Kuliah Umum: Pendidikan Ekonomi Pertahanan: PEP

Pendidikan Ekonomi Pertahanan

Ekonomi pertahanan (Defence Economic), merupakan studi tentang biaya-biaya pertahanan yang mengkaji masalah pertahanan dan perdamaian dengan menggunakan analisis dan metode ekonomi yang meliputi kajian mikroekonomi dan makroekonomi seperti optimiasi statis dan dinamis, teori-teori pertumbuhan, distribusi, perbandingan data statistik dan ekonometrik (penggunaan statistika model ekonomi).

John Perkins speaks at University of San Francsico

John Perkins adalah penulis asal Amerika Serikat (AS) yang mengungkapkan kejahatan korporatokrasi, jaringan yang bertujuan memetik laba melalui cara-cara korupsi, kolusi, dan nepotisme (KKN) dari negara-negara Dunia Ketiga, termasuk Indonesia. 

Dalam bukunya yang pertama, Confessions of An Economic Hit Man (2004) Perkins menyebut dirinya bandit ekonomi (Economic Hit Man (EHM) yang bekerja di perusahaan konsultan MAIN di Boston, AS.

Ekonomi Pertahanan

Sedangkan pelaku-pelaku dalam studi ekonomi pertahanan ini antara lain, Menteri Pertahanan, birokrat, kontraktor pertahanan, anggota parlemen, bangsa-bangsa yang bersekutu, para gerilyawan, teroris dan pemberontak (Sandler, 2000: 208). 

Bidang ini berkembang pesat setelah Perang Dunia II, yang topik-topiknya mencakup; perlombaan senjata, studi aliansi dan pembagian beban, kesejahteraan, penjualan senjata, kebijakan pembelian senjata, pertahanan dan pembangunan, industri senjata, persetujuan pembatasan senjata, dampak ekonomis dari suatu perjanjian, evaluasi usulan perlucutan senjata, pengalihan industri pertahanan, dan sebagainya. 

Ketika terjadi Perang Dingin Blok Barat dan Blok Timur, perhatian ekonomi pertahanan umumnya tertuju pada masalah-masalah beban pertahanan dan dampaknya terhadap pertumbuhan ekonomi.

Sedangkan pada pasca Perang Dingin, para ekonom pertahanan memusatkan perhatian pada konversi perindustrian militer, aspek sumber daya persenjataan, biaya pemeliharaan pasukan penjaga perdamaian, dan pengukuran keuntungan perdamaian (Sandler, 2000: 209).

Sumber:

1. Kementrian Pendidikan dan Kebudayaan
2. Kementrian Pertahanan
3. Pentagon

GAYA

Gaya-gaya di Alam

"Jika kita bergetar dan tertarik oleh seseorang percayalah itu bukan Gravitasi"

-Arip-

Gaya-gaya fundamental

Berbagai macam gaya yang diamati di alam dapat dijelaskan lewat 4 interaksi dasar yang terjadi antara partikel-partikel elementer:

1. Gaya gravitasi
2. Gaya elektromagnetik
3. Gaya nuklir kuat (juga dinamakan gaya hadronik)
4. Gaya nuklir lemah


Gaya gravitasi antara bumi dan sebuah benda di dekat permukaan bumi adalah berat benda.

Gaya gravitasi yang dikerjakan oleh Matahari pada bumi dan planet-planet lain bertanggung jawab untuk mempertahankan planet-planet dalam orbitnya mengelilingi Matahari.

Demikian pula, gaya gravitasi yang dikerjakan oleh Bumi pada bulan, menjaga Bulan dalam orbitnya yang mendekati lingkaran mengelilingi bumi.

Gaya gravitasi yang dikerjakan oleh bulan dan matahari pada lautan di bumi bertanggung jawab terhadap peristiwa pasang surut.

Gaya elektromagnetik mencakup gaya-gaya listrik dan gaya magnetik.

Sebuah contoh yang terkenal tentang gaya listrik adalah tarikan antara potongan-potongan kertas kecil dan sisir yang telah diberi muatan listrik dengan digosokan pada rambut.

Walaupun gaya magnetik yang terkenal antara sebuah magnet dan benda-benda besi tampaknya sangat berbeda dari gaya listrik, namun sebetulnya gaya magnetik muncul bila muatan listrik dalam keadaan bergerak.

Gaya elektromagnetik antara partikel elementer yang bermuatan sangat lebih besar daripada gaya gravitasi di antara partikel elementer sehingga gaya gravitasi dapat hampir selalu diabaikan.

Sebagai contoh, gaya tolak elektrostatik antara dua proton berorde 10^36 (Sepuluh pangkat 36) kali tarikan gravitasi antara dua proton.

Gaya nuklir kuat terjadi antara partikel-partikel elementer yang dinamakan hadron, yang di dalamnya termasuk proton dan neutron, unsur pokok inti atom.

Gaya ini bertanggung jawab untuk mengikat inti atom menjadi satu.

Sebagai contoh, kedua proton dalam atom helium terikat lewat gaya nuklir yang kuat, yang lebih dari mengimbangi tolakan elektrostatika proton.

Namun, gaya nuklir kuat mempunyai jangkauan sangat pendek. Gaya ini berkurang dengan cepat bersamaan dengan pemisahan partikel-partikel, dan dapat diabaikan jika partikel-partikel terpisah sejauh beberapa diameter nuklir.

Gaya nuklir lemah, yang juga mempunyai jangkauan pendek, terjadi antara elektron dan proton atau neutron.

Gaya inilah yang bertanggung jawab untuk sejenis peluruhan radioaktif tertentu yang dinamakan peluruhan beta.

Gaya-gaya fundamental bekerja di antara partikel-partikel yang terpisah dalam ruang.

Konsep ini dihubungkan dengan aksi pada jarak.

Newton menganggap, aksi pada suatu jarak sebagai suatu cacat dalam teori gravitasinya, tetapi beliau menolak memberikan hipotesis lain.

Dan akhirnya Prof. Newton menuliskan hal berikut ini:

Sir Isaac Newton, surat ketiga kepada Bentley (25 Februari 1692). J. Dodsley, London, 1756.

Tidaklah dapat dibayangkan bahwa benda mati, bahan kasar, tanpa perantara sesuatu yang lain, yang bukan materi, bekerja pada dan mempengaruhi benda lain tanpa saling kontak.

Seperti yang terjadi bila pengertian Gravitasi dalam pengertian Epicurus, adalah penting dan inheren di dalamnya.

Ini adalah satu sebab mengapa saya menginginkan Anda tidak menganggap swadaya gravitasi berasal dari saya.

Bahwa gravitasi haruslah swadaya, inheren dan penting bagi bahan, agar satu benda dapat bekerja pada benda lain pada suatu jarak lewat ruang hampa, tanpa perantaraan apa pun yang lain, oleh dan lewat aksi mereka dan gaya dapat diteruskan dari satu ke yang lainnya.

Untuk saya suatu kemustahilan yang demikian besarnya sehingga saya percaya tidak ada orang yang mempunyai kemampuan berpikir yang baik dalam masalah filosofi dapat jatuh kedalamnya.


Sumber:
Prof. Paul A. Tipler, Ph.D.
Professor of Physics, University of California at Berkeley.
Unduh Buku Physics:  http://www.jalurcepat.com/vzoq6p9r9nin/Physics__5_Ed._-_Paul_A._Tipler.pdf.htm

Can Science Save the World?

"The world spends nearly $7 trillion a year on energy and its infrastructure"

By: Prof. Martin John Rees, Ph.D.
http://www.ast.cam.ac.uk/~mjr/
Master of the University of Cambridge, and Professor of Cosmology and Astrophysics.

CAMBRIDGE – For most people, there has never been a better time to be alive than now. The innovations that drive economic advances – information technology, biotech, and nanotech – can boost living standards in both the developing and the developed world. We are becoming embedded in a cyberspace that can link anyone, anywhere, to all the world’s information and culture – and to every other person on the planet.

Twenty-first century technologies will offer environmentally benign lifestyles and the resources to ease the plight and enhance the life chances of the world’s two billion poorest people. Moreover, the greatest threat of the 1960’s and 1970’s – nuclear annihilation – has diminished. This threat could recur, however, if there is a renewed standoff between new superpowers. And there are other risks stemming from humanity’s greater collective impact on the planet, and from the growing empowerment of individuals.

Soon after World War II, physicists at the University of Chicago started a journal called the Bulletin of Atomic Scientists to promote arms control. The logo on the Bulletin’s cover is a clock, the proximity of whose hands to midnight indicates the editors’ judgment of the precariousness of the world situation. Every few years, the minute hand shifted, either forwards or backwards. It came closest to midnight in 1962 during the Cuban Missile Crisis.

When the Cold War ended, the Bulletin’s clock was put back to 17 minutes to midnight. But the clock has been creeping forward again. We are confronted by proliferation of nuclear weapons (by, say, North Korea and Iran). Al-Qaeda-style terrorists might willingly detonate a nuclear weapon in a city center, killing tens of thousands.

Even if the nuclear threat is contained, the twenty-first century could confront us with grave new global perils. Climate change looms as this century’s primary long-term environmental challenge. Human actions – burning fossil fuels – have already raised the carbon dioxide concentration higher than it has ever been in the last 500,000 years, and it is rising by about 0.5 % a year.

More disturbingly, coal, oil, and gas are projected to supply most of the world’s growing energy needs for decades to come. If that continues, the concentration of CO2 will rise to twice the pre-industrial level by 2050, and three times that level later in the century.

The world spends nearly $7 trillion a year on energy and its infrastructure; yet our current research and development efforts are not up to meeting the challenge of climate change. There is no single solution, but some measures, like better insulation of buildings, would save rather than cost money.

Efforts to economize on energy, storing it, and generating it by “clean” or low-carbon methods deserve priority and the sort of commitment from governments that were accorded to the Manhattan Project (which created the atomic bomb) or the Apollo moon landing.

The top priority should be a coordinated effort by Europe, the United States, and the other G-8+5 countries to build demonstration plants to develop carbon capture and storage (CCS) technology. This is crucial, because whatever technical advances there may be in solar and other renewable energy sources, we will depend on coal and oil for the next 40 years. Yet unless the rising curve of annual emissions can be reversed, the CO2 concentration will irrevocably reach a truly threatening level.

Mankind must also confront other global “threats without enemies” that are separate from (though linked with) climate change. Loss of biological diversity is one of the most severe such threats. The extinction rate is 1,000 times higher than normal, and is increasing.

Biodiversity is a crucial component of human well-being and economic growth. We are clearly harmed if fish stocks dwindle to extinction. Less evidently, there are plants in the rain forest whose gene pool might be useful to us.

The pressures on our planet depend, of course, on our lifestyle. The world could not sustain its 6.5 billion people if they all lived like present-day Americans. But it could if even prosperous people adopted a vegetarian diet, traveled little, and interacted virtually. New technology will determine our lifestyle, and the demands that we make on energy and environmental resources.

Nevertheless, our problems are aggravated by rapid growth in the human population, which is projected to reach eight or even nine billion by 2050. If the increase continues beyond 2050, one cannot help but be gloomy about most people’s prospects.

There are now, however, more than 60 countries where the fertility rate is below replacement level. If this were true of all countries, the global population would start to decline after 2050 – a development that would surely be benign.

All of today’s developments – cyber, bio, or nano – will create new risks of abuse. The American National Academy of Sciences has warned that, “Just a few individuals with specialized skills…could inexpensively and easily produce a panoply of lethal biological weapons.…The deciphering of the human genome sequence and the complete elucidation of numerous pathogen genomes…allow science to be misused to create new agents of mass destruction.”

Not even an organized network would be required; just a fanatic with the mindset of those who now design computer viruses. The global village will have its village idiots.

In our increasingly interconnected world, there are new risks whose consequences could be widespread – and perhaps global. Even a tiny probability of global catastrophe is unacceptable. If we apply to catastrophic risks the same prudent analysis that leads us to buy insurance – multiplying probability by consequences – we would surely prioritize measures to reduce this kind of extreme risk. The decisions that we will make both individually and collectively in the foreseeable future will determine whether twenty-first century science yields benign or devastating outcomes.

By:
Lord Rees is Britain’s Astronomer Royal, President of the Royal Society, Master of the University of Cambridge’s Trinity College, and Professor of Cosmology and Astrophysics.

Copyright: Project Syndicate/Europe’s World, 2008.

http://www.project-syndicate.org/

http://www.europesworld.org/

Energi Terbarukan Untuk Desa

Jika akses ke Teknologi Informasi modern penting bagi pemberdayaan ekonomi, begitu pula akses ke energi, terutama Listrik.

Bagaimana menciptakan energi Listrik dengan harga terjangkau dan dapat diakses oleh semua warga negara?

Menambah sambungan jaringan listrik nasional ke semua desa terpencil di seluruh negeri merupakan kerja besar dan mahal.

Terutama lagi, solusi seperti itu tak ramah lingkungan.

Saat ini bahan bakar fosil sudah menipis dan perubahan iklim karena emisi karbon merupakan ancaman yang makin membahayakan.

Kita ingin menemukan sumber energi yang sesuai dengan kebutuhan ekonomi rakyat tanpa menimbulkan lebih banyak masalah daripada yang dapat diselesaikan.

Sepertinya Tenaga Surya/Matahari, Tenaga Air, Tenaga Angin, Tenaga Gelombang Air laut merupakan alternatif pilihan.

Selanjutnya ialah biogas bentuk energi terbarukan memanfaatkan kotoran Sapi, Unggas, dan limbah lain yang ada di mana-mana.

Tiap desa nantinya mempunyai pusat-pusat produksi energi tersendiri, yang mampu menghasilkan energi bagi warganya sesuai dengan potensi desanya.

Saya sempat berpikir, bagaimana kalau seluruh atap rumah rakyat kita dipasang panel surya?

Mungkin tidak ada cerita lagi mengenai "Aliran" Atau mati listrik.

Semoga.

Photo by: Arip Nurahman

Wallohualam.

A Unified Physics By 2050 Part IV

"Aku hanya ingin menanamkan benih-benih cinta kasih kepada sesama" 

~Arip~  

 

  A Unified Physics by 2050?

Experiments at CERN and elsewhere should let us complete the Standard Model of particle physics, but a unified theory of all forces will probably require radically new ideas.

By: Prof. Steven Weinberg, Ph.D.

Outside of Space-time

Two great obstacles stand in the way of this task. One is that we do not know what physical principles govern the fundamental theory. In developing general relativity, Einstein was guided by a principle he had inferred from the known properties of gravitation, the principle of the equivalence of gravitational forces to inertial effects such as centrifugal force. The development of the Standard Model was guided by a principle known asgauge symmetry, a generalization of the well-known property of electricity that it is only differences of voltages that matter, not voltages themselves.

But we have not discovered any fundamental principle that governs M-theory. The various approximations to this theory look like string or field theories in space-times of different dimensionalities, but it seems probable that the fundamental theory is not to be formulated in space-time at all. Quantum field theory is powerfully constrained by principles concerning the nature of four-dimensional space-time that are incorporated in the special theory of relativity. How can we get the ideas we need to formulate a truly fundamental theory, when this theory is to describe a realm where all intuitions derived from life in space-time become inapplicable?

The other obstacle is that even if we were able to formulate a fundamental theory, we might not know how to use it to make predictions that could confirm its validity. Most of the successful predictions of the Standard Model have been based on a method of calculation known as perturbation theory. In quantum mechanics the rates of physical processes are given by sums over all possible sequences of intermediate steps by which the process may occur. 

Using perturbation theory, one first considers only the simplest intermediate steps, then the next simplest, and so on. This works only if increasingly complicated intermediate steps make decreasingly large contributions to the rate, which is usually the case if the forces involved are sufficiently weak. Sometimes a theory with very strong forces is equivalent to another theory with very weak forces, which can be solved by the methods of perturbation theory. This seems to be true of some pairs of the five string theories in 10 dimensions and the field theory in 11 dimensions mentioned earlier. Unfortunately, the forces of the fundamental theory are probably neither very strong nor very weak, ruling out any use of perturbation theory.

Image: Johnny Johnson

COUPLING STRENGTHS OF INTERACTIONS are not truly coupling "constants" and slowly change value depending on energy, a process that is accurately described by quantum field theory and verified by experiment up to 200 GeV. Theoretical extrapolation shows that the three Standard Model forces (the strong force and the unified weak and electromagnetic forces) have roughly equal strength at very high energy (a), and the equality is improved by allowing for supersymmetry (b). Curve thickness indicates approximate uncertainty in the coupling strengths.

Recognizing the Answer

It is impossible to say when these problems will be overcome. They may be solved in a preprint put out tomorrow by some young theorist. They may not be solved by 2050, or even 2150. But when they are solved, even though we cannot do experiments at 10¹⁶ GeV or look into higher dimensions, we will not have any trouble in recognizing the truth of the fundamental unified theory. The test will be whether the theory successfully accounts for the measured values of the physical constants of the Standard Model, along with whatever other effects beyond the Standard Model may have been discovered by then.

It is possible that when we finally understand how particles and forces behave at energies up to 10¹⁸ GeV, we will just find new mysteries, with a final unification as far away as ever. But I doubt it. There are no hints of any fundamental energy scale beyond 10¹⁸ GeV, and string theory even suggests that higher energies have no meaning.

The discovery of a unified theory that describes nature at all energies will put us in a position to answer the deepest questions of cosmology: Did the expanding cloud of galaxies we call the big bang have a beginning at a definite time in the past? Is our big bang just one episode in a much larger universe in which big and little bangs have been going on eternally? If so, do what we call the constants of nature or even the laws of nature vary from one bang to another?

This will not be the end of physics. It probably won't even help with some of the outstanding problems of today's physics, such as understanding turbulence and high-temperature superconductivity. But it will mark the end of a certain kind of physics: the search for a unified theory that entails all other facts of physical science.

The End

Further Reading:

1. Unified Theories of Elementary-Particle Interaction. Steven Weinberg in Scientific American, Vol. 231, No. 1, pages 50-59; July 1974.

2. Dreams of a Final Theory. Steven Weinberg. Pantheon Books, 1992.

3. Reflections on the Fate of Spacetime. Edward Witten in Physics Today, Vol. 49, No. 4, pages 24-30; April 1996.

4. Duality, Spacetime and Quantum Mechanics. Edward Witten in Physics Today, Vol. 50, No. 5, pages 28-33; May 1997.

5. The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory. Brian Greene. W. W. Norton,1999.

http://hera.ph1.uni-koeln.de/~heintzma/Weinberg/Weinberg.htm 

The Author
 

STEVEN WEINBERG is head of the Theory Group at the University of Texas at Austin and a member of its physics and astronomy departments. His work in elementary particle physics has been honored with numerous prizes and awards, including the Nobel Prize for Physics in 1979 and the National Medal of Science in 1991. 

The third volume (Supersymmetry) of his treatise The Quantum Theory of Fields is out from Cambridge University Press. The second volume (Modern Applications) was hailed as being "unmatched by any other book on quantum field theory for its depth, generality and definitive character."

Smile a While with Astro Physics

"Science without religion is lame. Religion without science is blind."
-Albert Einstein-
"Gravitation is not responsible for people falling in love."
-Albert Einstein-

Just Smile a While with Astro Physics

The Most Beautifulest and Most Handsome Physicist

Nominasi fisikawan Tercantik dan Terganteng {Lebai}


1. Lisa Randall (Harvard University)
2. Rosalind Franklin (Cambridge University)
3. Helen Quinn (Stanford University)
4. Myriam Sarachik(Columbia University)
5. Maria Goeppert Mayer (University of Goettingen)
6. Patricia Elizabeth Cladis (University of Rochester)
7. Hertha Sponer (Göttingen University)
8. Gail Gulledge Hanson (Massachusetts Institute of Technology)
9. Sau Lan Wu(Harvard University)
10. Sulamith Goldhaber(University of Wisconsin)
11. Louise Dolan()
12. Noemie Benczer Koller(Columbia University)
13. Jocelyn Bell Burnell (Cambridge University)
14. Mary Katharine Gaillard(Universite de Paris)
15. Marie Curie (Most Genius Women in Physics)













Louise Dolan at MIT

Astrophysics
Burbidge, E. Margaret Burnell, Jocelyn Bell Faber, Sandra Moore	Leavitt, Henrietta Swan Payne-Gaposchkin, Cecilia Helena Rubin, Vera Cooper
Atomic Molecular and Optical Physics
Bonnelle, Christiane Bramley, Jenny Rosenthal Cauchois, Yvette	Connes, Janine Sponer, Hertha
Condensed Matter Physics
Ancker-Johnson, Betsy Blodgett, Katharine Burr Cladis, Patricia Elizabeth Conwell, Esther Marly Dresselhaus, Mildred Spiewak	Ericson, Magda Galula Kaufman, Bruria Sarachik, Myriam P. Sengers, Johanna Levelt
Cosmic Rays
Freier, Phyllis S.
Crystallography
Franklin, Rosalind Hodgkin, Dorothy Crowfoot	Lonsdale, Kathleen Yardley Megaw, Helen
Distinguished for Public Service
Dowdy, Nancy M. O'Fallon
Education and the Profession
DeWitt-Morette, Cecile Franz, Judy R. Jackson, Shirley Ann Keith, Marcia Anna Laird, Elizabeth Rebecca Maltby, Margaret Eliza	Meyer, Kirstine Bjerrum Phillips, Melba Newell Stone, Isabelle Whiting, Sarah Frances Xie, Xide (Hsieh, Hsi-teh)
Fluid Dynamics
Pockels, Agnes Polubarinova-Kochina, P. Ya.
Fluid Dynamics and Plasma Physics
Ayrton, Hertha Marks
Geophysics
Lehmann, Inge
Material Physics
Kuhlmann-Wilsdorf, Doris Neumark, Gertrude Fanny
Mathematical Physics
Cartwright, Mary Lucy Choquet-Bruhat, Yvonne Dolan, Louise Ehrenfest-Afanaseva, Tatiana	Jeffreys, Bertha Swirles Kallosh, Renata Kaufman, Bruria Noether, Amalie Emmy
Nuclear Physics
Ajzenberg Selove,Fay Brooks, Harriet Curie, Marie Sklodowska Ericson, Magda Galula Gates, Fanny Cook Gleditsch, Ellen Goldhaber, Gertrude Scharff Hayward, Evans Joliot-Curie, Irene	Karlik, Berta Koller, Noemie Benczer Mayer, Maria Goeppert Meitner, Lise Meyer-Schutzmeister, Luise Noddack, Ida Tacke Perey, Marguerite Catherine Phillips, Melba Newell Way, Katharine Wu, Chien Shiung
Particle and Fields
Baldo-Ceolin, Milla Blau, Marietta Byers, Nina Edwards, Helen T. Gaillard, Mary Katharine Goldhaber, Sulamith	Hanson, Gail Gulledge Lee-Franzini, Juliet Quinn, Helen R. Sechi-Zorn, Bice Wu, Sau Lan
Physicist Distinguished in Other Fields
Quimby, Edith Hinkley Yalow, Rosalyn Sussman
Physics of Beams
Edwards, Helen T.
Space Physics
Herzenberg, Caroline Littlejohn Kivelson, Margaret Galland Neugebauer, Marcia

Fisikawan Terganteng:

1. Isaac Newton (Cambridge)

2. James Clerk Maxwell (Edinburgh)

3. Paul Sutcliffe (Kent at Canterbury)

4. Sean Carroll (CALTECH)

5. Richard Feynman (CALTECH) {"Surely You are Joking Mr. Feynman"}

6. Carl Sagan (University of Chicago, Harvard University, Cornell University)

7. Sheldon Cooper

8. Arip Nurahman (Ton kamu no 9 aja yah ha.,.ha,..upsss)

9. Anton Timur J. (Ah si aa mah licik euy.,.,)

Kami panitia sedang musyawarahkan kira-kira hukum atau teori fisika apa yang digunakan juri dalam penilaian untuk fisikawan tercantik dan terganteng ini, apakah Teori Relativitas Einstein atau Hukum ketidakpastian Heisenberg.

Senyum Sejenak
(^_^)

Dari Berbagai Sumber

Semoga Bermanfaat.

Astrophysics for Poets

WWW.BANJARASTROPHYSICS.CO.CC

A Vast and most Excellent Science

How often at night
When the heavens were bright
with the light of the glittering Star and Moon
have I stood there amazed and asked as I gazed
if their glory exceeds that of ours.
-Anonymous&H2O-


Pengalaman adalah:

Jika Hidup ini seumpama rel kereta api dalam eksperimen relativitas
maka pengalaman demi pengalaman yang mengempur kita dari waktu ke waktu
adalah cahaya yang melesat-lesat di dalam gerebong di atas rel itu.
Relativitasnya berupa seberapa banyak kita dapat mengambil pelajaran dari pengalaman yang melesat-lesat itu,
maka analoginya adalah jika pengalaman yang sama dapat menimpa siapa saja,
namun sejauh mana dan secepat apa pengalaman itu memberi pelajaran pada seseorang,
hasilnya akan berbeda, relatif satu sama lain.
-Andrea H-


Anyone who has never made a mistake has never tried anything new.

E= mc2 and All That

What is matter? - Never mind.
What is mind? - It doesn't matter.

The Birth of Relativity

But in Physics I soon learned to scent out the paths that led to the depths, and to disregard everything else, all the many things that clutter up the mind, and divert it from the essential, the hitch in all this was, of course, the fact that one had to cram all this stuff into one's mind for the examination, whether one liked it or not.


"The Velocity of light is the same for all observers, in all direction, regardless of the motion of either the observer or the light source"

The Wedding of Space and Time

Light laugh:"There's no use trying."
He said:"One cannot believe impossible things."
"I dare say you haven't had much practice" said Moon
"When I was your age, I always did it for 2 hours a day. Why, sometimes I've believed in as many as 8 impossible things before breakfast.
(H2O)

Space-Time: The Fourth Dimension

S2 = L2-(ct)2 = Lo2
Where: L = Distance between two poles way greater than Lo
S = Space-Time separation is equal to Lo
c = Speed of Light
t = Time

-Albert Einstein-


One Last Part for the Machine

With Earth's first clay they did, the last man knead
and
there of the last Harvest sowed the seed:
And the first Morning of Creation wrote what the last Dawn
of Reckoning shall read.

F=k qQ/r2 (Charles Coulomb law)
where: F= Force of Electricity,
k= a Universal constant,
qQ= are the electric charges to express this in a formula, we define something called"field strength" E,
and
Coulomb's law become two formulas. E=kQ/r2 & F= qE
-Fitz Gerald, the Rubaiyat of Omar K.-


WAVES

There is something Fascinating about science. one gets such whole sale returns of conjecture out such trifling investments of fact.

-Mark Twain-

Does the Earth Really Move?

It may be that it does not move, or moves but for some other reason:
Then let it be your boast to prove
(though some may think it out of season and worthily of a fossil Druid )
There is no Electric Fluid.

-James Clerk Maxwell-


Did God Have any Choice?

Within every creature incarnate sleeps the infinite Intelligent unevolved,
hidden, unfelt, unknown-yet destined from all eternities to waken at last,
to rend away the ghostly web of sensuous mind, to break forever it's chrysalises
of flesh, and to pass to the extreme conquest of Space and Time.

-Lafadio-

"What really interests me is whether God had any choice
in the creation of the world" (H2O)


The Atoms Returns


The telescope at one end of his beat
and at the other end the microscope two
instruments of nearly equal hope

-Robert Frost-


The Universe is not only queerer than
we imagine, it is queerer than we can imagine

-J.B.S. Haldone.-


The Atom and the Quantum

Hail to Max Planck, Einstein, Bohr, Pauli, Broglie, Schrödinger, Feynman,
and Young man in the Future from the worshipful! You are the Master by
whom we are led. Awed by your cryptic and proud affirmations. Each of us,
driven half out of their head, still remains true to you
wouldn't say boo to you, Swallows your theories from Alpha to Zed,
Even if (drink to him, tankards must clink to him!) None of us fathoms
a word you have said

-George G.& H2O-


Particles and Waves

We are trapped by language to such
a degree that every attempt to formulate
insight is a play on words.
(2πrmv = n h)
n = 2πr/λ
n = an integral number
λ = wave length
h = Planck's Constant
2πr = Circle's Constant (Orbit equation)

-Niels Bohr& H2O-


Does God Play Dice?

But you tell me of an invisible planetary system
where electrons gravitate around a nucleus. You explain
this to me with an image, I realize then that you have been
reduced to poetry:
" I shall never know. I have the time to become indignant?
you have changed theories. so that the sciences that was
to teach me everything ends up in a hypothesis,
that lucidity founders in metaphor, that uncertainty
is resolved in a work of art

-A.Camus, The Myth of Sisyphus.-



Schrödinger's Cat

The law of chaos is the law
of ideas, of improvisations
and seasons of belief

The Dreams stuff is made of

Like a gleam in the darkness, we have appeared
for an instant from the black nothingness of the
ever-unconscious matter, in order to make good
the demands of reason and create a life worthy
of ourselves and of the Goal we only dimly perceive
-Andrei Sakharov-

Quantum field Theories
"The nature of a field is completely determined by
the properties of the particle that transmit it,
while the nature of a particle depends solely on
the ways in, which it couples to fields.

QED = Quantum Electrodynamic
α = e2/ħc
QCD = Quantum Color Dynamic (Quantum Foam)
rp = Second root of Għ/c3 = 1,6 x 10-35(power) it is Planck's Length

-Richard Feynman,Julian Schwinger, Murray Gell-mann and George zweig
&
-H2O-


The whole Shebang

I am astounded by people who want
to "know" the universe when it's hard
enough to find your way around the world
-H2O-






Tentang Harapan dan Mimpi

By:

Arip Nurahman

WESTLIFE LYRICS

"I Have A Dream"

[Shane:]
I have a dream, a song to sing
To help me cope with anything
If you see the wonder (wonder) of a fairy tale
You can take the future even if you fail
I believe in angels
Something good in everything I see
I believe in angels
When I know the time is right for me
I'll cross the stream - I have a dream

[Bryan:]
Oh yeah
I have a dream (have a dream), a fantasy (fantasy)
To help me through (help me through) reality (reality)
And my destination (destination) makes it worth the while
Pushing through the darkness
([Mark:] pushing through the darkness baby)
Still another mile

[Shane:]
I believe in angels
Something good in everything I see
([Mark:] everything I see yeah)
I believe in angels
([Mark:] I believe in angels )
When I know the time is right for me
([Mark:] time is right for me)
I'll cross the stream - I have a dream

I have a dream (oh yeah), a song to sing(song to sing)
To help me cope with anything
If you see the wonder (if you see the wonder) of a fairy tale (of a fairy tale)
You can take the future even if you fail (yeah yeah yeah yeah)
I believe in angels
Something good in everything I see (everything)
I believe in angels (yeah)
When I know the time is right for me (right for me)
I'll cross the stream (cross the stream) - I have a dream (have a dream)
I'll cross the stream (cross the stream) - I have a dream

[Mark:]
Oh

"I HAVE A DREAM" (1963)

"I Have A Dream" is the popular name given to the historic public speech by Martin Luther King, Jr., when he spoke of his desire for a future where blacks and whites among others would coexist harmoniously as equals. King's delivery of the speech on August 28, 1963,

from the steps of the Lincoln Memorial during the March on Washington for Jobs and Freedom, was a defining moment of the American Civil Rights Movement. Delivered to over two hundred and fifty thousand civil rights supporters, the speech is often considered to be one of the greatest and most notable speeches in history and was ranked the top American speech of the 20th century by a 1999 poll of scholars of public address.^[1] According to U.S. Congressman John Lewis, who also spoke that day as the President of the Student Non-Violent Coordinating Committee, "Dr. King had the power, the ability and the capacity to transform those steps on the Lincoln Memorial into a modern day pulpit. By speaking the way he did, he educated, he inspired, he informed not just the people there, but people throughout America and unborn generations."^[2]

At the end of the speech, King departed from his prepared text for a partly improvised peroration on the theme of "I have a dream", possibly prompted by Mahalia Jackson's cry "Tell them about the dream, Martin!".^[3] He had delivered a speech incorporating some of the same sections in Detroit in June 1963, when he marched on Woodward Avenue with Walter Reuther and the Rev. C.L. Franklin, and had rehearsed other parts.^[4]

"I am happy to join with you today in what will go down in history as the greatest demonstration for freedom in the history of our nation.

Five score years ago, a great American, in whose symbolic shadow we stand today, signed the Emancipation Proclamation. This momentous decree came as a great beacon light of hope to millions of Negro slaves who had been seared in the flames of withering injustice. It came as a joyous daybreak to end the long night of their captivity.

But 100 years later, the Negro still is not free. One hundred years later, the life of the Negro is still sadly crippled by the manacles of segregation and the chains of discrimination. One hundred years later, the Negro lives on a lonely island of poverty in the midst of a vast ocean of material prosperity. One hundred years later, the Negro is still languished in the corners of American society and finds himself an exile in his own land. And so we've come here today to dramatize a shameful condition.

In a sense we've come to our nation's capital to cash a check. When the architects of our republic wrote the magnificent words of the Constitution and the Declaration of Independence, they were signing a promissory note to which every American was to fall heir. This note was a promise that all men - yes, black men as well as white men - would be guaranteed the unalienable rights of life, liberty, and the pursuit of happiness.

It is obvious today that America has defaulted on this promissory note insofar as her citizens of color are concerned. Instead of honoring this sacred obligation, America has given the Negro people a bad check, a check that has come back marked "insufficient funds."

But we refuse to believe that the bank of justice is bankrupt. We refuse to believe that there are insufficient funds in the great vaults of opportunity of this nation. And so we've come to cash this check, a check that will give us upon demand the riches of freedom and security of justice. We have also come to his hallowed spot to remind America of the fierce urgency of now. This is no time to engage in the luxury of cooling off or to take the tranquilizing drug of gradualism. Now is the time to make real the promises of democracy. Now is the time to rise from the dark and desolate valley of segregation to the sunlit path of racial justice. Now is the time to lift our nation from the quicksands of racial injustice to the solid rock of brotherhood. Now is the time to make justice a reality for all of God's children.

It would be fatal for the nation to overlook the urgency of the moment. This sweltering summer of the Negro's legitimate discontent will not pass until there is an invigorating autumn of freedom and equality. Nineteen sixty-three is not an end but a beginning. Those who hoped that the Negro needed to blow off steam and will now be content will have a rude awakening if the nation returns to business as usual. There will be neither rest nor tranquility in America until the Negro is granted his citizenship rights. The whirlwinds of revolt will continue to shake the foundations of our nation until the bright day of justice emerges.

But there is something that I must say to my people who stand on the warm threshold which leads into the palace of justice. In the process of gaining our rightful place we must not be guilty of wrongful deeds. Let us not seek to satisfy our thirst for freedom by drinking from the cup of bitterness and hatred. We must forever conduct our struggle on the high plane of dignity and discipline. We must not allow our creative protest to degenerate into physical violence. Again and again we must rise to the majestic heights of meeting physical force with soul force. The marvelous new militancy which has engulfed the Negro community must not lead us to a distrust of all white people, for many of our white brothers, as evidenced by their presence here today, have come to realize that their destiny is tied up with our destiny. And they have come to realize that their freedom is inextricably bound to our freedom. We cannot walk alone.

And as we walk, we must make the pledge that we shall always march ahead. We cannot turn back. There are those who are asking the devotees of civil rights, "When will you be satisfied?" We can never be satisfied as long as the Negro is the victim of the unspeakable horrors of police brutality. We can never be satisfied as long as our bodies, heavy with the fatigue of travel, cannot gain lodging in the motels of the highways and the hotels of the cities. We cannot be satisfied as long as the Negro's basic mobility is from a smaller ghetto to a larger one. We can never be satisfied as long as our children are stripped of their self hood and robbed of their dignity by signs stating "for whites only." We cannot be satisfied as long as a Negro in Mississippi cannot vote and a Negro in New York believes he has nothing for which to vote. No, no we are not satisfied and we will not be satisfied until justice rolls down like waters and righteousness like a mighty stream.

I am not unmindful that some of you have come here out of great trials and tribulations. Some of you have come fresh from narrow jail cells. Some of you have come from areas where your quest for freedom left you battered by storms of persecution and staggered by the winds of police brutality. You have been the veterans of creative suffering. Continue to work with the faith that unearned suffering is redemptive.

Go back to Mississippi, go back to Alabama, go back to South Carolina, go back to Georgia, go back to Louisiana, go back to the slums and ghettos of our northern cities, knowing that somehow this situation can and will be changed.

Let us not wallow in the valley of despair. I say to you today my friends - so even though we face the difficulties of today and tomorrow, I still have a dream. It is a dream deeply rooted in the American dream.

I have a dream that one day this nation will rise up and live out the true meaning of its creed: "We hold these truths to be self-evident, that all men are created equal."

I have a dream that one day on the red hills of Georgia the sons of former slaves and the sons of former slave owners will be able to sit down together at the table of brotherhood.

I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression, will be transformed into an oasis of freedom and justice.

I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character.

I have a dream today.

I have a dream that one day down in Alabama, with its vicious racists, with its governor having his lips dripping with the words of interposition and nullification - one day right there in Alabama little black boys and black girls will be able to join hands with little white boys and white girls as sisters and brothers.

I have a dream today.

I have a dream that one day every valley shall be exalted, and every hill and mountain shall be made low, the rough places will be made plain, and the crooked places will be made straight, and the glory of the Lord shall be revealed and all flesh shall see it together.

This is our hope. This is the faith that I go back to the South with. With this faith we will be able to hew out of the mountain of despair a stone of hope. With this faith we will be able to transform the jangling discords of our nation into a beautiful symphony of brotherhood. With this faith we will be able to work together, to pray together, to struggle together, to go to jail together, to stand up for freedom together, knowing that we will be free one day.

This will be the day, this will be the day when all of God's children will be able to sing with new meaning "My country 'tis of thee, sweet land of liberty, of thee I sing. Land where my father's died, land of the Pilgrim's pride, from every mountainside, let freedom ring!"

And if America is to be a great nation, this must become true. And so let freedom ring from the prodigious hilltops of New Hampshire. Let freedom ring from the mighty mountains of New York. Let freedom ring from the heightening Alleghenies of Pennsylvania.

Let freedom ring from the snow-capped Rockies of Colorado. Let freedom ring from the curvaceous slopes of California.

But not only that; let freedom ring from Stone Mountain of Georgia.

Let freedom ring from Lookout Mountain of Tennessee.

Let freedom ring from every hill and molehill of Mississippi - from every mountainside.

Let freedom ring. And when this happens, and when we allow freedom ring - when we let it ring from every village and every hamlet, from every state and every city, we will be able to speed up that day when all of God's children - black men and white men, Jews and Gentiles, Protestants and Catholics - will be able to join hands and sing in the words of the old Negro spiritual: "Free at last! Free at last! Thank God Almighty, we are free at last!"
KAMI PUNYA HARAPAN YANG TERUS MENYALA
(8 OKTOBER 2008 PUKUL; 00:01)

1. DI SETIAP KABUPATEN ATAU KOTA DI INDONESIA
MEMPUNYAI KLUB ASTRO FISIKA

2. PUTRA-PUTRI TERBAIK BANGSA MAMPU MENJUARAI
IVENT-IVENT ATAU KOMPETISI ILMIAH
DALAM BIDANG ASTRO FISIKA

3. PARA ALUMNI KLUB ASTRO FISIKA MAMPU MELANJUTKAN
STUDI KE JENJANG YANG LEBIH TINGGI
BAIK DI DALAM NEGERI MAUPUN LUAR NEGERI

4. MENGEMBANGKAN ORGANISASI LAPAN AGAR
SETARAF DENGAN ORGANISAI-ORGANISASI LUAR ANGKASA
NEGARA LAIN

5. MAMPU MEMBANGUN STATSIUN LUAR ANGKASA DI ORBIT BUMI
DAN DI BULAN

SEMOGA YANG MAHA PENGATRUR COSMOS
MENDEKAP HARAPAN KAMI

Hari Lahir Jagat Raya, Astro Fisika Luar Tata Surya (Cosmology)

Hari Lahir Jagat Raya
(How Old Our Universe? )

By:
Arip Nurahman
Department of Physics
Faculty of Sciences and Mathematics, Indonesia University of Education

and

Follower Open Course Ware at Massachusetts Institute of Technology
Cambridge, USA
Department of Physics
http://web.mit.edu/physics/
http://ocw.mit.edu/OcwWeb/Physics/index.htm
&
Aeronautics and Astronautics Engineering
http://web.mit.edu/aeroastro/www/
http://ocw.mit.edu/OcwWeb/Aeronautics-and-Astronautics/index.htm

"Ketika riwayat sang kala ditentukan maka terpancarlah cahaya penciptaan menerobos ruang berdimensi 0 tercabik oleh kekuatan tunggal yang menggenggam Alam Raya, telah lahir suatu sonata kehidupan yang akan diarungi oleh berbagai karya agung Sang Pencipta."
-(H2O)-

Introduction

Ada pertanyaan yang sangat 'menggoda' tentang alam semesta, yaitu: berapa usia jagat raya saat ini.? Menggoda karena jawaban pertanyaan ini tidak mudah, padahal pertanyaan ini telah ada sejak menusia ada. Kalaupun ada jawaban, tentu akan bertentangan dengan jawaban yang telah tersedia pada Kitab-Kitab Suci, tapi kalaulah kita tahu hari kapan, jam berapa, dimana? Kita pasti bisa memperingati hari kelahirannya yang agung, dan mengucap segenap rasa kasih kepada Sang Arsitek ulung Jagat Raya.

Namun, ada baiknya kita berjalan pada ilmu pengetahuan saja karena ini memang telaah kita. Perbedaan jawaban ilmu pengetahuan dengan jawaban agama marilah kita pandang sebagai salah satu bukti bahwa jagat raya ini masih berproses. Dalam berproses inilah terjadi perbedaan-perbedaan yang makin lama makin sedikit hingga pada suatu saat kelak tidak ada lagi perbedaan antara jawaban ilmu pengetahuan dan jawaban agama. Jawaban ilmu pengetahuan dan jawaban agama sama-sama menunjukkan suatu kebenaran. Kebenaran itu berasal dari Yang Mahabenar. Yang Mahabenar hanya satu. "The One and Only"

Contents

Kembali ke pertanyaan semula, yakni: berapa usia jagat raya saat ini?. Banyak cara yang dapat ditempuh para ahli untuk menjawab pertanyaan ini. Pada umumnya dapat dikelompokkan menjadi dua jenis, secara kimiawi dan secara fisik. Secara kimiawi pada umumnya didasarkan sifat-sifat radioaktivitas. Unsur radioaktif akan meluruh menjadi unsur lain. Dengan cara menghitung bagian yang telah meluruh dapat diperkirakan waktu yang diperlukan untuk meluruh semua. Unsur-unsur tertua pada batuan bumi, meteor atau benda-benda langit lainnya diamati. Secara umum diperoleh umur alam semesta ini berkisar antara 11-20 milyar tahun. Pengukuran-pengukuran paling sering menghasilkan nilai untara 13-15 milyar tahun.

Dengan menggunakan alat yang disebut spektrometer berkas cahaya dapat diuraikan menjadi seperti pelangi yang menyebar dari warna merah hingga warna biru/ungu. Spektrum-spektrum yang dihasilkan dari cahaya bintang di langit ini oleh para ilmuwan diperlakukan sebagai semacam sidik jari bintang. Karena, tiap bintang mengahsilkan spektrum yang khas.

Berdasarkan prinsip efek Doppler, pergeseran posisi spektrum dari seberkas cahaya yang dipancarkan oleh sebuah bintang digunakan untuk memperkirakan arah gerak dan kecepatannya saat itu. Jika spektrum yang terjadi bergeser mendekati warna merah maka bitang tersebut bergerak menjauhi bumi dan sebaliknya jika bergeser ke arah biru, bintang yang bersangkutan sedang mendekati bumi.

Pergeseran posisi spektrum ini mencerminkan pergeseran frekuensi dan tentunya pergeseran panjang gelombang dari posisi yang baku. Fraksi selisih panjang gelombang yang tergeser dan panjang gelombang yang baku menyatakan perbandingan kecepatannya relatif terhadap kecepatan cahaya. Fraksi ini digunakan untuk menetapkan kecepatan gerak bintang relatif terhadap tata surya kita, berarti juga relatif terhadap bumi.

Dengan perkakas yang lain, misalnya paralax, kita dapat memperkiran jarak bintang terhadap kita. Jarak itu, karena sangat panjang maka dinyatakan dalam tahun cahaya. Satu tahun cahaya adalah jarak yang ditempuh oleh seberkas cahaya setelah merambat selama satu tahun. Satu tahun cahaya itu sama dengan 9,5 x 10 pangkat 15 meter.

Dengan mengukur kecepatan gerak relatif terhadap tata surya kita dan jaraknya terhadap tata surya kita beberapa bintang dapatlah diperkirakan usia alam semesta ini. Lihat Gambar utama. Titik-titik itu merupakan representasi beberapa bintang yang diamati. Usia alam semesta ditetapkan sebagai berikut. Kita tarik sepenggal garis lurus vertikal ke atas melalui titik 1.0 pada sumbu X (kecepatan bintang) hingga memotong garis lurus (g) yang melewati titik-titik representasi bintang-bintang. Kemudian ditarik penggal garis lurus mendatar ke kiri hingga memotong sumbu Y (Jarak bintang). Titik potong itu menunjukkan usia alam semesta. Sekitar 16 milyar tahun.

Mencermati umur alam semesta yang telah mencapai puluhan milyar tahun itu, maka terasa bahwa umur kita (rata-rata sekitar 60 tahun) sangat pendek sekali. Apa lagi kalau kita bandingkan dengan waktu hidup yang abadi. Kita sangatlah kecil. Umur kita sangatlah pendek. Namun demikian, betapa pun pendeknya usia kita, kita sebagai manusia seorang demi seorang tetap unik. Tidak ada duanya di dunia ini. Karena itu, tentu Sang Pemilik Alam Semesta mempunyai penugasan khusus bagi kita masing-masing. Sudahkah Anda mempunyai jawaban tentang apa tugas Anda di dunia ini? Silahkan mencarinya di antara bintang-bintang di angkasa raya. Di sana ada jawabnya. Semoga berhasil!.

"Kalaulah hari ini hari lahir jagat raya dimana sang kala mulai berdetak maka selamat dan selamat (Happy Brith Universe)semoga keindahan alam semesta selalu terpacar ke segala arah penjuru Cosmos."

English Version

The age of the Universe has been a subject of religious, mythological and scientific importance. On the scientific side, Sir Isaac Newton's guess for the age of the Universe was only a few thousand years. Einstein, the developer of the General Theory of Relativity, preferred to believe that the Universe was ageless and eternal. However, in 1929, observational evidence proved his fantasy was not to be fulfilled by Nature.

n order to understand this evidence, let's think about how a train sounds to a person standing on the platform. An arriving train makes a noise that starts low and gets higher pitched as the train approaches the listener, sounding like oooooohEEEEEEEE. A departing train makes a noise that gets lower pitched as the train goes away from the listener, sounding like EEEEEEEEoooooooh. This change in the sound of the pitch of the train noise depending on whether it is arriving or departing the listener is called the Doppler shift.


The Doppler shift

. The Doppler shift happens with light as well as with sound. A source of light that is approaching the viewer will seem to the viewer to have a higher frequency than a source of light that is receding from that viewer. In 1929, observations of distant galaxies showed that the light from those galaxies behaved as if they were going away from us. If all the distant galaxies are all receding from us on the average, that means that the Universe as a whole could be expanding. It could be blowing up like a balloon.
. If the Universe is expanding, then what did it expand from?
. This is what tells us that the Universe probably does have a finite age, it probably is not eternal and ageless as Einstein wanted to believe.
. But then, okay, how old is the Universe?
. We know from studies of radioactivity of the Earth and Sun that our solar system probably formed about 4.5 billions years ago, which means that the Universe must be at least twice that old, because before our solar system formed, our Milky Way galaxy had to form, and that probably took several billions years by itself.
. It would be reasonable to guess that the Universe is at least twice as old as our Sun and Earth. However, we can't do radioactive dating on distant stars and galaxies. The best we can do is balance a lot of different measurements of the brightness and distance of stars and the red shifting of their light to come up with some ballpark figure. The oldest star clusters whose age we can estimate are about 12 to 15 billions years old.
. So it seems safe to estimate that the age of the Universe is at least 15 billion years old, but probably not more than 20 billion years old.
. This matter is far from being settled by astrophysicists and cosmologists, so stay tuned. There could be radical new developments in the future.

There are at least 3 ways that the age of the Universe can be estimated. I will describe

* The age of the chemical elements.
* The age of the oldest star clusters.
* The age of the oldest white dwarf stars.

The age of the Universe can also be estimated from a cosmological model based on the Hubble constant and the densities of matter and dark energy. This model-based age is currently 13.7 +/- 0.2 Gyr. But this Web page will only deal with actual age measurements, not estimates from cosmological models. The actual age measurements are consistent with the model-based age which increases our confidence in the Big Bang model.

The Age of the Elements

The age of the chemical elements can be estimated using radioactive decay to determine how old a given mixture of atoms is. The most definite ages that can be determined this way are ages since the solidification of rock samples. When a rock solidifies, the chemical elements often get separated into different crystalline grains in the rock. For example, sodium and calcium are both common elements, but their chemical behaviours are quite different, so one usually finds sodium and calcium in different grains in a differentiated rock. Rubidium and strontium are heavier elements that behave chemically much like sodium and calcium. Thus rubidium and strontium are usually found in different grains in a rock. But Rb-87 decays into Sr-87 with a half-life of 47 billion years. And there is another isotope of strontium, Sr-86, which is not produced by any rubidium decay. The isotope Sr-87 is called radiogenic, because it can be produced by radioactive decay, while Sr-86 is non-radiogenic. The Sr-86 is used to determine what fraction of the Sr-87 was produced by radioactive decay. This is done by plotting the Sr-87/Sr-86 ratio versus the Rb-87/Sr-86 ratio. When a rock is first formed, the different grains have a wide range of Rb-87/Sr-86 ratios, but the Sr-87/Sr-86 ratio is the same in all grains because the chemical processes leading to differentiated grains do not separate isotopes. After the rock has been solid for several billion years, a fraction of the Rb-87 will have decayed into Sr-87. Then the Sr-87/Sr-86 ratio will be larger in grains with a large Rb-87/Sr-86 ratio. Do a linear fit of

Sr-87/Sr-86 = a + b*(Rb-87/Sr-86)

and then the slope term is given by

b = 2x - 1

with x being the number of half-lives that the rock has been solid. See the talk.origins isochrone FAQ for more on radioactive dating.

When applied to rocks on the surface of the Earth, the oldest rocks are about 3.8 billion years old. When applied to meteorites, the oldest are 4.56 billion years old. This very well determined age is the age of the Solar System. See the talk.origins age of the Earth FAQ for more on the age of the solar system.

When applied to a mixed together and evolving system like the gas in the Milky Way, no great precision is possible. One problem is that there is no chemical separation into grains of different crystals, so the absolute values of the isotope ratios have to be used instead of the slopes of a linear fit. This requires that we know precisely how much of each isotope was originally present, so an accurate model for element production is needed. One isotope pair that has been used is rhenium and osmium: in particular Re-187 which decays into Os-187 with a half-life of 40 billion years. It looks like 15% of the original Re-187 has decayed, which leads to an age of 8-11 billion years. But this is just the mean formation age of the stuff in the Solar System, and no rhenium or osmium has been made for the last 4.56 billion years. Thus to use this age to determine the age of the Universe, a model of when the elements were made is needed. If all the elements were made in a burst soon after the Big Bang, then the age of the Universe would be to = 8-11 billion years. But if the elements are made continuously at a constant rate, then the mean age of stuff in the Solar System is

(to + tSS)/2 = 8-11 Gyr

which we can solve for the age of the Universe giving

to = 11.5-17.5 Gyr

238U and 232Th are both radioactive with half-lives of 4.468 and 14.05 Gyrs, but the uranium is underabundant in the Solar System compared to the expected production ratio in supernovae. This is not surprising since the 238U has a shorter half-life, and the magnitude of the difference gives an estimate for the age of the Universe. Dauphas (2005, Nature, 435, 1203) combines the Solar System 238U:232Th ratio with the ratio observed in very old, metal poor stars to solve simultaneous equations for both the production ratio and the age of the Universe, obtaining 14.5+2.8-2.2 Gyr.


Radioactive Dating of an Old Star

A very interesting paper by Cowan et al. (1997, ApJ, 480, 246) discusses the thorium abundance in an old halo star. Normally it is not possible to measure the abundance of radioactive isotopes in other stars because the lines are too weak. But in CS 22892-052 the thorium lines can be seen because the iron lines are very weak. The Th/Eu (Europium) ratio in this star is 0.219 compared to 0.369 in the Solar System now. Thorium decays with a half-life of 14.05 Gyr, so the Solar System formed with Th/Eu = 24.6/14.05*0.369 = 0.463. If CS 22892-052 formed with the same Th/Eu ratio it is then 15.2 +/- 3.5 Gyr old. It is actually probably slightly older because some of the thorium that would have gone into the Solar System decayed before the Sun formed, and this correction depends on the nucleosynthesis history of the Milky Way. Nonetheless, this is still an interesting measure of the age of the oldest stars that is independent of the main-sequence lifetime method.

A later paper by Cowan et al. (1999, ApJ, 521, 194) gives 15.6 +/- 4.6 Gyr for the age based on two stars: CS 22892-052 and HD 115444.

A another star, CS 31082-001, shows an age of 12.5 +/- 3 Gyr based on the decay of U-238 [Cayrel, et al. 2001, Nature, 409, 691-692]. Wanajo et al. refine the predicted U/Th production ratio and get 14.1 +/- 2.5 Gyr for the age of this star.


The Age of the Oldest Star Clusters

When stars are burning hydrogen to helium in their cores, they fall on a single curve in the luminosity-temperature plot known as the H-R diagram after its inventors, Hertzsprung and Russell. This track is known as the main sequence, since most stars are found there. Since the luminosity of a star varies like M3 or M4, the lifetime of a star on the main sequence varies like t=const*M/L=k/L0.7. Thus if you measure the luminosity of the most luminous star on the main sequence, you get an upper limit for the age of the cluster:

Age <> 11.5 Gyr.

Hansen et al. have used the HST to measure the ages of white dwarfs in the globular cluster M4, obtaining 12.7 +/- 0.7 Gyr. In 2004 Hansen et al. updated their analysis to give an age for M4 of 12.1 +/- 0.9 Gyr, which is very consistent with the age of globular clusters from the main sequence turnoff. Allowing allowing for the time between the Big Bang and the formation of globular clusters (and its uncertainty) implies an age for the Universe of 12.8 +/- 1.1 Gyr.

Until recently, astronomers estimated that the Big Bang occurred between 12 and 14 billion years ago. To put this in perspective, the Solar System is thought to be 4.5 billion years old and humans have existed as a species for a few million years. Astronomers estimate the age of the universe in two ways: 1) by looking for the oldest stars; and 2) by measuring the rate of expansion of the universe and extrapolating back to the Big Bang; just as crime detectives can trace the origin of a bullet from the holes in a wall.
Older Than the Oldest Stars?

Astronomers can place a lower limit to the age of the universe by studying globular clusters. Globular clusters are a dense collection of roughly a million stars. Stellar densities near the center of the globular cluster are enormous. If we lived near the center of one, there would be several hundred thousand stars closer to us than Proxima Centauri, the star nearest to the Sun.

The life cycle of a star depends upon its mass. High mass stars are much brighter than low mass stars, thus they rapidly burn through their supply of hydrogen fuel. A star like the Sun has enough fuel in its core to burn at its current brightness for approximately 9 billion years. A star that is twice as massive as the Sun will burn through its fuel supply in only 800 million years. A 10 solar mass star, a star that is 10 times more massive than the Sun, burns nearly a thousand times brighter and has only a 20 million year fuel supply. Conversely, a star that is half as massive as the Sun burns slowly enough for its fuel to last more than 20 billion years.

All of the stars in a globular cluster formed at roughly the same time, thus they can serve as cosmic clocks. If a globular cluster is more than 20 million years old, then all of its hydrogen burning stars will be less massive than 10 solar masses. This implies that no individual hydrogen burning star will be more than 1000 times brighter than the Sun. If a globular cluster is more than 2 billion years old, then there will be no hydrogen-burning star more massive than 2 solar masses.

The oldest globular clusters contain only stars less massive than 0.7 solar masses. These low mass stars are much dimmer than the Sun. This observation suggests that the oldest globular clusters are between 11 and 18 billion years old. The uncertainty in this estimate is due to the difficulty in determining the exact distance to a globular cluster (hence, an uncertainty in the brightness (and mass) of the stars in the cluster). Another source of uncertainty in this estimate lies in our ignorance of some of the finer details of stellar evolution. Presumably, the universe itself is at least as old as the oldest globular clusters that reside in it.
Extrapolating Back to the Big Bang

An alternative approach to estimating is the age of the universe is to measure the “Hubble constant”. The Hubble constant is a measure of the current expansion rate of the universe. Cosmologists use this measurement to extrapolate back to the Big Bang. This extrapolation depends on the history of the expansion rate which in turn depends on the current density of the universe and on the composition of the universe.

If the universe is flat and composed mostly of matter, then the age of the universe is
2/(3 Ho)

where Ho is the value of the Hubble constant.

If the universe has a very low density of matter, then its extrapolated age is larger:
1/Ho

If the universe contains a form of matter similar to the cosmological constant, then the inferred age can be even larger.

Many astronomers are working hard to measure the Hubble constant using a variety of different techniques. Until recently, the best estimates ranged from 65 km/sec/Megaparsec to 80 km/sec/Megaparsec, with the best value being about 72 km/sec/Megaparsec. In more familiar units, astronomers believe that 1/Ho is between 12 and 14 billion years.
An Age Crisis?

If we compare the two age determinations, there is a potential crisis. If the universe is flat, and dominated by ordinary or dark matter, the age of the universe as inferred from the Hubble constant would be about 9 billion years. The age of the universe would be shorter than the age of oldest stars. This contradiction implies that either 1) our measurement of the Hubble constant is incorrect, 2) the Big Bang theory is incorrect or 3) that we need a form of matter like a cosmological constant that implies an older age for a given observed expansion rate.

Some astronomers believe that this crisis will pass as soon as measurements improve. If the astronomers who have measured the smaller values of the Hubble constant are correct, and if the smaller estimates of globular cluster ages are also correct, then all is well for the Big Bang theory, even without a cosmological constant.
WMAP Can Measure the Age of the Universe

Measurements by the WMAP satellite can help resolve this crisis. If current ideas about the origin of large-scale structure are correct, then the detailed structure of the cosmic microwave background fluctuations will depend on the current density of the universe, the composition of the universe and its expansion rate. WMAP has been able to determine these parameters with an accuracy of better than 5%. Thus, we can estimate the expansion age of the universe to better than 5%. When we combine the WMAP data with complimentary observations from other CMB experiments (ACBAR and CBI), we are able to determine an age for the universe closer to an accuracy of 1%.

The expansion age measured by WMAP is larger than the oldest globular clusters, so the Big Bang theory has passed an important test. If the expansion age measured by WMAP had been smaller than the oldest globular clusters, then there would have been something fundamentally wrong about either the Big Bang theory or the theory of stellar evolution. Either way, astronomers would have needed to rethink many of their cherished ideas. But our current estimate of age fits well with what we know from other kinds of measurements: the Universe is about 13.7 billion years old!

Closing

Memang banyak sekali pendapat berbeda mengenai usia jagat raya itu, tapi yang terpenting adalah:"read in the name of lord who was created" karena ujung dari pencarian adalah Dia di Atas Segalanya.

sumber:
http:// astrophysicblogs.blogspot.com,
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