HOORAY FOR MR. MESSIER – 3/1/15
Hi everyone, I’m Darrell Heath with the UALR College of Arts, Letters, and Sciences; welcome to The Night Sky.
On a March evening in the year 1744 a 13-year-old boy living in Lorraine, France saw an amazing spectacle in the night sky that would inspire him to make astronomy his life’s work. The boy’s name was Charles Messier and the spectacle was the Great Comet of 1744. At the time that Messier observed the comet it had become so bright that it could be seen during the daytime and it displayed a stunning six tails that reached well above the horizon and fanned out in all directions.
This remarkable sight had a lasting impression upon the young Messier and he knew then that he wanted to become not only an astronomer but a famous comet hunter as well. Discovering a comet in those days meant fame and fortune for whomever found one and Messier was definitely bitten by the comet-hunting bug.
In 1751, at the age of 21, Messier moved to Paris where he became the assistant to astronomer Joseph-Nicolas Delisle of the Naval Observatory. The observatory itself was a rather humble affair located in the stair tower of the Hotel de Cluny, which had once been the residence of Benedictine monks, and, in terms of prestige, stood within the shadow of the French Royal Observatory. The Naval Observatory and Delisle were not part of the in-crowd of European astronomy and Messier would have to work hard to become accepted by his more formally trained academic peers.
For seven long years Messier toiled away at his apprenticeship and he finally got his first real assignment in 1758 when Halley’s Comet was predicted to reappear. Messier’s mentor had done his own calculations of the comet’s orbit and determined that it would make its closest approach to the Sun sometime in April of 1759. Delisle assigned Messier the task of finding it before anyone else could. He began hunting in the summer of 1758 and he stuck to his master’s predicted orbital path but he had no success until the night of January 21st, 1759. Unfortunately it wasn’t where Delisle said it would be and Messier soon found out that a farmer in Saxony had beaten him to the punch by spotting the comet a month before on Christmas night of 1758.
Even more frustrating for Messier was the fact that his master would not let him publish an account of his independent discovery; Delisle did not want the rest of the scientific community to know that he had erred in his calculations. Delisle finally allowed Messier to publish the news months later but the Royal astronomers were highly suspicious of the late publication and refused to acknowledge Messier’s discovery.
Prior to the 18th century comets were usually discovered with the unaided eye and Charles Messier was the first person to really apply a systematic approach to their discovery. He would scan regions of the sky with a telescope looking for faint and fuzzy blobs of light that might be a comet. After spotting such a blob he would then carefully record it’s position and then watch it over a period of many nights. If it moved relative to the background stars then it was a comet, if not then it was something else. The usual name given to these objects in the “something else” category was “nebula”, which simply meant it was a faint, misty patch and no one really knew what it was. The problem for Messier was that the night sky has a lot of these comet impostor objects and he began to get fed up with wasting so much time on them. He decided that he should catalog all of these nuisance nebulae to save him and any other comet hunters from having to concern themselves with them.
Messier would go on to become the most famous comet discoverer of his time. He was obsessed with finding these dirty snowballs in space, so much so that King Louis XV dubbed him the “comet ferret”. From 1758 to 1804 Messier would spend 1100 nights diligently searching for comets, he observed 44 altogether, more than the total known before him. He discovered 21 comets in total, 6 being co-discoveries. His most famous find was the Great Comet of 1769, sometimes called Napoleon’s Comet because Bonaparte was born a week after its discovery and who, years later, would award Messier with the Cross of the Legion of Honour. With these and other discoveries Messier finally became a member of the international scientific community and, eventually, he even gained acceptance among members of the French astronomy establishment.
After a long and fruitful life Charles Messier died on April 11th, 1817. But in a twist of fate it turned out that we remember Messier today, not for his comet discoveries, but for his catalog of nuisance nebula objects. You see, the great irony is, that in his attempt to create a list of objects that comet hunters should avoid he inadvertently created a catalog of some of the most amazing deep-sky objects the night sky has to offer.
Today the catalog contains a total of 109 celestial objects and while no one knew what they were in Messier’s time science and technology have allowed us to gain not only much better views than was available through 18th century telescopes but also a deeper understanding as to just what the objects are.
Here are just a few of my favorites.
Messier (or, M) 1, The Crab Nebula in the constellation of Taurus. While Messier was searching for Halley’s Comet in 1758 he came across this faint and fuzzy blob and mistook it for the famous comet. After spending several nights watching it to see if it moved against the background stars he came up with the idea for his catalog. We now know that the Crab Nebula is the remnant of a supernova seen by Chinese astrologers nearly a thousand years ago in the year 1054 A.D. Today we can still observe the cloud of gas and dust expanding out into space.
Messier 27, The Ring Nebula. This small, glowing cloud of gas and dust represents the last gasps of a dying star similar to our own Sun. The star’s core has ran out of fusible material, contracted in upon itself and become extremely hot. This has resulted in the star ejecting its outer layers in a glowing shell of gas that surrounds the white-hot core.
Messier 42, the Orion Nebula and arguably the most spectacular of all the Messier objects. M42 is a vast glowing cloud of gas and dust where stars are being born. It is also the most photographed of any deep sky object.
Messier 45, the Pleiades star cluster in Taurus. M45 is an open star cluster, a loose collection of hundreds of stars that were all born from within the same stellar nursery. The radiation from these hot young stars has cleared away all of the nebula material from which they were born and they now sparkle like diamonds in the night.
Messier 13, the Great Hercules Cluster is a spectacular example of a globular star cluster. Globular clusters can contain thousands or even a million or more stars all tightly packed together in a ball that is only a few hundred light years or so in diameter. They are also very ancient with some clusters being estimated at around 12 billion years old, almost as old as the universe itself.
Messier 81 and 82, Bode’s Galaxy and the Cigar Galaxy in Ursa Major. Both galaxies are about 12 million light years away and the thing I like best about them is that you can get both within the same field of view whether you are using binoculars or a small telescope.
Every amateur astronomer begins his or her adventures with a telescope by trying to see as many of the Messier objects as possible and during March or April every year astronomy clubs all across the northern hemisphere hold Messier Marathons in which participants stay up all night to try and see all 109 in a single night. It’s both a daunting and grueling challenge to say the least and it’s difficult to say whether the participants are just dedicated or a little crazy. Being an amateur astronomer myself I can say that it’s probably a little of both. Either way, a Messier marathon is just a lot of fun and it gives amateur astronomers a chance to not only hone their observing skills but to also enjoy the company of their fellow stargazers while engaging in a bit of friendly competition.
So, merci mon ami Messier. Even though your catalog serves an entirely different purpose now than the one you originally intended for it we astronomers are forever in your debt for cataloging this incredible assortment of celestial eye candy.
Until next time, get outside, look up, and wonder.