"....that which we call a rose, by any other name would smell as sweet." (Romeo and Juliet).
Perhaps so, but the naming of bands can be quite a serious affair. Would Led Zeppelin have been half as successful under the name Lead Balloon? (Keith Moon's suggestion, according to music industry legend). Or even the New Yardbirds, which name they used for their first few gigs?
Often a name comes to signify a particular style of music: Can you imagine the Sex Pistols playing any other music than punk? Of course they helped invent the genre, so will be forever identified with it. But they also helped set the pattern for many punk bands to have confrontational names.
Then there's prog rock: Pink Floyd, King Crimson, Yes, Rush, Genesis (early), Van der Graaf Generator; Marillion, Twelth Night, Pendragon, Haze; Mostly Autumn, Dream Theater, Spock's Beard, Porcupine Tree, The Mars Volta. All bands that seem to have been labelled as prog rock at one time or another. Can we spot any patterns there? I dunno, but there's a useful guide to choosing your prog rock band name about three quarters of the way down this page: http://www.cracked.com/funny-2359-progressive-rock/ If forced to change our band name, I might use this guide myself. Electric Mushroom Monolith, perhaps?
When we formed Dark Energy, I had in mind that the band would play old school progressive rock (yes I know that's sounds like a contradiction in terms!), so wanted a name to reflect that. Though I would add that most of the songs we have so far are fairly straightforward rock songs; I think only three or four could reasonably be characterised as "prog", though we intend to be doing more in future.
Why Dark Energy? I've always liked the idea of band names relating to scientific concepts, particularly physics. Many have been used, of course: For instance, a quick google search turns up several different bands called Schrodinger's Cat. No doubt there are more. Quantum Leap? There was a band called that in the '70s. Relativity? Yep - a covers band in Utah. The Michelson-Morley Experiment? Just found their Facebook page.
I was hoping to be ahead of the curve with Dark Energy, as a it's a relatively new concept. Not new enough, it seems; the term was coined a decade ago. So far I've found another band in the UK, one in LA, and several dance artists. Still, none of them have made it big yet, so we can still use the name.
What is Dark Energy? The short answer is, no one really knows. Hence the name!
Longer answer (the faint hearted and physics-challenged may wish to stop here):
It's now generally accepted by cosmologists that the Universe has been expanding since its origin in the Big Bang, around 13.7 billion years ago. As to whether there was anything before the Big Bang (yes, according to some theories), whether the Universe is infinite (Probably. But it may depend on what you mean by universe), and whether there are other universes (again, probably) - these are all questions for another time. What was also known was that the expansion was slowing down. What wasn't known was whether the expansion would continue slowing down but never quite stop, come to a halt completely, or reverse itself so that the universe would collapse in on itself (the Big Crunch). All these scenarios are allowed by relativity, the determining factor being the amount of mass in the universe. Many cosmologists liked the idea that the expansion would come to a halt, but there wasn't enough visible mass to cause this. Hence the suggestion of "Dark Matter": matter that has little interaction with ordinary matter, except for gravity. You can think of this of stuff that floats around in space somewhere, not making planets and stars, but still bound to them by gravity. This sounds like it was just made up, but there is some evidence for it. I don't think I have the space to go into that here though!
The big shock came in 1998: Observations of Type 1A supernovae showed that the expansion of the universe was actually accelerating! This type of supernova is a "standard candle": Because of the mechanism that causes them, they all have the same absolute luminosity. If you compare their observed brightness with their absolute brightness, you can work out how far away they are. But you can also calculate how far away they are by their red shift. The higher the red shift, the farther away. It turns out that Type 1A supernovae at billions of light years distance are fainter than they should be according to their redshift; thus implying that the universe's expansion is accelerating, and has been for the last 5 billion years.
No one knew why though, so initially, cosmologists dubbed the unknown force that was causing this expansion "Dark Energy", by analogy with Dark Matter. Another thing invisible, except for its effects.
Since then, of course, many ideas have been suggested for what Dark Energy is: For instance, it may be an antigravitational force that is stronger at large scales, which is why it was not apparent when the universe was younger and smaller. Or it may be a negative pressure arising from vacuum energy (Yes, the vacuum has energy! We'll deal with that another time, perhaps). This is sometimes known as the Cosmological Constant (see "Einstein's biggest mistake". Allegedly.). Or it may be a hypothetical energy field known as Quintessence. The jury is still out.
What we do know is this: Subsequent observations have confirmed the acceleration. Eventually the universe will stretch so much that no meaningful existence will be possible. The time is many billions, perhaps trillions, of years away, but ultimately this universe is doomed. But then it was doomed anyway (see Heat Death and Big Crunch). I guess we'll have to find another one.