一位天文学家可能已经看到彗星 41P/Tuttle-Giacobini-Kresák 做出一件极其罕见的事：先停止自转，然后可能逆转其旋转方向。这项发现于 3 月 26 日发表在《Astronomical Journal》，来自哈伯太空望远镜的存档影像，并承接了多年来对彗星如何随时间改变旋转方式的疑问；彗星在轨道和亮度上都以极难预测而著称。

这颗彗星在 2017 年初就已经显示出剧烈的旋转变化，当时它的转速从先前约 20 小时一转，放慢到每转约 46 到 60 小时，周期增加了一倍多。科学家表示，彗星确实可以改变自转速度，但通常只会变动几分钟，因此这种跨越数小时的变化足以让 Dennis Bodewits 说它是在如此规模下前所未见。David Jewitt 后来重新检视存档资料，发现 41P 在那之后的行为可能变得更加古怪。

如果得到确认，这项观测将成为彗星旋转研究中的首例，并意味著喷气逸出以及其他力量能比预期更大幅度地改变彗星的自转，甚至可能造成逆转。文章仍然保持谨慎，使用了诸如

An astronomer may have seen comet 41P/Tuttle-Giacobini-Kresák do something exceptionally rare: stop spinning and then possibly reverse its rotation. The finding, described on March 26 in the Astronomical Journal, came from archival Hubble Space Telescope images and follows years of uncertainty about how comets, which are notoriously hard to predict in both path and brightness, can change their rotation over time.

The comet had already shown dramatic rotational change in early 2017, when it slowed from an earlier roughly 20-hour spin to about 46 to 60 hours per rotation, more than doubling its period. Scientists say comets can alter spin rates, but usually only by minutes, making this multi-hour shift unusual enough for Dennis Bodewits to describe it as something never seen before at such a scale. David Jewitt later reexamined archival data and found evidence that 41P’s behavior may have become even stranger afterward.

If confirmed, the observation would mark a first for cometary rotation studies and would suggest that outgassing and other forces can alter a comet’s spin much more radically than expected, potentially even driving a reversal. The article remains cautious, using language such as