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CAC's Spaced-Out Challenge: the Dark Secret of the Swan

Summer is pretty much here, and with the end of May, arguably the best part of the whole night sky comes into view. Below, a guide to find your way about, and a dark secret hidden inside one of the most glorious of constellations.

Basic and Detailed Hop-To Guides for the Summer Sky

The sky for a total novice can seem impossible to navigate, but if you can remember just a few basic shapes, you can find your way around. The most obvious for residents of North America is the Big Dipper, made up of the seven brightest stars in Ursa Major, the Great Bear. The two stars in the lip of the tipper line up and point to the North Star and (if the right time of year) in the opposite direction towards Regulus, the brightest star in the "Sickle" shape that forms the mane of Leo the Lion.

Use the handle of the dipper, arc backwards until you hit a very bright star, this is Arcturus which makes up the junk of Bootes the Herdsman. Continuing further, you hit the very bright star Spica in Virgo. If you wander South-south-east you'll find a slightly less-bright star above the horizon, Menkent. This is the northernmost bright star in Centaurus.

Trace backwards, up through Spica, and back to Arcturus. Now, go south-southeast until you hit a bright red/orange star, the only of it's kind in the southern sky. That's Antares. Let your eye wander about Antares and you'll notice a fish-hook shape of stars. This asterism makes up the brightest stars in Scorpius the Scorpion.

Now, start back at the big dipper, and arc again to Arcturus. If you look east and north you should see a quartet of semi-bright stars in a keystone shape. Congratulations, you've found the heart of Hercules. Due north of it is a smaller keystone, which is the head of Draco.

In your eastern sky, you'll notice three very bright stars: Vega, Deneb, and Altair, in a huge triangle. The triangle "points" a bit back to the Keystone too. Mostly inside of this triangle is a cross-shape of stars headed by Deneb. These are the primary stars of Cygnus, the swan. Follow the cross south and west, until you see a simplified stick figure, the Large Man. This is Ophiuchus, the Serpent Bearer, and you'll notice he's "standing" on Scorpius, which you found earlier. To the Large Man and the Fish Hook/Scorpius "left" you'll notice a set of bright stars forming a teapot shape. Congrats again: you've found the brightest stars of Sagittarius.

Lastly, go back north to your big Summer Triangle, and look to it's east. Just rising during the summer nights should appear a great square of bright stars: the body of Pegasus the Winged Horse. Without more than hopping and spotting large shapes, you have found half of the key summer constellations. From these, you can hop to all the remaining summer sights:

This Week's Challenge: the Dark Secret of the Swan

Credit: NASA/CXC/M.Weiss

Rush, and more importantly Kip Thorne, were absolutely right.
For decades, scientists have argued over the existence of an object so gravitationally strong even light cannot escape it's pull: a black hole. Einstein himself believed they weren't physically real, and thanks to the near-unobservable nature of these elusive monsters, decades flew by without any real progress. Cygnus X-1 changed that.

Discovered in 1964, Cygnus X-1 was an intense X-ray source, as the name implies, in the constellation Cygnus. The intensity of it left scientists puzzled and excited, and in less than a decade, observations by astronomers like Tom Bolton, demonstrating a noticable tug on supergiant star HDE226868 (a.k.a. HIP98298), made the theoretical real. Stephen Hawking and Kip Thorne made a famous bet on the nature of the object emitting the X-rays, and once further X-ray observations were made in the 1980s, Thorne got his winnings: a year's subscription to Penthouse, much to the angst of his wife.

The most recent development out of the point-of-no-return in the heart of the Swan comes courtesy Japan's Suzaku satellite, which observed matter being gulped and eliminated through it's x-ray emissions:

What the Riken astronomers observed is gas being sucked across the event horizon and into oblivion. Suzaku measured the temperature of the gas as it fell into the black hole, and recorded a heat spike of more than 1 billion degrees Celsius in the last few milliseconds before it vanished. This, they report in Astrophysical Journal, is strong evidence that Cygnus X-1 is indeed a black hole (DOI reference: 10.1088/2041-8205/767/2/L34).

Now, as the nature of the object implies, you can't actually see the black hole. But you can see the supergiant victim slowly being gobbled away. Here's how to find it:

Dark sky denizens may even fish out the victim with binoculars, but anyone with even a small telescope can spot the faint shedding mass from an urban setting.

As always, check out the light pollution targets list here, visit Ace's storefront for your astro-needs, clear skies and keep looking up!