木星的极光及闪电

木星的极光及闪电

2021年03月24日 Aurorae and Lightning on Jupiter Image Credit: NASA, JPL-Caltech, SwRI; Text: Natalia Lewandowska Explanation: Why does so much of Jupiter’s lightning occur near its poles? Similar to Earth, Jupiter experiences both aurorae and lightning. Different from Earth, though, Jupiter’s lightning usually occurs near its poles — while much of Earth’s lightning occurs near its equator. To help understand the difference, NASA’s Juno spacecraft, currently orbiting Jupiter, has observed numerous aurora and lightning events. The featured image, taken by Juno’s Stellar Reference Unit camera on 2018 May 24, shows Jupiter’s northern auroral oval and several bright dots and streaks. An eye-catching event is shown in the right inset image — which is a flash of Jupiter’s lightning — one of the closest images of aurora…

朱诺号的木星景观

朱诺号的木星景观

2020年11月23日 A Jupiter Vista from Juno Image Credit: NASA/JPL-Caltech/SwRI/MSSS; Processing & License: Kevin M. Gill; Explanation: Why do colorful cloud bands encircle Jupiter? Jupiter’s top atmospheric layer is divided into light zones and dark belts that go all the way around the giant planet. It is high horizontal winds — in excess of 300 kilometers per hour — that cause the zones to spread out planet-wide. What causes these strong winds remains a topic of research. Replenished by upwelling gas, zonal bands are thought to include relatively opaque clouds of ammonia and water that block light from lower and darker atmospheric levels. One light-colored zone is shown in great detail in the featured vista taken by the robotic Juno spacecraft in 2017. Jupiter’s atmosphere is…

“精灵”在木星的大气中嬉戏

“精灵”在木星的大气中嬉戏

This illustration shows the lightning phenomenon known as a sprite and what a sprite could look like in Jupiter’s atmosphere. Named after a mischievous, quick-witted character in English folklore, sprites last for only a few milliseconds. They feature a central blob of light with long tendrils of light extending down toward the ground and upward. In Earth’s upper atmosphere, their interaction with nitrogen give sprites a reddish hue. At Jupiter, where the predominance of hydrogen in the upper atmosphere would likely give them a blue hue. Image Credit: NASA/JPL-Caltech/SwRI 这幅插图展示了被称为精灵的闪电现象,以及精灵在木星大气中的样子。精灵的名字来源于英国民间传说中一个调皮伶俐的角色,它的寿命只有几毫秒。他们的特点是一个中心斑点的光与长长的卷须的光向下延伸到地面和向上。在地球的高层大气中,它们与氮的相互作用使精灵呈现出红色。在木星上,氢在上层大气中占主导地位,可能会使它们呈现出蓝色。 图片来源: NASA/JPL-Caltech/SwRI

飞越木星的大红斑

飞越木星的大红斑

2020年10月19日 A Flight over Jupiter Near the Great Red Spot Image Credit: NASA/JPL-Caltech/SwRI/MSSS; Video Processing & License: Kevin M. Gill; Music: Vangelis Explanation: Are you willing to wait to see the largest and oldest known storm system in the Solar System? In the featured video, Jupiter’s Great Red Spot finally makes its appearance 2 minutes and 12 seconds into the 5-minute video. Before it arrives, you may find it pleasing to enjoy the continually changing view of the seemingly serene clouds of Jupiter, possibly with your lights low and sound up. The 41 frames that compose the video were captured in June as the robotic Juno spacecraft was making a close pass over our Solar System’s largest planet. The time-lapse sequence actually occurred over four…

木星北极的彩色旋风

木星北极的彩色旋风

Cyclones at the north pole of Jupiter appear as swirls of striking colors in this extreme false color rendering of an image from NASA’s Juno mission. The huge, persistent cyclone found at Jupiter’s north pole is visible at the center of the image, encircled by smaller cyclones that range in size from 2,500 to 2,900 miles (4,000 to 4,600 kilometers). Together, this pattern of storms covers an area that would dwarf the Earth. The color choices in this image reveal both the beauty of Jupiter and the subtle details present in Jupiter’s dynamic cloud structure. Each new observation that Juno provides of Jupiter’s atmosphere complements computer simulations and helps further refine our understanding of how the storms evolve over time. The Juno mission provided the…

木星上的月影

木星上的月影

Jupiter’s volcanically active moon Io casts its shadow on the planet in this dramatic image from NASA’s Juno spacecraft. As with solar eclipses on the Earth, within the dark circle racing across Jupiter’s cloud tops one would witness a full solar eclipse as Io passes in front of the Sun. Such events occur frequently on Jupiter because it is a large planet with many moons. In addition, unlike most other planets in our solar system, Jupiter’s axis is not highly tilted relative to its orbit, so the Sun never strays far from Jupiter’s equatorial plane (+/- 3 degrees). This means Jupiter’s moons regularly cast their shadows on the planet throughout its year. Juno’s close proximity to Jupiter provides an exceptional fish-eye view, showing a small…

木星壮丽的漩涡云

木星壮丽的漩涡云

A multitude of magnificent, swirling clouds in Jupiter’s dynamic North North Temperate Belt is captured in this image from NASA’s Juno spacecraft. Appearing in the scene are several bright-white “pop-up” clouds as well as an anticyclonic storm, known as a white oval. This color-enhanced image was taken at 4:58 p.m. EDT on Oct. 29, 2018 as the spacecraft performed its 16th close flyby of Jupiter. At the time, Juno was about 4,400 miles from the planet’s cloud tops, at a latitude of approximately 40 degrees north. Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft’s JunoCam imager. JunoCam’s raw images are available at www.missionjuno.swri.edu/junocam for the public to peruse and process into image products. Image Credit: Enhanced Image by…

木星上的高空雾

木星上的高空雾

NASA’s Juno mission captured this look at Jupiter’s tumultuous northern regions during the spacecraft’s close approach to the planet on Feb. 17, 2020. Notable features in this view are the long, thin bands that run through the center of the image from top to bottom. Juno has observed these long streaks since its first close pass by Jupiter in 2016. The streaks are layers of haze particles that float above the underlying cloud features. Scientists don’t yet know exactly what these hazes are made of or how they form. Two jet streams in Jupiter’s atmosphere flank either side of the region where the narrow bands of haze typically appear, and some researchers speculate those jet streams may influence the formation of the high hazes. This…

从未见过的木星!

从未见过的木星!

See Jupiter’s Great Red Spot as you’ve never seen it before in this work of art. Artist Mik Petter created this unique, digital artwork using data from the JunoCam imager on NASA’s Juno spacecraft. The art form, known as fractals, uses mathematical formulas to create art with an infinite variety of form, detail, color and light. The tumultuous atmospheric zones in and around the Great Red Spot are highlighted by the author’s use of colorful fractals. Vibrant colors of various tints and hues, combined with the almost organic-seeming shapes, make this image seem to be a colorized and crowded petri dish of microorganisms, or a close-up view of microscopic and wildly-painted seashells. The original JunoCam image was taken on July 10, 2017, at 10:10 p.m….

NASA“朱诺号”为木星的水之谜提供了新发现

NASA“朱诺号”为木星的水之谜提供了新发现

2017年9月1日,美国国家航空航天局(NASA)的朱诺号(Juno)木星探测器上的JunoCam成像仪捕捉到了这幅木星南部赤道地区的图片。由于该图像是定向拍摄的,因此木星的两级(不可见)从左至右分布在框架内。 版权:NASA/喷气推进实验室-加州理工学院(JPL-Caltech)/美国西南研究院(Southwest Research Institute, SwRI)/马林空间科学系统公司(Malin Space Science Systems, MSSS)/凯文•M•吉尔(Kevin M. Gill) NASA的朱诺号任务提供了其关于木星大气中水含量的首次测量结果。根据近期发表于《自然天文学》(Nature Astronomy)期刊上的朱诺号探测器的测量结果估计,在木星的赤道地区,水分子占大气中分子的0.25%左右,几乎是太阳的三倍。这也是自1995年NASA的伽利略号(Galileo)任务提出木星相对太阳而言可能是极其干燥的(该对比并不基于液态水,太阳中存在的氧氢的含量)以来,首次发现该气态巨行星上富含水分。 几十年来,行星科学家们一直希望能够准确估计木星大气中的水分总量。该数据是太阳系形成之谜中一个关键的缺失部分。木星很可能是太阳系中形成的第一颗行星,它包含了许多没有被太阳捕获的气体和尘埃。 关于木星形成的主要理论是基于其吸收的水量。水的丰度对这颗气态巨行星的气象(例如木星上的风如何流动)和内部结构同样具有重要意义。尽管由旅行者号(Voyager)和其他探测器在木星上所探测到的闪电(一种典型的由水汽引起的现象),暗示着木星上水的存在,但对木星大气层深处的水含量的准确估计仍然是难以实现的。 1995年12月,在“伽利略”号探测器停止传送,向木星表面下降之前57分钟,它用无线电发出了木星大气中深度约为75英里(120公里)处的水含量的光谱测量数据,那里的大气压达到了约320磅每平方英寸(22巴)。研究这些数据的科学家们惊讶地发现,水量仅达到了预期的十分之一, 更令人意外的是:在测量到的最大深度下,伽利略号探测器测量到的水含量似乎仍在增加,远低于理论上所认为的大气应该混合良好的深度。在均匀大气中,整个区域的水含量是恒定的,且更有可能体现全球平均水平;换句话说,更可能是整个木星水含量的一个体现。结合同时期由地面望远镜获得的红外线地图,结果表明探测任务可能只是运气不好,在木星上采集到了一个异常干燥且温暖的气象点。 位于圣安东尼奥的西南研究所朱诺号首席研究员斯科特•博尔顿(Scott Bolton)表示:“就在我们认为已经把事情搞清楚了的时候,木星却提醒我们仍然还有很多东西需要了解。朱诺号关于即使在云层之下大气也没有均匀混合的惊人发现,依旧是一个需要我们去解开的谜题。没有人能够猜到木星上的水分会如此变化无常。” 从高空测量水含量 在这张由JunoCam拍摄的木星赤道区域中出现了浓厚的白色云层。在微波频率下,这些云是透明的,这使得朱诺号的微波辐射计能够测量木星大气深层的水。这幅图像是于2017年12月16日朱诺号飞掠木星时所拍摄的。 版权:NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill 朱诺于2011年发射升空,是一艘采用自旋稳定的太阳能飞船。基于伽利略号探测器的前期经验,朱诺号任务的主要目标是获得这颗巨行星上大片区域的水丰度测量值。朱诺号上搭载了一种用于深空行星探测的新型仪器:微波辐射计(Microwave Radiometer,MWR)是,它能够利用6根天线同时测量多个深度的大气温度,实现从高空测量木星上的水含量。MWR利用的是水吸收特定波长的微波辐射这一事实,这与微波炉快速加热食物的原理相同。因此,它所测量的温度能够用于确定深层大气中的水和氨的含量范围,因为这两种分子都能吸收微波辐射。 朱诺号科学团队通过朱诺号前八次飞掠木星时所收集的数据,得出了上述发现。他们最开初的关注点在木星的赤道地区,因为那里的大气似乎比其他地区混合得均匀,即便在深处也是如此。从其轨道位置上来看,朱诺号的辐射计能够从比伽利略号探测器更深的地方收集数据,深度可达到93英里(150公里),那里的压力达到了480磅每平方英寸(33巴)。 加州大学伯克利分校的朱诺号科学家Cheng Li表示:“我们发现赤道地区上的水含量高于伽利略号探测器的测量值。因为木星的赤道地区非常独特,我们还需要将这些测量结果与木星上其他区域的水含量进行对比。” 向北移动 朱诺号的53天飞行轨道正按计划缓慢向北移动,每次飞越都会使木星北半球上的更多区域变得更加清晰。朱诺号科学团队迫切希望了解木星的大气含水量如何随纬度和地区而变化,以及富含气旋的极地能够告诉他们的关于这颗气态巨行星的全球水丰度。 2月17日,朱诺号第24次飞掠木星。下一次科学飞行拟于2020年4月10日进行。 博尔顿表示:“每一次科学飞行都是一次重大发现。木星总是给我们一些新的发现。朱诺号给我们上了重要的一课:我们需要通过和一颗星球的近距离亲密接触来验证我们的理论。” NASA位于加利福尼亚州帕萨迪纳市的喷气推进实验室负责为圣安东尼奥西南研究所的首席研究员斯科特•博尔顿(Scott Bolton)管理和执行朱诺号任务。朱诺号是NASA“新前沿”计划(New Frontiers Program)的一部分,该计划由位于阿拉巴马州亨茨维尔的NASA马歇尔太空飞行中心为NASA科学任务理事会进行管理。意大利航天局(Italian Space Agency, ISA)为朱诺号探测器提供了木星红外极光绘图仪(Jovian Infrared Auroral Mapper , JIRAM)和Ka波段翻译系统(Ka-Band translator system)。位于丹佛的洛克希德•马丁太空公司建造了这艘航天器,并提供飞行操作。 关于朱诺号的更多信息,请戳阅: https://www.nasa.gov/juno https://www.missionjuno.swri.edu 关于木星的更多信息,请戳阅: https://www.nasa.gov/jupiter 也可以通过以下链接在Facebook和Twitter上关注朱诺号任务: https://www.facebook.com/NASAJuno https://www.twitter.com/NASAJuno 来源: https://www.nasa.gov/feature/jpl/findings-from-nasas-juno-update-jupiter-water-mystery