词条 合
描述: 从地球上的观测者的角度来看，当两个天体在天空中看起来非常接近时，它们被称为处于合相（合）。合相不一定是肉眼可见的——例如，每当新月时，月亮和太阳近似在一条直线上，但在此时，我们看不到月亮，除非发生日食。在这种情况下，或者两个天体非常接近（合）以至于一个天体看起来遮住另一个天体时，天文学家就会将其描述为凌日或食。
相关词条
用其他语言查看该词条
词条和定义状态： 该术语的英文原始定义已通过天文研究人员和教师的审核 该术语及其定义的译文仍待审核
The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".
如果您发现此词汇术语或定义中的事实或翻译错误， 请向 发邮件 联系.
其他语言版本
- 阿拉伯语: الاقتران
- 德语: Konjunktion
- 英语: Conjunction
- 西班牙语: Conjunción
- 法语: Conjonction
- 意大利语: Congiunzione
- 日语: 合 (外部链接)
- 韩语: 합
- 巴西葡萄牙语: Conjunção
- 繁体中文: 合
相关媒体
木星、金星、月亮合相
图注： 这张照片是 2023 年 2 月在美国宾夕法尼亚州卢泽恩县上空用智能手机拍摄的，让我们得以一窥合相现象，这是一种迷人的天文现象，当从我们的视角看到两个或两个以上的天体在天空中紧紧相邻时就会发生这种现象，尽管这些天体实际上并不靠近彼此。在这张照片中，木星（上面）的光辉、金星的魅力（中间）和月亮熟悉的光芒（下面）在微妙的云层和树线轮廓的背景下翩翩起舞，这一刻值得珍藏。
来源： Joslynn Appel/IAU OAE (CC BY 4.0)
月球-水星-昴星团相合
图注： 2022年国际天文学联合会（IAU）OAE天文摄影比赛静态天体图案类别荣誉奖作品。
这张照片展示了年轻的月牙，其右侧是昴星团中的九颗最亮的恒星（其中一颗被云层遮挡）。照片中央是水星，看上去略带红色。
这幅图片更倾向于表明昴星团可能由七颗星组成。然而，观察者被云层误导了——五颗星组成了一辆小战车，一颗紧挨着车把，另外三颗在四边形的另一端。如果没有云层，八颗星将清晰可见。
蛾眉月与昴星团相伴的这种天象仅在北半球的春天才能看到。因此，古巴比伦人利用它来确定一年中的第二个月，并判断是否需要闰月。至少早在公元前第二个千年，巴比伦人就利用多个星群来确定月份。每隔五天，下一个星群就会在隐没于日光后再次出现。为了确定闰年的必要性，使太阳年和阴历年同步，巴比伦人使用了多个星群，而不仅仅是昴星团。例如，他们还利用了明亮的心宿二和天狼星，并观测到了它们伴月的天象以及偕日升的天象。现代犹太教和现代伊斯兰教仍在遵循传统，使用巴比伦的一些天文规则。然而，鉴于星座由于岁差而发生了移动，而且如今我们也有了计算历法的手段，这种蛾眉月和昴星团相伴的天象就不再那么有用了，尽管它依然如此优美。因此，古巴比伦和中巴比伦的传统仅存留了基本的形式。此外，长期以来一直声称青铜时代欧洲的内布拉星盘上描绘了这种天象，但这种说法不太可能属实。
本照片于2022年5月在意大利厄尔巴岛拍摄。
来源： Giulio Colombo/ IAU OAE
相关图表
Opposition and Conjunction
图注： This diagram shows the Earth's orbit around the Sun and the orbits of two other planets, one orbiting the Sun outside the Earth's orbit and one orbiting the Sun inside the Earth's orbit. At different times in the orbits of both of these planets, their positions appear to line up with the Earth and the Sun. At these points each planet would appear close to the Sun when viewed from Earth. When this happens each planet is said to be in conjunction with the Sun.
For the planet that orbits the Sun within the Earth's orbit it can be in conjunction with the Sun twice in its orbit, once when it is between the Sun and the Earth and once when it is on the other side of the Sun from the Earth. When the planet is in conjunction between the the Sun and Earth it is said to be in inferior conjunction and when it is in conjunction on the far side of the Sun from the Earth it is said to be in superior conjunction.
For the planet orbiting the Sun outside the Earth's orbit, it can sometimes be on the other side of the sky. At this point the Earth lies between the planet and the Sun. The planet in this case is said to be in opposition.
Opposition and conjunction are not just limited to planets and other types of solar system objects such as dwarf planets, comets and asteroids can also be in opposition and conjunction. However only those objects that have an orbit that takes them outside the Earth's orbit can be in opposition.
Conjunction is also used to refer to alignments in the sky between planets in the Solar System. For example when Jupiter and Venus appear very close on the sky when viewed from Earth they are said to be in conjunction with each other.
来源： Aneta Margraf/IAU OAE
