Tuesday, 27 January 2009

Annular Solar Eclipse on January 26, 2009

Annular Solar Eclipse on January 26, 2009

The year 2009 will feature a range of eclipses, starting with an annular solar eclipse on January 26. This particular eclipse will be visible from an area that covers the Indian Ocean and western Indonesia.

This illustration is not to scale and shows a general annular solar eclipse, not the January 2009 eclipse.

Where is the Eclipse Visible?

Sources such as NASA say that the eclipse will be seen in the larger path of the moon's penumbral shadow, which includes the southern third of Africa, Madagascar, many parts of Australia (except Tasmania), south-east India, south-east Asia and Indonesia, on January 26, 2009.
According to Harrington (1997), the cities of Kotabumi and Telukbetung in Indonesia will experience more than six minutes of annularity while Krakatoa (or Krakatau), which will be closer to the shadow’s edge, will experience less than five minutes of annularity. The town of Sampit, in Indonesia’s central Kalimantan province, and Samarinda, the capital of the Indonesian province of East Kalimantan, will witness a lopsided ring-of-fire sunset eclipse as they will be located near the southern extreme of annularity.

The Eclipse’s Path

The annular eclipse’s path first begins in the south Atlantic at 06:06 Coordinated Universal Time (UTC) when the moon’s antumbral shadow meets Earth and forms a 363-kilometer wide corridor. Traveling eastward, the shadow quickly sweeps south of the African continent, missing it by about 900 kilometers. Slowly curving to the northeast the path crosses the southern Indian Ocean. The image below shows the solar eclipse’s annular path on January 26, 2009. Timeanddate.com also created an animation for this eclipse.

This image shows the solar eclipse’s annular path on January 26, 2009. The different shades of red depict the eclipse's visibility, with the strongest and innermost shade depicting 75 percent visibility, followed by 50 percent visibility, 25 percent visibility, and down to as low as zero percent visibility. The maximum eclipse is visible at various locations.
The point of greatest eclipse, with seven minutes and 54 seconds of annularity, occurs where the Indian Ocean is, about halfway between Madagascar and Australia. It takes place at 07:58:39 UTC. The path width is about 280 kilometers at this point and the sun is 73 degrees above the flat horizon formed by the open ocean.
The central track continues north-east where it finally encounters land in the form of the Cocos Islands and onward to southern Sumatra and western Java in Indonesia. At 09:40 UTC, the central line duration is six minutes and 18 seconds and the sun's altitude at 25 degrees.
In its final minutes, the antumbral shadow cuts across central Borneo and clips the northwestern edge of Celebes before ending just short of Mindanao, Philippines at 09:52 UTC. During a three-hour and 46-minute trajectory across earth, the moon's antumbra travels about 14,500 kilometers and covers 0.9 percent of the planet’s surface area. An antumbra refers to the moon’s “negative” shadow that appears when the moon is on the far side of its orbit and its umbral shadow is not long enough to reach the earth. The eclipse’s partial phases are visible primarily from southern Africa, Australia, Southeast Asia and Indonesia.
This is the 50th eclipse of Saros 131. The Saros cycle refers to a period of about 18 years, 11 days and eight hours when eclipses would recur. A number of eclipses occur within the series. The Saros 131 family began with a long series of 22 partial eclipses that started in the northern hemisphere on August 1, 1125.
The first annular eclipse of Saros 131 occurred on August 4, 1720. The series will produce 29 more annular eclipses, with the last of these types of eclipses on June 18, 2243. Saros 131 will finish on September 2, 2369.

Eclipses in 2009

The eclipse set for January 26 is not the only eclipse that will occur in 2009. The list of eclipses for 2009 includes:
  • An annular solar eclipse on January 26.
  • A penumbral lunar eclipse on February 9.
  • A penumbral lunar eclipse on July 7.
  • A total solar eclipse on July 22.
  • A penumbral lunar eclipse on August 6.
  • A partial lunar eclipse on December 31.
Timeanddate.com will provide information about the other eclipses closer to the time of their occurrence and as more details about them come on hand.
Note: Eclipse information courtesy of Fred Espenak, NASA/Goddard Space Flight Center, and P. Harrington, author of Eclipse! The What, Where, When, Why & How Guide to Watching Solar and Lunar Eclipses.

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Saturday, 24 January 2009

Astrofisika iTV


Bertafakur dengan Astro Fisika Part 2

Bertafakur dengan Astrofisika Part 1

Jakarta, Animation Click for Dynamic

Jambu, Animation Click for Dynamic

Samarinda, Animation Click for Dynamic

Solar Eclipse in Bandung Past, Present, and Future

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Gerhana Matahari Cincin Tgl 26 Januari 2009

Gerhana-Gerhana yang Akan Terjadi pada Tahun 2009

2009 February 09
[ Lunar: Penumbral ]

2009 July 07
[ Lunar: Penumbral ]

[ Solar: Total ]

2009 August 05-06
[ Lunar: Penumbral ]

2009 December 31
[ Lunar: Partial ]

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E-mail: hmnao@ukho.gov.uk
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Her Majesty's Nautical Almanac Office (HMNAO), now part of the United Kingdom Hydrographic Office, was established in 1832 on the site of the Royal Greenwich Observatory (RGO), where the Nautical Almanac had been published since 1767.
In 1937 it became part of RGO and moved with it, first to Herstmonceux, near Hailsham in East Sussex in 1948, then to Cambridge in 1990. When RGO closed in 1998 HMNAO was transferred to the Rutherford Appleton Laboratory, near Abingdon in Oxfordshire. In December 2006, HMNAO was transferred to the United Kingdom Hydrographic Office, which is based in Taunton in Somerset.

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Tuesday, 20 January 2009

Nobel Fisika Indonesia

Central for Research and Development for Winning

Nobel Prize in Physics at Indonesia

"Belajar Kepada Dua Orang Hebat ini"

"in recognition of the extraordinary service they rendered by their researches into the influence of magnetism upon radiation phenomena"
Hendrik Antoon LorentzPieter Zeeman
Hendrik Antoon LorentzPieter Zeeman
half 1/2 of the prizehalf 1/2 of the prize
the Netherlandsthe Netherlands
Leiden University
Leiden, the Netherlands
Amsterdam University
Amsterdam, the Netherlands
b. 1853
d. 1928
b. 1865
d. 1943

“Everybody felt his (Lorentz’s) superiority, but nobody felt oppressed by it. Though he had no illusions about people and human affairs, he was full of kindness toward everybody and everything. Never did he give the impression of domineering, always of serving and helping. He was extremely conscientious, without allowing anything to assume undue importance; a subtle humour guarded him, which was reflected in his eyes and in his smile.”
Albert Einstein

"Pengakuan terhadap pelayanan yang luar biasa yang telah dilakukan mereka dalam riset pengaruh magnetisme dalam fenomena radiasi".

Hendrik Antoon Lorentz

Born18 July 1853
Died4 February 1928 (aged 74)
Alma materUniversity of Leiden
Doctoral advisorPieter Rijke
Doctoral studentsGeertruida L. de Haas-Lorentz
Adriaan Fokker
Leonard Ornstein
Known forTheory of EM radiation
Lorentz force
Notable awardsNobel Prize for Physics (1902)

Hendrik Antoon Lorentz (1853-1928) ialah fisikawan Belanda yang memenangkan Penghargaan Nobel dalam Fisika bersama dengan Pieter Zeeman pada 1902.

Dilahirkan di Arnhem, Belanda. Ia belajar di Universitas Leiden. Pada usia 19 tahun ia kembali ke Arnhem dan mengajar di salah satu SMA di sana. Sambil mengajar, ia menyiapkan tesis doktoral yang memperluas teori James Clerk Maxwell mengenai elektromagnet yang meliputi rincian dari pemantulan dan pembiasan cahaya.

Pada 1878 ia menjadi guru besar fisika teoretis di Leyden yang merupakan tempat kerja pertamanya. Ia tinggal di sana selama 34 tahun, lalu pindah ke Haarlem. Lorentz meneruskan pekerjaannya untuk menyederhanakan teori Maxwell dan memperkenalkan gagasan bahwa medan elektromagnetik ditimbulkan oleh muatan listrik pada tingkat atom. Ia mengemukakan bahwa pemancaran cahaya oleh atom dan berbagai gejala optik dapat dirunut ke gerak dan interaksi energi atom.

Pada 1896, salah satu mahasiswanya Pieter Zeeman menemukan bahwa garis spektral atom dalam medan magnet akan terpecah menjadi beberapa komponen yang frekuensinya agak berbeda. Hal tersebut membenarkan pekerjaan Lorentz, sehingga mereka berdua dianugerahi Hadiah Nobel pada 1902.Pada 1895, Lorentz mendapatkan seperangkat persamaan yang mentransformasikan kuantitas elektromagnetik dari suatu kerangka acuan ke kerangka acuan lain yang bergerak relatif terhadap yang pertama meski pentingnya penemuan itu baru disadari 10 tahun kemudian saat Albert Einstein mengemukakan teori relativitas khususnya.

Lorentz (dan fisikawan Irlandia G.F. Fitzgerald secara independen) mengusulkan bahwa hasil negatif eksperimen Michelson-Morley bisa dipahami jika panjang dalam arah gerak relatif terhadap pengamat mengerut. Eksperimen selanjutnya memperlihatkan bahwa meski terjadi pengerutan, hal itu bukan karena penyebab yang nyata dari hasil Michelson dan Edward Morley. Penyebabnya ialah karena tiadanya 'eter' yang berlaku sebagai kerangka acuan universal.

"According to well-known electrodynamic laws, an electron moving in a magnetic field is acted upon by a force which runs perpendicular to the direction of motion of the electron and to the direction of the magnetic field, and whose magnitude is easily determined. "
~P. Zeeman~

Pieter Zeeman

Born25 May 1865
Zonnemaire, Netherlands
Died9 October 1943 (aged 78)
Amsterdam, Netherlands
Alma materUniversity of Leiden
Doctoral advisorHeike Kamerlingh Onnes
Known forZeeman effect
Notable awardsNobel Prize for Physics (1902)

Pieter Zeeman (25 Mei 18659 Oktober 1943) (IPA [ze:mɑn]) ialah fisikawan Belanda yang menerima Penghargaan Nobel dalam Fisika pada 1902 dengan Hendrik Antoon Lorentz atas penemuan efek Zeeman.

Zeeman lahir di Zonnemaire (di pulau Schouwen-Duiveland, provinsi Zeeland) dari Wilhelmina Worst dan Catharinus Farandinus Zeeman, seorang menteri Lutheran. Ia bersekolah di HBS di Zierikzee yang berdekatan dan kemudian belajar bahasa-bahasa klasik di gimnasium di Delft selama 2 tahun. Selama masa ini, ia menerbitkan laporan tentang aurora borealis yang terlihat dari Zonnemaire. Ia memasuki Universitas Leiden pada 1885, di mana ia belajar dengan Hendrik A. Lorentz dan Heike Kamerlingh Onnes dan menjadi asisten di laboratorium Heike Kamerlingh-Onnes pada 1895. Ia menerima gelar doktor pada 1893 untuk disertasinya mengenai yang disebut efek Kerr, untuk penelitian di mana ia menerima medali emas dari Hollandsche Maatschappij di tahun sebelumnya. Setelah setahun di Institut Kohlrausch, Strasbourg, ia menjadi privatdozent di Leiden dan menikahi Elisabeth Lebret, yang dengannya ia memiliki seorang putra dan 3 putri. Dari 1896 hingga pensiun, Zeeman berada di fakultas di Universiteit van Amsterdam (dosen, 1896; luar biasa, 1900; biasa, 1908). Pada 1908 ia menggantikan Johannes van der Waals sebagai direktur laboratorium fisika universitas itu, Lembaga Fisika.

Selama di Leiden, Zeeman menemukan sebuah efek yang dinamaI menurut namanya. Ia sedang mencari interaksi antara efek magnet dan optik. Michael Faraday telah mengamati medan magnetik pada garis spektrum di awal 1862, namun tanpa hasil positif. Zeeman mengulangi eksperimen itu, menggunakan garangan difraksi tenaga resolusi tinggi dan menemukan bahwa garis emisi natrium diperluas (1896). Hendrik Lorentz dan Zeeman menjelaskan fenomena itu dengan memprkirakan bahwa elektron (ditemukan di tahun sebelumnya oleh Joseph John Thomson) pindah dalam atom dan cahaya yang dipancarkan. Pengukuran frekuensi puncak garis yang meluas memungkinkannya menentukan perbandingan e/m. Di Amsterdam, di tahun berikutnya, Zeeman bisa memecah garis natrium ke dalam triplet, seperti yang diperkirakan oleh Lorentz. Untuk karya ini Zeeman dan Lorentz menerima Penghargaan Nobel dalam Fisika pada 1902.

Zeeman melanjutkan penelitianya mengenai efek Zeeman, namun keterbatasan laboratoriumnya di Amsterdam mempersulit hasil yang lebih akurat. Masalah ini tak terpecahkan hingga pembangunan laboratorium baru pada 1923 (sejak 1940 Laboratorium Zeeman). Ia juga mengukur kecepatan cahaya dalam medium bergerak, menunjukkan bahwa harga koefisien Fresnel bervariasi menurut panjang gelombang, perkiraan dari teori relativitas. Hanya setelah 1923 ia kembali pada pengukuran efek Zeeman, mengukur garis spektrum beberapa gas mulia dan rhenium. Zeeman menjabat sebagai sekretaris (1912-1920) dan ketua (1931) Divisi Fisika Koninklijke Nederlandse Akademie van Wetenschappen; sebagai pimpinan Commission Internationale des Poids et Mesures di Paris dari 1940 hingga 1943; dan sebagai rector magnificus Universitas Amsterdam dari 1920 hingga 1923. Ia menerima gelar doktor kehormatan dari 10 perguruan tingi dan penghargaan dari kelompok ilmiah paling bergengsi, termasuk Académie des Sciences, Royal Society, dan National Academy of Sciences. Dengan A.D. Fokker, ia menyunting karya H.A. Lorentz ('s-Gravenhage: Martinus NijhofF, 1934-1939).

Ia meninggal di Amsterdam.

Award Ceremony Speech

Presentation Speech by Professor Hj. Théel, President of the Royal Swedish Academy of Sciences on December 10, 1902
Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.

The Royal Swedish Academy of Sciences has decided to award this year's Nobel Prize for Physics to Professor Dr. Hendrik Antoon Lorentz of Leiden and Professor Dr. Pieter Zeeman of Amsterdam for their pioneering work on the connection between optical and electromagnetic phenomena.

Since the law of the conservation of energy was recognized as the first basic principle of modern physics, no realm of that science during the remarkable developments which have been based on this foundation has proved more fruitful than that which has had as its object the investigation of the connection between the phenomena of light and electricity.

Faraday, the great founder of the modern science of electricity, suspected this connection and devoted a great part of his experimental research to this very question. However, Maxwell was the first to take up Faraday's ideas again and develop them into a complete mathematical theory. According to this theory electrodynamic effects are transmitted through space at a finite speed and cause electrical currents, so-called displacement currents, even in non-conductors. Hence, every electrical current of periodically changing direction gives rise to an electrical wave motion, and light consists of just such a wave motion with an extremely short period.

This so-called electromagnetic theory of light of Maxwell's at first aroused comparatively little interest. Twenty years after its first appearance however it led to a scientific discovery which demonstrated its great significance in no uncertain manner. The German physicist Heinrich Hertz then succeeded in demonstrating that the electrical vibrations - which are generated under certain conditions when an electrically charged body is discharged - are propagated through the surrounding space in the form of a wave motion, and that the wave motion spreads at the speed of light and also possesses its properties. This gave a firm experimental basis for the electromagnetic theory of light.

In certain respects however Maxwell's theory of light was inadequate, in that it left individual phenomena unexplained. The greatest credit for the further development of the electromagnetic theory of light is due to Professor Lorentz, whose theoretical work on this subject has borne the richest fruit. While Maxwell's theory is free from any assumptions of an atomistic nature, Lorentz starts from the hypothesis that in matter extremely small particles, called electrons, are the carriers of certain specific charges. These electrons move freely in so-called conductors and thus produce an electrical current, whereas in non-conductors their movement is apparent through electrical resistance. Starting from this simple hypothesis, Lorentz has been able not only to explain everything that the older theory explained but, in addition, to overcome some of its greatest shortcomings.

Alongside the theoretical development of the electromagnetic theory of light, experimental work also continued without interruption, and attempts were made to demonstrate in every detail the analogy between electrical wave motion and light. However, it was not sufficient to show a complete analogy between these phenomena; scientists wished far more to show that they were identical in nature, and to this end they attempted to demonstrate that magnetic forces act upon light in the same way as upon electric currents. It is this that Faraday was trying to prove, and the relevant experiments carried out by him led to the discovery of the rotation of the polarization plane of light by the effect of magnetic forces. His attempt to demonstrate the influence of magnetism on the radiation from a source of light - the last experiment with which Faraday was occupied - was, however, unsuccessful.

Professor Zeeman has recently succeeded in solving just this problem, which has up till now been the object of fruitless exertions on the part of many perspicacious research workers. Guided by the electromagnetic theory of light, Zeeman took up Faraday's last experiment, and, after many unsuccessful attempts, finally succeeded in demonstrating that the radiation from a source of light changes its nature under the influence of magnetic forces in such a way that the different spectral lines of which it consisted were resolved into several components. The consequences of this discovery give a magnificent example of the importance of theory to experimental research. Not only was Professor Lorentz, with the aid of his electron theory, able to explain satisfactorily the phenomena discovered by Professor Zeeman, but certain details which had hitherto escaped Professor Zeeman's attention could also be foreseen, and were afterwards confirmed by him. He showed, in fact, that the spectral lines which were split under the influence of magnetism consisted of polarized light, or in other words that the light vibrations are orientated in one particular way under the influence of the magnetic force, and in a way which varies according to the direction of the beam of light in relation to this force.

For the physicist this discovery - the Zeeman effect - represents one of the most important experimental advances that recent decades have to show. For, through the demonstration that light is affected by magnetism in accordance with the same laws as vibrating electrically charged particles, clearly not only has the strongest support been given to the electromagnetic theory of light, but the consequences of Zeeman's discovery promise to yield the most interesting contributions to our knowledge of the constitution of spectra and of the molecular structure of matter. For these reasons the Swedish Royal Academy of Sciences has come to the conclusion that the discovery outlined here is of such great importance for the understanding of the connection between the forces of Nature and for the development of physical science that its recognition by the award of the Nobel Prize for Physics is justified. The Academy also bore in mind the great part which Professor Lorentz has played in the following up of this discovery through his masterly theory of electrons, which is moreover of the greatest significance as a guiding principle in various other realms.

Since the discovery in physics which the Royal Academy of Sciences wishes to recognize on this occasion represents the result of the most perspicacious research, both theoretical and experimental, the Academy considers that a division of the Nobel Prize for Physics between the two outstanding research workers, Professor Lorentz and Professor Zeeman, for their work on the connection between light and magnetism, is not only justified, but just.
From Nobel Lectures, Physics 1901-1921, Elsevier Publishing Company, Amsterdam, 1967 


1. Wikipedia

2. Nobel Prize Org.

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1. DEPDIKNAS Republik Indonesia
2. Kementrian Riset dan Teknologi Indonesia
3. Lembaga Ilmu Pengetahuan Indonesia (LIPI)
4. Akademi Ilmu Pengetahuan Indonesia
5. Tim Olimpiade Fisika Indonesia
Disusun Ulang Oleh: 

Arip Nurahman

Pendidikan Fisika, FPMIPA, Universitas Pendidikan Indonesia
Follower Open Course Ware at MIT-Harvard University, USA.

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