---
title: Something about Sirius
date: '2005-06-04'
slug: something-about-sirius
---

Historically, many cultures have attached special significance to Sirius. Sirius was worshiped in the valley of the Nile long before Rome was founded, and many ancient Egyptian temples were constructed oriented so that light from the star could penetrate to their inner altars. The Egyptians based their calendar on the heliacal rising of Sirius, which occurred just before the annual flooding of the Nile and the Summer solstice. In Greek mythology, Orion's dog became Sirius. The Greeks also associated Sirius with the heat of summer: the name Sirius is derived from Seirios meaning "the scorcher". This also explains the phrase "dog days of summer".

There are a few unsolved mysteries regarding Sirius.

Firstly, it has been suggested that there is a third very small companion star, but it appears that this has not yet been definitely confirmed.

Secondly, ancient observations of Sirius describe it as a red star, when today Sirius A is bluish white. The possibility that stellar evolution of either Sirius A or Sirius B could be responsible for this discrepancy is rejected by astronomers on the grounds that the timescale of thousands of years is too short and that there is no sign of the nebulosity in the system that would be expected had such a change taken place. Alternative explanations are either that the description as red is a poetic metaphor for ill fortune, or that the dramatic scintillations of the star when it was observed rising left the viewer with the impression that it was red.

A third mystery is a suggestion that the Dogon tribe of Africa knew about unseen companion star(s) before they were discovered in the 19th century, although careful research reveals this was probably cultural contamination on the part of visiting astronomers who went to the region to observe a transit of Venus. This is a source of speculation for UFO enthusiasts and was the subject of the book The Sirius Mystery by Robert Temple.

说起天狼，当然不会不想起苏轼（跟本文没什么大关系哦）：

> 江城子·密州出猎

> 老夫聊发少年狂，左牵黄，又擎苍，锦帽貂裘，千骑卷平岗。为报倾城随太守，亲射虎，看孙郎。  
> 酒酣胸胆尚开张；鬓微霜，又何妨。持节云中，何日遣冯唐？会挽雕弓如满月，西北望，射天狼。

差差说我要是写英文将会失去大批读者，大家也表灰心，我不是存心写英文的；只是搜索时发现英文资料比较多，于是写英文了；另外，大家看看古希腊神坛的建筑跟天狼星的关系，还是很有意思的，当成一篇阅读理解看看吧：）
