Menu
News
All News
Dungeons & Dragons
Level Up: Advanced 5th Edition
Pathfinder
Starfinder
Warhammer
2d20 System
Year Zero Engine
Industry News
Reviews
Dragon Reflections
Columns
Weekly Digests
Weekly News Digest
Freebies, Sales & Bundles
RPG Print News
RPG Crowdfunding News
Game Content
ENterplanetary DimENsions
Mythological Figures
Opinion
Worlds of Design
Peregrine's Next
RPG Evolution
Other Columns
From the Freelancing Frontline
Monster ENcyclopedia
WotC/TSR Alumni Look Back
4 Hours w/RSD (Ryan Dancey)
The Road to 3E (Jonathan Tweet)
Greenwood's Realms (Ed Greenwood)
Drawmij's TSR (Jim Ward)
Community
Forums & Topics
Forum List
Latest Posts
Forum list
*Dungeons & Dragons
Level Up: Advanced 5th Edition
D&D Older Editions
*TTRPGs General
*Pathfinder & Starfinder
EN Publishing
*Geek Talk & Media
Search forums
Chat/Discord
Resources
Wiki
Pages
Latest activity
Media
New media
New comments
Search media
Downloads
Latest reviews
Search resources
EN Publishing
Store
EN5ider
Adventures in ZEITGEIST
Awfully Cheerful Engine
What's OLD is NEW
Judge Dredd & The Worlds Of 2000AD
War of the Burning Sky
Level Up: Advanced 5E
Events & Releases
Upcoming Events
Private Events
Featured Events
Socials!
Twitch
YouTube
Facebook (EN Publishing)
Facebook (EN World)
Twitter
Instagram
TikTok
Podcast
Features
Top 5 RPGs Compiled Charts 2004-Present
Adventure Game Industry Market Research Summary (RPGs) V1.0
Ryan Dancey: Acquiring TSR
Q&A With Gary Gygax
D&D Rules FAQs
TSR, WotC, & Paizo: A Comparative History
D&D Pronunciation Guide
Million Dollar TTRPG Kickstarters
Tabletop RPG Podcast Hall of Fame
Eric Noah's Unofficial D&D 3rd Edition News
D&D in the Mainstream
D&D & RPG History
About Morrus
Log in
Register
What's new
Search
Search
Search titles only
By:
Forums & Topics
Forum List
Latest Posts
Forum list
*Dungeons & Dragons
Level Up: Advanced 5th Edition
D&D Older Editions
*TTRPGs General
*Pathfinder & Starfinder
EN Publishing
*Geek Talk & Media
Search forums
Chat/Discord
Menu
Log in
Register
Install the app
Install
Community
General Tabletop Discussion
*Geek Talk & Media
Expanding Universe
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="tomBitonti" data-source="post: 6132881" data-attributes="member: 13107"><p>The maths get complicated rather quickly, and I'm hardly following them, but the contribution that the cosmological constant makes to Einstein's equation of general relativity seems to enter into the equation in a different place than the mass energy tensor. That affects the metric (using, say, the Robertson-Walker line element), and has an effect which is similar to that produced by the mast energy tensor, but still seems to be a different contribution.</p><p></p><p>I guess we need to clarify what we mean by "gravity" as opposed to the metric.</p><p></p><p>But, if the metric equation applies everywhere, won't that produce an effect even at small scales (since the equation applies everywhere). Though, since the effect is so very small at those small scales, does that mean that there is no effect (truncate to zero), or does the effect occur probabilistically, with there being a chance of the effect occurring as planck scale event just about everywhere, with an average contribution which adds up to match the overall effect implied by the metric equation?</p><p></p><p>Hopefully I've not butchered that too terribly.</p><p></p><p>Thx!</p><p></p><p>TomB</p><p></p><p>Edit: To make a crude analogy, would this be like putting a rubber band on a rubber surface, then stretching the rubber surface? The band will be pulled slightly as the surface stretches beneath it, with the pull being detectable as an extra force and perhaps a slight stretch of the band, but, since the band quickly reaches a steady state and does not move any further, no energy is added. This presumes some slight friction between the rubber band and the surface, and not that the band is glued to the surface.</p><p></p><p>Making this more concrete: A neutron orbiting a neutron star at a distance, with the orbit of the neutron slightly larger than it should be assuming just a contribution to the metric from the mass of the neutron star. This would appear as a slight change to the solution to the geodesic equation for the neutron, because the metric is not exactly that given by the star.</p></blockquote><p></p>
[QUOTE="tomBitonti, post: 6132881, member: 13107"] The maths get complicated rather quickly, and I'm hardly following them, but the contribution that the cosmological constant makes to Einstein's equation of general relativity seems to enter into the equation in a different place than the mass energy tensor. That affects the metric (using, say, the Robertson-Walker line element), and has an effect which is similar to that produced by the mast energy tensor, but still seems to be a different contribution. I guess we need to clarify what we mean by "gravity" as opposed to the metric. But, if the metric equation applies everywhere, won't that produce an effect even at small scales (since the equation applies everywhere). Though, since the effect is so very small at those small scales, does that mean that there is no effect (truncate to zero), or does the effect occur probabilistically, with there being a chance of the effect occurring as planck scale event just about everywhere, with an average contribution which adds up to match the overall effect implied by the metric equation? Hopefully I've not butchered that too terribly. Thx! TomB Edit: To make a crude analogy, would this be like putting a rubber band on a rubber surface, then stretching the rubber surface? The band will be pulled slightly as the surface stretches beneath it, with the pull being detectable as an extra force and perhaps a slight stretch of the band, but, since the band quickly reaches a steady state and does not move any further, no energy is added. This presumes some slight friction between the rubber band and the surface, and not that the band is glued to the surface. Making this more concrete: A neutron orbiting a neutron star at a distance, with the orbit of the neutron slightly larger than it should be assuming just a contribution to the metric from the mass of the neutron star. This would appear as a slight change to the solution to the geodesic equation for the neutron, because the metric is not exactly that given by the star. [/QUOTE]
Insert quotes…
Verification
Post reply
Community
General Tabletop Discussion
*Geek Talk & Media
Expanding Universe
Top