45億年前 嬰兒期的木星很可能被行星撞擊過

45億年前 嬰兒期的木星很可能被行星撞擊過

upiter has long been hailed as the mighty “king of planets” thanks to its massive size compared to most of the other planets in our solar system. It’s huge and it’s mostly made of gas, making it difficult for scientists to know what lies deep beneath its thick cloud cover.

與太陽系中的大多數(shù)其他行星相比，木星因其巨大的體積一直被譽(yù)為強(qiáng)大的“行星之王”。它很大，而且大部分是由氣體構(gòu)成的，這使得科學(xué)家很難知道它厚厚的云層下到底有什么。

NASA’s Juno spacecraft has been studying the planet in detail for over eight years now and it’s returned some surprising observations about the planet’s core. Now, a new study from an international team of researchers may offer an explanation.

美國(guó)國(guó)家航空航天局的朱諾號(hào)宇宙飛船，已經(jīng)對(duì)這顆行星進(jìn)行了8年多的詳細(xì)研究，并傳回了一些令人驚訝的關(guān)于該行星核心的觀測(cè)結(jié)果?，F(xiàn)在，來自國(guó)際研究團(tuán)隊(duì)的一項(xiàng)新研究可能會(huì)給出一個(gè)解釋。

Scans from Juno have hinted that Jupiter’s core isn’t exactly what scientists once thought it was. The core isn’t as dense as researchers suspected, but determining why that is has proven to be a challenge.

朱諾號(hào)的掃描顯示，木星的核心并不是科學(xué)家們?cè)?jīng)認(rèn)為的那樣。核心并不像研究人員所懷疑的那么密集，但要確定為什么會(huì)這樣顯然是一個(gè)挑戰(zhàn)。

“This is puzzling,” Andrea Isella, co-author of a new study published in Nature, said in a statement. “It suggests that something happened that stirred up the core and that’s where the giant impact comes into play.”

發(fā)表在《自然》雜志上的一項(xiàng)新研究的合著者安德里亞·伊塞拉在一份聲明中說：“這令人費(fèi)解。”“表明這里曾發(fā)生了什么事情，攪動(dòng)了核心，這就是巨大影響產(chǎn)生的地方。”

To get to the bottom of the mystery, the team ran computer simulations of early Jupiter to see what kind of interactions may have led to the planet’s present state. What they found was that a massive impact, while the planet was still forming, is likely the best explanation.

為了弄清這個(gè)謎團(tuán)的真相，研究小組對(duì)早期的木星進(jìn)行了計(jì)算機(jī)模擬，看看是什么樣的相互作用導(dǎo)致了這顆行星目前的狀態(tài)。他們發(fā)現(xiàn)，當(dāng)行星還在形成時(shí)，一次巨大的撞擊可能是最好的解釋。

“Because it’s dense and it comes in with a lot of energy, the impactor would be like a bullet that goes through the atmosphere and hits the core head-on,” Isella explains. “Before impact, you have a very dense core, surrounded by atmosphere. The head-on impact spreads things out, diluting the core.”

伊塞拉解釋說：“因?yàn)樗芏却?，而且能量也很大，撞擊器就像一顆子彈，穿過大氣層，迎面擊中核心。”在撞擊之前，有一個(gè)非常致密的核心，被大氣包圍。迎面撞擊會(huì)將物質(zhì)分散開來，稀釋核心。”

The planet that may have struck Jupiter would have to have been huge, according to the simulations. The researchers estimate that it would have been roughly 10 times as massive as Earth and it would have messed things up so dramatically that it would take billions of years to settle back down, explaining why the core of Jupiter isn’t nearly as dense and compact as scientists think it should be.

根據(jù)模擬，撞擊木星的那顆行星可能非常巨大。研究人員估計(jì)，它的質(zhì)量大約是地球的10倍，而且它會(huì)把事情搞得如此嚴(yán)重，以至于需要數(shù)十億年才能穩(wěn)定下來，這就解釋了為什么木星的核心不像科學(xué)家們認(rèn)為的那么致密和緊湊。