"All of the stars I examined were just type G stars, nothing else, but there was a difference in one of them. First, the spectroscope showed lines of reflected light passing through oxygen and hydrogen, water vapor and carbon dioxide. Pure planetary phenomena, never found on a star itself. Also it showed that a certain per cent of the light was polarized. Now remember that I examined it for a long time and I found out something else from the length of observation which convinces me. The light varied with a periodic irregularity. The chronometers aren't working exactly right out here, so I can't give you any explanation in terms of hours. But I find a number of regularly recurring changes in light intensity and character ... and that proves the presence of a number of planetary bodies circling the star. That's the only way one could explain the fluctuations for the G-type star is a steady type. It doesn't vary greatly and has no light fluctuations to speak of. Not like the Cepheid and Mira types."
"And that proves it's our Sun?" asked Chambers.
Craven nodded. "Fairly definitely, I'd say."
"How far away is it?" Stutsman wanted to know.
Craven snorted. "You would ask something like that."
"But," declared Stutsman, "there are ways of measuring how far a star is away from any point, measuring both the distance and the size of the star."
"Okay," agreed Craven, "you find me something solid and within reach that's measurable. Something, preferably, about 200 million miles or so across. Then I'll tell you how far we are from the Sun. This ship is not in an orbit. It's not fixed in space. I have no accurate way of measuring distances and angles simultaneously and accurately. Especially angles as small as these would be."
Craven and Stutsman glared at one another.
"It's a long way however you look at it," the financier said. "If we're going to get there, we'll have to start as soon as possible. How soon can we start, Doctor?"