太阳系的行星:倾斜与自转
影像来源与版权:NASA, Animation: James O’Donoghue (JAXA)

说明:你最喜欢的行星是如何自转的?它是围绕着近乎垂直的轴快速旋转,还是水平旋转,还是向后旋转?这段精彩视频生动地呈现了由美国航天局拍摄的太阳系所有八大行星,将它们并排旋转以便于比较。在这段延时视频中,地球上的一天即地球自转一圈,只需要几秒钟。木星的自转速度最快,而金星的自转速度不仅最慢(你能看到吗?),而且还向后旋转。在太阳系的早期,系内岩石行星(位于视频上部)肯定经历了剧烈的自转改变碰撞。行星自转和倾斜的原因仍然是一个研究课题,我们从现代计算机模拟和最近对数百颗系外行星(围绕其他恒星运行的行星)的发现和分析中获得了许多见解。
翻译:北京天文馆

Planets of the Solar System: Tilts and Spins
Image Credit & Copyright: NASA, Animation: James O’Donoghue (JAXA)

Explanation: How does your favorite planet spin? Does it spin rapidly around a nearly vertical axis, or horizontally, or backwards? The featured video animates NASA images of all eight planets in our Solar System to show them spinning side-by-side for an easy comparison. In the time-lapse video, a day on Earth — one Earth rotation — takes just a few seconds. Jupiter rotates the fastest, while Venus spins not only the slowest (can you see it?), but backwards. The inner rocky planets, across the top, most certainly underwent dramatic spin-altering collisions during the early days of the Solar System. The reasons why planets spin and tilt as they do remains a topic of research with much insight gained from modern computer modeling and the recent discovery and analysis of hundreds of exoplanets: planets orbiting other stars.
Astronomy Picture of the Day 05/20/2019