What the heck is energy?

Electricity, fuels, heating: energy is all around us. Physicists talk about it all the time to decode the mechanisms behind basically every process. Yet a good definition of energy is hard to come by: what is this “energy”?

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Enceladus: a song of ice and tides

An artist impression of Cassini diving into Enceladus water plumes. credit: NASA/JPL

Cassini will terminate its 20-odd-years-long mission in September. But it’s determined to go out with a bang. In yesterday’s press conference, NASA announced that the probe, during a 2015 flyby of Saturn’s moon Enceladus, found clues that the ocean within the icy moon has almost all we think it needs to spark life. Continue reading