Luna.极化Technology Helps Largest Radio Telescope in the World Measure 900mph Winds on Jupiter

从流行的科学摘录的部分

Luna.technology was used by an international team of astronomers who just measured Jupiter’s raging stratospheric winds for the very first time—and they used a 27-year-old comet to do it.

Scientists had already measured wind speeds down in Jupiter’s troposphere—where the planet’s iconic stripes lie—and way up in its ionosphere. But this new study was first to take wind speed measurements of Jupiter’s stratosphere using the incredibly sensitive Atacama Large Millimeter/submillimeter Array (ALMA). They measured wind speeds near the equator and near the poles.

Some results of the wind speed measurements weren’t too surprising — researchers found that wind speeds at the equator were roughly what models had predicted. “But what was completely unexpected is what we saw near the poles,” says study-author Thibault Cavalié, a planetary scientist at the Laboratoire d’Astrophysique de Bordeaux who led the experiment. The team found 300- to 400-meter-per-second winds— roughly 700 to 900 miles per hour—whipping across the poles in unanticipated directions.

几十年来，弄清楚行星风速的最简单的方法是简单地拍摄地球的快照，然后另一个时间稍后看到云在两个框架之间移动了多远，卡巴利说。但是，在较高的海拔中，这不起作用，因为风是看不见的。没有云来追踪。

但是自1994年受到Jupiter对木星影响的鞋匠 - 征收9彗星以来，研究人员在其中彗星递送的两种化合物上保持了选项卡：氰化氢和一氧化碳。该团队能够追踪化学品的独特光谱指纹。由于它们可以使用云的运动跟踪风，从而可以使用这些分子来通过检测与ALMA的频率来执行相同的操作。

然后，它们利用多普勒效应，这意味着这些频率根据分子是否朝向我们或远离我们而变化。因此，在木星上，随着分子吹向望远镜，它们会产生比远离移动的光谱信号略微不同。通过测量差异 - 频率撞到的频率有多少 - 团队可以测量分子（和风）移动的速度。

How Luna's Technology Helped

ALMA is currently the largest radio telescope in the world and uses aLuna Innovations远程极化稳定纤维担架组件to correct the timing for ALMA so that temperature changes and antenna motion effects are removed. This custom module combines several of Luna’s (formerly General Photonics’) patented technologies: a combination of fiber stretcher for optical path matching, polarization controller to dynamically control the polarization, and a polarimeter to analyze the polarization and use as a feedback signal. A specialty product for National Radio Astronomy Observatory (NARO), it generates up to 4mm of optical delay at up to 100Hz, an extremely precise level of control enabled by custom polarization control and monitoring circuits.

To provide the most accurate oscillator timing signals to the antennas, the approach adopted by ALMA uses a very accurate yardstick to probe the small changes in the fiber optic delay to each of the antennae. This is done via an ultra-stable “master laser” used in combination with an optoelectronic fiber optic line stretcher that continuously adjusts the overall fiber length to each antenna.

阅读完整的文章“Researchers just measured Jupiter’s stratospheric winds for the first time—and they’re a doozy”在受欢迎的科学这里.

Learn more about Luna’s极化Management and Emulation和Optical Polarization Controlsolutions.