyata ada sequele A Brief History of Time (1988) yahh?? A Briefer History of Time - by Stephen Hawking and Leonard Mlodinow diterbitin tahun 2005. Ada yang udah baca blom? Isinya apa ya, bedanya sama yang pertama apa?

Googling n liat wiki gak ngebantu  :-\ eh kok malah dapet versi parodinya  :P A Briefer History of Time (Schulman book). Yang ini ada format PDF lengkapnya. download di [pranala luar disembunyikan, sila masuk atau daftar.]

Tolong ceritain dikit ya yang udah baca  :-[

[pranala luar disembunyikan, sila masuk atau daftar.]

reborn

Gak bisa hadir di kuliahnya Hawkings, kita baca beritanya aja  ;D Sesuai topiknya, J. Robert Oppenheimer, mewakili Hawkings, ngebahas asal mula dunia. Di sini dibahas antara lain kenapa harus ada awal, apa akibatnya kalo dunia punya awal, kenapa scientists menolak gagasan adanya awal. Terus juga apa sebenernya waktu (hehe.. kayak post gw di sebelah nanya waktu itu apa)? Apa bener ada waktu? Karena menurut Einstein dalam relativitas umumnya, ruang dan waktu adalah relatif. Ruang dan waktu ada karena adanya materi dan energi yang "membentuk"nya. Artinya tidak ada artinya kita berbicara waktu sebelum dunia (materi) ini ada.

berkeley.edu/news/media/releases/2007/03/16_hawking_text.shtml

KutipHowever in 1915, Einstein introduced his revolutionary General Theory of Relativity. In this, space and time were no longer Absolute, no longer a fixed background to events. Instead, they were dynamical quantities that were shaped by the matter and energy in the universe. They were defined only within the universe, so it made no sense to talk of a time before the universe began. It would be like asking for a point south of the South Pole. It is not defined.

Nah, bicara soal makna, ternyata Oppenheimer juga bahas sedikit tentang sudut pandang positivisme logis di situ. Tentang good model dan bad model. Apakah suatu ide itu memiliki makna atau tidak/ Kita tidak lagi mempertanyakan sesuatu nyata ataui tidak, yang penting dapat dibuktikan.

KutipIn terms of the positivist approach, one can compare two models of the universe. One in which the universe was created last year, and one in which the universe existed much longer. The model in which the universe existed for longer than a year, can explain things like identical twins, that have a common cause more than a year ago. On the other hand, the model in which the universe was created last year, can not explain such events. So the first model is better. One can not ask whether the universe really existed before a year ago, or just appeared to. In the positivist approach, they are the same.

Terus apa masalahnya kalo memang dunia memiliki awal?

KutipMany scientists were still unhappy with the universe having a beginning, because it seemed to imply that physics broke down. One would have to invoke an outside agency, which for convenience, one can call God, to determine how the universe began. They therefore advanced theories in which the universe was expanding at the present time, but didn't have a beginning. One was the Steady State theory, proposed by Bondi, Gold, and Hoyle in 1948.

In the Steady State theory, as galaxies moved apart, the idea was that new galaxies would form from matter that was supposed to be continually being created throughout space. The universe would have existed for ever, and would have looked the same at all times. This last property had the great virtue, from a positivist point of view, of being a definite prediction, that could be tested by observation. The Cambridge radio astronomy group, under Martin Ryle, did a survey of weak radio sources in the early 1960s. These were distributed fairly uniformly across the sky, indicating that most of the sources, lay outside our galaxy. The weaker sources would be further away, on average.

Nyatanya memang sampai saat ini kita belum dapat menjelaskan, bagaimana sebenernya dunia ini terbentuk. Relativitas umum menunjukkan bahwa alam semesta inflasioner dan berawal dari bing bang namun tidak dapat menjelaskan bagaimana alam semesta ini berkembang dari bing bang hingga sekarang.

KutipWe have made tremendous progress in cosmology in the last hundred years. The General Theory of Relativity, and the discovery of the expansion of the universe, shattered the old picture of an ever existing, and ever lasting universe. Instead, general relativity predicted that the universe, and time itself, would begin in the big bang. It also predicted that time would come to an end in black holes. The discovery of the cosmic microwave background, and observations of black holes, support these conclusions. This is a profound change in our picture of the universe, and of reality itself.

Although the General Theory of Relativity, predicted that the universe must have come from a period of high curvature in the past, it could not predict how the universe would emerge from the big bang. Thus general relativity on its own, can not answer the central question in cosmology, Why is the universe, the way it is. However, if general relativity is combined with quantum theory, it may be possible to predict how the universe would start. It would initially expand at an ever increasing rate. During this so called inflationary period, the marriage of the two theories predicted that small fluctuations would develop, and lead to the formation of galaxies, stars, and all the other structure in the universe. This is confirmed by observations of small non uniformities in the cosmic microwave background, with exactly the predicted properties. So it seems we are on our way to understanding the origin of the universe, though much more work will be needed. A new window on the very early universe, will be opened when we can detect gravitational waves by accurately measuring the distances between space craft. Gravitational waves propagate freely to us from earliest times, unimpeded by any intervening material. By contrast, light is scattered many times by free electrons. The scattering goes on until the electrons freeze out, after 300,000 years.

Ada yang udah baca A Briefer History of Time? Share di sini dong  ;D

hotman

halo..

saya sedang membaca a brief history of time versi inggrisnya dari Steven Hawking. Apakah ada yang punya terjemahan indonesianya?

Kalau ada, tolong dibagi dong...tks

superstring39

nich saya terjemahin sedikit:
A Briefer History of Time : Sejarah yang lebih singkat darin sang kala.