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Programme élite hiver 2023

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Tyler Thorn
Tyler Thorn

Dark Matter Full Movie Hd Download !FREE!



Dark matter is a giant question mark looming over our knowledge of the Universe. There is more dark matter in the Universe than visible matter, but it is extremely elusive; it does not reflect, absorb or emit light, making it invisible. Because of this, it is only known to exist via its gravitational effects on the visible Universe (see e.g. heic1215a).




Dark Matter Full Movie Hd Download



"We know how gas and stars react to these cosmic crashes and where they emerge from the wreckage. Comparing how dark matter behaves can help us to narrow down what it actually is," explains David Harvey of the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, lead author of a new study.


The team found that, like the stars, the dark matter continued straight through the violent collisions without slowing down. However, unlike in the case of the stars, this is not because the dark matter is far away from other dark matter during the collisions. The leading theory is that dark matter is spread evenly throughout the galaxy clusters so dark matter particles frequently get very close to each other. The reason the dark matter doesn't slow down is because not only does it not interact with visible particles, it also interacts even less with other dark matter than previously thought.


"A previous study had seen similar behaviour in the Bullet Cluster," says team member Richard Massey of Durham University, UK. "But it's difficult to interpret what you're seeing if you have just one example. Each collision takes hundreds of millions of years, so in a human lifetime we only get to see one freeze-frame from a single camera angle. Now that we have studied so many more collisions, we can start to piece together the full movie and better understand what is going on."


By finding that dark matter interacts with itself even less than previously thought, the team have successfully narrowed down the properties of dark matter. Particle physics theorists have to keep looking, but they now have a smaller set of unknowns to work with when building their models[5].


Dark matter could potentially have rich and complex properties, and there are still several other types of interaction to study. These latest results rule out interactions that create a strong frictional force, causing dark matter to slow down during collisions. Other possible interactions could make dark matter particles bounce off each other like billiard balls, causing dark matter to be thrown out of collisions or for dark matter blobs to change shape. The team will be studying these next.


"There are still several viable candidates for dark matter, so the game is not over, but we are getting nearer to an answer," concludes Harvey. "These 'Astronomically Large' particle colliders are finally letting us glimpse the dark world all around us but just out of reach."


[4] To find out where the dark matter was located in the cluster the researchers studied the light from galaxies behind the cluster whose light had been magnified and distorted by the mass in the cluster. Because they have a good idea of the visible mass in the cluster, the amount the light is distorted tells them how much dark matter there is in a region.


Two great compilation videos are also available on Youtube: to compute the laws of nature (6:45 with music), and the Nature video a virtual universe (4:10 with narration). Time evolution of a 10Mpc (comoving) region within Illustris from the start of the simulation to z=0. The movie transitions between the dark matter density field, gas temperature (blue: cold, green: warm: white: hot), and gas metallicity.


We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity.


Multiple observations point to the existence of dark matter (DM), an elusive form of matter that comprises around 84% of the matter energy density in the Universe [2]. So far, all of the evidence for DM arises through its gravitational interaction, which provides little insight into the DM mass, but it is anticipated that DM also interacts with normal matter through interactions other than gravity.


As outlined in [18], AEDGE could also be sensitive to additional ranges of scalar DM masses via direct accelerations of the atoms produced by interactions with dark matter fields, and also through the indirect effects of the inertial and gravitational implications of the variations of the atomic masses and the mass of the Earth. It is estimated that several orders of magnitude of additional unexplored phase space for DM couplings in the mass range of \(\sim10^-2\text eV\) to \(\sim10^-16\text eV\) could be probed via these new effects.


Ultra-high-precision atom interferometry has been shown to be sensitive to other aspects of fundamental physics beyond dark matter and GWs, though studies of some such possibilities are still at exploratory stages. Examples include:


Probes of long-range fifth forces: Since atom interferometry can be used to detect the gravitational field of Earth [66], a set up with interferometers at different heights seems a natural one to study the possibility of any other long-range fifth force that couples to matter in ways different from gravity. The search for long-range forces is a very active area of research beyond the SM, with natural connections to dark matter and modified gravity, see, e.g., [67], and universally-coupled Yukawa-type fifth forces over these scales are already well constrained by classical searches for fifth forces [68].


For the sensitivity projections of AEDGE presented in this paper we assume that operation is performed mainly in the resonant mode, while also providing estimates for broadband operation for comparison. In order to generate the sensitivity curve for, e.g., a GW signal, from the phase response, we calculate the minimum strain h that is detectable given a phase noise spectral density \(\delta \phi _\mathrmnoise\). We optimize the LMT enhancement n for each frequency and resonant enhancement Q, taking into account the detector design constraints, which include the limits on the total number of pulses, \(n_p^ \mathrmmax = 2Q(2n-1)+1\), and on the maximum interferometer duration, \(2TQ m is the atom mass, is constrained to be less than 90 cm. As discussed in [40, 79], this constraint limits the amount of LMT enhancement. Using resonant enhancement while reducing LMT allows the interferometer region to remain small, but it has an impact on the achievable sensitivity when setup is operated in broadband mode. In this context, we would like to point out that a strontium-based single-photon atom interferometer has recently demonstrated 141 ħk LMT [84]. Although the demonstrated LMT does not yet reach the performance requirements for proposed ground-based detectors or AEDGE, it serves as a proof-of-principle for future LMT-enhanced clock atom interferometry for dark matter searches and gravitational wave detection. Planned improvements of this work, like significantly increased laser power, are expected to push the LMT transfer rate to about 1000 ħk in the near future, which would reach the conceptual design specification of AEDGE. An alternative design places the interrogation region outside the satellite [85]. This setup would support LMT values closer to what can be achieved in ground-based setups, which would not only increase broadband sensitivity but also make it possible to probe even lower frequencies. However, operating the interferometers in space would incur additional technical challenges such as vacuum stability, solar radiation shielding and magnetic field effects. While these challenges seem surmountable, conservatively we focus our sensitivity projections here on a design in which the atom interrogation region is within the satellite, which requires resonant mode operation to achieve maximal sensitivity. In the future, further investigations of using a much larger interrogation region in space could change this design choice.


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