Date: July 4, 2022.
Being a member of a species as daring and exciting as humans is thrilling. We do many things in our lifetime- discovering, inventing, building structures, etc. The night sky shows us how well we have harnessed and manipulated energy, and how vital it is to our existence. More crucially, energy is essential for life to sustain.
But, What is Energy?
It is the ability to do work.
To be alive means to be active. Thousands of complex processes occur within a living cell every second to keep it from dying. The essence of being alive is to constantly be moving, but never reaching anywhere, and when it halts, you cease to exist. (RIP!).
And to be in motion, you need …. Energy, of course!
A billion years ago, the first living cells got their energy from simple chemical reactions, and Voila! They found the energetic building block of life, which is made up of one Adenine (nitrogen base), one Ribose (five-carbon sugar), and three phosphate groups- Adenosine Triphosphate (ATP). It is an energy-carrying organic molecule found in all living things.
So, in biology, energy is ATP.
No ATP, no life.
The smartest evolutionary beings without conscious brains are the plants and the algae. They figured out how to use the greatest available source of energy- the Sun! (the energy emitted by the sun in 88 minutes can power the whole earth for a year) Creating a process called photosynthesis which transformed light energy into chemical energy to synthesize fuel for work. Those who could not synthesize their own fuel (heterotrophs) would simply consume the autotrophs and survive.
A few thousand years from then came into existence- the first mitochondria, the powerhouse of the cell. Let’s say that mitochondria was a successful start-up that later underwent scale-ups, collaborations, and mergers, and eventually launched its most evolutionary product with the ability of complex reasoning and introspection- YOU! Congratulations! Mitochondria acts like a battery that produces 1200 watts of equivalent energy in a day. (WOW!)
In physics, energy is a number, a quantity. Also, it is a mathematical relationship between fundamental quantities. There are many different kinds of energy, but the big categories are- kinetic (energy of motion) and potential (stored energy).
The Law of conservation of energy says- energy can neither be created nor can be destroyed, it can only be transformed from one form into another. This might imply that the energy we currently use is the same as that around 13.8 billion years ago when the universe came into existence (WHAT?!). Energy calculations are about balancing the books and accounting for all the places energy can be stored. German mathematician, Emmy Noether observed that the law of conservation of energy was based on time translational symmetry- if the very fundamental laws of nature remain unchanged over time, then energy would be conserved.
But, is the universe symmetric?!
On a cosmic scale, our universe looks fundamentally different from one moment to the next (quantum asymmetry), where its expansion becomes significant, and in those scales, energy is not conserved. This leads to effects like dark energy and accelerated expansion of the universe. Also, the conservation of energy is generally invalid in the context of Einstein’s general theory of relativity due to the changing size and geometry of time and space i.e. potential time evolution of space.
Energy is not conserved in an expanding universe.
Energy is still an open question that remains unanswered. Recognizing it is easier than defining it.
Energy is everything, it’s everywhere, and it’s a clue to the deeper, more fundamental properties of life, space, and time.
Oh well, that was an ENERGETIC start! Ha ha!
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