Like ordinary matter, dark matter interacts gravitationally with ordinary matter and radiation. Astronomers study the distribution of dark matter through observing its gravitational effects on ordinary matter in its vicinity and through its gravitational lensing effects on background radiation. The background image shows the bullet cluster, a famous example where the visible matter does not follow the mass distribution.
Combining all the available evidence, dark matter represents about 83% of the matter content of the universe. Read more about dark matter on this web page. Let us know your questions and comments on the message board.


I have come from Mondas to take over the World Liverpool are the greatest football team in the world when not seeking universal domination I am at...
Server upgrade planned for Dec 19
Hi everyone, we're upgrading the server to a new machine on Dec 19. Expect intermittent outages which could last as long as 24 hours. No action is needed from users during the upgrade. More workunits will be on the way shortly thereafter. Thanks!
19 Dec 2018, 5:56:03 UTC
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Preparation for a server upgrade
Dear users,
Over the next couple of weeks, we will be moving the Cosmology@Home server to a newer machine. No action is needed from you, and we hope to do so with minimal down time. This will solve lots of the work generation and validation problems the site has had over the last several months. It will also set us up to debut some new science applications which we have been working on and thinking about.
For now, we are letting the work queue get emptied out. Once that is done (it already is for camb_legacy), we will move forward and keep you updated.
Thanks for your continued support!
15 Nov 2018, 1:28:40 UTC
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Recent outage explanation
Hi all,
Over the last week we suffered a database corruption due to some disk errors. I've spent the last several days recovering the database from backups and from the corrupted files. Unfortunately, records of workunits from the last several weeks were lost, which means you will not receive credit for any of these jobs. I greatly apologize for this, and we've taken steps to make sure this doesn't happen again. The good news is that this was the only thing which could not be recovered, everything else is fine.
We're continuing to monitor things as the server comes back online, please report any problems you may find here.
Marius
11 Sep 2018, 13:40:40 UTC
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All tasks functioning normally
The problem affecting the camb_legacy tasks has been resolved. The server also recently received some under-the-hood upgrades which should improve performance and security.
10 Aug 2018, 2:47:15 UTC
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camb_legacy tasks temporarily suspended
Hi everyone, there's something wrong with the camb_legacy tasks, possibly related to a recent upgrade. I've temporarily disabled them (no validation, no new workunits created) until I can figure out the problem. The camb_boinc2docker application is still working normally.
25 Jun 2018, 15:53:23 UTC
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