Para ilmuwan NASA yang bekerja di
wahana antariksa Curiosity, meyakini telah memecahkan teka-teki terkait
gunung raksasa di planet Mars yang mengelilingi sebuah cekungan, atay
kawah raksasa 'Gale'.
Mereka percaya, gunung Sharp di lokasi
pendaratan robot mereka itu adalah sisa-sisa sedimen yang mengendap
dalam danau-danau yang memenuhi bagian dalam cekungan, selama mungkin
lebih dari puluhan juta tahun.
Tapi baru belakangan angin, dengan
hembusannya, menggali dataran sekeliling dan memunculkan puncak gunung
setinggi 5 km yang kita lihat sekarang.
Jika benar, ini memiliki dampak besar terkait iklim masa lalu di Planet Merah itu.
Ini berarti dunia mestinya telah jauh lebih hangat dan basah pada dua miliar tahun pertama, dibanding anggapan selama ini.
Mars
kuno, kata tim Curiosity, pasti menikmati siklus hidrologi global yang
kuat, yang melibatkan hujan atau salju, sehingga bisa menjaga kondisi
lembab seperti itu.
Salah satu konsekuensi menggoda dari
kemungkinan ini adalah bahwa planet ini bahkan mungkin pernah memiliki
laut di suatu tempat di permukaannya.
"Jika ada sebuah danau yang
bertahan selama jutaan tahun, kelembaban atmosfer praktis membutuhkan
suatu tubuh air seperti laut untuk memeliharanya dari penguapan," kata
Dr Ashwin Vasavada, salah satu ilmuwan Curiosity.
Selama beberapa
dekade, para peneliti telah berspekulasi bahwa dataran rendah bagian
utara Mars bisa menampung suatu samudera luas dalam sejarah awal Mars.
Hasil penelitian Curiosity terbaru pasti memicu lagi minat pada gagasan
itu.
Kawah seperti Gale sering menampilkan gundukan terpusat yang
tercipta ketika tanah mencuat akibat dampak benturan komet atau asteroid
yang membentuk cekungan.
Tapi Gunung Sharp terlalu besar untuk dijelaskan dengan cara ini.
Sungai kuno
Temuan
Curiosity didasarkan pada pengamatan geologis lebih dari setahun,
seiring penjelajahan wahana itu yang bergerak dari lokasi pendaratan
tahun 2012 ke arah selatan menuju puncak besar dan keluar di dataran
kawah.
Pada waktu itu, robot melihat sedimen berjalur yang sangat jelas diakibatkan oleh sungai kuno.
Dan
makin jauh ke selatan Curiosity bergerak, makin jelas bahwa kegiatan
fluvial -terkait sungai- ini berakhir di delta-delta dan danau statis di
pusat cekungan.
Tapi yang lebih penting dari kisah ini adalah
kecenderungan dari lapisan-lapisan sedimen, yang bisa dilihat wahana
ini, semuanya mengarah menuju gunung, kendati datarannya makin tinggi.
"Kita
selalu melihat adanya pola yang sistematis sama, yang cukup menarik,"
kata Prof Sanjeev Gupta, ilmuwan Curiosity dari Imperial College London,
Inggris.
Selama jutaan tahun, sedimen yang mengendap keluar dari tubuh air
yang statis akan membangun lapisan batuan -tumpukan demi tumpukan- yang
kini membentuk Gunung Sharp.
Ilmuwan Curiosity, Prof John
,berpendapat, pengungkapan misteri Gunung Sharp ini hanya dimungkinkan
dengan robot di permukaan Mars -tak bisa oleh pengamatan satelit.
"Tidak ada cara untuk mengamati ini dari orbit," katanya kepada wartawan.
Masih banyak pertanyaan yang muncul.
Para peneliti akan mesti mencari tahu seberakpa kuat daya tahan air melewati waktu.
Dan gagasan bahwa Mars jauh lebih hangat di masa lalu, bertentangan dengan model iklim saat ini untuk waktu itu.
Tim
berharap untuk menjawab beberapa pertanyaan ini dalam bulan-bulan dan
tahun-tahun mendatang, setelah Curiosity memanjat gunung itu dan
mempelajari lapisan batuan yang berbeda.
ENGLISH
NASA scientists are working on spacecraft Curiosity, is believed to have solved the puzzle related giant mountain on Mars that surrounds a hollow, or extending the giant crater 'Gale'.
They believe, Mount Sharp on their robot's landing site is the remains of sediment that settles in lakes that meet the inner basin, for perhaps more than tens of millions of years.
But the wind has only recently, with hembusannya, dig around the plains and mountain peaks raises as high as 5 km that we see today.
If true, this has a huge impact related to past climate in the Red Planet.
This means that the world should have a much warmer and wetter in the first two billion years, compared to the assumption so far.
Ancient Mars, Curiosity team said, surely enjoy strong global hydrological cycle, which involves the rain or snow, so they can keep moist conditions like that.
One consequence of the tantalizing possibility is that the planet may have even had a sea somewhere on its surface.
"If there is a lake that survived for millions of years, atmospheric humidity practically requires a body of water such as the ocean to keep it from evaporating," said Dr. Ashwin Vasavada, one of the scientists Curiosity.
For decades, researchers have speculated that the northern lowlands of Mars can accommodate a vast ocean in the early history of Mars. Curiosity latest research results will trigger further interest in the idea.
Gale crater as often displays a centralized mound created when soil sticking due to the impact of a comet or asteroid collision that formed the basin.
But Mount Sharp is too large to be explained in this way.
ancient river
Curiosity findings are based on geological observations more than a year, as the vehicle was moving exploration of the landing site in 2012 to the south toward the big top and out on the plains of the crater.
At that time, the robots look very clear multilane sediment caused by an ancient river.
And the further to the south Curiosity moves, it became clear that these rivers -related fluvial activity ended in deltas and lakes static in the central basin.
But more important than this story is the tendency of the layers of sediment, which can be seen this vehicle, it all leads to the mountain, despite the higher terrain.
"We always see the same systematic pattern, which is quite interesting," says Prof. Sanjeev Gupta, Curiosity scientists from Imperial College London, UK.
For millions of years, the sediment that settles out of the water body will build up static -tumpukan sake Piles of rock layers that now form the Mount Sharp.
Curiosity scientist, Prof. John, argues, the mystery of Mount Sharp disclosure is only possible with a robot on the surface of Mars could -not by satellite observations.
"There is no way to observe it from orbit," he told reporters.
There are still many questions that arise.
The researchers will have to figure out a strong seberakpa water resistance across time.
And the idea that Mars was much warmer in the past, contrary to current climate models for that time.
The team hopes to answer some of these questions in the months and years to come, after Curiosity climb the mountain and learn different rock layers.
They believe, Mount Sharp on their robot's landing site is the remains of sediment that settles in lakes that meet the inner basin, for perhaps more than tens of millions of years.
But the wind has only recently, with hembusannya, dig around the plains and mountain peaks raises as high as 5 km that we see today.
If true, this has a huge impact related to past climate in the Red Planet.
This means that the world should have a much warmer and wetter in the first two billion years, compared to the assumption so far.
Ancient Mars, Curiosity team said, surely enjoy strong global hydrological cycle, which involves the rain or snow, so they can keep moist conditions like that.
One consequence of the tantalizing possibility is that the planet may have even had a sea somewhere on its surface.
"If there is a lake that survived for millions of years, atmospheric humidity practically requires a body of water such as the ocean to keep it from evaporating," said Dr. Ashwin Vasavada, one of the scientists Curiosity.
For decades, researchers have speculated that the northern lowlands of Mars can accommodate a vast ocean in the early history of Mars. Curiosity latest research results will trigger further interest in the idea.
Gale crater as often displays a centralized mound created when soil sticking due to the impact of a comet or asteroid collision that formed the basin.
But Mount Sharp is too large to be explained in this way.
ancient river
Curiosity findings are based on geological observations more than a year, as the vehicle was moving exploration of the landing site in 2012 to the south toward the big top and out on the plains of the crater.
At that time, the robots look very clear multilane sediment caused by an ancient river.
And the further to the south Curiosity moves, it became clear that these rivers -related fluvial activity ended in deltas and lakes static in the central basin.
But more important than this story is the tendency of the layers of sediment, which can be seen this vehicle, it all leads to the mountain, despite the higher terrain.
"We always see the same systematic pattern, which is quite interesting," says Prof. Sanjeev Gupta, Curiosity scientists from Imperial College London, UK.
For millions of years, the sediment that settles out of the water body will build up static -tumpukan sake Piles of rock layers that now form the Mount Sharp.
Curiosity scientist, Prof. John, argues, the mystery of Mount Sharp disclosure is only possible with a robot on the surface of Mars could -not by satellite observations.
"There is no way to observe it from orbit," he told reporters.
There are still many questions that arise.
The researchers will have to figure out a strong seberakpa water resistance across time.
And the idea that Mars was much warmer in the past, contrary to current climate models for that time.
The team hopes to answer some of these questions in the months and years to come, after Curiosity climb the mountain and learn different rock layers.
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