Editing Observable universe (section)

=== Number of galaxies and stars ===
The observable universe contains as many as an estimated 2 trillion galaxies<ref name="BBC-20231129">{{cite news |last=Gunn |first=Alistair |date=29 November 2023 |title=How many galaxies are there in the universe? – Do astronomers know how many galaxies exist? How many can we see in the observable Universe? |url=https://www.skyatnightmagazine.com/space-science/how-many-galaxies-in-universe |url-status=live |archiveurl=https://archive.today/20231203021645/https://www.skyatnightmagazine.com/space-science/how-many-galaxies-in-universe |archivedate=3 December 2023 |accessdate=2 December 2023 |work=[[BBC Sky at Night]]}}</ref><ref>{{cite journal |title=New Horizons spacecraft answers the question: How dark is space? |website=phys.org |url=https://phys.org/news/2021-01-horizons-spacecraft-dark-space.html |access-date=January 15, 2021 |language=en |archive-date=January 15, 2021 |archive-url=https://web.archive.org/web/20210115110710/https://phys.org/news/2021-01-horizons-spacecraft-dark-space.html |url-status=live }}</ref><ref>{{cite news |last1=Howell |first1=Elizabeth |title=How Many Galaxies Are There? |url=https://www.space.com/25303-how-many-galaxies-are-in-the-universe.html |website=Space.com |access-date=March 5, 2021 |date=March 20, 2018 |archive-date=February 28, 2021 |archive-url=https://web.archive.org/web/20210228013433/https://www.space.com/25303-how-many-galaxies-are-in-the-universe.html |url-status=live }}</ref> and, overall, as many as an estimated 10<sup>24</sup> stars<ref name="ESA-2019">{{cite web |author=Staff |title=How Many Stars Are There In The Universe? |url=https://www.esa.int/Our_Activities/Space_Science/Herschel/How_many_stars_are_there_in_the_Universe |date=2019 |work=[[European Space Agency]] |access-date=September 21, 2019 |archive-date=September 23, 2019 |archive-url=https://web.archive.org/web/20190923134902/http://www.esa.int/Our_Activities/Space_Science/Herschel/How_many_stars_are_there_in_the_Universe |url-status=live }}</ref><ref>{{Cite book|chapter=The Structure of the Universe|doi=10.1007/978-1-4614-8730-2_10|title=The Fundamentals of Modern Astrophysics|pages=279–294|year=2015|last1=Marov|first1=Mikhail Ya.|isbn=978-1-4614-8729-6}}</ref> &ndash; more stars (and, potentially, Earth-like planets) than all the [[Sand|grains of beach sand]] on planet [[Earth]].<ref name="SU-20020201">{{cite web |last=Mackie |first=Glen |title=To see the Universe in a Grain of Taranaki Sand |url=http://astronomy.swin.edu.au/~gmackie/billions.html |date=February 1, 2002 |work=[[Centre for Astrophysics and Supercomputing]] |access-date=January 28, 2017 |archive-date=June 30, 2012 |archive-url=https://archive.today/20120630205715/http://astronomy.swin.edu.au/~gmackie/billions.html |url-status=live }}</ref><ref name="CNET-20150319">{{cite news |last=Mack |first=Eric |date=19 March 2015 |title=There may be more Earth-like planets than grains of sand on all our beaches – New research contends that the Milky Way alone is flush with billions of potentially habitable planets – and that's just one sliver of the universe. |url=https://www.cnet.com/science/the-milky-way-is-flush-with-habitable-planets-study-says/ |url-status=live |archiveurl=https://archive.today/20231201144523/https://www.cnet.com/science/the-milky-way-is-flush-with-habitable-planets-study-says/ |archivedate=1 December 2023 |accessdate=1 December 2023 |work=[[CNET]]}}</ref><ref name="MNRAS-20150313">{{cite journal |last1=Bovaird |first1=T. T. |last2=Lineweaver |first2=C. H. |last3=Jacobsen |first3=S. K. |date=13 March 2015 |title=Using the inclinations of Kepler systems to prioritize new Titius–Bode-based exoplanet predictions |url=https://academic.oup.com/mnras/article/448/4/3608/970734 |url-status=live |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume=448 |issue=4 |pages=3608–3627 |arxiv=1412.6230 |doi=10.1093/mnras/stv221 |doi-access=free |archiveurl=https://archive.today/20231201151205/https://academic.oup.com/mnras/article/448/4/3608/970734 |archivedate=1 December 2023 |accessdate=1 December 2023}}</ref> Other estimates are in the hundreds of billions rather than trillions.<ref name=":0">{{cite journal |last1=Lauer |first1=T. R. |last2=Postman |first2=M. |last3=Spencer |first3=J. R. |last4=Weaver |first4=H. A. |last5=Stern |first5=S. A. |last6=Gladstone |first6=G. R. |last7=Binzel |first7=R. P. |last8=Britt |first8=D. T. |last9=Buie |first9=M. W. |last10=Buratti |first10=B. J. |last11=Cheng |first11=A. F. |last12=Grundy |first12=W. M. |last13=Horányi |first13=M. |last14=Kavelaars |first14=J. J. |last15=Linscott |first15=I. R. |last16=Lisse |first16=C. M. |last17=McKinnon |first17=W. B. |last18=McNutt |first18=R. L. |last19=Moore |first19=J. M. |last20=Núñez |first20=J. I. |last21=Olkin |first21=C. B. |last22=Parker |first22=J. W. |last23=Porter |first23=S. B. |last24=Reuter |first24=D. C. |last25=Robbins |first25=S. J. |last26=Schenk |first26=P. M. |last27=Showalter |first27=M. R. |last28=Singer |first28=K. N. |last29=Verbiscer |first29=A. J. |last30=Young |first30=L. A. |date=2022 |title=Anomalous Flux in the Cosmic Optical Background Detected with New Horizons Observations |journal=The Astrophysical Journal Letters |volume=927 |issue=1 |pages=l8 | doi=10.3847/2041-8213/ac573d|arxiv=2202.04273 |bibcode=2022ApJ...927L...8L | doi-access=free}}</ref><ref name="ann21001">{{cite news |last=Lauer |first=Todd |title= NOIRLab Scientist Finds the Universe to be Brighter than Expected |url= https://noirlab.edu/public/announcements/ann21001/ |date=12 January 2021 |work=[[NOIRLab]] |access-date=12 January 2021 }}</ref><ref name="arxiv:2011.03052">{{cite journal |last1=Lauer |first1=Tod R. |last2=Postman |first2=Marc |last3=Weaver |first3=Harold A. |last4=Spencer |first4=John R. |last5=Stern |first5=S. Alan |last6=Buie |first6=Marc W. |last7=Durda |first7=Daniel D. |last8=Lisse |first8=Carey M. |last9=Poppe |first9=A. R. |last10=Binzel |first10=Richard P. |last11=Britt |first11=Daniel T. |last12=Buratti |first12=Bonnie J. |last13=Cheng |first13=Andrew F. |last14=Grundy |first14=W. M. |last15=Horányi |first15=Mihaly |last16=Kavelaars |first16=J. J. |last17=Linscott |first17=Ivan R. |last18=McKinnon |first18=William B. |last19=Moore |first19=Jeffrey M. |last20=Núñez |first20=J. I. |last21=Olkin |first21=Catherine B. |last22=Parker |first22=Joel W. |last23=Porter |first23=Simon B. |last24=Reuter |first24=Dennis C. |last25=Robbins |first25=Stuart J. |last26=Schenk |first26=Paul |last27=Showalter |first27=Mark R. |last28=Singer |first28=Kelsi N. |last29=Verbiscer |first29=Anne J. |last30=Young |first30=Leslie A. |title=New Horizons Observations of the Cosmic Optical Background |journal=The Astrophysical Journal |date=11 January 2021 |volume=906 |issue=2 |pages=77 |doi=10.3847/1538-4357/abc881 | arxiv= 2011.03052 |bibcode=2021ApJ...906...77L |hdl=1721.1/133770 |s2cid=226277978 |doi-access=free }}</ref> The estimated total number of stars in an [[Cosmic inflation|inflationary universe]] (observed and unobserved) is 10<sup>100</sup>.<ref name="SR-20200203">{{cite journal |last=Totani |first=Tomonori |title=Emergence of life in an inflationary universe |date=3 February 2020 |journal=[[Scientific Reports]] |volume=10 |number=1671 |page=1671 |doi=10.1038/s41598-020-58060-0 |pmid=32015390 |arxiv=1911.08092 |bibcode=2020NatSR..10.1671T |doi-access=free |pmc=6997386 }}</ref>