Most models of inflation suggest the expansion would have been accompanied by ripples of gravitational energy.
In this case you store electricity as the potential gravitational energy in the weight of water.
This means that at least some of the gravitational energy that enters them never comes back.
Anyone who can follow their closing paragraphs on the relation between negative gravitational energy and the creation of the universe probably knows it all already.
ECONOMIST: Understanding the universe: Order of creation | The
Closer to home, he neatly highlights the role of gravity as an energy "engine" by discussing how the Hoover Dam converts gravitational energy into electric power.
Her work uses cosmic gravitational lensing to measure dark energy in the universe in order to help understand how the Universe appears to be accelerating in its expansion.
Building a human-sized wormhole, for example, would require harnessing vast amounts of peculiar quantum field energy and deploying gravitational stabilizing technology that would need the resources of a cosmic super-civilization.
Indeed, in 1974 Russell Hulse and Joseph Taylor recorded an indirect sighting when they showed that a pair of stars spiralling towards each other was radiating energy in the form of gravitational waves at exactly the rate predicted by Einstein.
The pulsar and white dwarf pair emit gravitational waves and the binary star system gradually loses energy.
The camera should be able to gather enough data to allow all four possible avenues for exploring dark energy: galaxy clusters, supernovae, large-scale galaxy clumping and weak gravitational lensing, at the same time.
ENGADGET: DECam: Gazing deep into the final frontier in search of dark energy
The problem becomes less acute once they've cleared the atmosphere, but the high speeds required to escape the Earth's gravitational field (more than 6.8 miles per second) necessitate an enormous amount of energy.
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