There are comets, and then there are the big comets. It was the fires that swept the sky in 1743 and 1744 for sure one of the past.
As it passes Earth toward the sun, the comet will be bright enough that it can be seen in broad daylight and the eclipse of Venus in the evening sky. He also developed a long and clearly visible double tail, which was already very unusual. Then, when it reached perihelion and orbited the sun, the comet’s tail split into six clearly defined rays. In the morning, when the comet’s head was still hidden below the horizon, these six tails were bright and visible, reaching into the sky like a kind of “fan” that seemed to come from the sun.
Why the comet gave this appearance remains a mystery. There might actually be only one or two much larger tails, but there were areas that were darkened by the thick dust. In any case, it was recorded by astronomers all over the world, including in China, where court astronomers claimed that the comet actually made a crackling sound. It was a very strange guilt.
Young Catherine, who had not yet grown up, saw the comet while traveling to Russia for marriage. She seemed to consider it all about declaring her future greatness because…of course she did.
Back in France, a young Messier seems to have seen the comet, and that seems to have done a lot more to propel him into a future in astronomy, rather than the decidedly fascinating career of bringing people into the courtroom. Messier managed to get a position of assistant to Joseph Nicolas Delayle who was the official astronomer of the French Navy (he was planning a course, etc.) and perhaps most importantly, he is very wealthy.
Delile had a newly built observatory, and the young Messier quickly moved there. Over the next decade, he made a number of important discoveries, receiving a high position in government as well as a series of honors and memberships in scientific societies. As expected, comets remained of particular interest to Messier, and he seemed to be good at spotting a distant comet before other astronomers could get their names on the approaching snowball. Even King Louis XV gave Messier the nickname “The… Ferret of Comets,” if you want an address engraved on your tombstone, this should be the address.
But Messier’s later work with deep sky objects is best remembered today. Beginning in 1771, Messier began compiling a catalog of some of these misty spots in the night sky—things we know today as nebulae, galaxies, and star clusters. The first list included 45 such items. The final list, which included some objects taken from Messier’s footnotes and marginals, totaled 110. These became known as miserable beings.
Since then, the discovery of these Messier objects has been a right of passage for astronomers. Something like climbing the Seven Summits in mountaineering. Except for a much lower chance of dying in an avalanche.
And… well, it turns out Messier 13 is something known variously as Hercules Star Cluster, Hercules Globular Cluster, or Hercules Globular Cluster. Messier wasn’t the first to discover M13. This credit goes to another comet man, Edmund Halley, whom he met in 1714. But Messier put it in the catalog,
M13 is a group of hundreds of thousands of stars, but it is not a galaxy. In fact, it’s one of many such bubbles orbiting our good old galaxy, the Milky Way. It is located about 22,500 light-years from Earth. If you want to find it, look for the place its name suggests – in the constellation Hercules. But bring a telescope. Despite the number of stars in this group, its visible magnitude is greater than 11, which is too faint to be seen with the naked eye.
M13 is about 100 times more dense in stars than neighboring regions around Earth. There are only about 135 stars within 50 light-years of Earth. It’s interesting to think of what a sky with a few nearest neighbors might look like on a clear night. M13’s stars are close enough that the pair occasionally ends up merging into a short-lived blue-white giant.
Something about the M13 has made the spherical cluster of Hercules a recurring subject in science fiction novels. Perhaps that’s why, when SETI personnel were at the disappearing but not forgotten Arecibo Telescope looking for a target for a test message in 1974, they chose M13. Somewhere in between here and there a post with some basic math info, then expands that to describe the structure of atoms, then elements, then DNA, and then some basic facts about human life.
If someone was out there and had a really good receiver, they would have mail in about 22,450 years.
As with most of the images I show in this feature, the top image was taken on the small but clever Vespera telescope. And as usual with this feature, I expect some of you will do much better. But maybe not better than that…
Web countdown“NASA, in partnership with the European Space Agency and the Canadian Space Agency, will release the first color images and spectroscopic data from the James Webb Space Telescope during a telecast starting at 10:30 a.m. ET on Tuesday, July 12.” And we’ll cover it live.