2019 September 29 MyCn 18: The Engraved Hourglass Planetary Nebula Image Credit: NASA, ESA, Hubble; Processing & License: Judy Schmidt Explanation: Do you see the hourglass shape — or does it see you? If you can picture it, the rings of MyCn 18 trace the outline of an hourglass — al […]
2019 September 28 An Analemma of the Sun Image Credit & Copyright: Gyorgy Soponyai Explanation: This week the equinox found the Sun near the middle, but not at the crossing point, of an analemma in its annual trek through planet Earth’s skies. In this scenic view, that graceful, figure-8-
黑洞的最新可视化展示了黑洞的重力如何扭曲我们的视线及其周围的环境，就像在哈哈镜中看到的那样。可视化效果模拟了黑洞的外观：落入黑洞的物质积聚在一个又薄又热的结构中，称为吸积盘（accretion disk）。 随着磁场在气体的搅动中缠绕并扭曲，明亮的“结点”不断在吸积盘中形成并消散。最靠近黑洞的位置气体以接近光速运转，而外部速度更慢。这种速度差拉伸并剪切了这些明亮的“结点”，在吸积盘中产生了或明或暗的路线。 从侧面看，在黑洞周围的气体湍流呈现出神奇的双峰状外观。黑洞的极端重力会改变来自吸积盘不同部分的光的路径，从而产生这般扭曲的图像。侧视时扭曲的程度最大。 Credits: NASA’s God
