an SI Tour℠

Most recent addition: 17 January 2017.

Many conventional terms confound “velocity” and “speed”, for example “escape velocity”. As a practical matter that confusion has forced us to do the same in this entry. But remember that a measurement of velocity includes a direction, while a measurement of speed does not.

Velocity in
yoctometers per second
Velocity in
zeptometers per second
Velocity in
attometers per second
Velocity in
femtometers per second
Velocity in
picometers per second
Velocity in
nanometers per second
1.2 Rate at which Moon is withdrawing from Earth.
1.4 Estimated highest rate at which land is rising anywhere in Iceland in 2014. Largely caused by loss of mass as glaciers melt.

Kathleen Compton, Richard A. Bennett and Sigrún Hreinsdóttir.
Climate-driven vertical acceleration of Icelandic crust measured by continuous GPS geodesy.
Geophysical Research Letters, vol 42, issue 3, pages 743–750 (16 February 2015).

90 - 235 Rate at which a rabies virus infection moves along a nerve.
633 – 3010 Range of speeds of Alaskan tidewater glaciers.

M. F. Meier and A. Post.
Fast tidewater glaciers.
Journal of Geophysical Research, vol. 92, pages 9051-9053 (1987).

Velocity in
micrometers per second
6.3 - 9.5 Speed with which various tree species spread north following the end of the last North American glaciation.

Margaret B. Davis.
Quaternary History of Deciduous Forests of Eastern North America and Europe.
Annals of the Missouri Botanical Garden, vol. 70, pages 550-563 (1983).
Available online through

158.44 Speed with which Earth's south magnetic pole was moving in 2007. It was moving northwest.

Nils Olsen and Mioara Mandea.
Will the magnetic north pole move to Siberia?
Eos, vol. 88, no. 29, page 293 (17 July 2007)

181 Jakobshavn glacier in 1992.
277 Pace of the garden snail Cornu aspersum.

According to New Scientist 12 July 2014, page 37.

399 Fastest glacier in Greenland, Jakobshavn Isbræ, Spring 2003.

Ian Joughin, Waleed Abdalati and Mark Fahnestock.
Large fluctuations in speed on Greenland's Jakobshavn Isbræ glacier.
Nature vol. 432, pages 608-610 (2 December 2004)

532 Fastest glacier in Greenland, Jakobshavn Isbræ, Summer 2012. Thought to be the fastest flow rate ever recorded for any glacier in Greenland or Antarctica.

Ian Joughin, Benjamin E. Smith, David E. Shean and Dana Floricioiu.
Brief Communication: Further summer speedup of Jakobshavn Isbræ,
The Cryosphere, vol 8, pages 209-214. (2014)

Velocity in
millimeters per second
1.90 The Earth's north magnetic pole was moving northwest at somewhat less than this speed in 2003. This is the fastest known value for magnetic dip pole migration.

Nils Olsen and Mioara Mandea.
Will the magnetic north pole move to Siberia?
Eos, vol. 88, no. 29, page 293 (17 July 2007)

10 Average land speed of the Mars rovers Spirit and Opportunity.
30 - 50 Speed of a soft caress for optimal transmission from skin to brain in humans along C-tactile nerve fibers.
102.9 Maximum velocity of the rock Maia (A6, mass 8.2 kilograms) on Racetrack Playa, Death Valley, California, on 4 December 2013 at 7:08 pm. Turns out that the mysterious moving rocks of Racetrack Playa are shoved along by thin crusts of wind-driven floating ice.

Richard D. Norris, James M. Norris, Ralph D. Lorenz, Jib Ray and Brian Jackson.
Sliding rocks on Racetrack Playa, Death Valley National Park: First observation of rocks in motion.
PLoS ONE 9(8): e105948.

190.5 Most common speed (7½ inches per second) for quarter-inch magnetic recording tape.
780 Peak speed of a domestic cat's tongue when lapping up a liquid.

Pedro M. Reis, Sunghwan Jung, Jeffrey M. Aristoff, and Roman Stocker
How cats lap: Water uptake by Felis catus.
Science, vol. 330, no. 6008, pages 1231-1234 (26 November 2010)

Velocity in
meters per second
1.5 Speed of the current with which the bladderwort (genus Utricularia) sucks in its prey.

Olivier Vincent, Carmen Weißkopf, Simon Poppinga, Tom Masselter, Thomas Speck, Marc Joyeux, Catherine Quilliet and Philippe Marmottant.
Ultra-fast underwater suction traps.
Proceedings of the Royal Society B, vol. 278 no. 1720, pages 2909-2914 (7 October 2011).
doi: 10.1098/rspb.2010.2292

1.75 Record for a thoroughbred race horse over a mile course (Dr. Fager at Arlington Park, Illinois, August 24, 1968)
2 Speed with which an impulse is transmitted along a human type C nerve fiber.
3.53 Average speed of the pedal-powered Gossamer Albatross flying across the English Channel on 12 June 1979. Its top speed was 8.06 meters per second.
4.4 Peak speed at which the veiled chameleon shoots out its tongue, at 35° C. At 15°C, the speed drops to 3.4 m/s.

Christopher V. Anderson and Stephen Deban.
Ballistic tongue projection in chameleons maintains high performance at low temperature.
Proceedings of the National Academy of Science, vol. 107, no. 12, pages 5495–5499 (23 March 2010).

4.5 Human sneeze.

Julian W. Tang, Andre D. Nicolle, Christian A. Klettner, Jovan Pantelic, Liangde Wang, Amin Bin Suhaimi, Ashlynn Y. L. Tan, Garrett W. X. Ong, Ruikun Su, Chandra Sekhar, David D. W. Cheong and Kwok Wai Tham.
Airflow Dynamics of Human Jets: Sneezing and Breathing - Potential Sources of Infectious Aerosols.
PLoS ONE 8(4): e59970 (2013)

4.8 Maximum velocity of strike by rattlesnake preying upon kangaroo rats. In this instance, the snake missed. The maximum for catching a rat was 4.2 m/s.

Timothy E. Higham, Rulon W. Clark, Clint E. Collins, Malachi D. Whitford and Grace A. Freymiller.
Rattlesnakes are extremely fast and variable when striking at kangaroo rats in nature: Three-dimensional high-speed kinematics at night.
Scientific Reports 7, article number: 40412 (2017)

6 Mean vertical speed of short-finned pilot whales on deep dives. Their maximum vertical speed was about 9 meters per second.

Natacha Aguilar Soto, Mark P. Johnson, Peter T. Madsen, Francisca Díaz, Iván Domínguez, Alberto Brito and Peter Tyack.
Cheetahs of the deep sea: deep foraging sprints in short-finned pilot whales off Tenerife (Canary Islands)
Journal of Animal Ecology, vol 77, pages 936–947 2008
doi: 10.1111/j.1365-2656.2008.01393.x

7.5 White rhino urged on by a Jeep.

McNeill Alexander.

9.83 Slepcev Storch cruising at full flap and 30% power. The Slepcev is a ¾ copy of the WWII Fiesler Fi 156 Storch. It is the slowest fixed-wing, motorized aircraft we have found.
10 Salmon fired past dams by the Salmon Cannon.
10.29 Usain Bolt running the 100-meter in May 2008 (9.72 seconds).
11.5 Average fist velocity of karate players throwing a straight punch.¹ A test of 10 Olympic boxers showed an average velocity at impact of 9.14 m/s.²

1. P. K. Smith and J. Hamill.
The effect of punching glove type and skill level on momentum transfer.
Journal of Human Movement Studies vol. 12, pages 153–161 (1986).

2. T. J. Walilko, D. C. Viano and C. A. Bir.
Biomechanics of the head for Olympic boxer punches to the face.
British Journal of Sports Medicine, vol. 39, pages 710–719 (2005).
doi: 10.1136/bjsm.2004.014126

17 Ostriches running.

McNeill Alexander.

18 Pronghorn antelopes running.
20 Typical cruising speed of ducks, geese and swans in flight.
24.6 55-miles per hour speed limit for vehicles.
25.67 Windsurfer Antoine Albeau in 2008.
26.39 The French sailboat L'Hydroptere in September 2009.
28.63 Kitesurfer Robert Douglas in October 2010.
29 Cheetah on a 200-meter course.
31.2 Fastest recorded table tennis smash, by Lark Brandt at the 2003 World Fastest Smash Competition.
37.16 VeloX3 recumbent bike ridden by Sebastiaan Bowier, 15 September 2013. World record at the time.
40 Lava flow, 10 January 1977 eruption of Mt. Nyiragongo. Fastest recorded lava flow.
42 Very violent human sneeze. This old estimate is frequently encountered, but probably wrong. See 4.5 m/s, above.
~42 Wind velocity at which 60% of trees are knocked down, regardless of height, diameter or elasticity.

E. Virot, A. Ponomarenko, É. Dehandschoewercker, D. Quéré and C. Clanet.
Critical wind speed at which trees break.
Physical Review E, 93, 023001 – Published 2 February 2016.
doi: 10.1103/PhysRevE.93.023001

42.78 Slowest possible speed for an unladen Boeing 747 on approach for landing, no wind.
55 Terminal velocity of human falling in the Earth's atmosphere.
56 Calculated estimate of the maximum speed of hypothetical particles of non-clumped dark matter.

Cristian Armendariz-Picon and Jayanth T. Neelakanta.
How Cold is Cold Dark Matter?
arXiv:1309.6971 [astro-ph.CO]

56.95 Tennis ball served by Venus Williams (French Open, 2007)
58.1 Tennis ball served by Brenda Schultz-McCarthy (2006)
>60 Speed at which the mandibles of the trap-jaw ant Odontomachus bauri close (fastest moving animal appendage).

Joseph C. Spagna, Antonis I. Vakis, Chris A. Schmidt, Sheila N. Patek, Xudong Zhang, Neil D. Tsutsui and Andrew V. Suarez.
Phylogeny, scaling, and the generation of extreme forces in trap-jaw ants.
Journal of Experimental Biology, vol. 211, pages 2358-2368 (2008).
doi: 10.1242/jeb.015263

67 Tennis ball served by Greg Rusedski, Indian Wells, California, March 14, 1998.
69.29 Tennis ball served by Andy Roddick (Davis Cup, 2004)
73.1 Tennis ball served by William Tatem Tilden (1931). This was, obviously, before the age of radar and subject to reasonable skepticism.
84 Fastest pelota (in jai-lai).
89 Fastest badminton serve.
113.2 Maximum surface 3-second wind gust not related to tornados, at Barrow Island, Australia, 10 April 1996.

118.8 Hennessy Venom GT automobile, on 3 April 2013 (427.6 km/hour).
119.74 Bugatti Veyron EB 16.4 Super Sport. As of 2013, fastest street-legal production car in the world (431.072 km/hour).
141.98 Hydroplane boat Spirit of Australia on 8 October 1978.
164 Record set by Japan's maglev train, April 2015.
168.25 Measured 2-way speed of the motorcycle TOP 1 Oil Ack Attack on 25 September 2010.
204.7 Land speed record for a wheel-driven vehicle (737 km/h).
405 Ash thrown from Stromboli, the Italian volcano.
504 Maximum muzzle velocity of the APERS-T (M546) shell fired from the U.S. Army M101 105mm howitzer.
980 SR-71 Blackbird (2193 mph). It flew from New York to London at an average speed of 641.764 m/s (1435.587 miles per hour).
Velocity in
kilometers per second
1.023 Mean orbital speed of Moon around Earth.
2 Cruising speed of the Japanese space probe Hayabusa 2 (2014).
>2 Wind on the “hot Jupiter” exoplanet HD 189733b, measured by high resolution spectroscopy of the sodium absorption line on opposite edges of the planet.

Tom Louden and Peter J. Wheatley.
Spatially resolved eastward winds and rotation of HD 189733b.
To be published in Astrophysical Journal Letters.

2.4 Escape velocity at the surface of Earth's Moon.
2.989 NASA X-43A scramjet (unmanned, 6,686 mph).
4.3 Escape velocity at the surface of Mercury.
4.7 Mean orbital speed of Pluto.
5.0 Escape velocity at the surface of Mars.
5 Velocity at which fault ruptured in 1999 Izmit earthquake.

Michel Bouchon, Marie-Paule Bouin, Hayrullah Karabulut, M. Nafi Toksöz, Michel Dietrich and Ares J. Rosakis.
How fast is rupture during an earthquake? New insights from the 1999 Turkey Earthquakes.
Geophysical Research Letters, vol 28, issue 14, pages 2723–2726 (15 July 2001).
doi: 10.1029/2001GL013112

5.4 Mean orbital speed of Neptune.
5.8 Approximate velocity of DARPA's Falcon Hypersonic Technology Vehicle 2, just before it broke up (11 August 2011).
6.8 Mean orbital speed of Uranus.
8 Average speed of supershear rupture in a 24 May 2013 aftershock of the Sea of Okhotsk earthquake, occurring at a depth of 640 kilometers.

Zhongwen Zhan, Donald V. Helmberger, Hiroo Kanamori and Peter M. Shearer.
Supershear rupture in a Mw 6.7 aftershock of the 2013 Sea of Okhotsk earthquake.
Science, vol. 345, no. 6193, pages 204-207 (11 July 2014).
doi: 10.1126/science.1252717

9.6 Mean orbital speed of Saturn.
10.4 Escape velocity at the surface of Venus.
11.2 Escape velocity at the Earth's surface. The speed at which no further impulse is needed for a vehicle to escape Earth's gravity.
13.1 Mean orbital speed of Jupiter.
14 Velocity at which the star Gliese 710 is approaching us. It may pass through the Oort cloud in 1.5 million years.

Vadim V. Bobylev.
Searching for stars closely encountering with the solar system.
Astronomy Letters, vol 36, no. 3. (2010)

17.9 Mean orbital speed of Ceres.
21 Escape velocity at the surface of Uranus.
23.2 Sun's motion through the galaxy.

D. J. McComas, D. Alexashov, M. Bzowski, H. Fehr, J. Heerikhuisen, V. Izmodenov, M. A. Lee, E. Möbius, N. Pogorelov, N. A. Schwadron and G. P. Zenk.
The heliosphere's interstellar interaction: No bow shock.
Published online May 10 2012.
Science, vol. 336, no. 6086, pages 1291-1293 (8 June 2012).
doi: 10.1126/science.1221054

24 Escape velocity at the surface of Neptune.
29.8 Mean orbital speed of Earth.
35.0 Mean orbital speed of Venus.
36 Escape velocity at the surface of Saturn.
42.1 At Earth's orbit, the speed at which no additional impulse is needed to escape the Sun's gravity.
47.9 Mean orbital speed of Mercury.
53.2 Estimated velocity of a meteor photographed striking Mare Nubium, on the Moon, in September 2013, assuming it belonged to the September ε-Perseid swarm. If it was a sporadic, its velocity was estimated at only 17 km/s.

Josè M. Madiedo, Josè L. Ortiz, Nicolás Morales and Jesús Cabrera-Caño.
A large lunar impact blast on 2013 September 11.
Monthly Notices of the Royal Astronomical Society, vol. 439, pages 2364–2369 (2014)

56 Winds on Neptune.

The wind speed estimate and the claim that it is the fastest wind in the solar system was made by G. Orton in an ESO press release Their study was published as
G. S. Orton, T. Encrenaz, C. Leyrat, R. Puetter, and A. J. Friedson.
Evidence for methane escape and strong seasonal and dynamical
perturbations of Neptune’s atmospheric temperatures.
Astronomy and Astrophysics, vol. 473, L5–L8 (2007).
doi: 10.1051/0004-6361:20078277.

59.5 Escape velocity at the “surface” of Jupiter.
70.22 Maximum velocity of the Helios 2 spacecraft.
80 Present velocity with respect to the solar system of the small red dwarf star (WISE J072003.20-084651.2, “Scholz's star”) that passed through the Oort cloud about 70,000 years ago.

Eric E. Mamajek, Scott A. Barenfeld, Valentin D. Ivanov, Alexei Y. Kniazev, Petri Väisänen, Yuri Beletsky and Henri M. J. Boffin.
The closest known flyby of a star to the solar system.
The Astrophysical Journal Letters, vol. 800, no 1, L17 (10 February 2015)

239 ± 7 Speed with which the Sun travels around the center of the Milky Way.

Andreas Brunthaler et al.
The Bar and Spiral Structure Legacy (BeSSeL) Survey: Mapping the Milky Way with VLBI Astrometry.
Astronomische Nachrichten, vol. 332, issue 5, pages 461-466 (2011)
doi: 10.1002/asna.201111560

~100 Velocity of Large and Small Magellanic Clouds relative to the Milky Way.
~300 Velocity of Smith's Cloud, a giant gas cloud that orbits the Milky Way. It will pass through the galactic plane again in about 27,000,000 years.

Felix J. Lockman, Robert A. Benjamin, A. J. Heroux and Glen I. Langston.
The Smith Cloud: A high-velocity cloud colliding with the Milky Way.
The Astrophysical Journal, vol. 679, issue 1, pages L21-L24 (1 May 2008).

533 Escape velocity for the galaxy, in the neighborhood of the sun.

T. Piffl, C. Scannapieco, J. Binney, M. Steinmetz, R.-D. Scholz, M. E. K. Williams, R. S. de Jong, G. Kordopatis, G. Matijevic, O. Bienayme, J. Bland-Hawthorn, C. Boeche, K. Freeman, B. Gibson, G. Gilmore, E. K. Grebel, A. Helmi, U. Munari, J. F. Navarro, Q. Parker, A. Reid, G. Seabroke, F. Watson, F. G. Wyse, T. Zwitter
The RAVE survey: the Galactic escape speed and the mass of the Milky Way.
arXiv:1309.4293v3 [astro-ph.GA]

555 Orbital speed of red dwarf star in system with black hole MAXI J1659-152. A “year” passes in 2.4 hours.

E. Kuulkers et al.
MAXI J1659−152: The shortest orbital period black-hole transient in outburst.
Astronomy & Astrophysics, 552, A32 (2013).

635 Speed with which the Local Group of Galaxies is moving toward the Hydra-Centaurus supercluster of galaxies. Some think this movement is only apparent, and is caused by the higher density of matter in that direction compared to the opposite direction. The higher density causes space in the direction of Hydra-Centaurus to expand more slowly than it does in the opposite direction.
800  to 1600 Pulsar PSR B2224+65, a hypervelocity neutron star, thought to be the fastest star in our galaxy. The shock wave created by its passage through interstellar hydrogen creates the Guitar Nebula, which is visible only at the wavelengths of hydrogen alpha lines. Its velocity is so great that it will escape the Milky Way.

S. Chatterjee & J. M. Cordes
Smashing the Guitar: An Evolving Neutron Star Bow Shock.
Astrophysical Journal Letters, vol. 600, no. 1,  L51 (2004).

G. Hobbs, D. R. Lorimer, A. G. Lyne, and M. Kramer.
A statistical study of 233 pulsar proper motions.
Monthly Notices of the Royal Astronomical Society, vol. 360, no. 3, pages 974–992 (July 2005)
doi: 10.1111/j.1365-2966.2005.09087.x

Velocity in
megameters per second
1 Approximate velocity with which the shell of gas is ejected in a nova.

Abell, 506.

~1.2 The hypervelocity star US 708 (HVS2).

S. Geier, F. Fürst, E. Ziegerer, T. Kupfer, U. Heber, A. Irrgang, B. Wang, Z. Liu, Z. Han, B. Sesar, D. Levitan, R. Kotak, E. Magnier, K. Smith, W. S. Burgett, K. Chambers, H. Flewelling, N. Kaiser, R. Wainscoat, C. Waters.
The fastest unbound star in our Galaxy ejected by a thermonuclear supernova.
Science, vol. 347 no. 6226, pages 1126-1128 (6 March 2015).
doi: 10.1126/science.1259063

2.65 Estimated speed of the black hole in quasar SDSS J092712.65+294344.0. The merger of two black holes created a directional pulse of gravitational radiation; the recoil pushed the resulting supermassive black hole in the opposite direction. Its velocity is great enough to carry the black hole out of the galaxy in which it was formerly the center. The speed is estimated from emission lines.

Stefanie Komossa, H. Zhou and H. Lu.
A Recoiling Supermassive Black Hole in the Quasar SDSS J092712.65+294344.0?
The Astrophysical Journal, vol. 678, pages L81-L84 (10 May 2008).

5 Speed of the star S2 swinging by the black hole at the center of the Milky Way.

European Southern Oservatory.
Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours.
Press release, 16 October 2002:

8.9 Velocity of wind pushed by the stellar-mass black hole IGR J17091.

Ashley L. King, Jon M. Miller, John Raymond, Andy C. Fabian, Chris S. Reynolds, Tim R. Kallman, Dipankar Maitra, Edward M. Cackett, Michael P. Rupen.
An Extreme X-ray Disk Wind in the Black Hole Candidate IGR J17091-3624
ApJL, 746, L20; (10 January 2012)
arXiv:1112.3648 [astro-ph.HE]

10 Approximate velocity with which the shell of gas is ejected in a supernova.

Abell, 511.

60 Winds from quasar SDSS J023011.28+005913.6

Jesse A. Rogerson, Patrick B. Hall, Paola Rodríguez Hidalgo, Patrik Pirkola and William N. Brandt.
Multi-epoch observations of extremely high-velocity emergent broad absorption.
Monthly Notices of the Royal Astronomical Society vol 457, issue 1, pages 405-420 (21 March 2016).

93.8 Spin rate of the more massive black hole in the model of quasar OJ287.

M. J. Valtonen, S. Zola, S. Ciprini, A. Gopakumar, K. Matsumoto, K. SadaKane, M. Kidge, K. Gazeas, K. Nilsson and A. Berdyugin.
Primary black hole spin in OJ287 as determined by the General Relativity Centenary Flare.
Astrophysical Journal Letters, v. 819, no. 2, 10 March 2016

197 Spin rate of the black hole in quasar RX J1131-1231.

Rubens C. Reis, Mark T. Reynolds, Jon M. Miller, and Dominic J. Walton.
Reflection from the Strong Gravity Regime in a z=0.658 gravitationally lensed-quasar.
Nature. vol 507, page 207 (13 March 2014).
doi: 10.1038/nature13031

199 Spin rate of the black hole in quasar Q 2237+305

Mark T. Reynolds, Dominic J. Walton, Jon M. Miller, and Rubens C. Reis.
A rapidly spinning black hole powers the Einstein Cross.
The Astrophysical Journal Letters, vol. 792, no. 1

252 Spin rate of the central black hole of NGC 1365.

G. Risaliti, F. A. Harrison, K. K. Madsen, D. J. Walton, S. E. Boggs, F. E. Christensen, W. W. Craig, B. W. Grefenstette, C. J. Hailey, E. Nardini, Daniel Stern and W. W. Zhang.
A rapidly spinning supermassive black hole at the centre of NGC 1365.
Nature, vol 494, issue 7438, pages 449–451 (28 February 2013)

299.792 455 Velocity of protons in the Large Hadron Collider (at 7 TeV)
299.792 457 999 Velocity of the “Oh-My-God particles” (ultra high energy cosmic rays, assuming they are protons at 320 EeV). The 9's carry on for 17 more decimal places. For the obvious reason, we have not rounded the number off.
For more:
299.792 458 000 Velocity of light in a vacuum; the ultimate speed limit. Speeds faster than this are in part the result of expansion of the space through which the wave or object is moving.

want more?

McNeill Alexander.
Principles of Animal Locomotion.
Princeton University Press, 2003.

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