When this long cloudy period finally ends, let’s point our eyes toward arguably the most amazing thing in the universe. The heaviest black hole known to astronomers.
It’s truly simple to find. Really. You don’t need star charts or constellation knowledge. The next clear evening at nightfall, meaning around 9 p.m., just look straight overhead and you’ll start this romp by recognizing the familiar Big Dipper, which may look even larger than you remembered. Spring is when it’s at its very highest so it definitely won’t be blocked by trees or houses.
Now follow its famous curving handle downward. As they say in astronomy 101, “Arc to Arcturus.” Meaning, if you visually follow the handle’s curvature it will take you to Spring’s brightest star. This is the famous orange Arcturus. We could spend an hour just ranting about this special star but let’s just toss one odd fact at you: Although it’s 36 light years away, it’s so big that we receive a measurable amount of heat from it. How much? Well, raise your hand toward Arcturus and try to feel a discernible bit of its warmth. Turns out, Arcturus’ energy exactly equals the heat you’d get from a single candle located five miles away.
But we’re not stopping at Arcturus. We let the Big Dipper’s handle arc us downward to Arcturus, but now we’ll continue following that giant curve to the only bright star below it. This one’s not quite as bright as Arcturus and a close inspection shows it’s blue-white, forming a lovely contrast with orange Arcturus. This is Virgo’s brightest star, Spica. And now we’re set.
A few years ago, in 2019, the mass media circulated the first-ever photograph of a black hole. The image was really merely the shadow of one, a round black disk that was five times bigger than the actual black hole. No matter. An inky circular image was all we could have hoped for. Captions explained that this super massive tunnel entrance into oblivion lay at the center of a hyper-heavy galaxy named M87. And that this black blob itself equaled the weight of seven billion Suns. All that substance had collapsed inward, imploded by its own self gravity to form the core of one of the largest known galaxies, one that lies 50 million light years from us. Because it’s the most massive black hole known to science, it’s worth having some idea where it is.
You’re already fully armed with the information that’ll let you accurately gaze in its direction. Simply look far to the right of Arcturus or to the upper right of Spica and your eyes are now effortlessly gazing into the constellation Virgo where that super-massive black hole lurks.
See? Without any chart or sky knowledge we’ve found spring’s brightest star Arcturus, and the bluest star in the heavens, Spica, plus the most famous black hole in the known universe. Haul them all into your awareness the next clear evening.