IPB

Welcome Guest ( Log In | Register )

HST and 'dark matter'
Guest_PhilCo126_*
post May 11 2007, 05:13 PM
Post #1





Guests






ASA Updates Plans for Hubble 'Ring Of Dark Matter' Briefing

GREENBELT, Md. - NASA will hold a media teleconference at 1 p.m. EDT on May 15 to discuss the strongest evidence to date that dark matter exists. This evidence was found in a ghostly ring of dark matter in the cluster CL0024+17, discovered using NASA's Hubble Space Telescope. The ring is the first detection of dark matter with a unique structure different from the distribution of both the galaxies and the hot gas in the cluster. The discovery will be featured in the June 20 issue of the Astrophysical Journal.
Go to the top of the page
 
+Quote Post
 
Start new topic
Replies
Mongo
post Apr 25 2012, 09:26 PM
Post #2


Member
***

Group: Members
Posts: 631
Joined: 13-June 04
Member No.: 82



Beating an increasingly dead horse here:

Vast Structure of Satellite Galaxies Discovered: Do the Milky Way’s Companions Spell Trouble for Dark Matter?

QUOTE
Astronomers from the University of Bonn in Germany have discovered a vast structure of satellite galaxies and clusters of stars surrounding our Galaxy, stretching out across a million light years. The work challenges the existence of dark matter, part of the standard model for the evolution of the universe.


QUOTE
In their effort to understand exactly what surrounds our Galaxy, the scientists used a range of sources from twentieth century photographic plates to images from the robotic telescope of the Sloan Deep Sky Survey. Using all these data they assembled a picture that includes bright 'classical' satellite galaxies, more recently detected fainter satellites and the younger globular clusters.

"Once we had completed our analysis, a new picture of our cosmic neighbourhood emerged," says Pawlowski. The astronomers found that all the different objects are distributed in a plane at right angles to the galactic disk. The newly-discovered structure is huge, extending from as close as 33,000 light years to as far away as one million light years from the centre of the Galaxy.


QUOTE
The various dark matter models struggle to explain this arrangement. "In the standard theories, the satellite galaxies would have formed as individual objects before being captured by the Milky Way," explains Kroupa. "As they would have come from many directions, it is next to impossible for them to end up distributed in such a thin plane structure."


QUOTE
Kroupa concludes by highlighting the wider significance of the new work. "Our model appears to rule out the presence of dark matter in the universe, threatening a central pillar of current cosmological theory. We see this as the beginning of a paradigm shift, one that will ultimately lead us to a new understanding of the universe we inhabit."


Link to original article: The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way

QUOTE
These findings demonstrate that a near-isotropic infall of cosmological sub-structure components onto the MW is essentially ruled out because a large number of infalling objects would have had to be highly correlated, to a degree not natural for dark matter sub-structures. The majority of satellites, streams and YH GCs had to be formed as a correlated population. This is possible in tidal tails consisting of material expelled from interacting galaxies. We discuss the tidal scenario for the formation of the VPOS, including successes and possible challenges. The potential consequences of the MW satellites being tidal dwarf galaxies are severe. If all the satellite galaxies and YH GCs have been formed in an encounter between the young MW and another gas-rich galaxy about 10-11 Gyr ago, then the MW does not have any luminous dark-matter substructures and the missing satellites problem becomes a catastrophic failure of the standard cosmological model.
Go to the top of the page
 
+Quote Post

Posts in this topic
- PhilCo126   HST and 'dark matter'   May 11 2007, 05:13 PM
- - Littlebit   A dark matter ring? How/why would DM be corraled i...   May 11 2007, 05:35 PM
- - Mongo   Colour me sceptical on this one -- which should be...   May 11 2007, 11:04 PM
- - Tman   From the Hubble site http://hubblesite.org/newscen...   May 17 2007, 07:53 AM
- - Mongo   The wedding ring of MOND and non-exotic dark matte...   Jun 12 2007, 01:41 AM
- - nprev   I'm with you, man. Dark matter has always been...   Jun 12 2007, 03:46 AM
|- - dvandorn   QUOTE (nprev @ Jun 11 2007, 10:46 PM) ......   Jun 12 2007, 04:22 AM
- - Mongo   Using globular clusters to test gravity in the wea...   Jul 18 2007, 01:11 PM
- - nprev   MOND + neutrino mass is looking more and more plau...   Jul 18 2007, 02:40 PM
- - Mongo   Sorry to resurrect this long-dead thread, but a pa...   Mar 11 2010, 03:36 AM
- - Explorer1   So in layman's terms, this is a potential ...   Mar 11 2010, 04:46 AM
|- - Greg Hullender   QUOTE (Explorer1 @ Mar 10 2010, 08:46 PM)...   Mar 11 2010, 05:00 AM
- - Mongo   Just to give a taste of how (some) physicists are ...   Mar 11 2010, 05:42 AM
- - Mongo   Part 2 of 2 Modified gravity emerging from thermo...   Mar 11 2010, 05:46 AM
- - nprev   There's definitely a deterministic flavor to t...   Mar 11 2010, 05:47 AM
- - stevesliva   I find it interesting that physicists have been co...   Mar 11 2010, 05:08 PM
- - Mongo   From Inertia Theory -- Paul Davies: QUOTE Fill a ...   Mar 11 2010, 05:37 PM
- - djellison   Is it just me, or is this a catastrophically screw...   Mar 11 2010, 05:47 PM
|- - Mongo   That was my first thought too, but how does the wa...   Mar 11 2010, 06:04 PM
|- - stevesliva   QUOTE (Mongo @ Mar 11 2010, 01:04 PM) Ine...   Mar 11 2010, 07:13 PM
- - djellison   So it'snot a question about a bucket at all, i...   Mar 11 2010, 06:25 PM
|- - centsworth_II   QUOTE (djellison @ Mar 11 2010, 01:25 PM)...   Mar 11 2010, 06:46 PM
|- - Greg Hullender   QUOTE (djellison @ Mar 11 2010, 10:25 AM)...   Mar 11 2010, 10:25 PM
|- - Marz   QUOTE (Greg Hullender @ Mar 11 2010, 04:2...   Mar 11 2010, 10:56 PM
|- - Mongo   QUOTE (Marz @ Mar 11 2010, 11:56 PM) Mean...   Mar 12 2010, 12:27 AM
|- - AndyG   QUOTE (Marz @ Mar 11 2010, 10:56 PM) lol ...   Mar 12 2010, 11:05 AM
- - Shaka   If Earth were in an otherwise empty Universe, why ...   Mar 11 2010, 06:47 PM
- - Mongo   The following is just my own understanding of what...   Mar 11 2010, 07:30 PM
- - monty python   I'm really loving this thread, but for some re...   Mar 12 2010, 06:58 AM
- - SteveM   I've noticed that none of the arXiv papers are...   Apr 4 2010, 02:13 PM
- - Floyd   Mongo "As the example stated, if the Earth we...   Apr 4 2010, 03:38 PM
- - Greg Hullender   That begs the question, Floyd. --Greg   Apr 4 2010, 04:23 PM
- - stevesliva   The NY Times covers Verlinde, and does the newspap...   Jul 13 2010, 12:46 AM
|- - AndyG   QUOTE (stevesliva @ Jul 13 2010, 01:46 AM...   Jul 13 2010, 12:08 PM
- - nprev   No, it's not. But I liked the cartoon.   Jul 13 2010, 01:54 AM
- - Hungry4info   If I'm not mistaken, "order", in ref...   Jul 13 2010, 01:41 PM
|- - Juramike   Entropy would be maximum for an evenly diffused bu...   Jul 13 2010, 01:55 PM
- - Greg Hullender   Mike: if any of the separated atoms/particles can ...   Jul 13 2010, 02:17 PM
|- - Juramike   Full inline quote removed - Mike, you should know ...   Jul 13 2010, 03:05 PM
- - Greg Hullender   Which means the maximum entropy ought to be when a...   Jul 13 2010, 08:04 PM
- - stevesliva   Experiments would seem to indicate gravity is not ...   Aug 24 2011, 10:57 PM
- - nprev   Actually, seems that interpretation of the theorie...   Aug 25 2011, 12:18 AM
- - Mongo   This paper just came out on arXiv, in response to ...   Sep 14 2011, 12:56 AM
- - Mongo   No surprise at all to me. Maybe now the Dark Matt...   Apr 19 2012, 10:37 PM
- - Mongo   Dark Matter gone missing in many places: a crisis ...   Apr 20 2012, 03:51 PM
- - Mongo   Beating an increasingly dead horse here: Vast Str...   Apr 25 2012, 09:26 PM
- - stevesliva   Does make you wonder if "dark matter" wi...   Apr 26 2012, 02:33 AM


Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 1st August 2014 - 09:49 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.