Editing Terraforming (section)

=== Mercury ===
{{More citations needed|section|date=March 2021}}
[[File:TerraformedMercuryGlobe.jpg|thumb|An artist's conception of the terraformed Mercury]]

[[Mercury (planet)|Mercury]] would be difficult to terraform. Beech<ref name= "Beech-Mercury">Beech, Martin. ''[https://books.google.com/books?id=dwm72BO5zoMC&dq=terraforming+mercury&pg=PA219 Terraforming: The Creating of Habitable Worlds],'' pp. 217-219. Springer. Retrieved 29 Dec. 2023.</ref> states "There seems little prospect of terraforming Mercury such that any animals or plants might exist there," and suggests that its primary use in a terraforming project would be as a mining source for minerals. Nevertheless, terraforming has been considered.<ref name="Roy"/> Mercury's magnetic field is only 1.1% that of Earth's, and, being closer to the Sun, any atmosphere would be stripped rapidly unless it can be protected from the solar wind. It is conjectured that Mercury's magnetic field should be much stronger, up to 30% of Earth's, if it weren't being suppressed by certain solar wind feedback effects.<ref>{{Cite journal|last1=Gómez-Pérez|first1=Natalia|last2=Solomon|first2=Sean C.|date=2010|title=Mercury's weak magnetic field: A result of magnetospheric feedback?|journal=Geophysical Research Letters|language=en|volume=37|issue=20|pages=n/a|doi=10.1029/2010GL044533|bibcode=2010GeoRL..3720204G|issn=1944-8007|doi-access=free}}</ref> If some means of shielding Mercury from solar wind by placing an artificial [[magnetic shielding|magnetic shield]] at Mercury-Sun [[Lagrange point#L1|L<sub>1</sub>]] (similar to the proposal for Mars), then Mercury's magnetic field could possibly grow in intensity to a point where Mercury's magnetic field could be self-sustaining provided the field wasn't made to "stall" by another solar event.{{citation needed|date=March 2021}}

Despite being much smaller than Mars, Mercury has an [[escape velocity]] only slightly less than that of Mars due to its higher density and could, if a [[magnetosphere]] prevents atmospheric stripping, hold a [[nitrogen]]/[[oxygen]] [[atmosphere]] for millions of years.

To provide one atmosphere of pressure, roughly 1.1×10<sup>18</sup> [[kilogram]]s of gas would be required;<ref name="Roy">Roy, Kenneth (2015). "Terraforming Mercury". In ''Inner Solar System: Prospective Energy and Material Resources,'' pp. 421-435. Springer International Publishing. [https://www.researchgate.net/profile/Kenneth-Roy-2/publication/285603153_Terraforming_Mercury/links/5ffc8c8292851c13fe0692b4/Terraforming-Mercury.pdf pdf] retrieved 29 Dec. 2023.</ref> or a somewhat lower amount if lower pressure is acceptable. Water could be delivered from the outer [[Solar System]]. Once this water has been delivered, it would split the water into its constituent [[oxygen]] and [[hydrogen]] molecules, possibly using a photo-catalytic dust, with the hydrogen rapidly being lost to space. At an oxygen pressure of 20-30 kPa, the atmosphere would be breathable and [[nitrogen]] may be added as required to allow for plant growth in the presence of [[nitrate]]s.

Temperature management would be required, due to the equilibrium average temperature of ~159°C. However, millions of square kilometers at the poles have an average temperature of 0-50°C (''i.e.,'' an area the size of Mexico at each pole with habitable temperatures). The total habitable area could be even larger if the planetary albedo were increased from 0.12 to ~0.6, potentially increasing the habitable area. Roy proposes that the temperature could be further managed by decreasing the solar flux at Mercury to near the terrestrial value by solar sails reflecting sunlight. He calculates that 16 to 17 million sails, each with an area of one square kilometer would be needed.<ref name= "Roy" />