Mid-July presented one of those astronomical alignments that can soothe the mind: Venus and the moon were nearly cuddling, about one degree apart.
My wife Cory and I were out to shop and walk in the park. We first noticed the lovely conjunction as we prepared to enter a supermarket at bright twilight, and stood marveling and taking photos with our cellphones. As others arrived or exited from the store, they too stopped, looked up and pulled out their phones. The scene in the sky reminded me a little of the flag of Turkey, which shows the crescent moon and star.
A conjunction has no great cosmological significance. It was a coincidence that the orbits of the moon, Venus and Earth lined up so that, for just one night, our line of sight showed the satellite and the second planet as if they were close neighbors. Actually, they were 87 million miles apart.
Later in the evening, from time to time we watched the fascinating couple as we perambulated Liberty Park. Sinking deeper into the atmosphere, they took on an orange color, the same effect as at sunset when the sun’s rays penetrate thicker layers of air, moisture and dust. We walked in the night, thankful it wasn't as fiercely hot as the daytime, talking, saying hi to moms with children, keeping track of the cosmic pair as they appeared through ancient cottonwoods and over the park’s funky architecture. Several times we heard the high long squawk of a screech owl ring out from the darkened environs of Tracy Aviary.
This happened only two days after operators of the MeerKAT Radio Telescope in South Africa released the best view yet of the region around the supermassive black hole at the center of our Milky Way Galaxy.
David Mabuza, deputy president of the Republic of South Africa, inaugurated the radio-telescope array on July 13, after "10 years of design and construction," says the project's news release online at ska.ac.z. The 64 radio dishes work together to gather signals from the cosmos, which are processed and combined by computer. Eventually, MeerKAT will become part of the larger "square kilometer array" radio telescope.
"The dishes are of a highly efficient design with up to four cryogenic receiver systems operating in different bands of the radio spectrum," according to the release. "The first installed set of receivers operates between frequencies of 900 MHz and 1670 MHz."
MeerKAT officials quoted Farhad Yusef-Zadeh of Northwestern University in Evanston, Illinois, as saying the unprecedented clarity of the view shows many details never seen before associated with the strange filaments of energy that are present. "These long and narrow magnetised filaments were discovered in the 1980s using the Very Large Array radio telescope in New Mexico, but their origin has remained a mystery," they added. Yusef-Zadeh is one of the "leading experts on the mysterious filamentary structures present near the central black hole but nowhere else in the Milky Way."
Yusef-Zadeh said the image "shows so many features never before seen, including compact sources associated with some of the filaments, that it could provide the key to cracking the code and solve this three-decade riddle," the release adds.
The placid cosmos that we see when we gaze upward at night only seems calm because our perspective is limited. Remember supernovas, neutron stars and explosions of X-rays. At the center of our Milky Way Galaxy is a gigantic black hole seething with energy, an entity called Sagittarius A* (abbreviated as Sgr A*, with the asterisk pronounced "star"). It is an estimated 4 million times the mass of our sun. Whenever stars wander too close, it shreds them and pulls their remains in, except for energy that shoots out in streams. All black holes are such tremendous gravity sinks that light itself can't escape. At the center of a black hole, many physicists believe, is nothing except gravity, a single unimaginable point.
The contrast between the beautiful view from a park and the raging firestorm in the middle of our galaxy is striking. We should think of the black hole as a sort of astronomical memento mori, a reminder of the transitory nature of our seemingly settled lives and surroundings.
I find this realization a useful reminder of the wrenching changes that lurk in our everyday reality. There's the person who seems ordinary but may unexpectedly show blind hatred, chaotic misunderstanding and anger — probably most have known at least one of them. Or take the worldwide catastrophe that came unexpectedly from the blue, a comet with the dinosaurs' name on it.
In the end, something — a vehicle running a light, a germ, old age if we're lucky — has each of our names on it.