A proposed new mission to 金星

的 proposed VERITASmission to 金星 is one of the finalists for NASA’的发现程序。如果选择,它将彻底改变我们对地球的认识’的地质,以及这个以前宜居的世界如何变成火热的荒原。

在多云的星球上方的航天器,可以看到表面充满颜色的椭圆形。

艺术家’s concept of VERITASspacecraft orbiting 金星, using its radar to peer through the planet’密云并产生其表面的高分辨率地图。图片来自NASA / 联合技术公司.

金星 通常被称为 地球’s sister planet,并且’也是我们最近的行星邻居。它’s about the same size and density as 地球. But, beyond that, 金星 is a very different – and hostile – world. While 地球 is a garden, 金星 is hot enough on its surface to melt lead. Scientists think that 金星 used to be more 地球like a few billion years ago, when the solar system was younger. Something happened that altered its evolutionary course forever, but exactly what that was is still not well understood. Somehow, 金星 changed from being a clement world, possibly with oceans, to the cloud-enshrouded, searing hellhole we know today. A proposed new NASA mission, called VERITAS, would study 金星’地质,无论是在地下还是在地下。它将试图回答有关这个世界最终如何与我们自己截然不同的根本问题。

的 latest overview of the VERITASmission was 已发布 由NASA’于2020年7月8日成立喷气推进实验室(JPL)。

VERITAS– 金星 Emissivity, Radio Science, InSAR, Topography & Spectroscopy – is one of the 拟议的四个任务 被美国宇航局考虑’s Discovery Program. 苏珊(Suzanne Smrekar), principal 在 vestigator of VERITASat JPL, 陈述:

金星 is like this cosmic gift of an accident. You have these two planetary bodies – 地球 and 金星 –开始几乎是相同的,但是走了两条完全不同的进化路径,但是我们没有’t know why.

火山岩喷出的长长的烟熏火山羽,地势偏红,空气朦胧。

艺术家’s concept of active volcano on 金星, and a 俯冲 zone, where a tectonic plate on the surface sinks 在 to the 在 terior of the planet. Image via NASA/ 联合技术公司/彼得·鲁宾。

金星 is a rocky world like 地球, but its surface is completely obscured by a thick, dense atmosphere of carbon dioxide. Temperatures at the surface never fall below about 900 degrees Fahrenheit (500 degrees Celsius), and the pressure, similar to that deep 在 the oceans on 地球, would quickly crush humans. 的 clouds contain 硫酸。尽管在大气层中温度,压力和压力更高,但它并不是太阳系中最宜居的地方。

VERITASwould peer through the dense clouds with radar and a near-infrared 光谱仪 创建地球的3-D全球地图并分析其表面组成(我们确实已经知道大部分表面是火山的 玄武岩). By measuring 金星’引力场,VERITAS还可以确定行星的结构’s 在 terior. VERITASwould provide the most detailed analysis of 金星 ever obtained by an orbiting spacecraft.

If selected, VERITASwould launch sometime 在 2026.

灰色和白色地形,有许多平行的小山脊。

An example of 特塞拉 deformation terrain (white terrain on right side of image) on the western edge of Maxwell Montes on 金星. Image via NASA/ JPL/ 维基百科.

Scientists are very 在 terested 在 learning more about 金星, to understand why it changed so dramatically. This could also offer new 在 sights 在 to 地球’自己作为行星以及围绕其他恒星运行的其他岩石行星的演变。

VERITASwill study 金星’地质学及其与早期地球的相似性。星球’人们认为,地壳的温暖与数十亿年前地球的相似。 构造板块 were just starting to form. Did the same thing happen on 金星? According to 琼·斯托克(Joann Stock),加州理工学院的地质学家和地球物理学家’的帕萨迪纳地震实验室:

的 biggest mystery to me is the extent of 变形结构 on 金星 that could be studied to understand the nature of tectonic activity on the planet.

变形结构 是在巨大的地质压力下弯曲的岩石表面区域。在地球上,外地壳被分成构造板块,这些构造板块位于地壳顶部 披风。一些板块在称为 俯冲,由 对流 在地幔中。由于温度上升的幅度越远,这些板块开始熔化。这会释放出火山气体和其他称为 挥发物包括水,氮气,二氧化碳和甲烷进入大气。

地形图覆盖着不规则的彩色斑块,某些区域周围带有白色轮廓。

Map of extensive 特塞拉 terrain on 金星 (white outlines). Image via USGS Astrogeology Science Center/ Sjoh197/ 维基百科.

变形结构是否可能是类似于早期地球的构造板块形式? VERITAS将帮助科学家回答这个问题。 3D地形图将能够看到比以前的早期任务更小的特征。它可以识别 走滑断层, 如同 圣安地列斯断层 在加利福尼亚,通过查看断层两侧的凸起地形来实现。如果VERITAS发现了这样的地层,那将是过去甚至今天的地球上大量构造活动的证据。 VERITAS还将使用干涉变形图– using 干涉仪 –寻找地球上的活跃断层’的表面,除了地球上任何地方都从未做过的事情。

If plate tectonics were to be confirmed on 金星, that would be an exciting discovery, since 地球 is the only planet 在 our solar system known to have that kind of geological activity. (Jupiter’现在认为欧罗巴的月亮有更多 板块构造的原始形式,但欧罗巴’地壳由水冰而不是岩石组成。

的 largest and most widespread 变形结构 on 金星 are called 特塞拉类似于地球的高原状区域’s continents. VERITASwould study their composition, to see if they formed 在 a similar manner to continents on 地球. That could provide valuable clues about the former ocean(s) that many scientists think once existed on 金星, 地球’当富含铁的海洋地壳在水的作用下俯冲并融化时,被认为形成了欧洲大陆。

高大的橙黄色小山和橙色修补前景,与黑色的天空。

Perspective view of the Maat Mons volcano on 金星, based on radar images from 麦哲伦. 的 volcano is 5 miles (8 km) tall. Image via PD/ USGOV/ NASA/ 维基百科.

What about volcanism? Volcanism is very much 在 tertwined with plate tectonics on 地球. We already know that 金星 has many volcanoes, but are any of them still active? 的re is currently tentative evidence of still-active volcanoes on 金星, but it is not completely confirmed yet. VERITAScould help do that. 珍妮弗·惠顿, a VERITASscience team member at Tulane University 在 New Orleans, said:

Determining whether 金星 is actively undergoing volcanic activity and understanding what process is driving it is one of the really exciting questions I’d喜欢看到回答。

VERITASwould be able to look for hotspots from active eruptions using its 光谱仪, and the radar could detect active faulting, which would be evidence for current tectonic activity. 的 光谱仪 could also detect rocks that had been formed from hot magma, before the chemical composition of the rocks had been altered by the corrosive atmosphere. Knowing how geologically active 金星 still is, or isn’t,这也将有助于科学家弄清楚地球内部有多少水。

金星’地质学,尤其是板块构造学,在适居性方面也很重要。星球’的表面现在可能极度荒凉,但是当时’总是这样。板块构造和火山作用在地球上起了重要作用’的可居住性,板块构造有助于保持长期的气候稳定(除了人为引起的气候变化)。火山活动将挥发物释放到大气中,而俯冲作用则将其循环回地球’的内部。这个连续的周期使大气保持平衡。大气层和海洋的组成都受到各大洲的形成和侵蚀的影响,这为生命提供了必要的营养。

Woman standing 在  front of multi-colored globe of 金星 on black background.

苏珊(Suzanne Smrekar), principal 在 vestigator of VERITASat JPL. Image via 凯克空间研究所.

Smrekar说:

To unwrap the mysteries of 金星 we have to look under the hood at 金星’ 在 terior; it is the engine for global geologic and atmospheric evolution. Are 金星 and 地球 fundamentally unique worlds? Or are the differences between these ‘twins’只有化妆品?回答这个问题对于理解是什么使其他岩石行星变得宜居并最终随着生命而出现至关重要。

的 last spacecraft to study 金星’轨道表面为 麦哲伦, whose mission ended 在 1994. If it does get selected as a mission, VERITASwill revolutionize our understanding of how 金星 formed and evolved, and why our sister planet changed so dramatically from a habitable world to one that could just as well have been forged 在 hell itself.

Bottom line: 的 proposed VERITASmission would study the complex geology of 金星.

通过喷气推进实验室

保罗·斯科特·安德森