Loading...

And because of black holes, they can't be seen directly. Their physical characteristics are obtained by observing gravitational effects on light and physical objects around them. Sigma Stacks 1 is a black hole in the constellation Sigma. And that was first discovered indirectly by its influence on a star in the area. It's Tom Bolton, the astronomer here in Toronto, the report at the David Dunlap Observatory. And his painstaking observations, he noticed that there was a star out there doing some really wonky things. Its position was really changing in ways that it shouldn't because there was nothing around it that would account for it. There wasn't another star near enough around it to have that big effect. So after numerous calculations and observations, it was concluded that there was a black hole nearby that was pulling on it. So there's an indirect means of detecting them. Stopping.