Extragalactic planet

An extragalactic planet, also known as an extragalactic exoplanet or an extroplanet,^[1]^[2]^[3] is a star-bound planet or rogue planet located outside of the Milky Way Galaxy. Due to the immense distances to such worlds, they would be very hard to detect directly. However, indirect evidence suggests that such planets exist.^[4]^[5]^[6] Nonetheless, the most distant known planets are SWEEPS-11 and SWEEPS-04, located in Sagittarius, approximately 27,710 light-years from the Sun, while the Milky Way is about 87,400 light-years in diameter. This means that even galactic planets located further than that distance have not been detected.

^ Smith, Kiona (26 October 2021). "Extroplanet: Astronomers may have just found the first planet outside our galaxy". Inverse. Retrieved 2021-11-08.
^ Planet Song M51 ULS 1b Messier 51 Whirlpool Galaxy, retrieved 2021-11-08
^ Sandhya Ramesh (2021-10-29). "NASA telescope may have just helped find the first planet spotted outside Milky Way". ThePrint. Retrieved 2021-11-08.
^ Dai, Xinyu; Guerras, Eduardo (2 February 2018). "Probing Planets in Extragalactic Galaxies Using Quasar Microlensing". The Astrophysical Journal. 853 (2): L27. arXiv:1802.00049. Bibcode:2018ApJ...853L..27D. doi:10.3847/2041-8213/aaa5fb. S2CID 119078402.
^ Zachos, Elaine (5 February 2018). "More Than a Trillion Planets Could Exist Beyond Our Galaxy - A new study gives the first evidence that exoplanets exist beyond the Milky Way". National Geographic Society. Archived from the original on February 5, 2018. Retrieved 5 February 2018.
^ Mandelbaum, Ryan F. (5 February 2018). "Scientists Find Evidence of Thousands of Planets in Distant Galaxy". Gizmodo. Retrieved 5 February 2018.

[:0-1] Smith, Kiona (26 October 2021). "Extroplanet: Astronomers may have just found the first planet outside our galaxy". Inverse. Retrieved 2021-11-08.

[:1-2] Planet Song M51 ULS 1b Messier 51 Whirlpool Galaxy, retrieved 2021-11-08

[3] Sandhya Ramesh (2021-10-29). "NASA telescope may have just helped find the first planet spotted outside Milky Way". ThePrint. Retrieved 2021-11-08.

[ARX-20180202-4] Dai, Xinyu; Guerras, Eduardo (2 February 2018). "Probing Planets in Extragalactic Galaxies Using Quasar Microlensing". The Astrophysical Journal. 853 (2): L27. arXiv:1802.00049. Bibcode:2018ApJ...853L..27D. doi:10.3847/2041-8213/aaa5fb. S2CID 119078402.

[NG-20180205-5] Zachos, Elaine (5 February 2018). "More Than a Trillion Planets Could Exist Beyond Our Galaxy - A new study gives the first evidence that exoplanets exist beyond the Milky Way". National Geographic Society. Archived from the original on February 5, 2018. Retrieved 5 February 2018.

[GZM-20180205-6] Mandelbaum, Ryan F. (5 February 2018). "Scientists Find Evidence of Thousands of Planets in Distant Galaxy". Gizmodo. Retrieved 5 February 2018.

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