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posted by cmn32480 on Thursday March 15 2018, @03:27PM   Printer-friendly
from the the-forrester-found-it-outback dept.

Submitted via IRC for boru

A research team of multiple institutes, including the National Astronomical Observatory of Japan and University of Tokyo, released an unprecedentedly wide and sharp dark matter map based on the newly obtained imaging data by Hyper Suprime-Cam on the Subaru Telescope. The dark matter distribution is estimated by the weak gravitational lensing technique (Figure 1, Movie). The team located the positions and lensing signals of the dark matter halos and found indications that the number of halos could be inconsistent with what the simplest cosmological model suggests. This could be a new clue to understanding why the expansion of the Universe is accelerating.

[...] The team is leading a large scale imaging survey using Hyper Suprime-Cam (HSC) to probe the mystery of the accelerating Universe. The key here is to examine the expansion history of the Universe very carefully.

In the early Universe, matter was distributed almost but not quite uniformly. There were slight fluctuations in the density which can now be observed through the temperature fluctuations of the cosmic microwave background. These slight matter fluctuations evolved over cosmic time because of the mutual gravitational attraction of matter, and eventually the large scale structure of the present day Universe become visible. It is known that the growth rate of the structure strongly depends on how the Universe expands. For example, if the expansion rate is high, it is hard for matter to contract and the growth rate is suppressed. This means that the expansion history can be probed inversely through the observation of the growth rate.

It is important to note that growth rate cannot be probed well if we only observe visible matter (stars and galaxies). This is because we now know that nearly 80 % of the matter is an invisible substance called dark matter. The team adopted the 'weak gravitation lensing technique.' The images of distant galaxies are slightly distorted by the gravitational field generated by the foreground dark matter distribution. Analysis of the systematic distortion enables us to reconstruct the foreground dark matter distribution.

Source: https://www.subarutelescope.org/Pressrelease/2018/02/26/index.html


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  • (Score: 3, Informative) by Gaaark on Thursday March 15 2018, @06:40PM (8 children)

    by Gaaark (41) on Thursday March 15 2018, @06:40PM (#653040) Journal

    "we now know that nearly 80 % of the matter is an invisible substance called dark matter. "

    We know no such thing!

    We know magic is just hand waving, but we do not KNOW dark matter exists... It is speculation at best.

    --
    --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
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  • (Score: 2) by PinkyGigglebrain on Thursday March 15 2018, @07:09PM (7 children)

    by PinkyGigglebrain (4458) on Thursday March 15 2018, @07:09PM (#653054)

    How about they just simplify the whole thing?

    There is a force pushing galaxies apart.

    There is something keeping the stars in galaxies from flying away hither and yon.

    Maybe the force that is pushing galaxies apart is also pushing the stars at the edges of a galaxy towards it's center.

    So now instead of trying to figure out two mysteries the boffins only need to sort out one mystery.

    So, when does the Nobel committee call to inform you of your prize? I want to be sure I'm near my phone.

    --
    "Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
    • (Score: 0) by Anonymous Coward on Thursday March 15 2018, @08:00PM (2 children)

      by Anonymous Coward on Thursday March 15 2018, @08:00PM (#653082)

      So... you're saying galaxies are simply eddies in the space-time continuum?

      • (Score: 2) by NewNic on Thursday March 15 2018, @08:18PM (1 child)

        by NewNic (6420) on Thursday March 15 2018, @08:18PM (#653093) Journal

        It's probably all a simulation, so who cares?

        --
        lib·er·tar·i·an·ism ˌlibərˈterēənizəm/ noun: Magical thinking that useful idiots mistake for serious political theory
    • (Score: 2) by Gaaark on Thursday March 15 2018, @08:27PM (3 children)

      by Gaaark (41) on Thursday March 15 2018, @08:27PM (#653094) Journal

      So you also believe they don't KNOW dark matter exists!

      Then why does he say it like it's fact? Because that is the state of physics today.

      Wave your hand and: SCIENTIFIC FACT!

      I dunno about you, but I deserve better than MAGIC in my science.

      --
      --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
      • (Score: 2) by dry on Friday March 16 2018, @04:35AM (2 children)

        by dry (223) on Friday March 16 2018, @04:35AM (#653366) Journal

        Got a better theory that explains all these observations of something with gravity such as the lensing that this article is talking about having been observed?