Editing Eta Carinae (section)

===Possible effects on Earth===
[[File:Gamma ray burst.jpg|thumb|upright=1.1|right|alt=Shells of progressive element burning, hydrogen, helium, carbon-oxygen-nitrogen, silicon, magnesium-neon and iron, followed by collapse with gamma ray burst jets developing from the poles|One theory of η&nbsp;Carinae's ultimate fate is collapsing to form a [[black hole]]—energy released as jets along the axis of rotation forms [[gamma-ray burst]]s.]]
A typical core collapse supernova at the distance of η&nbsp;Carinae would peak at an apparent magnitude around −4, similar to [[Venus]]. A SLSN could be five magnitudes brighter, potentially the brightest supernova in recorded history (currently [[SN 1006]]). At 7,500 light-years from the star it is unlikely to directly affect terrestrial lifeforms, as they will be protected from [[gamma ray]]s by the atmosphere and from some other cosmic rays by the [[magnetosphere]]. The main damage would be restricted to the upper atmosphere, the [[ozone layer]], spacecraft, including [[satellite]]s and any astronauts in space.

At least one paper has projected that complete loss of the Earth's ozone layer is a plausible consequence of a ''nearby'' supernova, which would result in a significant increase in UV radiation reaching Earth's surface from the Sun, but this would require a typical supernova to be closer than 50&nbsp;light-years from Earth, and even a potential hypernova would need to be closer than η&nbsp;Carinae.<ref name="KoezM">{{cite journal |last1=Ruderman |first1=M. A. |year=1974 |title=Possible Consequences of Nearby Supernova Explosions for Atmospheric Ozone and Terrestrial Life |journal=Science |volume=184 |issue=4141 |pages=1079–1081 |doi=10.1126/science.184.4141.1079 |bibcode=1974Sci...184.1079R |pmid=17736193 |s2cid=21850504}}</ref> Another analysis of the possible impact discusses more subtle effects from the unusual illumination, such as possible [[melatonin]] suppression with resulting [[insomnia]] and increased risk of cancer and depression. It concludes that a supernova of this magnitude would have to be much closer than η&nbsp;Carinae to have any type of major impact on Earth.<ref name="thomas">{{cite journal |last1=Thomas |first1=Brian |last2=Melott |first2=A.L. |last3=Fields |first3=B.D. |last4=Anthony-Twarog |first4=B.J. |year=2008 |title=Superluminous supernovae: No threat from Eta Carinae |journal=American Astronomical Society |volume=212 |pages=193 |bibcode=2008AAS...212.0405T}}</ref>

η&nbsp;Carinae is not expected to produce a gamma-ray burst, and its axis is not currently aimed near Earth.<ref name="thomas"/> The Earth's atmosphere protects its inhabitants from all the radiation apart from UV light (it is opaque to gamma rays, which have to be observed using space telescopes). The main effect would result from damage to the [[ozone layer]]. η&nbsp;Carinae is too far away to do that even if it did produce a gamma-ray burst which was aimed at our Solar System.<ref name="Threat">{{cite journal |last1=Thomas |first1=B.C. |year=2009 |title=Gamma-ray bursts as a threat to life on Earth |journal=International Journal of Astrobiology |volume=8 |issue=3 |pages=183–186 |doi=10.1017/S1473550409004509 |arxiv=0903.4710 |bibcode=2009IJAsB...8..183T |s2cid=118579150}}</ref><ref name="Effects">{{cite journal |last1=Martin |first1=Osmel |last2=Cardenas |first2=Rolando |last3=Guimarais |first3=Mayrene |last4=Peñate |first4=Liuba |last5=Horvath |first5=Jorge |last6=Galante |first6=Douglas |year=2010 |title=Effects of gamma ray bursts in Earth's biosphere |journal=Astrophysics and Space Science |volume=326 |issue=1 |pages=61–67 |doi=10.1007/s10509-009-0211-7 |bibcode=2010Ap&SS.326...61M |s2cid=15141366 |arxiv=0911.2196}}</ref>