The Chameleon Field: Will We Ever Find This “Fifth Force”?

Physics





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And why does it get its name from this animal? Steve Wilson/Flickr. (CC BY 2.0)

The universe isn't just expanding, it's accelerating. And no one knows why. Dark energy was proposed to fill in this knowledge gap: a sort of "repulsive gravity" that pushes matter and space-time away instead of dragging it closer. Rather than gathering around regions of dense matter (such as stars or galaxies), dark energy prefers to hang out in the most isolated neighborhoods of the universe in the vast regions of empty space.