# How Modern Astronomy Evolved

Stargazing has always inspired people to wonder what was out there in the night sky. Some thought the stars were past relatives or ghosts. Others thought they were Gods. One thing for sure was that no one knew for sure. From the beginning of time this has been the case. We have always wondered. Even in modern times where we know many things, we still wonder how modern astronomy evolved. As science and technology evolved, our understanding of astronomy has increased steadily though. Stargazing will forever be popular and rightly so. How modern astronomy evolved will forever be a journey to people.

## How Modern Astronomy Evolved

Our understanding of the universe is faulty at best. It's not for lack of trying though. We are constantly refining our ideas and collecting knowledge. This process started thousands of years ago and I hope it continues for another thousand years. The picture below shows the wondrous nature of this field.

### Science Methods

The main reasons for our eventual increase of knowledge were better telescopes and improved scientific methods. Better telescopes allowed us to see stars better and make better judgements. Galileo was the first who really made significant improvements to the telescope. He refined what it did and indeed made it better.  Refracting telescopes were what he used and improved.

They had their issues though which is why the reflecting telescope was then invented. Reflecting telescopes bypassed the limitations of the refracting telescope. It allowed even further refinement to celestial images of the day. How modern astronomy evolved depended very much on establishing methods to test and review results.

• Form an hypothesis
• Make a prediction
• Test the prediction
• Analyze it

That is roughly the scientific method. It never really ends though. You keep making more hypotheses, more tests, and more analyses. This process helped early scientists sort through early ideas.

### Systems

What good were these new devices if we did not use them well? This is where scientific method and the development of systematic observation made good use of the new telescopes we now had.  With a defined set of procedures, science itself progressed more quickly. Why is the scientific method important? For one it formalizes the process. This means that everyone is testing and evaluating observations and results in the same way.

It was important because you could eliminate things that did not make sense and gain an interesting answer much quicker than just guessing your way through it. That is my analysis anyway. With a system of observation now in place, everyone could make assertions based off equal conditions. If done correctly, there should be no outlandish results. Everything that was then inferred had at least a chance of being correct until more testing and observation was done.

### Better Telescopes

Telescopes have not been around for very long. There are many claims for earlier telescopes but even then the 1500's is the earliest it could have appeared. Galileo developed the first good one it seems. It used concave lenses. He used it to start observing various planets and other objects in the night sky.

This happened around 1609 and was the turning point for Astronomy. He continued to improve his designs throughout his career.
Johannes Kepler again made another great improvement by using a convex lens. This greatly magnified objects in space. Switching to this style also gave him a much larger field of view.

This was very helpful. His telescopes suffered from light distortion which today is called chromatic aberration.
Johannus Hevelius wanted to construct longer telescopes because he theorized that the longer they were the sharper they would be. It was reported that he developed one that was 140 feet long! The telescope was impractical to use much because it kept moving.

Isaac Newton developed the first reflector telescope using a mirror and a combination of lenses. This was a huge discovery. There were still problems but viewing instruments were getting better.

Sir William Herschel was the great Astronomer who built a huge reflector telescope with a 4 foot mirror in it. The advantage of this is that it could gather much more light. This helped resolve pictures much more clearly.

### Heliocentrism

This led to the heliocentric view of our galaxy.  This idea contrasted greatly with the predominant view of most people. Most, since anyone thought about it, thought that our own planet was the center of our galaxy and all there was.

While we know this is wrong today, you can not really blame those who first thought it.This earth was all that was understood and that was just on a basic level. Because of that, it took a long time for people to accept that everything in our galaxy would revolve around the Sun. It was just too new of a concept and something that very few could understand.

How modern astronomy evolved , though , would have to lead us toward heliocentrism eventually anyway. Our little earth and many other heavenly bodies have some kind of orbit around the star that is our sun.You would think that the life-giving light and radiation from the Sun would make it seem more important to our ancestors.

Indeed, not many made this connection. Nicolaus Copernicus was one of the very few. He was the most influential man in Astronomy. He read a lot of history books and anything on Astronomy. After he proposed his heliocentric view of the solar system he became very unpopular. No one believed in this new system.

However, the math that he and many others had been working on suddenly worked out when you considered the Sun at the center of our solar system. He published his theories a year before his death. He did this in case there was major backlash with the church. There would be of course.His heliocentric theory was revolutionary even after all the troubles it caused himself and others. We now know it to be accurate and was the key to finding more planets in our solar system.

### Celestial Mechanics

This topic deals with how the many objects, stars for example, in our solar system and how they are affected by other celestial bodies. This really confused people for literally ages. First, without the idea of heliocentrism mentioned above, these principles could not even begin to take off. If you think about the words, celestial mechanics, it really how it sounds. It is the mechanics that we know and love applied to celestial objects.

Celestial mechanics is ultimately the doing of Johannes Kepler. His laws of planetary motion were instrumental in explaining the motion of celestial bodies. This motion showed how everything interacted with each other. The key equation behind these laws of his was:
$$F = \frac{G*m1*m2}{r^2}$$

It described the gravitational force that any two particular objects exerted on each other. This equation therefore says that the masses of those objects are multiplied together along with the gravitational constant. Then divide this figure by the square of the distance between the two bodies.

When we use this equation on all of the planets, moons, and other objects, we then see a better picture of what is going on in our solar system.
Now Newton had his theories about celestial mechanics but it was Kepler that solidified everything that they knew in that time.

This theory made it know that the Sun was the major force in the solar system. All other objects of any significant size acted upon everything else too. If the effect was too small then the effect would not be measurable. When all of this was taken into account it made it easy to predict planets and their locations during orbits.

### Gravity

The laws of gravity were the next huge accomplishment. They spurred great innovations and knowledge about how bodies in space interact with each other. You see, everything in space has some effect on something else. It can be a very minor effect like causing a slight wobble as something passes by. A more prominent example would be our Earth keeping the Moon close by which is due to gravity as well.

It can also be a huge effect like bringing the object into orbit because it got too close.Even objects that get taken into orbit of a larger mass slightly effect that larger mass. I will say it again, everything in space affects something else to some degree. This is because of gravity.You might then ask what exactly is gravity?

Well we are still working on that. There are many ideas of course. Newton said it was a force and that every object in the universe has an attraction on everything else. The masses of any 2 objects you select and their respective distances apart will tell you what force is applied on each.

Unless at least one of the objects are very large, however, the effects are so slight you will not notice.So telling the pretty girl sitting next to you that the closer we get the more attraction we will have for each other will probably not work. I know, I tried it once during high school. She did not look convinced.Gravity has an effect on everything.

It is part of our daily lives. It always has been. Its effect at the Earth's surface is $$9.8 \frac{m}{s^2}$$. The force is one of acceleration. This means that for every $$s^2$$ our acceleration increases by $$9.8$$ if we are in free fall. The effect of gravity is also different on every other celestial object in space.

### Light and Distance

These developments led us to better understand the speed of light and distances in our galaxy. The speed of light is pretty fast. More accurately, it is the fastest thing we know of for sure. There have been guesses that other things in space might be faster but right now that is all conjecture.

Knowing this speed allowed us to then measure distances to many objects in space.For example you can measure the distance to a comet and then a week later do it again. By doing this you get an idea of how fast it is moving and its direction of movement. See how this is important?

Now that we can measure distances we begin to understand the vast distances to other planets and stars.  Maybe understand is too much credit but at least we are starting to get an idea. Once astronomers started getting distances for everything and their movements, they realized how much more there was to learn. This opened up many avenues of study.  How modern astronomy evolved led us toward discovering the vast distances in space as you can see below.

### Spectroscopy

Once a reasonable level of understanding had been gained of the speed of light and distances, astronomers began focusing more on the light being emitted from stars and planets. Just about everything broadcasts some sort of light or radiation. Looking at this light and analyzing it became huge for inferring a lot of characteristics about stars. Over time scientists of the day realized they could look at different wavelengths of light.

This development yielded a great deal of additional information. Using a spectroscope, astronomers studied the light captured and could tell how hot the star was and partly what it was even made of. Once it was known how hot it was, you could then infer its age and size based other conditions.

Knowing what it was made of also helped. Stars with higher compositions of some elements had different characteristics than stars with other compositions.

This became an important field of study called spectroscopy.

### Conclusion

Basically that is where we are now in modern times. There are, of course better technology innovations and telescopes out in space to get more accurate readings. Everything is progressing steadily like it always has. We are gaining insight continually and our understanding of the universe slowly evolves. Will we ever have a true understanding?

Probably not but it is seeing and discovering the wonders that is out there that has always kept us trying and hopefully forever will. How modern Astronomy evolved is a fascinating subject. Looking at past developments can also give us clues today.