AB741. Milankovitch Soal Orbit Bumi Jadi Lebih Elips

 
 

Rahma Sarita: assalamualaikum wr wb

HAL:  Milankovitch Soal Orbit Bumi Jadi Lebih Elips

 
 

 ……
 ……
astronomybasics.org
 ……
wikipedia.org
 ……
nasa.gov
 ……
The earth’s orbit around the sun changes from being nearly circular to highly elliptical. The period of this cycle is about 100,000 years.  Michael Pidwirny / http://www.eoearth.org
 ……
Milankovitch Cycles.   Schematic of the earth’s orbital changes (Milankovitch Cycle) that drive the ice age cycles.  “T” denotes changes in the tilt (or obliquity) of the earth’s axis, “E” denotes changes in the eccentricity of the orbit (due to variations in the minor axis of the ellipse), “P” denotes precession, that is, changes in the direction of the axis tilt at a given point of the orbit. ossfoundation.us – source: Rahmstorf and Schellnhuber (2006).
 ……
http://www.indiana.edu
 ……
 ……
oceanworld.tamu.edu
 ……
 ……
Milutin Milankovitch
(1879-1958)
 ……
The Serbian astrophysicist Milutin Milankovitch is best known for developing one of the most significant theories relating Earth motions and long-term climate change. Born in 1879 in the rural village of Dalj (then part of the Austro-Hungarian Empire, today located in Croatia), Milankovitch attended the Vienna Institute of Technology and graduated in 1904 with a doctorate in technical sciences. After a brief stint as the chief engineer for a construction company, he accepted a faculty position in applied mathematics at the University of Belgrade in 1909—a position he held for the remainder of his life. Milankovitch dedicated his career to developing a mathematical theory of climate based on the seasonal and latitudinal variations of solar radiation received by the Earth. Now known as the Milankovitch Theory, it states that as the Earth travels through space around the sun, cyclical variations in three elements of Earth-sun geometry combine to produce variations in the amount of solar energy that reaches Earth:

  1. Variations in the Earth’s orbital eccentricity—the shape of the orbit around the sun.
  2. Changes in obliquity—changes in the angle that Earth’s axis makes with the plane of Earth’s orbit.
  3. Precession—the change in the direction of the Earth’s axis of rotation, i.e., the axis of rotation behaves like the spin axis of a top that is winding down; hence it traces a circle on the celestial sphere over a period of time.

Together, the periods of these orbital motions have become known as Milankovitch cycles.

 ……
But, for about 50 years, Milankovitch’s theory was largely ignored. Then, in 1976, a study published in the journal Science examined deep-sea sediment cores and found that Milankovitch’s theory did in fact correspond to periods of climate change (Hays et al. 1976). Specifically, the authors were able to extract the record of temperature change going back 450,000 years and found that major variations in climate were closely associated with changes in the geometry (eccentricity, obliquity, and precession) of Earth’s orbit. Indeed, ice ages had occurred when the Earth was going through different stages of orbital variation. Since this study, the National Research Council of the U.S. National Academy of Sciences has embraced the Milankovitch Cycle model.
 ……
source: earthobservatory.nasa.gov
Milutin Milankovitch – Orbital Variations – Milankovitch Theory
 ……
 ……
 ……
John Kerry: Climate change as big a

threat as terrorism, poverty, WMDs

By Steve Almasy, CNN
updated 8:42 AM EST, Mon February 17, 2014

U.S. Secretary of State John Kerry gestures during a speech on climate change in Jakarta, Indonesia.
 ……
(CNN) — Saying that climate change ranks among the world’s most serious problems — such as disease outbreaks, poverty, terrorism and the proliferation of weapons of mass destruction — U.S. Secretary of State John Kerry called on all nations to respond to “the greatest challenge of our generation.”

Kerry, speaking before college students in Jakarta, Indonesia, also criticized climate-change deniers, saying “a few loud interest groups” shouldn’t be given the chance to misdirect the conversation.

Kerry reiterated U.S. President Barack Obama’s assertion in the State of the Union address that climate change is an undeniable fact.

“We should not allow a tiny minority of shoddy scientists and science and extreme ideologues to compete with scientific fact,” Kerry said at the U.S. Embassy’s @america function in Jakarta.

Too many ecosystems such as Indonesia’s are in peril because of climate change, he said. He said Indonesia’s important fishing trade would be adversely affected, citing a study that said catches in the island nation will decline by 40 percent.

 ……
 ……
Secretary of State John Kerry talks with reporters before taking off for a flight to South Korea, Wednesday, Feb. 12, 2014, at Andrews Air Force Base, Md. Kerry is visiting South Korea, China, Indonesia, and the United Arab Emirates on a 7 day trip. ( AP Photo / Evan Vucci, Pool ) – February 12, 2014    3:09 PM
 ……
U.S. Secretary of State John Kerry, center, works on his phone during a refueling stop at Elmendorf Air Force Base on Wednesday, Feb. 12, 2014, in Anchorage, Alaska. Kerry is visiting South Korea, China, Indonesia, and the United Arab Emirates on a 7 day trip. ( AP Photo / Evan Vucci, Pool ) – February 13, 2014     3:03 AM
 ……
Staff members for Secretary of State John Kerry walk to his plane after a refueling stop at Elmendorf Air Force Base on Wednesday, Feb. 12, 2014, in Anchorage, Alaska. Kerry is visiting South Korea, China, Indonesia, and the United Arab Emirates on a 7 day trip. ( AP Photo / Evan Vucci, Pool ) – February 13, 2014     3:03 AM
 ……
U.S. Secretary of State John Kerry, center left, looks over his notes before delivering remarks on climate change after a tour of the Foton Cummins Engine plant in Beijing, China Saturday, Feb. 15, 2014. Kerry toured the plant and made remarks on climate change cooperation between the United States and China. ( AP Photo / Evan Vucci, Pool ) – February 15, 2014    6:47 PM
 ……
Secretary of State John Kerry steps off his plane after arriving at Halim Air Field on Saturday, Feb. 15, 2014, in Jakarta, Indonesia. ( AP Photo / Evan Vucci, Pool ) – February 15, 2014     7:12 AM
 ……
U.S. Secretary of State John Kerry, right, tours the Istiqlal Mosque with Grand Imam K.H. Ali Mustafa Yaqub on Sunday, Feb. 16, 2014, in Jakarta. The Istiqlal Mosque is the largest mosque in Southeast Asia, capable of holding 120,000 people, and is the National Mosque of Indonesia. ( AP Photo / Evan Vucci, Pool ) – February 16, 2014    1:15 AM
 ……
U.S. Secretary of State John Kerry greets a class of students while touring the Istiqlal Mosque with Grand Imam K.H. Ali Mustafa Yaqub (2nd R) in Jakarta February 16, 2014. REUTERS / Evan Vucci/Pool ( INDONESIA – Tags: POLITICS RELIGION ) – February 15, 2014    11:57 PM
 ……
Indonesian police stand guard the Istiqlal Mosque ahead of the visit of U.S. Secretary of State John Kerry in Jakarta, Indonesia, Sunday, Feb 16, 2014. Kerry is scheduled to visit the world’s most populous Muslim country on Sunday. ( AP Photo / Achmad Ibrahim ) – February 16, 2014     12:09 AM
 ……
Indonesia police bomb squad guards Istiqlal Mosque ahead of the visit of U.S. Secretary of State John Kerry in Jakarta, Indonesia, Sunday, Feb 16, 2014. Kerry is scheduled to visit the world’s most populous Muslim country on Sunday. ( AP Photo / Achmad Ibrahim ) – February 16, 2014    12:09 AM
 ……
U.S. Secretary of State John Kerry, left, speaks as Indonesian Foreign Minister Marty Natalegawa, right, listens during a press conference after their meeting Monday, Feb. 17, 2014, in Jakarta, Indonesia. ( AP Photo / Tatan Syuflana ) – February 17, 2014     12:27 AM
 ……
U.S. Secretary of State John Kerry (C) arrives for a news conference with Indonesian Foreign Minister Marty Natalegawa (front L) at the Pancasila building in Jakarta, February 17, 2014. REUTERS / Evan Vucci / Pool ( INDONESIA – Tags: POLITICS ) – February 17, 2014    12:43 AM
 ……
U.S. Secretary of State John Kerry gestures during a speech on climate change in Jakarta, February 16, 2014. REUTERS / Evan Vucci / Pool ( INDONESIA – Tags: POLITICS ENVIRONMENT ) – February 16, 2014    6:15 AM
 ……
Students listen as Secretary of State John Kerry delivers a speech on climate change on Sunday, Feb. 16, 2014, in Jakarta, Indonesia. Climate change may be the world’s “most fearsome” weapon of mass destruction and urgent global action is needed to combat it, Kerry said on Sunday, comparing those who deny its existence or question its causes to people who insist the Earth is flat. ( AP Photo / Evan Vucci, Pool ) – February 16, 2014   6:36 AM
 ……
AP 10 ThingsToSee – Secretary of State John Kerry takes a selfie with a group of students before delivering a speech on climate change on Sunday, Feb. 16, 2014, in Jakarta, Indonesia. Climate change may be the world’s “most fearsome” weapon of mass destruction and urgent global action is needed to combat it, Kerry said on Sunday, comparing those who deny its existence or question its causes to people who insist the Earth is flat. ( AP Photo / Evan Vucci, File ) – February 20, 2014    11:21 AM
 ……
U.S. Secretary of State John Kerry, left, signs a guest book as Secretary-General of Association of Southeast Asian Nations (ASEAN), Le Luong Minh at the ASEAN headquarters in Jakarta, Indonesia, Sunday, Feb 16, 2014. ( AP Photo / Achmad Ibrahim ) – February 16, 2014    5:57 AM
 ……
U.S. Secretary of State John Kerry waves as he departs Halim Perdanakusuma airport in Jakarta February 17, 2014. REUTERS /Evan Vucci/Pool ( INDONESIA – Tags: POLITICS ) – February 17, 2014    1:16 PM
 ……
 ……
 ……

 
 

Sekitar 4 hari sebelum gunung Kelud meletus, berita-berita sedang ramai soal gunung Sinabung yang sudah sekitar empat bulan terjadi aktivitas vulkanik pada status Awas dengan beberapa kali meletus, dan pada awal Februari 2014 satu dari beberapa letusan itu telah menyebabkan 14 orang tewas di tempat lalu bertambah jadi 17 karena yang sempat dibawa ke rumah sakit kemudian juga tewas. Berita soal gunung Kelud juga saat itu sudah mulai ramai karena telah menunjukkan aktivitas vulkanik yang meningkat sebelum kemudian meletus pada 13 Februari 2014.

Pada saat itu pula, sekitar empat hari sebelum gunung Kelud meletus, muncul di kepalaku pikiran seperti yang pernah juga aku ungkapkan sebelum ini, mengenai apa yang akan terjadi kalau beberapa puluh dari 127 gunung berapi aktif di Indonesia meletus secara bersamaan, apakah akan terjadi perubahan rute orbit bumi. Kurang lebih seperti kalau balon ditiup sampai maksimal, lalu tidak diikat di bagian untuk meniup itu, dan dilempar saja ke atas, maka akan terjadi pergerakan tak tentu arah dari balon itu akibat dorongan angin yang keluar dari balon.

Semula aku pikir gunung Kelud tidak akan meletus, agar tidak menambah dramatis apa yang sedang ada di pikiranku itu. Tahun 2007 pernah juga gunung Kelud menunjukkan aktifitas yang meningkat, namun tidak meletus melainkan muncul anak Kelud pada kawah gunung Kelud. Akan tetapi ternyata kali ini lain, gunung Kelud meletus juga pada 13 Februari 2014, dengan letusan yang lebih besar dari letusan-letusan beberapa tahun terdahulu.

Saat aku mencari info lebih lanjut soal apakah orbit bumi bisa berubah kalau beberapa puluh gunung meletus bersamaan pada lokasi yang berdekatan pada suatu kawasan regional, yang aku temukan adalah sebuah teori oleh Milutin Milankovitch soal jaman es di bumi yang diperkirakan terjadi akibat orbit bumi berubah, dari cenderung berbentuk lingkaran ke cenderung berbentuk elips, dengan beberapa siklus antara lain 100 ribu tahun sekali.

Teori oleh Milutin Milankovitch itu selama 50 tahun tidak terlalu diperhatikan, karena kurang data yang lengkap untuk mendukung teori itu. Sampai kemudian pada 10 Desember 1976 muncul artikel di jurnal Science dengan judul “Variations in the Earth’s Orbit Pacemaker of the Ice Ages” hasil penelitian  J.D. Hays, J. Imbrie, dan N.J. Shackleton,  berdasarkan data yang dikumpulkan dari ekspedisi pengambilan contoh sedimen di dasar laut yang dapat mengungkap data perubahan iklim selama 450 ribu tahun belakangan ini. Disimpulkan bahwa teori Milutin Milankovitch sesuai dengan periode-periode perubahan iklim.

Beberapa hari kemudian pada 17 Februari 2014 berketepatan dengan menlu AS John Kerry berkunjung ke Jakarta. Dan pada ceramah yang diberikan di kedutaan AS di Jakarta yang dihadiri para pelajar Indonesia, John Kerry menyebut soal bahaya perubahan iklim yang dapat disamakan dengan bahaya terorisme, kemiskinan, dan senjata pemusnah massal.

Dan, ini yang menarik, Milutin Milankhovitch itu seperti terkait dengan persoalan kita. Selain karena meninggal pada tahun 1958 seperti tahun kelahiranku, juga nama Milutin Milankhovitch seperti terkait dengan persoalan kita.

Nama depan Milutin seperti memuat kata Pemilu yang pada tahun 2014 ini akan dijalani oleh bangsa Indonesia. Juga seperti memuat nama teman sekolah dan juga tetanggaku yang dulu tinggal di jalan Sukabumi 19 yaitu Tutin, adik dari temanku Wisnu yang sering juga aku sebut di surat sebelum ini. Pada suratku soal CEO baru Microsoft yaitu Satya Nadella yang pada tanggal 4 Februari 2014 secara resmi diumumkan sebagai orang ketiga yang menempati jabatan CEO Microsoft setelah Bill Gates dan Steve Balmer, aku menyebutkan pula soal temanku yang lain yang juga bernama Wisnu, dan mempunyai adik bernama Satya yang pernah satu kantor denganku di American Express tahun 1989.

Sedangkan nama belakang Milankovitch seperti terkait dengan klub sepakbola Inter Milan yang pada tahun 2013 dibeli oleh pak Erick Thohir pemilik Jak-TV tempat kamu bekerja.

Semua ini seperti pesan dari langit, bahwa soal pergerakan bumi menyimpang keluar dari jalur orbit yang ada, bukanlah soal yang tidak mungkin. Dan mengingat sudah muncul beberapa bencana besar yang seperti terkait persoalan kita, kalau kita tidak hati-hati dalam menangani persoalan kita, dapat berujung ke bumi ini keluar orbit, menubruk planet lain di tata surya kita, lalu kiamat dan kita akan mengalami kesulitan besar di akherat kelak.

 
 

Jakarta,  28 Februari 2014.
wassalam,

 
 

a.m. firmansyah
sms +62812 183 1538

 
 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: