Mars Canyon Formed When Plug Was Pulled, Study Suggests

By Andrea Thompson
Senior Writer
posted: 25 August 2009
11:28 am ET

Mars' great canyon complex, Valles Marineris, dwarfs the size and splendor of Earth's own Grand Canyon. But while geologists have a formed a fairly complete picture of how the Grand Canyon formed, the mechanisms that carved out Valles Marineris and its component canyons have been a longstanding mystery, with explanations ranging from massive floods to tectonic processes like those that cause earthquakes and build mountains on Earth.

"How did these gigantic canyons really form? Were they all formed by floods, or were other things going on?" asks John Adams of the University of Washington in Seattle and lead author of a new study that seeks to answer the questions. "These have been controversial questions going back to the very first Mariner pictures of Mars. And they're still controversial questions, which means we don't really fully understand what's going on yet."

The answer for how at least parts of the canyon complex formed may lie in Hebes Chasma, a 190-mile-long (310-kilometer) scar cut into the Martian surface and connected to the main body of Valles Marineris.

Adams and his colleagues, Alan Gillespie and David Montgomery, think that Hebes, and other chasms, might have formed after salts in the surface layers were heated up, causing water to melt out below the surface. This water then rushed out through underground plumbing, causing the layers of dirt and rock above to collapse, creating the canyon scar in the surface.

Heating salts

Montgomery and Gillespie began with the observation of sulfate salts in the area of the canyons. (These compounds have been found in numerous spots around the Martian surface by orbiting spacecraft and robotic rovers.)

These salts are hydrated, which means that molecules of water are attached to the sulfate molecules. Montgomery and Gillespie thought about what would happen if those hydrated salts were heated up. The physics and chemistry involved in the process indicated that the water would separate out from the salts, taking with it some dissolved materials. This muddy, briny water would pool up underground, causing an increase in volume under the surface.

The heating of these salts on Mars isn't a stretch, "because it gets hotter as you go down with depth of course," Adams explained. "But more importantly, the huge canyon complex of Mars is right next to the huge volcanic complex, the Tharsis plateau." The heat involved with volcanic processes could have warmed up the salts in the Martian regolith.

Once the muddy water was separated, it would have to escape somehow from its subterranean well because there wasn't enough room under the dirt and rocks to hold all that newly formed water. The two possibilities for the water's escape were: bursting out over the surface; or funneling out below it, like a plug pulled from a bathtub drain.

The scientists needed a place to test out the drain part of the theory, which is where Hebes Chasma came in.

No way in or out

Hebes Chasma was of interest because it is "the very best example of a fairly large canyon in the Valles Marineris complex that has absolutely no inlet or outlet on the surface," Adams told SPACE.com. "There's no way that water could have gone out and over the edge there." So Hebes Chasma could not have formed by erosion from giant floods, like the carving of the Grand Canyon but on a larger scale.

Montgomery and Gillespie and other researchers looked to see if the landforms found in Hebes Chasma were what would be expected of a situation in which the muddy brine drained out of it underground pool through a series of subsurface channels, like pipes. Adams and his colleagues made detailed geologic maps of the region to see if the features were consistent.

They also enlisted the help of geologists at the University of Texas at Austin, who built a desktop-sized scale model of Hebes Chasma and filled it with silicon gel and sand mixtures, then drained it to see what would happen.

"The results of that were absolutely astounding to us," Adams said — they matched the formations found in Hebes Chasma to a T.

The match of the two approaches led Adams and his colleagues to conclude that Montgomery and Gillespie's process likely explained the formation of Hebes Chasma.

There are, of course, still plenty of unanswered questions.

More drained chasms?

For one thing, the scientists don't know exactly when Hebes formed or how long the process took.

Adams said the chasm likely formed early in Mars' history, with the process stopping several billion years ago.

"It may have taken a few million years, or a hundred million years, we just don't know the answer to that," Adams said.

Another mystery is where all that muddy brine went to.

"This is still the big mystery," Adams said.

It's possible that the briny mixture traveled underground and came up and out elsewhere — a possible source of the outflow floods thought to have formed other parts of the canyon.

Adams and his colleagues plan to look closely at more chasms that also show evidence of material sliding down into depressions in the surface to see if they can also be explained by this mechanism.

How much of Valles Marineris might have formed from the drainage of muddy brines isn't known, and it's likely that the whole system formed from a "mixed bag" of mechanisms, including floods, drainage and tectonic forces, Adams said.

The new study was detailed in the August issue of the journal Geology.

New Asian Communications Satellite Launches to Space

By Stephen Clark


posted: 11 August 2009
04:51 pm ET

A Proton rocket sent an Asian communications satellite on the way to orbit Tuesday, successfully completing the first leg of a 9-hour mission to deliver the four-ton craft to its new home in space.

With six engines blazing a fiery trail through the night sky, the 185-foot-tall rocket lifted off at 1947 GMT (3:47 p.m. EDT) from the Baikonur Cosmodrome in Kazakhstan.

AsiaSat 5, a new 8,289-pound broadcasting and networking satellite for Asia, was bolted atop the Russian booster for the launch. The spacecraft will be operated by Hong Kong-based Asia Satellite Telecommunications Co. Ltd.

The Proton broke the sound barrier and soared into the upper atmosphere within two minutes, before igniting its second stage main engine and shedding its spent lower stage.

The launcher's third stage took over five-and-a-half minutes after liftoff for a four-minute burn, during which the Proton jettisoned the clamshell-like nose cone protecting the AsiaSat 5 satellite.

After emptying its fuel tanks, the third stage released the rocket's Breeze M upper stage in a ballistic trajectory just short of orbital velocity.

The Breeze M, fueled by toxic hydrazine propellant, ignited for the first of four burns about 11 minutes into the flight and shut down at about the 18-minute mark.

The first Breeze M firing put AsiaSat 5 into a low-altitude parking orbit, according to International Launch Services, the U.S.-based firm that oversees commercial Proton missions.

The upper stage will ignite three more times to raise AsiaSat 5's orbit and reduce its inclination.

Spacecraft separation is scheduled for about 0502 GMT (1:02 a.m. EDT) Wednesday. AsiaSat 5 should be deployed in an orbit with a high point of 22,236 miles, a low point of 11,154 miles and an inclination of 6 degrees, according to ILS.

AsiaSat 5's own engines will be used to nudge the satellite higher over the next few weeks, eventually settling in a circular geosynchronous orbit 22,300 miles above the equator.

Built by Space Systems/Loral in Palo Alto, Calif., AsiaSat 5's operational station will be at 100.5 degrees east longitude. The satellite's orbital speed will match the rate of Earth's rotation, allowing the craft to hover directly above the island of Sumatra.

The spacecraft carries 26 C-band transponders able to reach more than 53 countries spanning from Russia to New Zealand and from Japan to parts of Africa, according to AsiaSat.

AsiaSat 5's 14 Ku-band transponders will be attached to beams covering East Asia and South Asia. A third Ku-band beam can be switched to satisfy market demands.

Designed for a 15-year lifetime, the satellite will replace the aging AsiaSat 2 platform launched in 1995.

MEASAT-3a berjaya dilancarkan

Daripada HERMAN HAMID

pengarang@utusan.com.my

RAIS Yatim (tengah) bersama kumpulan pelajar Malaysia (kanan), Filipina dan India di hadapan pusat pelancaran MEASAT-3a di Baikonur, Kazakhstan, semalam. – BERNAMA

---

MOSCOW 22 Jun – Selepas enam jam 25 minit dilancarkan di Baikonur Cosmodrome, Kazakhstan, satelit Asia Timur Malaysia yang keempat atau MEASAT-3a berjaya memasuki ruang orbit seperti yang dijadualkan petang ini.

Berita kejayaan itu diumumkan oleh Ketua Pegawai Operasi Measat Satelitte System Sdn. Bhd. (Measat), Paul Brown-Kenyon pada sidang akhbar di Lapangan Terbang Demodedevo di sini petang ini.

Ia merupakan detik kritikal dalam pelancaran sesebuah satelit apabila ia berpisah dengan kenderaan pelancarnya kerana kejayaan tersebut akan memastikan kejayaan operasinya kelak.

Rombongan meliputi kira-kira 50 orang jemputan dan wakil media dari Malaysia menunggu penuh debaran sama ada pelancaran itu mampu mengikut jadual setiap peringkat pemisahan roket berkenaan yang mengambil masa enam jam 25 minit.

Sea Launch merupakan perkhidmatan pelancaran antarabangsa bertanggungjawab terhadap pelancaran MEASAT-3a.

Sebelum itu delegasi Malaysia yang diketuai Menteri Penerangan, Komunikasi dan Kebudayaan, Datuk Seri Dr. Rais Yatim berada di Baikonur awal pagi ini bagi menyaksikan pelancaran roket yang membawa MEASAT-3a.

Baikonur adalah tapak pelancaran yang digunakan oleh angkasawan Rusia, Yuri Gagarin pada 1961 untuk menjadi manusia pertama sampai ke angkasa lepas.

Pelancaran MEASAT-3a dilakukan mengikut jadual pada pukul 3.50 pagi (5.50 pagi waktu Malaysia) dalam keadaan cuaca yang baik.

Sebaik saja kenderaan pelancar Zenit-3SLB meluncur ke angkasa, anggota delegasi Malaysia bersorak gembira memerhatikan dari dek terbuka.

Walaupun berada dalam kedudukan empat kilometer daripada roket itu dilancarkan, rombongan Malaysia termasuk lima pelajar cemerlang dapat melihat dengan jelas kerana cuaca yang cerah.

Seperti dijangka, perjalanan roket yang membawa satelit itu mengambil masa enam jam 25 minit minit sejauh lebih 35,000 kilometer dari bumi sebelum memasuki orbit pada pukul 10.15 tengah hari (12.15 petang waktu Malaysia).

“Segalanya mengikut jadual dan Measat berbangga misi ini akhirnya berjaya,” kata Brown sambil mengucapkan tahniah kepada seluruh pasukan teknikal Measat dan syarikat yang terlibat dengan pelancaran ini.

Menurut beliau, apabila MEASAT-3a mula beroperasi pada penghujung Julai kelak, sektor telekomunikasi negara khususnya akan memperoleh manfaat besar dengan kemampuan satelit ini.

‘‘Bagi pihak syarikat pula sudah tentu ia akan mengembangkan lagi perniagaan sekali gus mengukuhkan Measat sebagai pemain utama di rantau ini,” jelasnya.

MEASAT-3a yang mempunyai jangka hayat selama 15 tahun dibina oleh Orbital Sciences Corporation of Dulles yang berpangkalan di Virginia, Amerika Syarikat.

Satelit seberat 2.417 tan itu akan bertindak sebagai pelengkap kemampuan MEASAT-3 yang mempunyai capaian liputan ke lebih 100 negara yang mewakili lebih 70 peratus daripada jumlah penduduk dunia.

MEASAT-3a direka bentuk dengan 12 transponder C-band berkuasa tinggi dan 12 transponder Ku-Band berkuasa tinggi untuk menyokong peningkatan perniagaan terus ke rumah (DTH), penyiaran dan telekomunikasi Measat.

Dengan liputan Ku-Band di Malaysia dan Indonesia serta pancaran C-Band yang meliputi lebih 100 negara mewakili 70 peratus penduduk dunia, satelit berkenaan akan menyokong pertumbuhan syarikat dalam bidang perniagaan penyiaran dan telekomunikasi.

Pada 12 Disember 2006, MEASAT 3 turut dilancarkan di Baikonur manakala dua satelit yang terdahulu iaitu MEASAT-1 dan MEASAT-2 dilancarkan di Pusat Angkasa Guiana (CSG) Arianespace di Kouru, French Guiana pada 13 Januari 1996 dan 13 November 1996.

Sementara itu, turut menyaksikan pelancaran bersejarah itu ialah Timbalan Duta Malaysia ke Rusia, Abdul Razak Abdul Wahab, Ketua Pegawai Eksekutif TM, Datuk Zamzamzairani Mohd. Isa, Naib Presiden Orbital Sciences, L. Lewis dan Pengarah Intelset Corporation, Brian S. Sing.

Furuu’ Al Massa il buah tangan terbaru Abu Hassan

BENARLAH bagai dikata menerusi pepatah berbahasa Inggeris, Don't judge a book by it's cover.

Pada deretan kemas buku-buku agama koleksi peribadi Datuk Abu Hassan Din al-hafiz yang diletakkan di rak kayu sebelah meja komputer pada salah sebuah ruang tamu rumah banglo dua tingkat itu, selain koleksi buku-buku Arab, rupa-rupanya terselit sebuah kitab lama yang bukan sebarangan kitab.

Akui Hassan, kitab berwarna kuning dalam bahasa Melayu klasik yang ditulis dengan tulisan Jawi lama itu, tidak lebih seperti kitab-kitab lain yang pernah dibaca sebelum ini.

Lantaran itulah, kitab itu sudah lama terperap sebagai sebahagian daripada koleksi khazanah ilmu malah jarang sekali dibuka untuk tujuan rujukan. Tidak hairanlah, jika dikatakan empunya milik kitab lama ini juga tidak mengetahui bila dan di mana ia diperoleh.

"Tetapi entah macam mana, bila hendak merujuk tentang satu masalah, saya dapati permasalahan yang cuba dicari itu tidak ada di dalam kitab-kitab Arab dan tanpa disengajakan, tangan saya tercapai dan terbuka kitab Furuu' Al Massa il ini. Kebetulan pula di dalamnya ada mengenai masalah yang saya cari itu.

"Sejak itu, minat membuat rujukan berkaitan masalah fikah mula berubah iaitu kalau dahulu lebih kepada kitab-kitab bahasa Arab, kini beralih kepada kitab-kitab hasil ulama nusantara terutamanya buku Furuu' Al Massa il yang telah diterjemahkan oleh Sheikh Daud bin Abdullah Fatani, seorang ulama Melayu yang tersohor suatu masa dahulu.

"Semakin lama saya tatap buku ini, saya dapati ia mempunyai satu khazanah ilmu yang amat bernilai walaupun ia hanya sebuah kitab lama yang telah dialihbahasakan daripada kitab asalnya yang berbahasa Arab.

"Saya dapati isi kandungannya amat padat sekali, walaupun ia ditulis beratus tahun yang lalu. Tambah pula isu perbahasannya masih relevan membicarakan permasalahan semasa yang timbul pada hari ini," jelas Abu Hassan mengenai kerja penulisan terbarunya itu.

Menurut beliau lagi, kitab itu merupakan sebuah karya terjemahan dalam bentuk soal jawab yang menyentuh soal-soal syariat yang merangkumi aspek-aspek ibadat, munakahat, muamalat dan jinayat, cuma bezanya ia ditulis dengan menggunakan bahasa Jawi lama yang hanya boleh difahami segelintir orang tertentu sahaja.

"Akhirnya dengan kehendak Allah jua, terdetik persoalan di hati saya, kenapa kitab yang seindah ini, disimpan hanya untuk menjadi tatapan dan rujukan golongan tertentu sahaja.

"Alangkah baiknya sekiranya kitab yang bermutu seperti ini dapat dimanfaat oleh generasi masa kini, khazanah ilmu yang terkandung di dalamnya dapat dikongsi dan ditatapi bersama.

"Maka timbullah keinginan serta membulatkan tekad saya untuk menyusun semula atau memodenkan kitab tersebut dengan gaya bahasa masa kini untuk memudahkan generasi hari ini membaca dan memahaminya, khususnya bagi mereka yang sentiasa dahagakan ilmu.

"Cuma persoalannya, oleh kerana penulisnya telah lama kembali ke rahmatullah, kepada siapakah sepatutnya saya memohon untuk mendapatkan kebenaran dan keizinan bagi menyalin semula kitab tersebut, sedangkan penulis asalnya dan berkemungkinan para warisnya bukan dari negara ini?," cerita beliau lagi.

Kepada Allah diserahkan segalanya, Abu Hassan segera melaksanakan beberapa kali solat sunat Istikharah dan akhirnya terbukalah hati beliau untuk meneruskan cita-cita, menyalin semula serta memodenkan kitab ini dalam susunan bahasa yang mudah difahami tanpa terlebih dahulu mendapat restu dan keizinan daripada para warisnya. Apa yang beliau harapkan, sekiranya usaha ini ada ganjarannya, maka ganjarannya akan turut dikongsi bersama oleh penulis asalnya.

Kata Abu Hassan, hanya dengan cara ini sahaja beliau berkeyakinan akan dapat dimanfaatkan oleh generasi masa kini yang berminat untuk mendalam urusan agama mereka.

Akhirnya pada hari Rabu tanggal 23 Julai 2003 bersamaan 23 Jamadilawal 1424, tangan Abu Hassan mula mengetuk kekunci komputer bagi mencoret semula tinta pujangga yang hampir pudar ditelan masa, sekali gus bererti beliau mengambil masa selama hampir dua tahun untuk menyalin semula kitab tersebut.

"Jangka masa yang begitu lama adalah disebabkan kesibukan tugas harian saya, di samping kesukaran untuk memahami susunan bahasanya.

"Untuk menyelami ke dasar maksud dan mafhumnya, terkadang satu soalan dan jawapannya mengambil masa sehari suntuk untuk memahaminya, malah ada yang terpaksa saya tinggalkan terus kerana tidak dapat hendak memahami maksud soalan maupun jawapannya.

"Di sesetengah tempat pula, ada yang saya terpaksa tokok tambah sedikit penjelasan dan huraian dengan menggunakan huruf condong agar ia lebih jelas dan mudah difahami. Ada sesetengah soalan dan jawapannya pula terpaksa diubah atau dirombak supaya apa yang dibicarakan itu tersusun kemas," kata Abu Hassan tentang buku yang dijangka berada di pasaran pada Julai ini. Insya-Allah.

Jelas Abu Hassan lagi, di awal penyiapan kitab ini, beliau tidak memikirkan sangat tentang penerbit untuk kitab ini. Yang penting, beliau mahukan kandungannya itu dikongsi umat Islam. Namun apabila buku tersebut hampir siap iaitu sekitar 2005, beliau mula memikirkan tentang penerbit.

Kebetulan pula kerjasama di antara beliau dengan sebuah syarikat penerbitan Telaga Biru Sdn. Bhd. sudah lama bermula, atas platform penerbitan cakera padat.

Siapa sangka usaha terbaru beliau itu telah menarik minat Telaga Biru, lantas persetujuan kerjasama termeterai. Kini, ia sudah berada di peringkat akhir penyiapan.

Exploding Stars: Is Earth at Risk?

By Michael Schirber Astrobiology Magazine posted: 18 June 2009 08:58 am ET

When stars go pop, a murderous torrent of energy is released. Life on Earth may have been partly extinguished by just such a violent outburst, but there's little hard evidence yet to justify such a claim. A new study plans to fill in the forensic details.

"We are trying to get a better estimate of how dangerous a particular event will be," says Brian Thomas of Washburn University in Topeka, Kansas.

Thomas and his colleagues will be studying the wide-range of astrophysical phenomena that could fling high energy radiation across interstellar space to Earth's doorstep [as occured in a colossal blast detected in 2004]. The team also will radiate different types of phytoplankton to understand how life would be affected by a stellar blast, since life around the globe is highly dependent on these microscopic plants.

The danger from stellar explosions has been considered before, but this will be the first comprehensive study. "We are building on previous work by broadening it to a wide range of astrophysical events and by making the biological modeling more precise," Thomas says. The project is part of NASA's Exobiology and Evolutionary Biology Program.

The usual suspects

Stars are generally too far away to be a concern for life on our planet. But certain stellar eruptions have the potential to reach across tens or even thousands of light-years.

The most familiar of these is a supernova, which is the curtain call of a massive star with eight or more times the mass of our sun. When the nuclear fuel runs out for such a behemoth, the collapsing core generates an explosion that outshines an entire galaxy-worth of stars while it lasts.

A couple supernovae go off in our galaxy every century. But for one of these to have serious consequences for Earth, we would need to be roughly within a 10 light-year radius of the blast.

Certain star explosions, called hypernovae, have much greater reach. Ten times more powerful than typical supernovae, hypernovae are the source for long-duration gamma ray bursts (GRBs), which are high-energy beams emitted along the dying star's axis. A GRB could travel 6,500 light-years and still inflict terrific damage on Earth, Thomas says.

The number of GRBs is much less than the number of supernovae, but the exact rate in our galaxy is still a matter of debate. A few years ago, a group of astronomers calculated that the likelihood of a GRB going off near us was very low, due to the fact that GRBs tend to arise in young galaxies with less heavy elements than the Milky Way.

But Thomas says that subsequent analyses have called this calculation into question, partly because our galaxy has merged in the past with smaller, younger galaxies that could have brought GRB-ticking-time-bombs in with them. "Our likelihood for hosting a GRB could vary with time," Thomas says.

He speculates that on average a GRB lights up our galaxy about once every 10 million years.

Other possible culprits

Long-duration GRBs and supernovae may be the best-understood, but they are not the only super-stellar calamities.

Short-duration GRBs do not arise from massive star deaths, but instead are believed to mainly be the merger of two neutron stars. Although less energy is released than in a long-duration GRB, the fraction of high-energy gamma rays is higher. Moreover, short-duration GRBs are more likely to occur in mature galaxies like ours, where neutron stars are more common.

Soft gamma-ray repeaters also originate from neutron stars – supposedly when the super-dense surface cracks. If one of these happened 10 light-years away, the effects could be dramatic. Indeed, on Dec. 27, 2004, the radiation from a soft gamma-ray repeater disrupted radio wave transmissions on Earth. Nothing was damaged, but the source object was an amazing 50,000 light-years away.

Thomas and his colleagues will be pulling together recent data from the Swift satellite and the Fermi Gamma-Ray Space Telescope to better estimate the rates and radiation output of soft gamma-ray repeaters, GRBs and supernovae.

Although there's no evidence that one of these went off recently in our neighborhood, it's important to note that our sun migrates around the galaxy and therefore could have brushed next to a star having a high-energy fit.

Worldwide ozone hole

The other half of the study will look at the possible biological aftermath of an astrophysical firework going off nearby.

Gamma rays and X-rays cannot penetrate very far into the Earth's atmosphere, but they still can have a long-lasting impact. The high-energy radiation breaks apart nitrogen and oxygen molecules in the Earth's stratosphere, allowing them to reform as nitric oxide (NO). This molecule destroys ozone in the same way that chlorofluorocarbons (CFCs) do.

"The effect is like the current ozone hole, but spread over the globe," Thomas says.

Ozone protects life on Earth from the sun's ultraviolet rays. By shattering this atmospheric shield, an astrophysical blast could lead to higher rates of DNA and protein damage in organisms from greater sunlight exposure.

Thomas' group has previously determined that a relatively close GRB could destroy 75 percent of the ozone in certain regions, with a globally averaged depletion of around 35 to 40 percent. In contrast, the ozone hole that currently hovers over Antarctica is at most 60 percent depleted but only accounts for a globally-averaged depletion of 3 to 5 percent.

Thomas says that the ozone destruction would begin as soon as the radiation hits, and would continue for several years. It may take more than a decade for the Earth's ozone shield to return to full strength.

Fried plankton

The loss of ozone would have serious effects on life across the planet. One of the most susceptible organisms would be phytoplankton. These single-celled organisms live at the top of the water column, where UV light is able to reach. They also reproduce quickly, so DNA damage would accumulate over several generations.

If phytoplankton began dying off, the effects would ripple throughout the ocean, since these photosynthetic microbes are the base of the marine food chain. They also produce at least half of the world's oxygen.

The team has selected a couple representative species of phytoplankton to irradiate at different levels, and see how their productivity levels change. The results of the study should give astrobiologists a better sense of how likely it is that our planet or another planet in our galaxy was zapped by a stellar eruption.

Possible signs of such astrophysical foul play are seen in the Ordovician extinction, which occurred 450 million years ago and resulted in the loss of 60 percent of marine invertebrates. The fossil record shows that organisms near the top of the water column and at mid-latitudes were hardest hit, as one would expect from a sudden loss of ozone.

Rahsia tahannuth Rasulullah

Susunan SITI AINIZA KAMSARI

INILAH suasana di Gua Hira' masa kini yang menjadi kunjungan umat Islam, khususnya yang datang untuk mengerjakan haji dan umrah di Kota Mekah.

ORIENTALIS terkenal Itali, Profesor Dr. Laura Veccia Vaglieri (1893-1989) yang banyak menulis artikel mengenai Islam, pernah menulis mengenai Junjungan Besar Nabi Muhammad SAW, yang antaranya, "Semasa menyeru manusia supaya menyembah Allah Yang Maha Esa, Muhammad (Nabi) tidak pernah menggunakan pendekatan yang menghalang manusia daripada berfikir mengenai kebenaran. Beliau (Baginda) tidak menggunakan pendekatan-pendekatan magis, yang memukau penglihatan dan tidak juga menyeru dengan menggunakan ancaman serta ugutan.

"Apakah yang beliau lakukan? Muhammad menyuruh mereka supaya menggunakan akal dan bertafakur mengenai kejadian alam dan rahsia kejadiannya. Dalam bahasa mudah, dia menyuruh mereka membaca "Buku Alam" dan berfikir mengenainya supaya dengannya mereka yakin pada kewujudan Ilahi."

Jika dalam bahasa yang terjemahkan ke dalam Bahasa Inggeris, Dr Vaglieri menyebut; "He simply called them to contemplate." Contemplate sama ada tepat atau layak untuk dirujuk, tetapi tentulah di sini dimaksudkan dengan berkhalwat, yang berasal daripada perkataan khulwah bermakna bersunyi-sunyian

Kisah Nabi Muhammad berkhalwat di gua Hira sebelum Baginda diperintahkan secara rasmi oleh Allah SWT menjadi seorang Rasul merupakan catatan sejarah yang sangat dipegang atau menjadi pengetahuan setiap umat Islam.

Ini kerana di gua itulah Nabi Muhammad menerima wahyu pertama, iaitu surah al-Alaq, ayat 1-3 yang disampaikan oleh malaikat Jibrail.

Menyendiri

Namun mengapa Nabi Muhammad lebih memilih untuk menyendiri di Gua Hira' sedangkan Baginda sudah mempunyai kehidupan yang cukup baik terutama selepas mengahwini Siti Khadijah dan dikurniakan putera dan puteri.

Mungkin kita pernah mendengar, kerana Baginda seorang yang bersifat pendiam, maka tidak menghairankan jika Baginda suka hidup menyendiri di Gua Hira' itu. Tetapi benarkah hanya kerana Baginda seorang pendiam?

Maka di sini, mungkin terdapatnya amalan-amalan yang harus kita dapat bezakan atau persamaan makna setiap satunya, iaitu sama ada beruzlah, berkhulwah, bertahanuth dan bertahanuf apabila merujuk kepada tindakan Nabi Muhammad yang mengasingkan diri itu.

Dari aspek kebudayaan itu sendiri, sebenarnya telah ada amalan yang menjadi kebiasaan orang-orang Arab pada masa itu, di mana golongan berfikir, mereka selama beberapa waktu pada setiap tahun menjauhkan diri daripada keramaian dan majlis-majlis untuk berkhalwat semata-mata mendekatkan diri kepada tuhan-tuhan mereka dengan bertapa dan berdoa.

Mereka mengharapkan agar diberi rezeki dan pengetahuan. Pengasingan untuk beribadat seperti ini mereka namakan bertahannuth.

Namun penulis sejarah Islam terkemuka, Hussein Haekal menyebut perbuatan Nabi Muhammad itu sebagai bertahannuf (asal perkataan tahannafa atau Hanif) iaitu perbuatan yang cenderung kepada kebenaran dengan meninggalkan penyembahan berhala dan beribadat kepada Allah semata-mata.

Maka jika dikatakan, Baginda seorang yang pendiam itu tetapi harus difahami sebagai keadaan Baginda banyak memberikan laluan kepada mindanya untuk berfikir daripada berkata-kata demi untuk mencari kebenaran.

Atas sifat fitrah dan akhlak Baginda yang bersih, Baginda melihatkan pelbagai kebejatan yang semakin hidup subur dalam masyarakat Arab. Melihatkan kepada segala urusan-urusan, aktiviti dan hal ehwal masyarakat itu menyebabkan Baginda semakin tidak mampu menerimanya.

Ini lebih-lebih lagi melibatkan soal penyembahan berhala, sebagaimana sejak usia kecilnya dan Baginda semakin jengkel dengan sembahan-sembahan yang palsu ini, sehinggakan tidak ada sesuatu yang paling dibenci oleh Baginda melainkan berhala-berhala itu.

Baginda tidak tahan mendengar orang bersumpah dengan menyebut nama al Lata dan al Uzza itu.

Tersayat pedih

Hati Baginda turut tersayat pedih mengenangkan bangsanya yang suka berjudi. Malah dikisahkan pada suatu hari di pasar Mekah, Baginda melihat sendiri seseorang yang berjudi.

Akibatnya si kaki judi itu kehilangan unta dan rumahnya sendiri kerana menjadi mangsa pertaruhan. Tidak cukup unta dan rumah, malah dia juga bertaruh akan kehilangan 10 tahun daripada hidupnya.

Apakah maknanya itu, sehingga begitu teruk sekali ketagihan berjudi menyebabkan bertaruh pada perkara yang tidak masuk akal!

Baginda sangat tergugat hatinya oleh peristiwa malang ini dan terus pergi ke bukit-bukit berdekatan dan duduk memikirkan kembali tabiat-tabiat buruk bangsanya itu. Baginda berfikir dan hairan atas kebodohan mereka yang tersesat jauh itu.

Kebodohan lain yang tidak mampu Baginda terima termasuklah minum arak dan tidak akan makan sembelihan-sembilan haiwan yang dikorbankan untuk berhala. Baginda juga tidak pernah datang untuk menyertai perayaan atau keramaian di tempat-tempat berhala itu.

Ini membawakan Baginda untuk memisahkan dirinya dengan tanpa sebarang gangguan di Gua Hira' di samping Baginda semakin tercari-cari akan rahsia alam, sebagaimana yang disebut oleh orientalis Itali itu tadi.

Gua Hira' terletak di Gunung atau Bukit Nur (Jabal Nur) iaitu kira-kira enam kilometer dari utara Kota Mekah tanpa ada sebarang tanda-tanda kehidupan manusia di situ.

Gua itu sendiri dikatakan yang mempunyai laluan masuk yang tidak lebih daripada tinggi manusia sahaja. Iaitu sebuah gua yang kecil yang sebahagian gua ini ditembusi cahaya, manakala sebahagian yang lain dalam keadaan yang sangat gelap.

Dikatakan di dalam gua itu hanya boleh memuatkan dua orang sahaja masuk ke dalamnya.

Dikatakan Nabi Muhamad akan memanjat atau mendaki laluan yang sukar dan curam semata-mata untuk berkhalwat di Gua Hira', iaitu hanya sepanjang bulan Ramadan setiap tahun.

Ini kerana pada masa-masa lain, seperti yang diceritakan oleh Haekal, Baginda sebenarnya sebagaimana anggota masyarakat yang lain, ada masa-masanya tetap bermasyarakat dengan para penduduk yang lain.

Bahkan Baginda lebih dihormati di tengah-tengah masyarakat itu. Ini disebabkan sifatnya yang suka merendah diri, bila ada yang ajak berbicara, Baginda akan mendengar tanpa menoleh kepada orang lain.

Bicaranya sedikit kerana lebih banyak mendengar. Tetapi apabila berbicara, Baginda akan berbicara bersungguh-sungguh namun tetap tidak lupa untuk berkata-kata yang lucu dan bersenda gurau.

Malah kadang kala Baginda ketawa sehingga menampakkan gerahamnya. Pendek kata, Baginda tetap bijak dan mudah bergaul. Ini menimbulkan rasa hormat yang tinggi di kalangan masyarakat Arab terhadap Baginda.

Ini sebagaimana Baginda berada di tengah-tengah masyarakat dalam peristiwa Majlis Tahkim atau La'aqat'd-Damm (jilatan darah) apabila Bani Abd'd-Dar dan Adi tidak dapat membenarkan kabilah yang lain untuk campur tangan dalam urusan meletakkan batu Hajaral Aswad (Batu Hitam) selepas Kaabah berjaya dibina semula selepas berlaku peristiwa Banjir Besar (Aram).

Namun timbul juga persoalan-persoalan berhubung tindakan Baginda meninggalkan isteri, keluarga dan masyarakatnya semata-mata untuk menyendiri dalam gua yang gelita dengan hanya membawa sedikit bekalan setiap hari.

Ibadat

Dalam melakukan ibadat selama dalam tahannuth itu, adakah Baginda menganut syariat tertentu? Dalam hal ini ulama-ulama berlainan pendapat. Dalam Tarikhnya Ibnu Kathir menceritakan sedikit tentang pendapat-pendapat mereka mengenai syariat yang digunakan oleh Baginda sepanjang berada dalam Gua itu.

Ada yang mengatakan menurut syariat Nabi Nuh, ada yang mengatakan mengikut Nabi Ibrahim, yang lain berkata menurut syariat Nabi Musa dan Isa as dan ada pula yang mengatakan tiada kepastian.

Mengikut Yunus Ali Al Muhdhor dalam bukunya, Kehidupan Nabi Muhammad SAW dan Amirul Mukminin Ali bin Abi Thalib R.A (Victory Agencie, KL 1993) syariat Nabi Muhammad ketika berada di gua Hira' itu adalah mengikut syariat Nabi Ibrahim kerana sesuai dengan persekitaran yang diwarisi oleh kebanyakan kaum keluarga Baginda.

Tetapi mengapa Baginda tidak melakukan sahaja uzlah di dalam Kaabah sahaja, sebagai rumah ibadat pertama dibina di muka bumi ini? Atau mengapa Baginda tidak berguru dengan ramai pendita-pendita Yahudi dan Nasrani seperti Waraqah Bin Naufal yang merupakan sepupu isterinya sendiri? Ikuti jawapannya semua persoalan ini dan kisah seterusnya di keluaran akan datang!

Nakhla meteorite

From Wikipedia, the free encyclopedia

Jump to: navigation, search

The Nakhla meteorite, the first example of a Nakhlite type meteorite of the SNC Group type of meteorites, fell to Earth, from Mars, on the 28th of June, 1911, at approximately 09:00 in the Nakhla region of Abu Hommos, Alexandria, Egypt.^[1][2] The meteorite fell in about forty pieces and was witnessed by many individuals to have exploded in the upper atmosphere and to have fallen into the ground, the fragments burying themselves up to a meter in depth in some places. The stones recovered from this meteorite ranged in size from 20g to 1813g, and it is estimated a total weight of 10kg (22 pounds) had fallen.^[1]

Martian origins

As of 2008, there are a total of seventy-seven cataloged meteorites recovered from around the world that are thought to have originated from Mars,^[3] including the Nakhla meteorite. These are considered to have been ejected by the impact of another large body colliding with the Martian surface and traveled through the solar system for an unknown period of time before penetrating the Earth's atmosphere.

Examination of the Nakhla meteorite in March 1999, using an optical microscope and a powerful scanning electron microscope (SEM), by a team from NASA's Johnson Space Center, has revealed rounded particles of a limited size range.^[4] London's Natural History Museum, which holds several intact fragments of the meteorite, agreed on 2006 for NASA researchers to break one open, providing fresh samples.^[5] Upon publishing the results, a debate was opened by some at the 37th Lunar and Planetary Science Conference in March 2006 in Houston, Texas, and postulated that the carbon-rich content within the pores of the rocks hinted at remains of living matter.

Because Carbon is the fourth most abundant element in the universe after hydrogen, helium, and oxygen, most scientists, curious and minute shapes in meteorites are not enough to convince them that bacteria once lived on Mars.^[6]

The Nakhla dog

One such fragment of the Nakhla meteorite was said to be observed by a farmer named Mohammed Ali Effendi Hakim in the village of Denshal, near Nakhla, to have landed, not only in his field, but on a dog and, apparently, vaporized the animal. Since, therefore, no remains of the dog were ever recovered and only one known eyewitness to the dog's death is known, this story remains apocryphal at best.^[1] However, the story of the Nakhla dog has become something of a legend among astronomers and is even recorded in several editions of The Catalog of Meteorites.

At the time, the dog's death publicized in both Arabic and English newspapers as being the first recorded death of an animal, including humans, by a meteorite, though since then both the facts as to whether a dog was actually killed by meteorite in Nakhla and the notion that this was the first ever recorded animal fatality by meteorite have come into question.