2025年1月16日天文系系主任换届，通过民主推荐和考察，经学校研究决定，清华大学讲席教授李菂担任系主任一职。原系主任毛淑德教授不再担任系主任。

毛淑德于2014年任清华大学任天体物理中心（天文系前身）主任，2019年开始担任新成立的天文系首任系主任。在任期间，积极引进国内外优秀青年师资，推动大科学项目发展，搭建国际化培养平台，搬迁新办公楼。毛淑德牵头基金委创新群体、国家重点研发计划等多项科研项目，在本科生教学、研究生培养方面积极作为，培养了一批青年人才，为天文系的早期发展做出了贡献。在交接工作中，毛淑德老师表示将不遗余力，继续关心支持天文系发展。

李菂老师表示，感谢毛淑德老师的贡献，感谢学校及同事的信任和肯定，表示将竭尽全力投入工作，团结带领全系教师不断开创事业发展新局面。

现在附上新任主任李菂对全系的寄语：

人类拥有同一片天空，每个人却有自己的宇宙。

从玉泉路到永定路就是我小时候宇宙膨胀的极限。中关村和清华大学那时只能是幼年宇宙学理论上的可能。即使这样有限的宇宙，也有复杂的事物和难解的存在。所以成年以后，第一次看到开普勒的日记，虽然能看懂却大受震撼。大意是他刚刚完成了三定律，猜测这样神圣而优美的见解估计还需要100年才能被世人接受：“十年或百年都无关紧要。我找到了天堂的定律。”这是几乎荒废一生试图纯用正多面体构建宇宙学的开普勒，也是多次面临经费困难、亲人夭亡的开普勒。他的定律还在被使用。其更深刻的影响是表明了天空存在法则，而法则可以被个人揭示，被人类理解。

我们比开普勒幸运的多。我们有清华大学的支持。我们有李惕碚、陶嘉琳、毛淑德这些具备远见卓识的实干家。我们有最优秀的学生。从2019年4月21日开始，我们还有了天文系这样一个家园，支撑对天堂的定律的探究。目前，天文系有将近20位全职教师，主要从事高能天体物理、星系宇宙学、系外行星和射电天文4个方向。天文系的规模在迅速扩大的中国天文领域中并不显著，也凸显了清华天文进一步发展需要强调系统原创、交叉学科的必要性。作为原创和交叉的范例，宽视场巡天望远镜（MUST）和宇宙热重子探寻计划（HUBS）都进入了《清华大学2030创新行动计划》，成为清华大学天文系的发展重心。

“博学之，审问之，慎思之，明辨之，笃行之。”天文系将依托前辈奠定的基础，践行学校内涵式发展的战略，尝试开拓动态宇宙“时间前沿”等探索方向，揭示天空共同的法则，拓展每一个宇宙的边界。

李菂

2025年1月17日

Humanity shares the same sky, yet each person has their own universe.

From Yuquan Road to Yongding Road marked the limits of my expanding universe during childhood. Back then, places like Zhongguancun and Tsinghua University were no more than theoretical possibilities within my adolescent cosmology. Even within such a confined universe, there were already intricate phenomena and enigmatic existence. When I came across Kepler’s diary for the first time, I was profoundly touched. He had just formulated his three laws and suspected that such sacred and elegant insights have to take another hundred years to be widely accepted: “ten or a hundred years—time is inconsequential. I have discovered the laws of heaven.” This was the Kepler: who almost wasted a full lifetime trying to build a cosmology with regular polyhedrons. This was the Kepler who endured numerous financial hardships and the loss of loved ones. His laws are still in use today. Even more profoundly, his laws demonstrate that the sky follows rules—rules that can be discovered by individuals and understood by humanity.

We are far more fortunate than Kepler. We have the support of Tsinghua University. We have visionary and pragmatic pioneers, such as Li Tipei, Tao Charling, and Mao Shude. We have the most outstanding students. And as of April 21, 2019, we have a home, the Department of Astronomy, for exploring the laws of heaven. Currently, the department has nearly 20 full-time faculties, focusing on four main areas: high-energy astrophysics, galaxies and cosmology, exoplanets, and radio astronomy. Such a scale is not prominent in the rapidly expanding field of astronomy in China. Tsinghua Astronomy has to emphasize systematic originality and interdisciplinary research. Exemplifying this vision, the MUltiplexed Survey Telescope (MUST) and the Hot Universe Baryon Surveyor (HUBS) have been included in the《Tsinghua University 2030 Innovation Action Plan》and thus the key focal points for the department’s development.

“Study extensively, inquire earnestly, think carefully, discern clearly, and act resolutely.” Building on the foundation laid by our predecessors, the Department of Astronomy at Tsinghua University will carry forward the school’s strategy of intrinsic growth, will explore new horizons such as the dynamic universe’s “time frontier”, will strive to reveal the common laws of the sky as well as to extend the boundaries of every individual universe.

Di Li

2025-01-17