Energy & Green Tech

US power sector is halfway to zero carbon emissions

Concerns about climate change are driving a growing number of states, utilities, and corporations to set the goal of zeroing out power-sector carbon emissions. To date 17 states plus Washington, D.C. and Puerto Rico have ...

Energy & Green Tech

Aluminum-anode batteries offer sustainable alternative

The cost of harvesting solar energy has dropped so much in recent years that it's giving traditional energy sources a run for their money. However, the challenges of energy storage—which require the capacity to bank an ...

Business

NFTs: Why digital art has such a massive carbon footprint

How much would you be willing to pay for a one-of-a-kind work of art? For some collectors, the limit lies somewhere in the region of hundreds of millions of dollars. What about a work of art that has no tangible form, and ...

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Energy

In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and systems that is subject to a conservation law. Different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. The forms of energy are often named after a related force.

Any form of energy can be transformed into another form, but the total energy always remains the same. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.

Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy relative to the Earth.

This text uses material from Wikipedia, licensed under CC BY-SA