I first got into astronomy by Carl Sagan through Cosmos. Since then, the world around me has shaped incredibly fascinating and mind-blowing. I will write a blog on Cosmos and how it impact me in the future, but now I want to share another tinder for my journey to the great universe, an interesting book, which in large chance also might trigger your thoughts.
An astrophysicist by training but an energetic, effective communicator by nature, Neil deGrasse Tyson offers a brief introduction into the origin and evolution of the universe with Astrophysics for a People in a Hurry.
Compacting the entirety of the universe into a mere two-hundred pages requires Tyson to move swiftly through his analysis, often employing wit, anecdotes, and science-fiction references to maintain his upbeat pace. His goal through this book is as astronomically large as the cosmos itself: to create a scientifically literate population.
Each chapter of the book covers a fundamental facet of the universe, such as gravity, dark matter, and light travel. Targeted at casual readers looking for more information about the universe, science students, and anyone who wonders why we are here in the cosmos. Also, it does not confine itself to astrophysics, rather describes how fields such as chemistry, biology, and astrophysics are intrinsically linked. For instant, it is quite impossible to understand the fundamentals of the big bang without also understanding the Periodic Table, the basic elements of life.
Cosmic Wonder, Cosmic Origins
Neil deGrasse Tyson explains that the universe began about 14 billion years ago. At this time, everything in the universe was smaller than a dot on the paper and extremely hot. Then came the big bang, which is when these forces differentiated into what we know today – gravity, the electromagnetic force and strong nuclear force. Matter coalesced into a wide range of subatomic particles – electrons, neutrinos and quarks.
After the big bang, the universe cooled and expanded. Quarks formed into hadrons, which led to neutrons and protons. The early activity featured a crucial asymmetry: there was more matter than antimatter. If this weren’t true, then all of the matter would have been annihilated by its corresponding antiparticle in a blaze of light. When the universe was roughly one second old, it had cooled to a billion degrees Fahrenheit.
Most of the particles that existed in the early universe were annihilated with their antimatter opposites. As it continued to cool, only one electron was left for every proton. At roughly two minutes into its existence, simple elements such as hydrogen and helium came about. These are still the most abundant elements in our universe today.
The universe started out with a hot, dense state. After that, it cooled down to 3000 kelvins (4940.33°F or 2726.9°C). At this temperature, the protons were slow enough for electrons to get captured by them and form atoms. The universe stayed in this state for billions of years before the stars formed and exploded into space, spreading heavy elements like carbon everywhere—which is essential for life on Earth as we know it today.
Newton’s Universal Laws
Neil deGrasse Tyson says that when Isaac Newton explained gravity, he changed how people think about the universe. Before that, people thought of Earth and the heavens as separate entities. But Newton showed them that they operated under the same laws, so there was no reason why celestial activity couldn’t be understood by humans on earth.
The principle of universality is central to science. It led to other discoveries, such as helium being discovered even before it was found on Earth. Analysis of the sun’s spectrum also revealed helium, which comes from the Greek word for sun. Since these laws are in effect everywhere in space and time, humanity may encounter alien races someday. Regardless of their culture or behavior, they will be based on these same principles.
Science also depends on universal laws. One of them is the law of gravity, which allows scientists to determine facts about distant objects. Another universal law is the speed of light, which allows scientists to analyze things that are far away from us and understand their behavior. However, even though there are many universal laws in science, they can be difficult to figure out because they interact with each other and create specific phenomena.
Gravity, Dark Matter and Dark Energy
Proving his genius again, Tyson explains how Newton figured out the attributes of matter that make objects gravitate toward each other. He described this “force” between objects with a relatively simple equation that scientists have used for centuries. Einstein later showed it’s more accurate to think of gravity as working like a “warp in the fabric of space-time.” But he also demonstrated how mass bends light and proved Newton’s model theory didn’t work all the time.
Astrophysicists have observed massive objects in the universe that are moving faster than they should. They can’t explain this motion using all of the matter and energy that we know about, so there must be some additional mass out there that we can’t detect. Scientists don’t think this missing mass is contained in black holes because it would lead to other effects we could observe more directly. We call this invisible matter dark matter, but scientists don’t know what it is or how much of it exists in the universe.
Humans have developed an observer-observed view of the world along with history. We perceive the world as “out there”, while we are somewhere inside our body. We consider ourselves as independent of the world out there with us objectively watching events unfolding in the world. But the truth is, we are stardust brought to life, then empowered by the universe to figure itself out – and we have only just begun.