Summer solstice 2025 is here! Today marks the longest day of the year for the Northern Hemisphere

2025年夏至来临了！今天是北半球一年中最长的一天

Sunlovers rejoice, for the summer solstice is upon us, bringing the longest day of 2025 while heralding the beginning of astronomical summer in the northern hemisphere.

热爱阳光者欢欣鼓舞，因为夏至即将来临，带来了2025年最长的一天，同时也预示着北半球天文夏季的开始。

The summer solstice occurs because of a 23.5 degree tilt in Earth's rotational axis that may have arisen when an ancient Mars-sized body slammed into our planet billions of years ago, triggering the formation of our moon. The angle of this tilt is — to all intents and purposes — consistent all year round, and is currently fixed with the north celestial pole pointing close to Polaris, the current north star.

夏至的发生是因为地球自转轴倾斜了23.5度，这可能是数十亿年前一个火星大小的古老天体撞击我们的星球，引发了我们月球的形成。这种倾斜的角度——实际上——全年都是一致的，目前是固定的，北极指向北极星，也就是现在的北极星。

Thanks to this tilt, we experience the changing seasons, equinoxes and solstices — events that have been celebrated by cultures around the world for thousands of years. Some of humanity's most iconic ancient monuments like Stonehenge and the Mayan Chichén Itzá Pyramid were purpose built to align with these seasonal markers.

由于这种倾斜，我们经历了季节的变化、春分和夏至、冬至——这些事件已经被世界各地的文化庆祝了几千年。一些人类最具标志性的古代遗迹，如巨石阵和玛雅奇琴伊察金字塔，都是为了与这些季节性标志保持一致而专门建造的。

In the northern hemisphere the summer solstice occurs when the sun reaches its northernmost point relative to Earth's celestial equator (which is simply our planet’s regular equator projected out into space). Conversely, the winter solstice takes place when the sun is in its southernmost position relative to the celestial equator.

在北半球，夏至发生在太阳到达相对于地球天赤道的最北端的时候。相反，冬至发生在太阳相对于赤道处于最南端的位置时。

The 2025 summer solstice arrives at 10:42 p.m. EDT on June 20 (0242 GMT June 21). On this day, skywatchers across the northern hemisphere will enjoy the longest stretch of daylight all year. In New York, for example, the sun will spend more than 15 hours beating a path through the sky.

2025年夏至于晚上10:42，美国东部时间6月20日（格林威治时间6月21日0242）。在这一天，北半球的天空观察者将享受全年最长的日光。例如，在纽约，太阳将花费超过15个小时在天空中穿行。

At the same time, those in the southern hemisphere will mark the winter solstice, which heralds the shortest day of 2025 below the equator. You can calculate exactly how much daylight you will experience in the days around the summer and winter solstices online using TimeandDate.com's daylight tracker.

与此同时，南半球的人将迎来冬至，这预示着2025年赤道以下白昼最短的一天。你可以使用日光追踪器来在线准确计算夏至和冬至前后的日光量。

Naturally this amount of sunlight makes it a challenging time of year for amateur astronomers, but that doesn't mean that the summer months aren't bursting with deep space targets and beautiful asterisms.

自然地，如此多的阳光使它成为业余天文学家一年中具有挑战性的时间，但这并不意味着夏季没有深空目标和美丽的星群。

Be sure to check out our daily guide to June's night sky to discover which targets to prioritize during those short summer nights.

请务必查看我们的六月夜空每日指南，以便了解在那些短暂的夏夜中应该优先考虑哪些目标。

Editor's Note: If you find a creative way to capture the Summer Solstice and want to share it with Space.com's readers, then please send your photo(s), comments, and your name and location to spacephotos@space.com.

编者注意：如果你找到了捕捉夏至的创造性方法，并想与Space.com的读者分享，那么请将你的照片、评论以及你的姓名和位置发送到spacephotos@space.com。