Spacetime - Revision history

Aschlafly at 22:11, August 21, 2024

2024-08-21T22:11:24Z

Aschlafly: add quotation

2024-08-21T22:10:56Z

add quotation

DavidB4: -move requests

2017-04-08T00:25:39Z

-move requests

DavidB4: DavidB4 moved page Curvature of spacetime to Spacetime: moving as requested

2017-04-08T00:25:14Z

DavidB4 moved page Curvature of spacetime to Spacetime: moving as requested

SamHB: Bring over stuff from other article. Just delete current contents of "spacetime" article.

2017-04-07T15:50:19Z

Bring over stuff from other article. Just delete current contents of "spacetime" article.

SamHB: Long past time to move this. The old name comes from its origins as a JimJast "article".

2017-04-07T15:40:38Z

Long past time to move this. The old name comes from its origins as a JimJast "article".

FredericBernard: Corrected category

2017-04-07T14:00:32Z

Corrected category

FredericBernard: Changed category to relativity

2017-04-07T13:59:55Z

Changed category to relativity

DavidB4-bot: clean up & uniformity

2016-07-13T07:13:35Z

clean up & uniformity

SamHB: Don't be captious. Vector spaces embody concepts. That doesn't make them tangible objects. Everyone understands the terminology.

2015-12-29T19:11:31Z

Don't be captious. Vector spaces embody concepts. That doesn't make them tangible objects. Everyone understands the terminology.

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 '''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin.  The more sophisticated term "manifold" is correct.</ref> that simultaneously embodies the concepts of time and 3-dimensional space.  Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition.  But that doesn't matter&mdash;"separate existence" or not, physicists working in the field understand spacetime as a useful concept.
 {{cquote|Space tells matter how to move; matter tells space how to curve - John Archibald Wheeler, in Misner, Thorne and Wheeler ''Gravitation'' (1973) p.5, and ''Geons, Black Holes, and Quantum Foam'' (2000), p. 235.<ref>https://en.wikiquote.org/wiki/John_Archibald_Wheeler</ref>}}
 Under Newtonian/Galilean physics or Newtonian/Galilean relativity at the high-school and general undergraduate level, one typically thinks of time, and the 3 dimensions of space, completely separately.  One can solve many problems of physics with this formulation.

← Older revision		Revision as of 22:10, August 21, 2024
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	'''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin. The more sophisticated term "manifold" is correct.</ref> that simultaneously embodies the concepts of time and 3-dimensional space. Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition. But that doesn't matter—"separate existence" or not, physicists working in the field understand spacetime as a useful concept.		'''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin. The more sophisticated term "manifold" is correct.</ref> that simultaneously embodies the concepts of time and 3-dimensional space. Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition. But that doesn't matter—"separate existence" or not, physicists working in the field understand spacetime as a useful concept.
		+
		+	{{cquote\|Space tells matter how to move; matter tells space how to curve - John Archibald Wheeler, in Misner, Thorne and Wheeler ''Gravitation''(1973) p.5, and ''Geons, Black Holes, and Quantum Foam'' (2000), p. 235.<ref>https://en.wikiquote.org/wiki/John_Archibald_Wheeler</ref>}}

	Under Newtonian/Galilean physics or Newtonian/Galilean relativity at the high-school and general undergraduate level, one typically thinks of time, and the 3 dimensions of space, completely separately. One can solve many problems of physics with this formulation.		Under Newtonian/Galilean physics or Newtonian/Galilean relativity at the high-school and general undergraduate level, one typically thinks of time, and the 3 dimensions of space, completely separately. One can solve many problems of physics with this formulation.

← Older revision		Revision as of 00:25, April 8, 2017
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−	~~{{Move\|Spacetime}}~~
−
	'''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin. The more sophisticated term "manifold" is correct.</ref> that simultaneously embodies the concepts of time and 3-dimensional space. Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition. But that doesn't matter—"separate existence" or not, physicists working in the field understand spacetime as a useful concept.		'''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin. The more sophisticated term "manifold" is correct.</ref> that simultaneously embodies the concepts of time and 3-dimensional space. Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition. But that doesn't matter—"separate existence" or not, physicists working in the field understand spacetime as a useful concept.

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 The '''curvature of spacetime''' refers to this.  It gives rise to the "fictitious forces" that are perceived as gravity under [[General theory of relativity|General Relativity]].  The Einstein Field Equations explain how that curvature arises from the presence of massive objects like the Earth or the Sun.  Analyzing the resultant gravitational fictitious force arising from massive objects obtains the same result as Newton's law of gravity for non-relativistic objects.
 == References ==
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 [[Category:Cosmology]]
 [[Category:Relativity]]

← Older revision		Revision as of 15:40, April 7, 2017
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		+	{{Move\|Spacetime}}
		+
	'''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin. The more sophisticated term "manifold" is correct.</ref> that simultaneously embodies the concepts of time and 3-dimensional space. Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition. But that doesn't matter—"separate existence" or not, physicists working in the field understand spacetime as a useful concept.		'''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin. The more sophisticated term "manifold" is correct.</ref> that simultaneously embodies the concepts of time and 3-dimensional space. Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition. But that doesn't matter—"separate existence" or not, physicists working in the field understand spacetime as a useful concept.

← Older revision	Revision as of 00:25, April 8, 2017
(No difference)

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 [[Category:Astronomy]]
 [[Category:Cosmology]]
-[[Category:Relativty]]
+[[Category:Relativity]]

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 This "transforming away" is similar to the difference between Cartesian and polar coordinates on a flat sheet of paper.  The Cartesian coordinate system is flat, and the polar system is curved.  But they are both coordinate systems on a flat sheet of paper.  However, there are surfaces ("curved surfaces"), like a sphere, that have no flat coordinate system at all.<ref>The bane of mapmakers.</ref>  In spacetime, this is equivalent to something that has no flat coordinate systems, and hence gives rise to fictitious forces that can't be transformed away.  Gravity is an example of this, a fictitious force that, unlike the centrifugal or Coriolis force, can't be transformed away.  That is, there is no place where one can stand and see gravity as just a case of people being pushed on by a floor that is accelerating upward.
-The '''curvature of spacetime''' refers to this.  It gives rise to the "fictitious forces" that are perceived as gravity under [[General_theory_of_relativity|General Relativity]].  The Einstein Field Equations explain how that curvature arises from the presence of massive objects like the Earth or the Sun.  Analyzing the resultant gravitational fictitious force arising from massive objects obtains the same result as Newton's law of gravity for non-relativistic objects.
+The '''curvature of spacetime''' refers to this.  It gives rise to the "fictitious forces" that are perceived as gravity under [[General theory of relativity|General Relativity]].  The Einstein Field Equations explain how that curvature arises from the presence of massive objects like the Earth or the Sun.  Analyzing the resultant gravitational fictitious force arising from massive objects obtains the same result as Newton's law of gravity for non-relativistic objects.
 == References ==
 <references />
-[[Category: Astronomy]]
+[[Category:Astronomy]]
-[[Category: Cosmology]]
+[[Category:Cosmology]]
-[[Category: Physics]]
+[[Category:Physics]]

← Older revision		Revision as of 19:11, December 29, 2015
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−	'''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin. The more sophisticated term "manifold" is correct.</ref> that~~, by hypothesis,~~ simultaneously embodies the concepts of time and 3-dimensional space. Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition. But that doesn't matter—"separate existence" or not, physicists working in the field understand spacetime as a useful concept.	+	'''Spacetime''' is the 4-dimensional [[vector space]] or [[manifold]]<ref>Often treated as a vector space when working examples, but that isn't really correct because it has no origin. The more sophisticated term "manifold" is correct.</ref> that simultaneously embodies the concepts of time and 3-dimensional space. Whether one can ascribe a separate existence to spacetime itself, depends on one's physical intuition. But that doesn't matter—"separate existence" or not, physicists working in the field understand spacetime as a useful concept.

	Under Newtonian/Galilean physics or Newtonian/Galilean relativity at the high-school and general undergraduate level, one typically thinks of time, and the 3 dimensions of space, completely separately. One can solve many problems of physics with this formulation.		Under Newtonian/Galilean physics or Newtonian/Galilean relativity at the high-school and general undergraduate level, one typically thinks of time, and the 3 dimensions of space, completely separately. One can solve many problems of physics with this formulation.