Big Apple Sky Calendar: July 2022
In the 1990s, astronomy professor Joe Patterson wrote and illustrated a seasonal newsletter, in the style of an old-fashioned paper zine, of astronomical highlights visible from New York City. His affable style mixed wit and history with astronomy for a completely charming, largely undiscovered cult classic: Big Apple Astronomy. For Broadcast, Joe shares current monthly issues of Big Apple Sky Calendar, the guide to sky viewing that used to conclude the seasonal newsletter. Steal a few moments of reprieve from the city’s mayhem to take in these sights. As Oscar Wilde said, “we are all in the gutter, but some of us are looking at the stars.”
—Janna Levin, editor-in-chief
July 1
Sunrise 5:27 am EDT
Sunset 8:33 pm EDT
July 4
Earth at aphelion. Today the Earth is 1.017 AU (95 million miles) from the Sun—as distant as it ever gets. Yet it's the hottest time of year for us borealites. The reason is that the Sun's local heating of the Earth depends not on distance, but on the angle of the noontime sun (now nearly overhead for us) and on the length of sunlight (now 15 hours).
July 4 (1054)
The traditional date for the appearance of the most famous supernova [celestial explosion] in history. What we know for sure is that in the early summer of the year 1054, a very bright “guest star” (the Chinese word) appeared suddenly, and was closely observed by Far Eastern astronomers (Chinese, Japanese, and Korean). It was described as “visible in daylight” for 23 days, and in the night sky for over a year. It must have been amazing to stargazers everywhere—but strangely enough, no definite record exists for its visibility in Europe or the Americas.
There is today a little elliptical nebula in the sky, the Crab Nebula, which is the remnant of the 1054 explosion. Virginia Trimble, an American astronomer famous for her quick wit and insightful astrophysics, found that the nebula is rapidly expanding, such that it must have originated from a single point around the year 1100. (And for once, she wasn't kidding.) This proved that the Crab Nebula originated in an explosion from a tiny, faint star at the center of the Nebula, or perhaps from the ancestor of that star. A few years later, it was found that this star is a pulsar—a solid star, made entirely of neutrons and spinning at a rate of 30 times a second.
This star is 6500 light years away—and if you do the math, you find that in the summer of 1054, this object was about as luminous (intrinsically) as an entire galaxy.
Holy mackerel! This was basically the beginning of modern stellar astrophysics. Two years later, the first black hole was discovered—and we were off and running.
But what's this “July 4th” business? That's mainly a USA obsession. The ancient Chinese were exacting at dates, but not that exacting! (Or at least our knowledge of their dates is not that precise.) We do know three things that underlie the modern myth:
(1) On the morning of 5 July 5th, 1054, as viewed from the western USA, the waning crescent Moon was just northwest of the Crab Nebula's position; (2) several cave paintings/carvings from that region and era seem to show a round object (the supernova?) next to a crescent-shaped object of equal size (the Moon?); and (3) the Pueblo Indians of that era commonly made early-morning observations of the sky, perhaps to mark the seasons.
Despite this ultra-thin reed of evidence, few USA astronomy teachers can resist the re-telling of the patriotic supernova story. I certainly can't.
July 6
First quarter Moon. 10:14 pm EDT.
July 9
Birthday of John Archibald Wheeler in 1911. Wheeler was probably the most important American physicist of the 20th century (OK, Richard Feynman fans; you'll have your say later). Wheeler became a teacher and mentor to nearly all American scientists working on general relativity—Einstein's theory of gravity. He invented the terms “black hole,” “wormhole,” and “quantum foam.” And he came up with a single, short sentence that perfectly expresses the basic idea of Einstein's theory, and that replaces Newton's theory: “Space-time tells matter how to move, and matter tells space-time how to curve.”
July 9
8-10 pm tonight, weather permitting, the New York Amateur Astronomers Association will hold a telescopic observing session at Lincoln Center (near the fountain). These events are for the public, so questions are welcome/solicited. But be warned: to astronomers, “weather permitting” generally means “clear sky required.” It's not a baseball game!
July 13
Full moon. 2:37 pm EDT.
July 18
Around midnight tonight, the Moon passes just south of Jupiter.
July 20
On this famous day in 1969, two astronauts landed and walked on the Moon. The story has been told a thousand times. Less well known is exactly what happened right after the quite perilous landing. The original schedule called for the astronauts to catch some sleep before attempting the famous walk. But after all the excitement of the trip and peril of the landing, sleep was the last thing on their minds. Even though they had landed on… ahem... the Sea of Tranquility.
So NASA changed the plan and said “OK, do the walk.” Then it was “one small step for a man...” The most-watched live event in television history.
Until, of course, the 2006 FIFA World Cup final between Italy and France, ending in a shoot-out. Now there was a reason to get excited!
July 20
Last quarter Moon.
July 23
Reprise of the July 9 stargazing event at Lincoln Center (8-10 pm). Same comments.
July 28
New Moon. 1:54 pm EDT.
July 28-31
Stellafane! This is the oldest and most famous annual gathering of amateur astronomers in the nation. Back after two canceled years. Beautiful night skies if clouds stay away. Events are spread over four days, so google “Stellafane” and take your pick. It's in the tiny town of Springfield, Vermont… which can present challenges in housing and dining. The deeply committed (there are plenty) camp out on Stellafane's hill.
July 31
Sunrise 5:50 am EDT.
Sunset 8:14 pm EDT. ♦
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