Editing Cosmic ray (section)

==Effects==

===Changes in atmospheric chemistry===
Cosmic rays ionize nitrogen and oxygen molecules in the atmosphere, which leads to a number of chemical reactions. Cosmic rays are also responsible for the continuous production of a number of [[Radionuclide|unstable isotopes]], such as [[carbon-14]], in the Earth's atmosphere through the reaction:

{{block indent|n + <sup>14</sup>N → p + <sup>14</sup>C}}

Cosmic rays kept the level of carbon-14<ref>{{cite book|last=Trumbore|first=Susan|author-link=Susan Trumbore|title=Quaternary Geochronology: Methods and Applications|year=2000|publisher=American Geophysical Union|location=Washington, D.C.|isbn=978-0-87590-950-9|pages=41–59|url=http://www.agu.org/books/rf/v004/|editor=J. S. Noller|editor2=J. M. Sowers|editor3=W. R. Lettis|access-date=28 October 2011|archive-date=21 May 2013|archive-url=https://web.archive.org/web/20130521094616/http://www.agu.org/books/rf/v004/|url-status=dead}}</ref> in the atmosphere roughly constant (70 tons) for at least the past 100,000 years,{{citation needed|date=July 2017}} until the beginning of above-ground nuclear weapons testing in the early 1950s. This fact is used in [[radiocarbon dating]].

====Reaction products of primary cosmic rays, radioisotope half-lifetime, and production reaction====
<!-- Converting this to a table would be nice-->
{{columns-list|colwidth=30em|
* [[Hydrogen-1]] (stable): [[cosmic ray spallation|spallation]] from nitrogen and oxygen, decay of neutrons from such spallation
* [[Helium-3]] (stable): spallation or from tritium
* [[Helium-4]] (stable): spallation producing alpha rays
* [[Tritium]] (12.3 years): <sup>14</sup>N(n, <sup>3</sup>H)<sup>12</sup>C (spallation)
* Beryllium-7 (53.3 days)
* [[Beryllium-10]] (1.39 million years): <sup>14</sup>N(n,p α)<sup>10</sup>Be (spallation)
* [[Carbon-14]] (5730 years): <sup>14</sup>N(n, p)<sup>14</sup>C ([[neutron activation]])
* Sodium-22 (2.6 years)
* Sodium-24 (15 hours)
* Magnesium-28 (20.9 hours)
* Silicon-31 (2.6 hours)
* Silicon-32 (101 years)
* [[Phosphorus-32]] (14.3 days)
* Sulfur-35 (87.5 days)
* Sulfur-38 (2.84 hours)
* Chlorine-34 m (32 minutes)
* [[Chlorine-36]] (300,000 years)
* Chlorine-38 (37.2 minutes)
* Chlorine-39 (56 minutes)
* Argon-39 (269 years)
* [[Krypton-85]] (10.7 years)<ref>{{cite web|title=Natürliche, durch kosmische Strahlung laufend erzeugte Radionuklide|url=http://www.um.baden-wuerttemberg.de/servlet/is/34839/Natuerliche_durch_kosmische_Strahlung_laufend_erzeugte_Radionuklide.pdf?command=downloadContent&filename=Natuerliche_durch_kosmische_Strahlung_laufend_erzeugte_Radionuklide.pdf|access-date=11 February 2010|language=de|archive-url=https://web.archive.org/web/20100203174117/http://www.um.baden-wuerttemberg.de/servlet/is/34839/Natuerliche_durch_kosmische_Strahlung_laufend_erzeugte_Radionuklide.pdf?command=downloadContent&filename=Natuerliche_durch_kosmische_Strahlung_laufend_erzeugte_Radionuklide.pdf|archive-date=3 February 2010|url-status=dead}}</ref>
}}

===Role in ambient radiation===
Cosmic rays constitute a fraction of the annual radiation exposure of human beings on the Earth, averaging 0.39{{nbsp}}mSv out of a total of 3{{nbsp}}mSv per year (13% of total background) for the Earth's population. However, the background radiation from cosmic rays increases with altitude, from 0.3{{nbsp}}mSv per year for sea-level areas to 1.0{{nbsp}}mSv per year for higher-altitude cities, raising cosmic radiation exposure to a quarter of total background radiation exposure for populations of said cities. Airline crews flying long-distance high-altitude routes can be exposed to 2.2{{nbsp}}mSv of extra radiation each year due to cosmic rays, nearly doubling their total exposure to ionizing radiation.

{| class="wikitable" style="text-align:center"
|- style="background:#ececec;"
|+ Average annual radiation exposure ([[millisievert]]s)
|-
! colspan="2" |Radiation
! colspan="2" |[[UNSCEAR]]<ref>UNSCEAR [http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_Annex_B.pdf "Sources and Effects of Ionizing Radiation"] page 339 retrieved 29 June 2011</ref><ref>[[:ja:放射線医学総合研究所|Japan NIRS]] [http://www.aec.go.jp/jicst/NC/iinkai/teirei/siryo2010/siryo59/siryo1.pdf UNSCEAR 2008 report] page 8 retrieved 29 June 2011</ref>
! Princeton<ref>Princeton.edu [http://web.princeton.edu/sites/ehs/osradtraining/backgroundradiation/background.htm "Background radiation"] {{Webarchive|url=https://web.archive.org/web/20110609095603/http://web.princeton.edu/sites/ehs/osradtraining/backgroundradiation/background.htm|date=9 June 2011}} retrieved 29 June 2011</ref>
! Wa State<ref>Washington state Dept. of Health [http://www.doh.wa.gov/ehp/rp/factsheets/factsheets-htm/fs10bkvsman.htm "Background radiation"] {{webarchive|url=https://web.archive.org/web/20120502102254/http://www.doh.wa.gov/ehp/rp/factsheets/factsheets-htm/fs10bkvsman.htm |date=2 May 2012 }} retrieved 29 June 2011</ref>
! MEXT<ref>Ministry of Education, Culture, Sports, Science, and Technology of Japan [http://www.kankyo-hoshano.go.jp/04/04-1.html "Radiation in environment"] {{Webarchive|url=https://web.archive.org/web/20110322231148/http://www.kankyo-hoshano.go.jp/04/04-1.html |date=22 March 2011 }} retrieved 29 June 2011</ref>
! rowspan="2" | Remark
|-
! Type !! Source !! World<br /> average !! Typical range !! US !! US !! Japan
|-
| rowspan="5" | Natural || Air || 1.26 || 0.2–10.0<sup>a</sup> || 2.29 || 2.00 || 0.40 || <small>Primarily from radon,</small> <sup>(a)</sup><small>depends on indoor accumulation of radon gas.</small>
|-
| Internal || 0.29 || 0.2–1.0<sup>b</sup> || 0.16 || 0.40 || 0.40 || <small>Mainly from radioisotopes in food ([[potassium-40|<sup>40</sup>K]], <sup>14</sup>C, etc.)</small> <sup>(b)</sup><small>depends on diet.</small>
|-
| Terrestrial || 0.48 || 0.3–1.0<sup>c</sup> || 0.19 || 0.29 || 0.40 || <sup>(c)</sup><small>Depends on soil composition and building material of structures.</small>
|- style="background:orange;"
| Cosmic || 0.39 || 0.3–1.0<sup>d</sup> || 0.31 || 0.26 || 0.30 || <sup>(d)</sup><small>Generally increases with elevation.</small>
|-
| '''Subtotal''' || 2.40 || 1.0–13.0 || 2.95 || 2.95 || 1.50 ||
|-
| rowspan="4" | Artificial || Medical || 0.60 || 0.03–2.0 || 3.00 || 0.53 || 2.30 ||
|-
| Fallout || 0.007 || 0–1+ || – || – || 0.01 || <small>Peaked in 1963 (prior to the [[Partial Test Ban Treaty]]) with [[Chernobyl nuclear accident|a spike in 1986]]; still high near nuclear test and accident sites.<br />For the United States, fallout is incorporated into other categories.</small>
|-
| Others || 0.0052 || 0–20 || 0.25 || 0.13 || 0.001|| <small>Average annual occupational exposure is 0.7 mSv; mining workers have higher exposure. <br />Populations near nuclear plants have an additional ≈0.02 mSv of exposure annually.</small>
|-
| '''Subtotal''' || 0.6 || 0 to tens || 3.25 || 0.66 || 2.311 ||
|-
| colspan="2" | '''Total''' || 3.00 || 0 to tens || 6.20 || 3.61 || 3.81 ||
|}
<small>Figures are for the time before the [[Fukushima Daiichi nuclear disaster]]. Human-made values by UNSCEAR are from the Japanese National Institute of Radiological Sciences, which summarized the UNSCEAR data.</small>

===Effect on electronics===
{{See also|Radiation hardening}}Cosmic rays have sufficient energy to alter the states of circuit components in [[electronics|electronic]] [[integrated circuit]]s, causing transient errors to occur (such as corrupted data in [[random-access memory|electronic memory devices]] or incorrect performance of [[CPU]]s) often referred to as "[[soft error]]s". This has been a problem in [[electronics]] at extremely high-altitude, such as in [[satellite]]s, but with [[transistor]]s becoming smaller and smaller, this is becoming an increasing concern in ground-level electronics as well.<ref>[http://www.research.ibm.com/journal/rd/401/curtis.html "IBM experiments in soft fails in computer electronics (1978–1994)"]. In [http://www.research.ibm.com/journal/rd40-1.html "Terrestrial cosmic rays and soft errors"], ''IBM Journal of Research and Development'', Vol. 40, No. 1, 1996. Retrieved 16 April 2008.</ref> Studies by [[IBM]] in the 1990s suggest that computers typically experience about one cosmic-ray-induced error per 256 megabytes of [[Random-access memory|RAM]] per month.<ref>{{cite web|author=Scientific American|author-link=Scientific American|date=21 July 2008|title=Solar Storms: Fast Facts|url=https://www.scientificamerican.com/article/solar-storms-fast-facts/|publisher=[[Nature Publishing Group]]}}</ref> To alleviate this problem, the [[Intel Corporation]] has proposed a cosmic ray detector that could be integrated into future high-density [[microprocessor]]s, allowing the processor to repeat the last command following a cosmic-ray event.<ref>[http://news.bbc.co.uk/2/hi/technology/7335322.stm "Intel plans to tackle cosmic ray threat"]. ''BBC News'', 8 April 2008. Retrieved 16 April 2008.</ref> [[ECC memory]] is used to protect data against data corruption caused by cosmic rays.

In 2008, data corruption in a flight control system caused an [[Airbus A330]] airliner to twice [[Qantas Flight 72|plunge hundreds of feet]], resulting in injuries to multiple passengers and crew members. Cosmic rays were investigated among other possible causes of the data corruption, but were ultimately ruled out as being very unlikely.<ref>[https://www.atsb.gov.au/media/3532398/ao2008070.pdf "In-flight upset, 154&nbsp;km west of Learmonth, Western Australia, 7 October 2008, VH-QPA, Airbus A330-303"] {{Webarchive|url=https://web.archive.org/web/20220505014942/https://www.atsb.gov.au/media/3532398/ao2008070.pdf |date=5 May 2022 }} (2011). Australian Transport Safety Bureau.</ref>

In August 2020, scientists reported that ionizing radiation from environmental radioactive materials and cosmic rays may substantially limit the [[Quantum decoherence|coherence]] times of [[qubit]]s if they are not shielded adequately which may be critical for realizing fault-tolerant superconducting [[quantum computer]]s in the future.<ref>{{cite news|title=Quantum computers may be destroyed by high-energy particles from space|url=https://www.newscientist.com/article/2252933-quantum-computers-may-be-destroyed-by-high-energy-particles-from-space/|access-date=7 September 2020|work=New Scientist}}</ref><ref>{{cite news|title=Cosmic rays may soon stymie quantum computing|url=https://phys.org/news/2020-08-cosmic-rays-stymie-quantum.html|access-date=7 September 2020|work=phys.org}}</ref><ref>{{cite journal|last1=Vepsäläinen|first1=Antti P.|last2=Karamlou|first2=Amir H.|last3=Orrell|first3=John L.|last4=Dogra|first4=Akshunna S.|last5=Loer|first5=Ben|last6=Vasconcelos|first6=Francisca|last7=Kim |first7=David K.|last8=Melville|first8=Alexander J.|last9=Niedzielski|first9=Bethany M.|last10=Yoder|first10=Jonilyn L.|last11=Gustavsson|first11=Simon|last12=Formaggio|first12=Joseph A.|last13=VanDevender|first13=Brent A.|last14=Oliver|first14=William D.|title=Impact of ionizing radiation on superconducting qubit coherence|journal=Nature|date=August 2020|volume=584|issue=7822 |pages=551–556|doi=10.1038/s41586-020-2619-8|pmid=32848227|arxiv=2001.09190|bibcode=2020Natur.584..551V|s2cid=210920566|url=https://www.nature.com/articles/s41586-020-2619-8|access-date=7 September 2020|issn=1476-4687}}</ref>

===Significance to aerospace travel===
{{Main|Health threat from cosmic rays}}
Galactic cosmic rays are one of the most important barriers standing in the way of plans for interplanetary travel by crewed spacecraft. Cosmic rays also pose a threat to electronics placed aboard outgoing probes. In 2010, a malfunction aboard the ''[[Voyager 2]]'' space probe was credited to a single [[Single-event upset|flipped bit]], probably caused by a cosmic ray. Strategies such as physical or magnetic shielding for spacecraft have been considered in order to minimize the damage to electronics and human beings caused by cosmic rays.<ref>{{cite web|url=http://settlement.arc.nasa.gov/75SummerStudy/5appendE.html|archive-url=https://web.archive.org/web/20100531210412/http://settlement.arc.nasa.gov/75SummerStudy/5appendE.html|url-status=dead|archive-date=31 May 2010|title=Appendix E: Mass Shielding|publisher=NASA|work=Space Settlements: A Design Study|date=10 July 2002|access-date=24 February 2013|author=Globus, Al}}</ref><ref>{{cite news|url=http://www.thespacereview.com/article/308/1|title=Magnetic shielding for spacecraft|work=The Space Review|date=24 January 2005|access-date=24 February 2013|author=Atkinson, Nancy}}</ref>

On 31 May 2013, NASA scientists reported that a possible [[Human mission to Mars|crewed mission to Mars]] may involve a greater radiation risk than previously believed, based on the amount of [[radiation|energetic particle radiation]] detected by the [[Radiation assessment detector|RAD]] on the [[Mars Science Laboratory]] while traveling from the [[Earth]] to [[Mars]] in 2011–2012.<ref name=SCI-20130531a/><ref name=SCI-20130531b/><ref name=NYT-20130530/>

[[File:PIA17601-Comparisons-RadiationExposure-MarsTrip-20131209.png|thumb|upright=1.1|left|Comparison of radiation doses, including the amount detected on the trip from Earth to Mars by the [[radiation assessment detector|RAD]] on the [[Mars Science Laboratory|MSL]] (2011–2013).<ref name="SCI-20130531a">{{cite journal|last=Kerr|first=Richard|title=Radiation Will Make Astronauts' Trip to Mars Even Riskier|date=31 May 2013|journal=Science|volume=340|page=1031|doi=10.1126/science.340.6136.1031|issue=6136|pmid=23723213|bibcode=2013Sci...340.1031K}}</ref><ref name="SCI-20130531b">{{cite journal|title=Measurements of Energetic Particle Radiation in Transit to Mars on the Mars Science Laboratory|journal=Science|date=31 May 2013|volume=340|pages=1080–1084|doi=10.1126/science.1235989|pmid=23723233|author=Zeitlin, C.|issue=6136|last2=Hassler|first2=D. M.|last3=Cucinotta |first3=F. A.|last4=Ehresmann|first4=B.|last5=Wimmer-Schweingruber|first5=R.F.|last6=Brinza|first6=D. E.|last7=Kang|first7=S.|last8=Weigle|first8=G.|last9=Bottcher|first9=S.|display-authors=8|bibcode=2013Sci...340.1080Z|s2cid=604569}}</ref><ref name="NYT-20130530">{{cite news|last=Chang|first=Kenneth|title=Data Point to Radiation Risk for Travelers to Mars|url=https://www.nytimes.com/2013/05/31/science/space/data-show-higher-cancer-risk-for-mars-astronauts.html|date=30 May 2013|work=[[The New York Times]]|access-date=31 May 2013}}</ref>]]

Flying {{convert|12|km|ft|}} high, passengers and crews of [[jet airliner]]s are exposed to at least 10 times the cosmic ray dose that people at [[sea level]] receive. Aircraft flying [[polar route]]s near the [[geomagnetic pole]]s are at particular risk.<ref>{{cite web|last=Phillips|first=Tony|title=The Effects of Space Weather on Aviation|work=Science News|publisher=NASA|date=25 October 2013|url=https://science.nasa.gov/science-news/science-at-nasa/2013/25oct_aviationswx/|access-date=12 July 2017|archive-date=28 September 2019|archive-url=https://web.archive.org/web/20190928003535/https://science.nasa.gov/science-news/science-at-nasa/2013/25oct_aviationswx/|url-status=dead}}</ref><ref>{{YouTube|bAKdaYumlq4|"Converting Cosmic Rays to Sound During a Transatlantic Flight to Zurich"}}</ref><ref>{{Cite web|url=http://sol.spacenvironment.net/raps_ops/current_files/globeView.html|title=NAIRAS Real-time radiation Dose|website=sol.spacenvironment.net}}</ref>

===Role in lightning===
Cosmic rays have been implicated in the triggering of electrical breakdown in [[lightning]]. It has been proposed that essentially all lightning is triggered through a relativistic process, or "[[runaway breakdown]]", seeded by cosmic ray secondaries. Subsequent development of the lightning discharge then occurs through "conventional breakdown" mechanisms.<ref>[http://physicstoday.scitation.org/doi/pdf/10.1063/1.1995746 "Runaway Breakdown and the Mysteries of Lightning"], ''Physics Today'', May 2005.</ref>

===Postulated role in climate change===
A role for cosmic rays in climate was suggested by [[Edward P. Ney]] in 1959<ref>{{cite journal| title=Cosmic Radiation and the Weather|journal=Nature|date=14 February 1959|first=Edward P.|last=Ney|volume=183|pages=451–452|bibcode=1959Natur.183..451N|doi=10.1038/183451a0|issue=4659|s2cid=4157226}}</ref> and by [[Robert E. Dickinson]] in 1975.<ref>{{cite journal|title=Solar Variability and the Lower Atmosphere|last=Dickinson |first=Robert E.|journal=Bulletin of the American Meteorological Society|date=December 1975|volume=56|issue=12|pages=1240–1248|doi=10.1175/1520-0477(1975)056<1240:SVATLA>2.0.CO;2|bibcode=1975BAMS...56.1240D|doi-access=free}}</ref> It has been postulated that cosmic rays may have been responsible for major climatic change and mass extinction in the past. According to Adrian Mellott and Mikhail Medvedev, 62-million-year cycles in biological marine populations correlate with the motion of the Earth relative to the galactic plane and increases in exposure to cosmic rays.<ref>{{Cite web|url=http://news.nationalgeographic.com/news/2007/04/070420-extinctions.html|archive-url=https://web.archive.org/web/20070423085401/http://news.nationalgeographic.com/news/2007/04/070420-extinctions.html|url-status=dead|archive-date=23 April 2007|title=Ancient Mass Extinctions Caused by Cosmic Radiation, Scientists Say |work=National Geographic |year=2007}}</ref> The researchers suggest that this and gamma ray bombardments deriving from local supernovae could have affected [[cancer]] and [[mutation rate]]s, and might be linked to decisive alterations in the Earth's climate, and to the [[Extinction event|mass extinctions]] of the [[Ordovician]].<ref>{{cite journal|last1=Melott |first1=A. L.|last2=Thomas |first2=B. C.|year=2009|title=Late Ordovician geographic patterns of extinction compared with simulations of astrophysical ionizing radiation damage|journal=Paleobiology|volume=35|pages=311–320|doi=10.1666/0094-8373-35.3.311|issue=3|arxiv=0809.0899|bibcode=2009Pbio...35..311M |s2cid=11942132}}</ref><ref>{{Cite web|url=https://www.space.com/33379-supernova-explosions-earth-life-mass-extinction.html|title=Did Supernova Explosion Contribute to Earth Mass Extinction?|website=Space.com|date=11 July 2016}}</ref>

Danish physicist [[Henrik Svensmark]] has controversially argued that because [[solar variation]] modulates the cosmic ray flux on Earth, it would consequently affect the rate of cloud formation and hence be an indirect cause of [[global warming]].<ref>{{cite web|last=Long|first=Marion|title=Sun's Shifts May Cause Global Warming|publisher=[[Discover (magazine)|Discover]]|date=25 June 2007|url=http://discovermagazine.com/2007/jul/the-discover-interview-henrik-svensmark/|access-date=7 July 2013}}</ref><ref>{{Cite journal| first=Henrik |last=Svensmark|title=Influence of Cosmic Rays on Earth's Climate|journal=[[Physical Review Letters]]|year=1998|volume=81|pages=5027–5030|doi=10.1103/PhysRevLett.81.5027|issue=22|bibcode=1998PhRvL..81.5027S|url=http://ruby.fgcu.edu/courses/twimberley/EnviroPol/EnviroPhilo/Svensmark.pdf |archive-url=https://web.archive.org/web/20170809142617/http://ruby.fgcu.edu/courses/twimberley/EnviroPol/EnviroPhilo/Svensmark.pdf |archive-date=2017-08-09 |url-status=live|citeseerx=10.1.1.522.585}}</ref> Svensmark is one of several scientists outspokenly opposed to the mainstream scientific assessment of global warming, leading to concerns that the proposition that cosmic rays are connected to global warming could be ideologically biased rather than scientifically based.<ref>{{cite news|last1=Plait|first1=Phil|title=No, a new study does not show cosmic-rays are connected to global warming|url=http://blogs.discovermagazine.com/badastronomy/2011/08/31/no-a-new-study-does-not-show-cosmic-rays-are-connected-to-global-warming/|access-date=11 January 2018|work=Discover|publisher=Kalmbach|date=31 August 2011|archive-date=12 January 2018|archive-url=https://web.archive.org/web/20180112042455/http://blogs.discovermagazine.com/badastronomy/2011/08/31/no-a-new-study-does-not-show-cosmic-rays-are-connected-to-global-warming/|url-status=dead}}</ref> Other scientists have vigorously criticized Svensmark for sloppy and inconsistent work: one example is adjustment of cloud data that understates error in lower cloud data, but not in high cloud data;<ref>{{Cite web|last=Benestad|first=Rasmus E.|title='Cosmoclimatology' – tired old arguments in new clothes|date=9 March 2007|url=http://www.realclimate.org/index.php/archives/2007/03/cosmoclimatology-tired-old-arguments-in-new-clothes/|access-date=13 November 2013}}</ref> another example is "incorrect handling of the physical data" resulting in graphs that do not show the correlations they claim to show.<ref>Peter Laut, [http://stephenschneider.stanford.edu/Publications/PDF_Papers/Laut2003.pdf "Solar activity and terrestrial climate: an analysis of some purported correlations"], ''Journal of Atmospheric and Solar-Terrestrial Physics'' 65 (2003) 801–812</ref> Despite Svensmark's assertions, galactic cosmic rays have shown no statistically significant influence on changes in cloud cover,<ref>{{cite journal|last1=Lockwood|first1=Mike|title=Solar Influence on Global and Regional Climates|journal=Surveys in Geophysics|date=16 May 2012|volume=33|issue=3–4|pages=503–534|doi=10.1007/s10712-012-9181-3|bibcode=2012SGeo...33..503L|doi-access=free}}</ref> and have been demonstrated in studies to have no causal relationship to changes in global temperature.<ref>{{cite journal|last1=Sloan|first1=T.|last2=Wolfendale|first2=A. W.|author-link2=Arnold Wolfendale|title=Cosmic rays, solar activity and the climate|journal=Environmental Research Letters|date=7 November 2013|volume=8|issue=4|pages=045022|doi=10.1088/1748-9326/8/4/045022|bibcode=2013ERL.....8d5022S|doi-access=free}}</ref>

===Possible mass extinction factor===
{{See also|Pliocene#Supernovae}}
A handful of studies conclude that a nearby supernova or series of supernovas caused the [[Pliocene]] marine megafauna extinction event by substantially increasing radiation levels to hazardous amounts for large seafaring animals.<ref>{{cite journal|last1=Melott|first1=Adrian L.|first2=F. |last2=Marinho|first3=L. |last3=Paulucci|title=Muon Radiation Dose and Marine Megafaunal Extinction at the end-Pliocene Supernova|journal=Astrobiology|volume=19|issue=6|pages=825–830|date=2019|doi=10.1089/ast.2018.1902|pmid=30481053|arxiv=1712.09367|s2cid=33930965}}</ref><ref>{{cite journal|last=Benitez|first=Narciso|date=2002|title=Evidence for Nearby Supernova Explosions|journal=Physical Review Letters|volume=88|issue=8|pages=081101|doi=10.1103/PhysRevLett.88.081101|pmid=11863949|display-authors=et al.|arxiv=astro-ph/0201018|bibcode=2002PhRvL..88h1101B|s2cid=41229823}}</ref><ref>{{cite journal|last1=Fimiani|first1=L.|last2=Cook|first2=D. L.|last3=Faestermann|first3=T.|last4=Gómez-Guzmán|first4=J. M.|last5=Hain|first5=K.|last6=Herzog|first6=G.|last7=Knie|first7=K.|last8=Korschinek|first8=G.|last9=Ludwig|first9=P.|last10=Park|first10=J.|last11=Reedy|first11=R. C.|last12=Rugel|first12=G.|title=Interstellar 60Fe on the Surface of the Moon|journal=Physical Review Letters|date=2016|volume=116|issue=15|page=151104|doi=10.1103/PhysRevLett.116.151104|pmid=27127953 |bibcode=2016PhRvL.116o1104F}}</ref>