也許二氧化硫比磷化氫更可以解釋金星上神秘的大氣特征

也許二氧化硫比磷化氫更可以解釋金星上神秘的大氣特征

Last September, a cautious but exciting result was reported. Venus appears to have an abundance of phosphine in its clouds. Phosphine is mostly produced by living organisms so that certainly got people talking. In good science praxis, other scientists got involved to test if the finding was correct. Questions were asked and some problems with the data were found, leaving the mystery wide open.

去年9月，報道了一個謹慎但令人興奮的結果。金星的云層中似乎有大量的磷化氫。磷化氫主要是由生物體產(chǎn)生的，這當然引起了人們的討論。在良好的科學實踐中，其他科學家也參與進來測試這個發(fā)現(xiàn)是否正確。人們提出了一些問題，也發(fā)現(xiàn)了一些數(shù)據(jù)上的問題，讓這個謎團沖出了迷霧。

Now a different team has put forward evidence to solve this. It was never phosphine at all. It was the most-like but less-exciting sulfur dioxide. The new scenario is accepted for publication in The Astrophysical Journal and is currently available as a pre-print, which means it has not yet been peer-reviewed.

現(xiàn)在，一個不同的團隊提出了解決這個問題的證據(jù)。根本就不是磷化氫。它是最像但不那么刺激的二氧化硫。這一新的設想將在《天體物理學雜志》上發(fā)表，目前是預印本，這意味著它還沒有經(jīng)過同行評審。

"Instead of phosphine in the clouds of Venus, the data are consistent with an alternative hypothesis: They were detecting sulfur dioxide," co-author Victoria Meadows, a UW professor of astronomy stated in the press release. "Sulfur dioxide is the third-most-common chemical compound in Venus' atmosphere, and it is not considered a sign of life."

“不是在金星的云層中發(fā)現(xiàn)了磷，數(shù)據(jù)與另一種假設一致:他們檢測到了二氧化硫，”合著者維多利亞·梅多斯，華盛頓大學的天文學教授在新聞發(fā)布會上說。“二氧化硫是金星大氣中第三常見的化合物，它不被認為是生命的跡象。”

Dr Alfredo Carpineti

Chemicals in outer space are discovered by looking at the emission of electromagnetic radiation at particular frequencies. These signatures can sometimes get confusing because our instruments are not perfect and this is why observations are followed up with other instruments to find more evidence to confirm detection.

通過觀察特定頻率的電磁輻射發(fā)射，可以發(fā)現(xiàn)外層空間的化學物質。這些信號有時會讓人感到困惑，因為我們的儀器并不完美，這就是為什么觀測之后會有其他儀器來尋找更多的證據(jù)來證實檢測結果。

Let’s take a step back to the first detection of this signal. Back in 2017, the original research team used the James Clerk Maxwell Telescope (JCMT) and discovered a particular radio wave emission from the clouds of Venus. There were two molecules that would fit that signature. Phosphine and sulfur dioxide. The team decided to use the Atacama Large Millimeter/submillimeter Array (ALMA) to distinguish between the two. In that dataset (which we now know had other issues) they found that sulfur dioxide was not abundant enough, so they concluded that phosphine was likely the source of the original signal.

讓我們回到第一次探測到這個信號的時候。早在2017年，最初的研究團隊就使用了詹姆斯·克拉克·麥克斯韋望遠鏡(JCMT)，發(fā)現(xiàn)了金星云層中發(fā)出的一種特定的無線電波。有兩個分子符合這個特征。膦和二氧化硫。該團隊決定使用阿塔卡馬大型毫米/亞毫米陣列(ALMA)來區(qū)分這兩者。在那個數(shù)據(jù)集(我們現(xiàn)在知道有其他問題)中，他們發(fā)現(xiàn)二氧化硫不夠多，因此他們得出結論，磷化氫可能是原始信號的來源。

The new work took a different approach. They modeled the atmosphere of Venus and used that to interpret what was seen and not seen in the data from the two telescopes. Their model indicates that the signals are not coming from the clouds of Venus but from 80 kilometers (50 miles) above them, in the mesosphere. Not a place where phosphine is likely to survive.

新工作采用了一種不同的方法。他們模擬了金星的大氣層，并用它來解釋這兩個望遠鏡的數(shù)據(jù)中看到的和沒有看到的東西。他們的模型表明，信號不是來自金星云層，而是來自云層上方80公里(50英里)的中間層。磷化氫不太可能在這里生存。

"Phosphine in the mesosphere is even more fragile than phosphine in Venus' clouds," explained Meadows. "If the JCMT signal were from phosphine in the mesosphere, then to account for the strength of the signal and the compound's sub-second lifetime at that altitude, phosphine would have to be delivered to the mesosphere at about 100 times the rate that oxygen is pumped into Earth's atmosphere by photosynthesis."

“中間層的磷化氫比金星云層中的磷化氫更脆弱，”梅多斯解釋說。“如果JCMT的信號來自中間層的磷化氫，那么考慮到信號的強度和這種化合物在那個高度的亞秒壽命，磷化氫被輸送到中間層的速度必須是地球通過光合作用輸送到大氣中的氧氣速度的100倍。”

The other major find is that they think that the ALMA data most likely underestimated the amount of sulfur dioxide present in the Venus atmosphere, giving the false impression that the bulk of the JMCT signal was likely coming from phosphine.

另一個重要發(fā)現(xiàn)是，他們認為ALMA的數(shù)據(jù)很可能低估了金星大氣中二氧化硫的含量，從而產(chǎn)生了大量JMCT信號可能來自磷化氫的錯誤印象。

"The antenna configuration of ALMA at the time of the 2019 observations has an undesirable side effect: The signals from gases that can be found nearly everywhere in Venus' atmosphere—like sulfur dioxide—give off weaker signals than gases distributed over a smaller scale," added co-author Alex Akins, a researcher at the Jet Propulsion Laboratory.

“ALMA在2019年觀測時的天線配置有一個不良的副作用:來自金星大氣中幾乎無處不在的氣體(比如二氧化硫)發(fā)出的信號比分布在較小范圍內的氣體發(fā)出的信號更弱，”噴氣推進實驗室的研究人員、共同作者亞歷克斯·埃金斯補充道。

The original team is currently re-examining the whole data set, and we look forward to seeing what their analysis comes up with.

最初的團隊目前正在重新檢查整個數(shù)據(jù)集，我們期待看到他們的分析結果。