Dark Energy Survey reveals most accurate measure of night affair construction inwards the universecelebrating a novel final result yesteryear the Dark Energy Survey (DES), a multinational collaboration studying night affair in addition to night unloose energy using a telescope inwards Chile, at an height of 2,200 meters.
DES wants to create similar results every bit Planck – the modern sibling of WMAP in addition to COBE, a satellite that studies the cosmic microwave background temperature inwards diverse directions real finely – but its method is real different. The DES telescope looks at things inwards the infrared – but it is looking at "regular things" such every bit the lay out of galaxy clusters, weak gravitational lensing, type IA supernovae, in addition to baryon acoustic oscillations.
It sounds incredible to me but the DES transnational squad is capable of detecting tiny distortions of the images of distant galaxies that are caused yesteryear gravitational lensing in addition to yesteryear measuring how much distortion in that place is inwards a given direction, they decide the density of night affair inwards that direction.
At the end, they decide some of the same cosmological parameters every bit Planck, e.g. that night unloose energy makes well-nigh lxx pct of the unloose energy density of our Universe inwards average. And particularly if you lot focus on a two-dimensional plane, you lot may run into a slight disagreement betwixt Planck's measure based on the CMB in addition to "pretty much all other methods" to mensurate the cosmological parameters.
Planck (the bluish blob) implies a slightly higher fraction of the affair inwards the Universe, possibly 30-40 percent, in addition to a slightly higher clumpiness of affair than DES whose fraction of the affair is betwixt 24-30 percent. Meanwhile, all the measurements aside from the genuinely historicaly "pure CMB" Planck measure – which includes DES in addition to Planck's ain analysis of clusters – seem to endure inwards a amend understanding alongside each other.
So it's disappointing that cosmology withal allows us to mensurate the fraction of affair just every bit "something betwixt 25 in addition to xl pct or so" – the accuracy is lousier than nosotros used to say. On the other hand, the disagreement is just 1.4-2.3 sigma, depending on what is precisely considered in addition to how. This is a real depression signal-to-noise ratio – the disagreement is real far from a regain (we ofttimes similar v sigma).
More importantly, fifty-fifty if the disagreement could endure calculated to endure four sigma or something similar that, what's troubling is that such a disagreement gives us almost no clue well-nigh "how nosotros should alter our measure cosmological model" to improve the fit. An extra sterile neutrino could endure the thing nosotros need. Or some cosmic strings added to the Universe. Or a modified profile for some galactic night matter. But maybe some holographic MOND-like alteration of gravity is desirable. Or a dissimilar model of night unloose energy – some variable cosmological constant. Or something totally dissimilar – if you lot weren't impressed yesteryear the key multifariousness of the possible explanations I bring mentioned.
The disagreement inwards ane or ii parameters is just way likewise trivial data to give us (by us, I hateful the theorists) useful clues. So fifty-fifty if I tin post away imagine that inwards some distant future, possibly inwards the twelvemonth 2200, people volition already concord that our model of the cosmological constant was seriously flawed inwards some way I can't imagine now, the observations render us alongside no guide telling us where nosotros should larn from here.
Aside from the DES telescope, Republic of Chile has similar compartments in addition to colors on their national flag every bit Czech Republic in addition to they also bring overnice protocol pens alongside pretty adept jewels that every wise president just has to credibly appreciate. When I state "credibly", it agency non just yesteryear words in addition to clichés but yesteryear acts, too.
So fifty-fifty if the disagreement were four sigma, I just wouldn't switch to a revolutionary vogue – partly because the statistical significance isn't quite persuasive, partly because I don't know what sort of a revolution I should envision or participate in.
That's why I prefer to translate the final result of DES every bit something that isn't quite novel or ground-breaking but that withal shows how nontrivially nosotros empathize the life of the Universe that has been or in addition to then for 13.800002017 ;-) billion years in addition to then far in addition to how real dissimilar ways to translate the fields inwards the Universe seem to yield (almost) the same outcome.
You may expect for some interesting relevant tweets yesteryear cosmologist Shaun Hotchkiss.
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