A comprehensive analysis of distorted galaxies from the most ambitious cosmic survey ever undertaken by the Hubble Space Telescope has confirmed the mysterious cosmic acceleration. It has also provided the equivalent of a 3D map of part of the Universe.
A group of astronomers, led by Tim Schrabback of Leiden Observatory, conducted an intensive study of more than 446,000 galaxies within the Cosmological Evolution Survey (COSMOS) field. COSMOS is the largest survey conducted with Hubble, which photographed 575 slightly overlapping views of the same part of the Universe using its Advanced Camera for Surveys. In total, the survey took nearly 1000 hours of observations.
In addition to the Hubble data, the researchers used ground-based observations to assign distances to 194 000 of the galaxies. “The sheer number of galaxies included in this type of analysis is unprecedented, but more important is the wealth of information we could obtain about the invisible structures in the Universe from this exceptional dataset,” says team member Patrick Simon from Edinburgh University.
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According to theory, the invisible Universe consists of dark matter and dark energy. It is not known what either component is; yet astronomers believe that they exist because of their effects on the motion of celestial objects. Dark matter contributes more gravity to the Universe on smaller scales, while dark energy resists gravity on the larger scales.
In the new analysis, the astronomers ‘weighed’ the large-scale matter distribution in space. This information is encoded in the distorted shapes of distant galaxies, a phenomenon referred to as ‘weak gravitational lensing’. The team’s new algorithms improve the standard method and measures galaxy shapes to an unprecedented precision.
The meticulous detail and scale of this study has confirmed that the Universe is accelerated by an additional, mysterious component: the dark energy. Only a handful of other such independent confirmations exist. “Dark energy affects our measurements for two reasons. First, when it is present, galaxy clusters grow more slowly. Secondly, it changes the way the Universe expands, leading to more distant galaxies that are more efficiently lensed. Our analysis is sensitive to both effects,” says team member Benjamin Joachimi,
This study is leading to a clearer map of this part of the Universe. “With more accurate information about the distances to the galaxies, we can measure the distribution of the matter between them and us more accurately,” says team member Jan Hartlap, University of Bonn.
“Before, most of the studies were done in 2D, like taking a chest X-ray. Our study is more like a 3D reconstruction of the skeleton from a CT scan,” says William High from Harvard University, another team member.
The astronomers specifically chose the COSMOS survey because it is thought to be a representative sample of the Universe. The results of the study will be published in an upcoming issue of Astronomy and Astrophysics. Astronomers will one day be able to apply these techniques to wider areas of the sky, forming a clearer picture of what is truly out there.
The NASA/ESA Hubble Space Telescope looks back in time to ‘map’ the evolution of dark matter. The dataset is created by splitting the background source galaxy population into discrete epochs of time, like cutting through geological strata. This is calibrated by measuring the cosmological redshift of the lensing galaxies used to map the dark matter distribution and putting them into different time and distance ‘slices’.
Background galaxies are lensed, or distorted, by all structures in their foreground. Thus, the more distant background galaxies are selected, the more structures can be detected. Here, the respective strengths of the lensing effect depend on the distances involved.
The projected mass distributions inferred from the low, intermediate and high redshift galaxies are shown in blue, green and red, respectively. Nearby structures may be detected by all subsets (as exemplified by the ‘blob’ appearing on the top left of each panel), while very distant structures can only be detected by even more distant background galaxies, and thus appear in the red map only.
The new study presents the most comprehensive analysis of data from the COSMOS survey. These researchers have, for the first time, used Hubble and the natural ‘weak lenses’ in space to characterise the accelerated expansion of the Universe. Credits: NASA/ESA/P. Simon (University of Bonn)/T. Schrabback (Leiden Observatory)
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Distant parts of the Universe can and do expand faster than light.
That does not violate the "speed of light" rule, which applies within a single Lorentz frame. The ultraluminal expansion of the Universe does not violate causality.
'Science' doesn't say anything about the 'creation' of energy or the universe. Science is only concerned with what can be measured empirically.
The universe is a closed system: all the energy/mass in the universe is constant. I can't possibly say what the properties of the system were at the point of the Big Bang or where the energy came from – maybe it is always constant? We can only hypothesise.
The point is, time and space are dimensions *of* the universe. It makes no sense to talk of 'before' or 'outside' the universe, hence it also makes no sense to talk of causes of the universe because causality only makes sense within the concept of time.
I don't think there is any reason to consider the oscillating universe model – measurements show the expansion of the universe is accelerating and the universe is 'flat', both of which suggest the universe isn't going to contract.
ETA: Sorry, I meant to say accelerating at an increasing rate.
Dark matter and dark energy are supposed to be most (97%) of the mass energy of the universe. In other words, the percentage of what Darling's tax on bank bonuses ought to be… But it's good someone did something (following the Netherlands).
This being said, the existence of all this darkness depends upon theories we are in no way not sure of, such as the large scale theory of gravitation…
We will see… It's an exciting time in physics, though, when absolutely all the basic theories are being questioned…
PA
Check out this youtube link on the Hubble space telescope deep field images. Named 'the most important image ever taken.' It is all about when they aimed the telescope at the emptiest part of the sky they could see, then stared, zoomed, magnified heaps and heaps and saw literally tens of thousands of galaxy's like our own. In a seemingly empty part of space it is anything but. It is improbable that we are alone.
http://www.youtube.com/watch?v=mcBV-cXVWFw
Gravity couples to anything and everything. Gravity is space and time itself. If there is something more primordial than Quantum Mechanics, then Gravity doesn’t just have to interact with the post-Quantum, Gravity must be post-Quantum. I think we will solve Gravity after we figure out dark matter and dark energy, not before. yeah… it’ll be nice.
I saw that article and one other on the subject.
While the evidence provided in the research does suggest the presence of dark matter, it's important not to jump to conclusions regarding the results of one research project. Unless those results can be repeated someplace else, the jury is still out on dark matter.
Presently both dark matter and dark energy are exotic solutions to observed phenomena. This does not make them real. In fact, they may never be less insubstantial than our mathematical models for subatomic objects – the quantum models certainly work well, but whether or not those objects exist as corporeal "things" is arguable. At best, they're only "present" or "moving" statistically.
But I could be dead wrong, partially wrong, whatever. It may be that WIMPS (Weakly Interacting Massive Particles) exist and can be quantified better than subatomic particles. Likewise, negative energy may be measureable using classical methods. Who knows?
Last time I looked, the breakdown of the universe was something like:
5% matter
25% dark matter (gravitation that binds galaxies and superclusters together)
70% dark energy (causes acceleration of universal expansion.
I could be wrong about those numbers, too, depending on the dark matter/energy Flavor of the Day.
Tell you what I'd like a better handle on: local properties of intertia. If I suddenly find myself alone in the universe, I'll no doubt be weightless; but how will I know whether or not I'm rotating on one or more axes? Does it matter? Common sense says that if I'm rotating, blood will rush to my extremities. If there's nothing else in the universe, why should my blood do that?
Remember, blood rushing to the extremities in a rotating ape in this universe is not the result of gravitation. Something else is going on. In the universe of only me, there is no gravity AND no inertia. Somehow the other things in this universe cause intertia as well as gravity. Are they related? Are dark matter and energy involved?
Hint: models of inertial force use linear relationships to distance, as opposed to the inverse square law of Newton's Second law. If the intertial force is directly proprtional to distance, it means that intertial forces are caused by the most distant objects in the universe.
That's as coherent as I can make it. Maybe I'd better post my own questions.