Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

Tweak Gravity: What If There Is No Dark Matter?
Scientific American ^ | Thursday, November 5, 2009 | John Matson

Posted on 11/08/2009 6:07:35 PM PST by SunkenCiv

What if the discrepancy arises from a flaw in our theory of gravity rather than from some provider of mass that we cannot see? In the 1980s physicist Mordehai Milgrom of the Weizmann Institute of Science in Rehovot, Israel, proposed a modification to Newtonian dynamics that would explain many of the observational discrepancies without requiring significant mass to be hidden away in dark matter. But it fell short of describing all celestial objects, and to incorporate the full span of gravitational interactions, a modification to Albert Einstein's theory of general relativity is needed. A review article in the November 6 Science checks in on the status of these modified-gravity theories, including a proposal put forth by physicist Jacob Bekenstein of The Hebrew University of Jerusalem in 2004. Pedro Ferreira, a University of Oxford cosmologist and one of the review paper's co-authors, says that there is good news and bad news for proponents of such models.

(Excerpt) Read more at scientificamerican.com ...


TOPICS: Astronomy; Science
KEYWORDS: darkenergy; darkforce; darkmatter; stringtheory
Navigation: use the links below to view more comments.
first previous 1-2021-31 last
To: republicangel; BenKenobi; ColdSteelTalon; Kevmo; SunkenCiv

While looking around for this article instead of simply the abstract, I ran across a very good article by one of the major researchers in this field, Dr. Jacob Bekenstein. Written in 2006, it is an overview of where Modified theories Of Newtonian Dynamics /gravity (MOND) were at that time. Someone with less than 3 years of advanced mathematics will get completely lost in that part of the discussion (I get baffled with my 5+yrs), but there is sufficient material other than the hard math that many here might find it tantalizing:

http://xxx.tau.ac.il/pdf/astro-ph/0701848

Have fun. (R-Angel: I would definitely give this link to any physics student, even if a freshman, or a wannabe physicist)


21 posted on 11/09/2009 8:17:11 AM PST by AFPhys ((Praying for our troops, our citizens, that the Bible and Freedom become basis of the US law again))
[ Post Reply | Private Reply | To 7 | View Replies]

To: Diana in Wisconsin

Worth a try. :’)


22 posted on 11/09/2009 5:06:20 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 5 | View Replies]

To: republicangel

:’) My pleasure.


23 posted on 11/09/2009 5:06:43 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 7 | View Replies]

To: rdl6989

/bingo


24 posted on 11/09/2009 5:06:56 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 9 | View Replies]

To: DannyTN

No, it’s your brother. /rimshot!


25 posted on 11/09/2009 5:09:07 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 15 | View Replies]

To: ColdSteelTalon

The speed of dark must be at least one mile per second faster than the speed of light, because ya never see dark leaving the room when you turn on the lights.


26 posted on 11/09/2009 5:09:49 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 16 | View Replies]

To: Kevmo; tlb

Thanks Kevmo and tlb.


27 posted on 11/09/2009 5:10:09 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 18 | View Replies]

To: AFPhys

Thanks AFP!


28 posted on 11/09/2009 5:10:39 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 21 | View Replies]

To: onedoug

:’)


29 posted on 11/09/2009 5:10:49 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 20 | View Replies]

To: JoeProBono

Gotta be from the Borg cube set on ST:TNG... ;’)


30 posted on 11/09/2009 5:19:19 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
[ Post Reply | Private Reply | To 8 | View Replies]

To: SunkenCiv

I need to test that.. Let me turn on and off the lights... Where is my stopwatch????


31 posted on 11/09/2009 5:25:54 PM PST by ColdSteelTalon (Light is fading to shadow, and casting its shroud over all we have known...)
[ Post Reply | Private Reply | To 26 | View Replies]


Navigation: use the links below to view more comments.
first previous 1-2021-31 last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson