in present time or in past time more energy from external sources is consumed and why
Answers
Humans are driven to find ways to amplify their own force — to get stronger and move things faster. This has meant an increase in consumption and a never-ending search for new energy sources. The results: greatly expanded capabilities and lasting implications for the world around us. Balancing the benefits and the costs of each successive innovation is a crucial part of the quest — a quest begun 13.8 billion years ago.
It’s hard to fathom that all of the energy in the Universe was created with the Big Bang. Since then, the Universe has developed according to that finite amount of energy, transforming nothingness to atomic matter and ultimately into everything around us: the planet we live on, the food we eat, the cars we drive, and so on.
While life on Earth may have begun at the deep-sea vents in the ocean floor, thriving on chemical energy from beneath the crust, prokaryotes first floated to the ocean’s surface about 3.5 billion years ago. Using photosynthesis, these organisms consumed energy from the Sun and converted it to fuel for growth and ultimately reproduction — and the adaptations that came with subsequent generations. Thus the Sun played an important role in the evolution of life from single-celled organisms to highly complex beings, like people.
The Arrival of Humans
Humans produce power (as do all life forms). We lift, lower, pull, push, turn, and twist things — in essence, we can exert force on the world around us. To do so, we must consume food, which gets converted to energy, or calories. This fuels our bodies and makes it possible for us to expend energy.
Human power enabled early Homo sapiens to walk, find and prepare food, and shape and build habitats. It also quickly became a limiting factor for growth, as early humans could only move physical obstacles or kill predators with their hands and bodies. But through collective learning, innovation, and human power itself, new energy sources were developed, initially with the making of tools.
Tools first came to prominence in the Lower Paleolithic era. They allowed the transfer of human power to formed objects that could more efficiently carve, cut, smooth, pierce, or gore stone, wood, animals, and other materials. These axes, awls, and various technologies aided progress in hunting and other methods of gathering food, speeding the rate of change and impacting the environment in the process.
The same era saw the harnessing of fire. Fire proved that humans could radically transform things without exerting much of their own energy. Fire could rip through forests, clearing land in minutes. It could cook meat and vegetables, changing their taste, composition, and “shelf life.” It could burn skin, light the darkness, and exude heat for warmth. Fire was a life-altering form of energy and it was relatively “cheap” — you just had to rub two sticks together (very fast and hard). But it had its limitations.
All energy forms have benefits and costs, and the latter tend to fall into four categories: (1) creation or extraction, (2) storage, (3) transportation, and (4) waste created through the process. Fire was easy to create, impossible to store and transport, and created minimal amounts of waste. For many things it worked well, but it was also quite dangerous and not always highly controllable. The search for additional sources of energy continued.