moonflower

Canis Major as depicted in Urania's Mirror, a ...

Canis Major as depicted in Urania’s Mirror, a set of constellation cards published in London c.1825. Next to it are Lepus and Columba (partly cut off). (Photo credit: Wikipedia)

“Your fist like this”, she said, “covers about 10 degrees of the night sky.”  She moved my hand slowly over the dark water and spoke in her methodical way, no use to interrupt her. “20 degrees south-east of the belt of Orion, you see, there is the brightest star in the night sky, right in the constellation of Canis Major.” She waited for a moment for me to catch up with her. Our entwined hands travelled over the night sky and stopped. And there it was, deep underneath us, the brightest star of the night sky, as far as I could see. “Do you see this star?” she asked. “It is called Sirius. It is 23 times more luminous than our sun, twice the mass and the diameter of the sun. It is only 8.5 light years away.” The way she said “only 8.5 light years”, it sounded as if she was talking about a Sunday picnic destination. It sounded like: We could take the bike. It’s only 8.5 light years away. Before I had a chance to point that out to her, however, she had started talking again, and almost without warning, though in answer of my question, switched from her facts, from degrees between two points of light in the celestial sphere, luminosity and brightness, and mass of celestial objects, to a startling revelation.