Editing Motion (section)

== Orders of magnitude ==
Humans, like all known things in the universe, are in constant motion;<ref name=Tyson />{{rp|8–9}} however, aside from obvious movements of the various external [[anatomy|body]] parts and [[animal locomotion|locomotion]], humans are in motion in a variety of ways that are more difficult to [[Motion perception|perceive]]. Many of these "imperceptible motions" are only perceivable with the help of special tools and careful observation. The larger scales of imperceptible motions are difficult for humans to perceive for two reasons: [[Newton's laws of motion]] (particularly the third), which prevents the feeling of motion on a mass to which the observer is connected, and the lack of an obvious [[frame of reference]] that would allow individuals to easily see that they are moving.<ref>{{cite web|last=Safkan|first=Yasar|title=Question: If the term 'absolute motion' has no meaning, then why do we say that the earth moves around the sun and not vice versa?|url=http://www.physlink.com/education/askexperts/ae118.cfm|work=Ask the Experts|publisher=PhysLink.com|access-date=25 January 2014|archive-date=3 November 2013|archive-url=https://web.archive.org/web/20131103182340/http://physlink.com/Education/AskExperts/ae118.cfm|url-status=live}}</ref> The smaller scales of these motions are too small to be detected conventionally with human [[sense]]s.

=== Universe ===
[[Spacetime]] (the fabric of the universe) is [[Metric expansion of space|expanding]], meaning everything in the [[universe]] is stretching, like a [[rubber band]]. This motion is the most obscure, not involving physical movement but a fundamental change in the universe's nature. The primary source of verification of this expansion was provided by [[Edwin Hubble]] who demonstrated that all galaxies and distant astronomical objects were moving away from Earth, known as [[Hubble's law]], predicted by a universal expansion.<ref>{{cite journal |last=Hubble |first=Edwin |date=1929-03-15 |title=A relation between distance and radial velocity among extra-galactic nebulae |journal=Proceedings of the National Academy of Sciences |volume=15 |issue=3 |pages=168–173 |doi=10.1073/pnas.15.3.168|pmid=16577160 |pmc=522427 |bibcode=1929PNAS...15..168H |doi-access=free }}</ref>

=== Galaxy ===
The [[Milky Way Galaxy]] is moving through [[space]] and many astronomers believe the velocity of this motion to be approximately {{convert|600|km/s|mph|sigfig=3}} relative to the observed locations of other nearby galaxies. Another reference frame is provided by the [[Cosmic microwave background]]. This frame of reference indicates that the Milky Way is moving at around {{convert|582|km/s|mph|sigfig=3}}.<ref name="dipole">
{{cite journal
 |author1=Kogut, A. |author2=Lineweaver, C. |author3=Smoot, G.F. |author4=Bennett, C.L. |author5=Banday, A. |author6=Boggess, N.W. |author-link6=Nancy Boggess|author7=Cheng, E.S. |author8=de Amici, G. |author9=Fixsen, D.J. |author10=Hinshaw, G. |author11=Jackson, P.D. |author12=Janssen, M. |author13=Keegstra, P. |author14=Loewenstein, K. |author15=Lubin, P. |author16=Mather, J.C. |author17=Tenorio, L. |author18=Weiss, R. |author19=Wilkinson, D.T. |author20=Wright, E.L.
 | title=Dipole Anisotropy in the COBE Differential Microwave Radiometers First-Year Sky Maps
 | journal=Astrophysical Journal
 | year=1993
 | volume=419
 | page=1
 | bibcode=1993ApJ...419....1K  | doi = 10.1086/173453
 |arxiv = astro-ph/9312056 |s2cid=209835274 }}</ref>{{Failed verification|date=August 2016
}}

=== Sun and Solar System ===
{{See also|Planetary motion}}
The Milky Way is [[rotation|rotating]] around its [[density|dense]] [[Galactic Center]], thus the [[Sun]] is moving in a circle within the [[galaxy]]'s [[gravity]]. Away from the central bulge, or outer rim, the typical stellar [[velocity]] is between {{convert|210|and|240|km/s|mph}}.<ref name="fn4">
{{cite web
 | last=Imamura
 | first=Jim
 | date=August 10, 2006
 | url=http://zebu.uoregon.edu/~imamura/123/lecture-2/mass.html
 | title=Mass of the Milky Way Galaxy
 | publisher=[[University of Oregon]]
 | access-date=2007-05-10 |archive-url = https://web.archive.org/web/20070301055338/http://zebu.uoregon.edu/~imamura/123/lecture-2/mass.html <!-- Bot retrieved archive --> |archive-date = 2007-03-01
}}</ref> All planets and their moons move with the Sun. Thus, the [[Solar System]] is in motion.

=== Earth ===
The Earth is [[rotation|rotating]] or spinning around its [[Axis of rotation|axis]]. This is evidenced by [[day]] and [[night]], at the equator the earth has an eastward velocity of {{convert|0.4651|km/s|mph}}.<ref name="nasa goodard">[http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970401c.html Ask an Astrophysicist] {{Webarchive|url=https://web.archive.org/web/20090311000016/http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970401c.html |date=2009-03-11 }}. NASA Goodard Space Flight Center.</ref> The Earth is also [[orbit]]ing around the [[Sun]] in an [[orbital revolution]]. A complete orbit around the Sun takes one [[year]], or about 365&nbsp;days; it averages a speed of about {{convert|30|km/s|mph}}.<ref name="earth_fact_sheet">{{cite web | last = Williams | first = David R. | date = September 1, 2004 | url = http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html | title = Earth Fact Sheet | publisher = [[NASA]] | access-date = 2007-03-17 | archive-date = 2013-05-08 | archive-url = https://web.archive.org/web/20130508021904/http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html | url-status = live }}</ref>

=== Continents ===
The Theory of [[Plate tectonic]]s tells us that the [[continent]]s are drifting on [[convection current]]s within the [[Mantle (geology)|mantle]], causing them to move across the surface of the [[planet]] at the slow speed of approximately {{convert|2.54|cm|in|sigfig=1}} per year.<ref>
{{cite web
 | author =Staff
 | url =http://sideshow.jpl.nasa.gov/mbh/series.html
 | title =GPS Time Series
 | publisher =[[NASA JPL]]
 | access-date =2007-04-02
 | archive-date =2011-07-21
 | archive-url =https://web.archive.org/web/20110721050552/http://sideshow.jpl.nasa.gov/mbh/series.html
 | url-status =live
}}</ref><ref>
{{cite web
 | last =Huang
 | first =Zhen Shao
 | year =2001
 | url =http://hypertextbook.com/facts/1997/ZhenHuang.shtml
 | title =Speed of the Continental Plates
 | work =The Physics Factbook
 | editor-first =Glenn
 | editor-last =Elert
 | access-date =2020-06-20
 | archive-date =2020-06-19
 | archive-url =https://web.archive.org/web/20200619200724/https://hypertextbook.com/facts/1997/ZhenHuang.shtml
 | url-status =live
}}</ref> However, the velocities of plates range widely. The fastest-moving plates are the oceanic plates, with the [[Cocos Plate]] advancing at a rate of {{convert|75|mm|in}} per year<ref>
{{cite web
 | author1 = Meschede, M.
 | author2 = Udo Barckhausen, U.
 | date = November 20, 2000
 | url = http://www-odp.tamu.edu/publications/170_SR/chap_07/chap_07.htm
 | title = Plate Tectonic Evolution of the Cocos-Nazca Spreading Center
 | work = Proceedings of the Ocean Drilling Program
 | publisher = [[Texas A&M University]]
 | access-date = 2007-04-02
 | archive-date = 2011-08-08
 | archive-url = https://web.archive.org/web/20110808174226/http://www-odp.tamu.edu/publications/170_SR/chap_07/chap_07.htm
 | url-status = live
}}</ref> and the [[Pacific Plate]] moving {{convert|52|-|69|mm|in}} per year. At the other extreme, the slowest-moving plate is the [[Eurasian Plate]], progressing at a typical rate of about {{convert|21|mm|in}} per year.

=== Internal body ===
The human [[heart]] is regularly contracting to move [[blood]] throughout the body. Through larger veins and arteries in the body, blood has been found to travel at approximately 0.33&nbsp;m/s. Though considerable variation exists, and peak flows in the [[venae cavae]] have been found between {{convert|0.1|and|0.45|m/s|ft/s}}.<ref>{{cite journal|last=Wexler|first=L.|author2=D H Bergel |author3=I T Gabe |author4=G S Makin |author5=C J Mills |title=Velocity of Blood Flow in Normal Human Venae Cavae|journal=Circulation Research|date=1 September 1968|volume=23|issue=3|pages=349–359|doi=10.1161/01.RES.23.3.349|pmid=5676450|doi-access=free}}</ref> additionally, the [[smooth muscle]]s of hollow internal [[viscera|organs]] are moving. The most familiar would be the occurrence of [[peristalsis]], which is where digested [[food]] is forced throughout the [[digestive tract]]. Though different foods travel through the body at different rates, an average speed through the human [[small intestine]] is {{convert|3.48|km/h|mph}}.<ref>{{cite web|last=Bowen|first=R|title=Gastrointestinal Transit: How Long Does It Take?|url=http://www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/transit.html|work=Pathophysiology of the digestive system|publisher=[[Colorado State University]]|date=27 May 2006|access-date=25 January 2014|archive-date=3 April 2015|archive-url=https://web.archive.org/web/20150403015943/http://www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/transit.html|url-status=live}}</ref> The human [[lymphatic system]] is also constantly causing movements of excess [[fluids]], [[lipids]], and immune system related products around the body. The lymph fluid has been found to move through a lymph capillary of the [[human skin|skin]] at approximately 0.0000097&nbsp;m/s.<ref>
{{cite journal
 | author1=M. Fischer |author2=U.K. Franzeck |author3=I. Herrig |author4=U. Costanzo |author5=S. Wen |author6=M. Schiesser |author7=U. Hoffmann |author8=A. Bollinger
 | title=Flow velocity of single lymphatic capillaries in human skin
 | journal=Am J Physiol Heart Circ Physiol
 | date=1 January 1996
 | volume=270
 | pages=H358–H363
 | pmid=8769772
 | issue=1
 | doi=10.1152/ajpheart.1996.270.1.H358
}}</ref>

=== Cells ===
The [[cell (biology)|cells]] of the [[human body]] have many structures and organelles that move throughout them. [[Cytoplasmic streaming]] is a way in which cells move molecular substances throughout the [[cytoplasm]],<ref>{{cite encyclopedia|url=https://www.britannica.com/eb/article-9028448/cytoplasmic-streaming|title=cytoplasmic streaming – biology|encyclopedia=Encyclopædia Britannica|access-date=2022-06-23|archive-date=2008-06-11|archive-url=https://web.archive.org/web/20080611094209/http://www.britannica.com/eb/article-9028448/cytoplasmic-streaming|url-status=live}}</ref> various [[motor proteins]] work as [[molecular motors]] within a cell and move along the surface of various cellular substrates such as [[microtubules]], and motor proteins are typically powered by the [[hydrolysis]] of [[adenosine triphosphate]] (ATP), and convert chemical energy into mechanical work.<ref>{{cite web|url=http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/kinesin.htm|title=Microtubule Motors|work=rpi.edu|url-status=dead|archive-url=https://web.archive.org/web/20071130175151/http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/kinesin.htm|archive-date=2007-11-30}}</ref> [[Vesicle (biology)|Vesicles]] propelled by motor proteins have been found to have a velocity of approximately 0.00000152&nbsp;m/s.<ref>{{cite journal| bibcode=2002APS..SES.EA002H | title=Velocity and Drag Forces on motor-protein-driven Vesicles in Cells | journal=APS Southeastern Section Meeting Abstracts | volume=69 | pages=EA.002 | last1=Hill | first1=David | last2=Holzwarth | first2=George | last3=Bonin | first3=Keith | year=2002 }}</ref>

=== Particles ===
According to the [[laws of thermodynamics]], all [[Subatomic particle|particles]] of [[matter]] are in constant random motion as long as the [[temperature]] is above [[absolute zero]]. Thus the [[molecule]]s and [[atom]]s that make up the human body are vibrating, colliding, and moving. This motion can be detected as temperature; higher temperatures, which represent greater [[kinetic energy]] in the particles, feel warm to humans who sense the thermal energy transferring from the object being touched to their nerves. Similarly, when lower temperature objects are touched, the senses perceive the transfer of heat away from the body as a feeling of cold.<ref>[http://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/physics/PhysicsInitiative/Physics2000/bec/temperature.html Temperature and BEC.] {{webarchive|url=https://web.archive.org/web/20071110174808/http://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/physics/PhysicsInitiative/Physics2000/bec/temperature.html |date=2007-11-10 }} Physics 2000: Colorado State University Physics Department</ref>

=== Subatomic particles ===
Within the standard [[atomic orbital model]], [[electron]]s exist in a region around the nucleus of each atom. This region is called the [[electron cloud]]. According to [[Bohr model|Bohr's model]] of the atom, electrons have a high [[Electron velocity|velocity]], and the larger the nucleus they are orbiting the faster they would need to move. If electrons were to move about the electron cloud in strict paths the same way planets orbit the Sun, then electrons would be required to do so at speeds that would far exceed the speed of light. However, there is no reason that one must confine oneself to this strict conceptualization (that electrons move in paths the same way macroscopic objects do), rather one can conceptualize electrons to be 'particles' that capriciously exist within the bounds of the electron cloud.<ref>{{cite web|url=http://www.newton.dep.anl.gov/newton/askasci/1993/physics/PHY112.HTM|title=Classroom Resources|publisher=Argonne National Laboratory|work=anl.gov|access-date=2009-03-09|archive-date=2010-06-08|archive-url=https://web.archive.org/web/20100608223005/http://www.newton.dep.anl.gov/newton/askasci/1993/physics/PHY112.HTM|url-status=live}}</ref> Inside the [[atomic nucleus]], the [[proton]]s and [[neutron]]s are also probably moving around due to the electrical repulsion of the protons and the presence of [[angular momentum]] of both particles.<ref>{{Cite web |url=http://www.lbl.gov/abc/wallchart/teachersguide/pdf/Chap02.pdf |title=Chapter 2, Nuclear Science- A guide to the nuclear science wall chart. Berkley National Laboratory. |access-date=2009-03-09 |archive-date=2009-03-04 |archive-url=https://web.archive.org/web/20090304064927/http://www.lbl.gov/abc/wallchart/teachersguide/pdf/Chap02.pdf |url-status=live }}</ref>