May 1921 geomagnetic storm
 Artist's depiction ofsolar windstriking Earth'smagnetosphere(size and distance not to scale) | |
| Geomagnetic storm | |
|---|---|
| Initial onset | 13 May 1921 |
| Dissipated | 15 May 1921 |
| PeakDst | −907±132 nT |
| Impacts | Substantial damage to overhead and underwatertelegraphequipment;electrical fires;localizedelectric gridinterruptions |
Part ofsolar cycle 15 | |
The three-dayMay 1921 geomagnetic storm,also known as theNew York Railroad Storm,was caused by the impact of an extraordinarily powerfulcoronal mass ejectiononEarth'smagnetosphere.It occurred on 13–15 May as part ofsolar cycle 15,and was the most intense geomagnetic storm of the 20th century.[1]
Since it occurred before the extensive interconnectivity of electrical systems and the general electrical dependence of infrastructure in the developed world, its effect was restricted; however, its ground currents were up to an order of magnitude greater than those of theMarch 1989 geomagnetic stormwhich interrupted electrical service to large parts of northeastern North America.[2]
Effects[edit]
The storm's electrical current sparked a number of fires worldwide, including one nearGrand Central Terminalwhich made it known as the "New York Railroad Storm".[1]Contemporary scientists estimated the size of thesunspot(AR1842)[1]which began on May 10—and caused the storm—as 151,000 by 34,000 km (94,000 by 21,000 miles).[3][4]
The storm was extensively reported inNew York City,which was a center of telegraph activity as a railroad hub.[5]Auroras( "northern lights" ) appeared throughout the easternUnited States,creating brightly lit night skies.Telegraphservice in the U.S. first slowed and then virtually stopped at about midnight on 14 May due to blown fuses and damaged equipment.[6]Radio propagation was enhanced during the storm due to ionosphere involvement, however, enabling unusually good long-distance reception. Electric lights were not noticeably affected.[7]
Undersea telegraph cables were affected by the storm. Damage to telegraph systems was also reported in Europe[8]and theSouthern Hemisphere.[9]
Comparison to other geomagnetic storms[edit]
In space weather, thedisturbance storm time index(Dst index) is a measure often used for determining the intensity of solar storms. A negative Dst index means thatEarth's magnetic fieldis weakened—particularly the case during solar storms—with a more negative Dst index indicating a stronger solar storm.
A paper in 2019 estimated that the May 1921 geomagnetic storm had a peak Dst of −907±132 nT.[10]
For comparison, theCarrington Eventof 1859 had a peak Dst estimated to be between−800 nTand−1750 nT.[11]TheMarch 1989 geomagnetic stormhad a peak Dst index of −589 nT.[12]
See also[edit]
References[edit]
Footnotes[edit]
- ^abcPhillips, Tony (12 May 2020)."The Great Geomagnetic Storm of May 1921".spaceweather.Retrieved1 June2020.
- ^Dr Tony Phillips (January 21, 2009)."Severe Space Weather - Social and Economic Impacts".NASA.RetrievedDecember 18,2012.
- ^"Borealis Cause, Sun Spots, Will Diminish Today"(PDF).Chicago Daily Tribune.May 16, 1921. p. 4. Archived fromthe original(PDF)on August 12, 2014.RetrievedDecember 19,2012.
- ^"Sun Spots Vanishing"(PDF).The Los Angeles Times.May 16, 1921. pp. 1 & 2. Archived fromthe original(PDF)on August 12, 2014.RetrievedDecember 19,2012.
- ^"May 13, 1921 – The New York Railroad Storm".SolarStorms.org.Archivedfrom the original on 28 September 2006.Retrieved31 May2020.
- ^M. Hapgood (2019)."The great storm of May 1921: An exemplar of a dangerous space weather event".Space Weather.17(7): 950–975.Bibcode:2019SpWea..17..950H.doi:10.1029/2019SW002195.
- ^"Sunspot Aurora Paralyses Wires"(PDF).New York Times.May 15, 1921. pp. 1 & 3. Archived fromthe original(PDF)on October 22, 2013.RetrievedDecember 19,2012.
- ^"Cables Damaged by Sunspot Aurora"(PDF).New York Times.May 17, 1921. pp. 1 & 4. Archived fromthe original(PDF)on August 12, 2014.RetrievedDecember 19,2012.
- ^"Aurora Borealis".Hawera & Normanby Star.May 16, 1921. p. 8.RetrievedDecember 18,2012.
- ^Jeffrey J. Love; Hisashi Hayakawa; Edward W. Cliver (2019)."Intensity and Impact of the New York Railroad Superstorm of May 1921".Space Weather.17(8): 1281–1292.Bibcode:2019SpWea..17.1281L.doi:10.1029/2019SW002250.
- ^"Near Miss: The Solar Superstorm of July 2012".NASAScience.Archivedfrom the original on 11 May 2024.Retrieved11 May2024.
- ^Boteler, D. H. (10 October 2019)."A 21st Century View of the March 1989 Magnetic Storm".Space Weather.17(10): 1427–1441.Bibcode:2019SpWea..17.1427B.doi:10.1029/2019SW002278.ISSN1542-7390.
Bibliography[edit]
- The Aurora Borealis of May 14, 1921JSTOR40710695
- "May 13, 1921 – The New York Railroad Storm".Solarstorms.org.RetrievedFebruary 9,2019.A bibliography of newspaper and journal articles.
- "Northern Lights Are Busy"(PDF).New York Times.May 14, 1921. p. 10. Archived fromthe original(PDF)on March 3, 2016.RetrievedDecember 19,2012.
- "Aurora Borealis Halts Telegraph Service to City"(PDF).The Atlanta Constitution.May 15, 1921. p. 1. Archived fromthe original(PDF)on March 3, 2016.RetrievedDecember 19,2012.
- Henry K. Bunn (May 15, 1921)."The Story The Week Has Told"(PDF).The Atlanta Constitution.p. 8. Archived fromthe original(PDF)on March 4, 2016.RetrievedDecember 19,2012.
- "Tricky Aurora Snarls Up Wires"(PDF).Chicago Daily Tribune.May 15, 1921. p. 1. Archived fromthe original(PDF)on March 3, 2016.RetrievedDecember 19,2012.
- "Aurora is Disturber"(PDF).The Los Angeles Times.May 15, 1921. pp. 1 & 2. Archived fromthe original(PDF)on March 3, 2016.RetrievedDecember 19,2012.
- "The Aurora Borealis"(PDF).The Los Angeles Times.May 16, 1921. p. 14. Archived fromthe original(PDF)on March 3, 2016.RetrievedDecember 19,2012.
- "Aurora Borealis Effect on Wires Laid to Sun Spot"(PDF).The Atlanta Constitution.May 16, 1921. p. 3. Archived fromthe original(PDF)on March 3, 2016.RetrievedDecember 19,2012.
- "Sunspot Credited with Rail Tie-Up"(PDF).New York Times.May 16, 1921. p. 2. Archived fromthe original(PDF)on March 4, 2016.RetrievedDecember 19,2012.
- "Magnetic Tremors Expected to Pass Within 48 Hours"(PDF).New York Times.May 16, 1921. p. 1. Archived fromthe original(PDF)on March 4, 2016.RetrievedDecember 19,2012.
- "Cables Still Show Effects of Aurora"(PDF).New York Times.May 18, 1921. p. 12. Archived fromthe original(PDF)on March 3, 2016.RetrievedDecember 19,2012.
- "Electric Disturbances Affect French Wires: Aurora Not Visible, Its Absence Being Attributed to Atmospheric Conditions"(PDF).New York Times.May 18, 1921. p. 12. Archived fromthe original(PDF)on March 4, 2016.RetrievedDecember 19,2012.
- "Magnetic Storms Don't Affect Radio"(PDF).New York Times.May 26, 1921. p. 23.RetrievedDecember 19,2012.[permanent dead link]
- S.M. Silverman; E.W.Cliver (March 2001)."Low-latitude auroras: the magnetic storm of 14–15 May 1921".Journal of Atmospheric and Solar-Terrestrial Physics.63(5): 523–525.Bibcode:2001JASTP..63..523S.doi:10.1016/S1364-6826(00)00174-7.RetrievedDecember 18,2012.