Messier Objects

Podcast Transcript

In the 18th century, a French astronomer who was a regular comet hunter kept finding things in the sky that weren’t comets, but they also weren’t stars or planets.

So, he created a list of these objects, not because he was trying to catalog the night sky, but rather to help other comet hunters avoid these common objects.

It turned out his list consisted of some of the most incredible objects inside and outside of our galaxy.

Learn more about Messier Objects, how they were documented and what they are on this episode of Everything Everywhere Daily.

I’ve done a fair number of astronomy related episodes. Many of these episodes have dealt with subjects that are in the realm of professional astronomers who focus on cutting edge cosmology.

Unless it is something major within our solar system like planets, the moon, or the sun, it is hard to personally observe many things in astronomy.

The subject of this episode is something you can observe in the night sky. Some of the objects you might already be familiar with from famous photos taken by larger professional telescopes, but all of them can be seen with smaller, amateur telescopes, or possibly even a good pair of binoculars.

….but more on that in a bit.

This story starts in the 18th century in France.

In the late 18th century, astronomy was undergoing significant advancements, driven by improved telescopes and observational techniques. Newtonian physics had already provided a solid framework for understanding planetary motion, and astronomers like William Herschel were discovering new celestial bodies, such as Uranus.

The field was transitioning from cataloging stars and deep-sky objects to studying their nature and structure….however, there was still a lot of cataloging going on.

Enter into the picture the astronomer Charles Messier.

Charles Messier, born in 1730, was a rising astronomer in France. He was deeply fascinated by celestial discoveries. Born in Badonviller, France, he developed an early interest in astronomy and began working at the Paris Observatory in 1751 under Joseph-Nicolas Delisle. His meticulous observational skills and talent for comet hunting quickly earned him recognition.

By the mid-1750s, he had already begun recording comet positions and celestial objects, refining his expertise with telescopes. His first major discovery came in 1758, when he independently observed Halley’s Comet and confirmed its predicted return. This event solidified his reputation and set the stage for his work cataloging deep-sky objects to assist comet hunters.

He conducted most of his observations with a 100 mm or four-inch telescope in the center of Paris. A telescope this powerful is something that is easily within the grasp of most amateur astronomers today.

Comet hunting at the time consisted of looking for fuzzy objects that were moving across the sky. Moving fuzzy objects weren’t planets and they weren’t stars.

The problem was, he was coming across things in the sky that were fuzzy, like a comet, but didn’t move. They weren’t comets, stars, or planets.

Oddly enough, his concern wasn’t trying to figure out what these things were; he was more concerned about just making sure he avoided them in the future so he wasn’t chasing false comets.

Messier and his assistant, Pierre Méchain, compiled a list of these objects between 1771 and 1781.

His first list of objects was published in 1774. It consisted of 45 objects, 18 of which he had discovered, the rest of which had been previously discovered by other people.

The criteria for inclusion on the list were:

Objects that appeared as faint, fuzzy patches resembling comets.
Objects visible from the Northern Hemisphere.
Objects bright enough to be seen through telescopes at that time.

The catalog was not intended to be a comprehensive list of deep-sky objects but rather a practical reference for comet hunters.

Over the years, the list grew as he found more objects. By 1781, the list had 103 entries.

Over time, other astronomers added to the list until it reached 110 entries.

Eventually, the objects on Messier’s list were named after him and were dubbed Messier Objects. A classification developed where each object was given a Messier number based on its position on the list. M1 through M110.

While Messier himself didn’t particularly investigate what those fuzzy objects were in the sky, later astronomers certainly did.

So what were these mysterious fuzzy objects?

Well, they weren’t any one particular thing. They were a bunch of different things. They just happened to all appear fuzzy with low resolution telescopes.

The 110 Messier objects can be roughly divided into four categories: galaxies, Nebulae, Star Clusters, and Supernova Remnants.

Some of the greatest images you’ll see in astronomy come from Messier objects. The reason is because, regardless of the type of object, they all tend to be the closest of their kind to the Earth.

I obviously don’t have the time, and you probably don’t have the patience, for me to go through all 110 Messier objects, but there are a few highlights that are definitely worth going over.

You are probably familiar with these objects, at least by name, if you have a basic knowledge of astronomy.

The first is the first object on the list and has the classification of M1, the Crab Nebula.

The Crab Nebula is a supernova remnant located in the constellation Taurus, approximately 6,500 light-years from Earth. It is the remains of a massive star that exploded in a supernova event recorded by Chinese and Middle Eastern astronomers in 1054. At its peak, the supernova was bright enough to be visible in daylight for several weeks before fading.

The nebula is now expanding at a rate of about 1,500 km/s, stretching across 11 light-years in diameter. It is one of the most studied celestial objects because it provides insight into the life cycle of massive stars and the physics of supernovae.

At the heart of the Crab Nebula lies the Crab Pulsar, a rapidly rotating neutron star that emits beams of electromagnetic radiation, including radio waves, visible light, X-rays, and gamma rays. This pulsar spins about 30 times per second and powers the nebula’s eerie glow through its intense magnetic field and high-energy particle emissions.

The nebula is a strong source of synchrotron radiation, produced by electrons spiraling around magnetic fields at relativistic speeds. This makes it an important object for studying high-energy astrophysics, particle acceleration, and the interactions between pulsars and their surrounding environments.

Messier Object 31 is the Andromeda Galaxy.

The Andromeda Galaxy is the closest major galaxy to the Milky Way and the largest in our Local Group of galaxies, which also includes the Triangulum Galaxy, which is categorized as M33, and numerous dwarf galaxies.

Located approximately 2.5 million light-years from Earth in the constellation Andromeda, it is a spiral galaxy spanning about 220,000 light-years—more than twice the diameter of the Milky Way. Andromeda contains an estimated one trillion stars, significantly more than the Milky Way’s 200–400 billion.

It is visible to the naked eye under dark skies and appears as a faint, elongated smudge. Early astronomers mistook it for a nebula until Edwin Hubble confirmed in the 1920s that it was a separate galaxy beyond the Milky Way, fundamentally reshaping our understanding of the universe.

Andromeda is on a collision course with the Milky Way, moving toward us at about 110 km/s. In approximately 4.5 billion years, the two galaxies will merge in a vast cosmic event, likely forming a giant elliptical galaxy.

Despite the collision, individual stars are unlikely to collide due to the vast distances between them. Andromeda’s structure consists of a bright central bulge, a dense core with a supermassive black hole, well-defined spiral arms, and several satellite galaxies, including M32 and M110.

Its active star-forming regions, along with evidence of past mergers with smaller galaxies, make it an important subject of study for understanding galactic evolution.

Messier Number 42 is the Orion Nebula, one of the brightest and most well-known nebulae in the night sky, located about 1,344 light-years away in the constellation Orion. Spanning roughly 24 light-years across, it is an emission nebula, meaning it glows due to the ionization of its gas by high-energy radiation from young, hot stars.

Visible to the naked eye as a fuzzy patch in Orion’s sword, it is one of the most accessible and studied star-forming regions in the universe. The nebula is part of the Orion Molecular Cloud Complex, a vast region rich in gas and dust, serving as a stellar nursery where thousands of new stars are actively forming.

At the heart of the Orion Nebula lies the Trapezium Cluster, a group of four massive, young stars that emit intense ultraviolet radiation, causing the surrounding gas to glow. These stars play a crucial role in shaping the nebula’s structure and dispersing its gas over time.

The nebula’s dynamic environment contains protoplanetary disks—regions where new planets may be forming around young stars—offering a glimpse into how solar systems develop. The Orion Nebula is a vital object for astronomers studying stellar evolution, star formation, and the interactions between newborn stars and their surroundings.

Messier Object 45 is the Pleiades, also known as the Seven Sisters. It is one of the most famous and easily recognizable open star clusters in the night sky. Located in the constellation Taurus, it lies approximately 444 light-years from Earth and contains over 1,000 stars, though only a handful are visible to the naked eye under dark skies.

The cluster spans about 17.5 light-years across and is estimated to be around 100 million years old, making it a relatively young star cluster in cosmic terms. The Pleiades stars formed from the same molecular cloud and are still loosely bound by gravity, though they will eventually disperse over time.

Messier Object 104 is the Sombrero Galaxy. It is a striking spiral galaxy located about 29 million light-years away in the constellation Virgo. It is named for its resemblance to a Mexican sombrero hat, due to its bright central bulge and an exceptionally large, dark dust lane encircling its disk. With a diameter of approximately 50,000 light-years,

M104 is smaller than the Milky Way but is notable for its enormous supermassive black hole at its core, one of the most massive ever discovered relative to its galaxy’s size. The dark dust lane is rich in gas and dust, suggesting active star formation, while the bright halo surrounding the galaxy contains numerous globular clusters. The Sombrero Galaxy is a popular object for amateur astronomers and an important subject for studying galactic structure and black hole interactions.

There are a bunch of other really interesting Messier Objects including:

M13, The Hercules Globular Cluster
M57, the Ring Nebula
M87, Virgo A, a massive elliptical galaxy in the Virgo Cluster
and M101, The Pinwheel Galaxy

At the start of the episode I mentioned that these objects are something that you can observe yourself, and that’s true.

All of these objects can be viewed with amateur telescopes, and in fact, they often are. They are some of the most common and popular objects that amateur astronomers observe.

If you want to see these celestial objects yourself, and I highly recommend you do it if you’ve never done it, check to see if there are local astronomy groups in your area.

They will often have star parties where the public is welcome to come and look through their telescopes. They are usually more than happy to have people come and observe with them.

Every so often, astronomy groups will have Messier marathons where they attempt to view every Messier object in a single evening. It requires a very clear night and a willingness to stay up late.

Local universities with astronomy departments will often have nights where the public can observe through their telescope as well.

While Charles Messier created his catalog as essentially a list of objects to avoid, it ironically became one of astronomy’s most valuable resources. Many fundamental discoveries about stellar evolution, galaxy formation, and cosmology have come from studying Messier objects.

What makes the Messier catalog truly remarkable is that it was compiled with 18th-century technology yet remains relevant in the age of space-based observatories and computerized telescopes.

The Executive Producer of Everything Everywhere Daily is Charles Daniel. The Associate Producers are Austin Oetken and Cameron Kieffer.

Today’s review comes from listener Rio Gaines over on Apple Podcasts in the United States. They write.

Great show

One of the best shows out there. Me and my dad listen to this often and talk about what we learn. However, I do wonder if Gary could travel back in time, where/when would he go, and why?

Thanks, Rio Gaines! There are two episodes in history that I would love to have witnessed first hand.

The first would be back to the early Roman Empire was Sejanus was condemned to death on the Senate floor….when he thought he was about to get a promotion.

The second would be going to 1815 to watch Napoleon convert an entire French army to his side by just walking up to them and giving a speech.

Remember, if you leave a review or send me a boostagram, you too, can have it read on the show.