巨型隕石撕開了海底並煮沸了地球的海洋 (1/2)

Recently Yahoo News on-line picked up the following:

Mega meteorite tore up seabed and boiled Earth's oceans (1/2)

BBC - Georgina Rannard - Climate and science reporter

Wed, October 23, 2024 at 2:08 a.m. GMT+8·4 min read

A huge meteorite first discovered in 2014 caused a tsunami bigger than any in known human history and boiled the oceans, scientists have discovered.

The space rock, which was 200 times the size of the one that wiped out the dinosaurs, smashed into Earth when our planet was in its infancy three billion years ago.

Carrying sledge hammers, scientists hiked to the impact site in South Africa to chisel off chunks of rock to understand the crash.

The team also found evidence that massive asteroid impacts did not bring only destruction to Earth - they helped early life thrive.

“We know that after Earth first formed there was still a lot of debris flying around space that would be smashing into Earth,” says Prof Nadja Drabon from Harvard university, lead author of the new research.

“But now we have found that life was really resilient in the wake of some of these giant impacts, and that it actually bloomed and thrived,” she says.

The meteorite S2 was much larger than the space rock we are most familiar with. The one that led to the dinosaurs’ extinction 66 million years ago was about 10km wide, or almost the height of Mount Everest.

But S2 was 40-60km wide and its mass was 50-200 times greater.

It struck when Earth was still in its early years and looked very different. It was a water world with just a few continents sticking out of the sea. Life was very simple - microorganisms composed of single cells.

The impact site in Eastern Barberton Greenbelt is one of the oldest places on Earth with remnants of a meteorite crash.

Prof Drabon travelled there three times with her colleagues, driving as far as possible into the remote mountains before hiking the rest of the way with backpacks.

Rangers accompanied them with machine guns to protect them against wild animals like elephants or rhinos, or even poachers in the national park.

They were looking for spherule particles, or tiny fragments of rock, left behind by impact. Using sledge hammers, they collected hundreds of kilograms of rock and took them back to labs for analysis.

Prof Drabon stowed the most precious pieces in her luggage.

"I usually get stopped by security, but I give them a big spiel about how exciting the science is and then they get really bored and let me through," she says.

The team have now re-constructed just what the S2 meteorite did when it violently careened into Earth. It gouged out a 500km crater and pulverised rocks that ejected at incredibly fast speeds to form a cloud that circled around the globe.

“Imagine a rain cloud, but instead of water droplets coming down, it's like molten rock droplets raining out of the sky,” says Prof Drabon.

(to be continued)

Translation

巨型隕石撕開了海底並煮沸了地球的海洋 (1/2)

科學家發現，首次於2014 年發現的一顆巨大隕石引發了人類史上規模最大的海嘯，導致海洋沸騰。

這塊太空岩石的大小是消滅恐龍的岩石的 200 倍，30 億年前。當我們的星球還處於嬰兒期時，它撞向了地球。

科學家攜帶大錘徒步前往南非的撞擊地點，鑿出大塊岩石以了解撞撃情況。

研究團隊還發現證據表明，大規模的小行星撞擊不僅給地球帶來了破壞，還幫助早期生命繁衍生息。

這項新研究的主要作者、哈佛大學教授Nadja Drabon表示：“我們知道，在地球最初形成後，仍有大量碎片在太空中飛舞，這些碎片可能會撞擊地球。”

她說:「但現在我們發現，在經歷了一些巨大的撞擊之後，生命確實具有復原力，而且它實際上蓬勃發展」。

隕石S2比我們最熟悉的太空岩石大得多。 6,600萬年前導致恐龍滅絕的那條寬約10公里，幾乎與珠穆朗瑪峰一樣高。

但S2寬40-60公里，重量大了50-200倍。

撞擊發生於當地球還處於早期階段及看起來非常不同之時。那是一個水世界，只有幾塊大陸伸出海面。生命非常簡單－微生物由單細胞組成。

位於 Eastern Barberton Greenbelt 的撞擊地點是地球上最古老的地方之一，仍有隕石撞擊的遺跡。

Drabon教授與她的同事們曾三次前往那裡，盡可能開車進入偏遠的山區，然後背著背包徒步走完剩下的路。

護林員帶著機關槍陪伴他們，保護他們免受大像或犀牛等野生動物的傷害，甚至是國家公園裡的偷獵者。

他們正在尋找撞擊留下的小球顆粒或微小的岩石碎片。他們使用大錘收集了數百公斤的岩石並將其帶回實驗室進行分析。

Drabon 教授將最珍貴的物品存放在她的行李中。

她說:「我通常會被保安攔住，但我會向他們長篇大論講出科學是多麼令人興奮，然後他們感到非常無聊，就讓我過去了」。

團隊現在已經重建了 S2 隕石猛烈撞擊地球時的情況。它挖出了一個 500 公里長的隕石坑，粉碎的岩石以極快的速度噴出，並形成一個環繞着地球的雲。

Drabon 教授說: 「想像一下雨雲，但它不是水點滴落下，而是像熔化了的液岩從天而降」。

（待續）

Note:

1. A spherule is a small, spherical particle that is typically formed by large meteorite impacts on the Earth. These particles are characterized by their round shape and can be distinguished from other similar particles like accretionary lapilli or carbonate ooliths. (https://www.sciencedirect.com/topics/physics-and-astronomy/spherule#:~)