1600-1800: Bringing Order to the Heavens

We go to the observatory in France and listen to the stories of science, reaching for the stars.

Thus we continue our exploration of the universe.

A lot can happen in 200 years.  Certainly people know of a variety of revolutions (American, French, etc.) that occurred.  What of science?  Through these years many discoveries are notable in the sciences.  Possibly from Kepler we could call it a Scientific Revolution!

We will split this into the 1600’s and the 1700’s, where we discuss a variety of people.  A majority of the discoveries involve the Solar System, but these years made some stellar improvements to Physics as well.


At this time the telescope was improved by a variety of people, which allowed for a growth in our knowledge of the Solar System and its contents.  Gregory James designed the first reflecting telescope known as the Gregorian telescope.  The first actual refracting (Galilean) telescope was made by the Dutch Hans Lippershey, Zacarias Janssen and Jacob Metius who created lenses.  Refracting telescopes like the ones Galileo made and used were more common and used by ancient Astronomers.  Now reflecting telescopes are used more since it was found eventually that lenses had limitations in viewing objects.  John Flamsteed cataloged over 3000 stars, such an enormous number that the catalog was even needed by Newton and Halley.  There is also Christiaan Huygens, a famous physicist who worked with telescopes and Optics to find Saturn’s rings and its moon Titan.  For this he gets a spacecraft named after him, which  is fittingly supposed to visit Saturn.

Cassini-Huygens spacecraft

Artist’s rendition of Saturn and spacecraft.

Another famous Astronomer who worked with Huygens was Giovanni Domenico Cassini.  The spacecraft that was named for Huygens is actually called the Cassini-Huygens since Cassini also made multiple observations of Saturn and Titan.  He was actually more of an Astronomer than Huygens, since he ended up observing four of Saturn’s moons, discovered the Great Red Spot of Jupiter with Robert Hooke, and found differential rotation in Jupiter’s atmosphere.  Cassini and Jean Richer even managed to use parallax to calculate the distance to Mars, an important use of a method of distance calculation (which will be explained later).

So yes, there were definitely people besides Galileo, Newton, and Kepler who were important during the 1600’s.


But the 1700’s had some extremely important people as well.  One of the most important would be Charles Messier.  By looking at the sky for comets, he found many comet-like objects that weren’t actually comets.  For this he made a catalog of 110 objects, most of which turned out to be nebulae and star clusters.  This catalog could be said to be as important as the telescope since it organizes the objects and explains where they are; that surely puts us in our place!  This list is still used by Astronomers today, especially amateur Astronomers, and for the Science Olympians out there you would know it from some of the Deep Sky Objects.  We have this man to thank for helping make our lives somewhat easier in finding information on them.  Messier sadly doesn’t have any fancy satellites named for him.  He just gets a crater, and a whole catalog of objects with his name tacked on instead.

Entire Messier catalog

^ This whole thing.

Next is Edmond Halley.  Now, we all know about the famous Halley’s Comet.  He got his name attached to one of the world’s most famous comets for calculating the orbit of that very comet.  No easy task since he figured it out by looking to four observations and their calculated orbits that weren’t all his own.  He sadly didn’t see his prediction come true for the comet’s next appearance, but Halley did many other things too.  Similar to Messier, he constructed a catalog of stars of the Southern Hemisphere for 341 stars and observed the transit of Mercury across the Sun.  Halley may have also persuaded Newton to publish some of his works on celestial mechanics.  He also looked towards the famous Transit of Venus to determine the distance from the Sun to the Earth.

Pierre-Simon Laplace was an important mathematician and Astronomer.  He made a lot of math, but this is an Astronomy blog, so we’ll ignore most of his math work.  He restated the “nebular hypothesis” of the origin of the solar system, which pretty much says that a giant cloud of stuff (hydrogen and whatnot) condensed into a star with dust forming the planets as well.  Laplace also was one of the first scientists to theorize black holes and gravitational collapse.  Yes, he theorized black holes almost 100 years before modern physicists did, by working with a man named John Michell who also described gravity’s effects on light.  Of course, Michell himself was one of the first to propose binary stars, so obviously these people were pretty intelligent for their day.

Lastly is the Herschel family.  The family was more known for its music, but there were three famous for Astronomy.  Possibly the most famous is William Herschel.  By reading books on Astronomy and Optics, he learned to become a skilled telescope maker and sky observer by creating mirrors for observation.  Herschel also investigated the proper motion of stars, and from this he discovered that our solar system is moving.  He proposed that other universes exist, hinting at the idea of multiple galaxies.  He’s most well-known for discovering Uranus and two major moons of the planet.  Yes, by 1781 there were still undiscovered planets, but we can thank this man for an inappropriate planet-related joke.  For all this Herschel was able to meet Napoleon (yes, that Napoleon), Laplace, and Messier.  It’s appropriate that Herschel met Messier since Herschel made his own catalog of objects, and in the same year that he discovered Uranus he received a copy of Messier’s catalog which spurred on his interests.  But there isn’t really a better reward than getting a satellite named after you.  Oh wait, Herschel got one of those too. It works in the infrared range. Because he discovered infrared light.

William and Caroline Herschel

P. Fouché. Caroline Herschel Taking Notes as Her Brother William Observes on March 13, 1781, the Night William Discovered Uranus, (Brooklyn Museum)

To continue with his family, he had a sister.  Caroline Herschel was sick with Typhus from a young age.  Despite surviving this she wasn’t able to do much in the opinion of her father since she couldn’t grow any taller.  Since her brother had sympathy for her, she had multiple discussions with him about Astronomy, and eventually she decided to help him.  Caroline made a major contribution to the discovery of Uranus with her brother, but she also did her own observations with a small telescope and found a total of 8 comets in 11 years along with 3 nebulae.  Discovering comets and nebulae may not sound so significant, but many Astronomers at the time (including the notable Messier) were searching for these objects. Caroline Herschel is recognized as the first woman with a scientific position specifically in Astronomy and received a pension for it.  There may be no satellite named directly for her, but she certainly showed that despite not learning as much, she was a capable observational Astronomer.  This is especially unique since she lived in a time where women were expected to be married off and become housewives.

Others to mention:

  • Johann Heinrich Lambert – First to propose Milk Way’s disk-like shape
  • Johann Daniel Titius – Found asteroid belt and with Johann Elert Bode created a law for the distances of planets
  • Giuseppe Piazzi – Discovered the dwarf planet Ceres and has a crater named for him
  • Heinrich Wilhelm Matthias Olbers – Calculated comet orbits, discovered asteroids and proposed the existence of the asteroid belt.  Most famous for Olbers’ Paradox, which states that since the night sky is dark, the universe and the number of stars in it cannot be infinite and static.  This contributes to support of the Big Bang model that the universe is always changing.
  • Ole Rømer – had to be mentioned both for the fancy O and for measuring the speed of light, which was improved on by James Bradley
  • Leonhard Euler  Said incorrectly that light must travel through an “aether”.  But to make up for this, he calculated the orbits of comets, the parallax of the Sun, and tons of other useful math (or maths for our British readers).  Also, his last name is pronounced similar to “Oyler” or “Oiler”, please don’t make the mistake.  A Geometry or math(s) teacher may be mad if you do.
  • Alexander von Humboldt – first detailed study of Leonid Meteor Shower

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This entry was posted in History.

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