Physics and Cosmos
From Defining mankind to the end of cosmos where we all govern by scientific knowledge.
For my science and learning obsession, I mentioned about Science and Religion in my previous topic. This time I want to write about Physics that related to our universe in fact how we are looking at, in our daily lives.
As far as history goes, mankind has started to look at the cosmos ever since the day of the beginning. I am not going to talk about the people who changed our understanding of the Universe as time passes. Listing out our achievements as one is the best way we can march with our humanity forward.
In the early ages of mankind, we all knew about the fact that earth is the center of the universe and all other celestial bodies revolve around it. This perception has the reason, Astrology. Our ancestors looked at the sky and the position of celestial bodies which includes stars, constellations, planets and other bodies in the night sky and was figuring out whether and time depends on the movements of them. They were also using stars to navigate and set up meetings with the other tribes on a yearly basis.
This raised to the fact that earth is the center of the universe where all the celestial bodies revolve around it.
This theory stood for ages and centuries. Even people thought the earth is flat. To disprove this theory, we experimented by sticking a stick on the ground in one place and placing another stick 1000 miles apart. At exact 12 PM, the shadow of those sticks is measured. One stick has no shadow because Sun was in the mid of the sky and on the other side, the shadow was inclined and found that shadow existed. This idea gave researchers to think, “if the earth is flat, at the same time, the shadow would have not seen from both the sticks from different places hence, the earth is spherical.” This experiment helped to create timezones later. Timezones are created depending on the incident of sunlight to the ground.
Now, let’s come back to the topic about the earth is the center of the universe. This is also disproved in the 16th century. It was explained as the sun is the center of the universe. It is called a heliocentric model. There is no evidence that how we got to this model but It is said that Nicholas Copernicus, influenced by Aristarchus of Samos from 4th Century BC. His astronomical ideas were often rejected in favor of the geocentric theories of Aristotle and Ptolemy.
There are a number of uncertainties in history. It is also believed that in Hinduism, their ancestors were predicted this model before any of the civilizations. It scales back to 6,000 to 7,000 years ago. In the end, truth matters and now we have the technology to prove those myths and verify them. Scientifically, from 16th-century modern astronomy was grown. When the first telescope was invented in 1608, things started to get an explaination. Looking at the sky using a telescope, planets and their moons are discovered. As far as the telescope can reach, we started to get proof.
With the help of explorers, we started to uncover the real shape of our planet i.e. geoid. Also, the heliocentric model got its upgrade as planets revolve around sun and sun revolve around our galaxy, Milky Way. All those planets revolve in an elliptical path. This has proved with the observations of weather changes on earth. When the earth is closer to the sun, the temperature on the ground increases and when it goes farther we encounter season like winter. We call perigee and apogee respectively.
Gravity and Space-Time:
That was a lot for the history of our discoveries. Now let’s come to the laws of gravitation. Which were proposed in the 18th century? Also, a reflection telescope has been invented. This is the commonly used telescope now to observe the night sky. It all started when Apple fell on the head of Issac Newton. He was 23 at that time and he took 20 years to prove that gravitation is a force responsible for the phenomena, not magnetism. Before this, it was believed that the attractive force is the only force that is magnetism.
Until he discovered this phenomenon, everyone believed that any object will be at rest if the force is not acting upon it. He disproved that all the objects move in a straight line unless an external force is acting upon it. This established the reason why planets revolve around the sun and moons around planets.
Even though it seemed that we are on the verge of knowing everything, there is a strange and interesting observation that has been made with respect to the speed of light. Newton’s laws of motion suggested that the movement of an object is relative to the observer or to the movement of something else. When it comes to light, the speed of it remains the same irrespective of the observer’s movement.
“It doesn’t matter who is viewing the light or how quickly they are traveling, its speed will always be the same.” — A Brief History of Time
This observation led to the theory of relativity and this includes time as one of the factors that affect the movement of an object.
The theory of relativity states that the laws of science are the same for all freely moving observers. This means that no matter what someone’s speed might be, they would observe the same speed of light.
What this means is that because the speed of light doesn’t change for observers moving at different speeds, observers traveling relative to one another would actually measure different times for the same event.
All these observations about the speed of light, celestial bodies exert gravity on every object that comes to its field, how they revolve around bigger bodies demanded more explanation. Hence, Einstein came up with an understanding of the gravitational force and given an explanation relating the three dimensions and adding time as the 4th dimension. This is called space-time.
An event is something that occurs at a particular position in space and time. So when calculating an event’s position along with the three-dimensional coordinates, scientists add a fourth coordinate to indicate time. This led to the modern understanding of space-time and how gravity works on another object.
Gravity is the result of massive objects curving space-time. A huge mass, like that of our sun, curves and actually alters space-time. Think of it like this: Imagine space-time to be a blanket stretched out and held in the air. If you place an object in the middle of the blanket, the blanket will curve and the object will sink a little. This is what massive objects due to space-time.
Creation of the Universe:
When this happened, great discoveries are made about the universe. We also discovered 3 other different forces along with gravitation. They are,
- Electromagnetic force: The force exists between a magnet and a metal. We observe this every day in our lives.
- Weak nuclear force: The force exists between electrons and nucleons in an atom.
- Strong nuclear force: The force that exists to contain Protons, Neutrons, and Quarks at the center of an atom.
Concepts of these forces are simple, At very high energy called Grand Unification Energy, Strong nuclear force became weak and weak nuclear force and electromagnetic force got stronger. This lead to all these forces attains the same energy levels. When all 3 became equal, this led to the Big Bang. This formed our universe.
We study 2 subjects in our modern physics about the universe. One is Quantum Physics and the other is General Relativity. Quantum physics deals with the study of the nature of smaller particles like Atoms. Whereas General relativity concentrates on Gravity and Time.
These 2 subjects never cross the same roads, quantum theory suggests that all the empty space in the universe is made up of virtual pairs of particles and antiparticles. However, the existence of these virtual pairs causes difficulties for general relativity.
The Journey of Humankind:
Now we know how our universe is formed or at least we have an idea about what physics knows about our existence. As the final piece of information, I just want to take you all to the journey of Cosmos. Just broaden your mind imaging the place you are standing or sitting and look above. What do you observe? Don’t say roof or fan, I am talking about the open field. If you are not there, try to find one when you find free time. You already know that time is relative so let’s relate that to our Universe.
When you look at the sky, start to feel the field of view as you fly across the sky. When you reach the top of the atmosphere, you can view the whole city. As you go further, observe the earth from the sky. A blue body filled with white clouds. The view of our home from space is spectacular.
We do enjoy the view and the beauty of the planet when we go up there. In this infinitely larger universe, we find infinite mysteries. With the infinity, we add one more infinity as a constant to discover another infinity. This list goes on. As much as we explore, the value of infinity increases. Currently, we have to see up to 97 billion light-years in distances. Our universe is 13.8 Billion years old as we know but there are places where it takes more than that duration to reach but we can observe using a number of laws and workarounds like magnifying telescopes, sending telescopes to space to observe the cosmos.
The most popular space telescope is the Hubble Space Telescope. With the help of this, we discovered objects that are millions of light-years away. Now, humanity is on the verge of going further with the James Webb space telescope.
Along with Physics, the revolution of Optics is also an instrumental. As long as we discover infinities, we get close to another infinity.
Searching for Another Life:
After all these growths in space exploration, we can ask ourselves a question and we definitely deserve that, “Are we alone in the universe?”
Let’s discuss the probability, As we predicted there are 10¹¹ galaxies in the observable universe and in each one of them there are 10¹¹ stars and planets. So our planet is 10²² among the planets in the universe. Now, think about the question again.
I highly doubt that. We don’t have proof of extraterrestrials but we can definitely say the probability of their existence is more. Our nearest star is Alpha Centauri which is 4 light-years away from the sun and this is the closest star system to start searching for planets that can support life.
We are in the experiment of it but here are the statistics of it. We launched Voyager 1 and 2 spacecraft to search for extraterrestrials in the 1970s. After almost 50 years, Voyager able to travel out of our solar system.
To reach Alpha Centauri, it stills needs 74,950 years this is because our technology engines are made to travel 0.00571% the speed of light i.e. 1/17500th speed of light. Precisely 17.142kms/second.
So, the probability of us finding alien lives except in our solar system is very less certain in this lifetime. There is a leap from us to reach our closest star within one lifetime that is 100years.
The project name called Project Longshot. It is under development in which the engine will be able to reach up to 4.5% the speed of light having a speed of 13,411km/s. With this speed, we can reach our next closest star Alpha Centauri B in 100years.
Conclusion:
We can say that reaching to other lives are difficult but not impossible. We may need FTL (Faster than Light) engines to travel across the universe. There are 7 Billion human lives on this planet and the people contributing to space exploration are just less than 1%.
Our humanity can achieve a greater feat when we can come together and more great minds are put to work. Let’s contribute and learn about the home we are in and let’s go and find some neighbors.
Stay educated and keep thinking about marching forward. To do impossible things we are creating Artificial Intelligence. The wit of the human brain and the speed of an AI can take humanity to the next level and someday we hope that we can see what is our place in this infinite universe.
If you’re alive, there’s a purpose for your life
— Rick Warren
We all have the purpose and we find ours when we learn about being great and driven by our values.
Happy reading and enjoy the infinite space when you feel you have less space.
