Astronomy Picture of the Day [1]Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2019 December 14 [2]See Explanation. Clicking on the picture will download the highest resolution version available. Interstellar Comet 2I/Borisov Image Credit: [3]NASA, [4]ESA, and [5]D. Jewitt ([6]UCLA) et al. Explanation: [7]From somewhere else in the Milky Way galaxy, [8]Comet 2I/Borisov is just visiting the Solar System. Discovered by Crimean amateur astronomer Gennady Borisov on August 30, 2019, the first known interstellar comet is captured in these two recent [9]Hubble Space Telescope images. On the left, a distant background galaxy near the line-of-sight to Borisov is blurred as [10]Hubble tracked the speeding comet and dust tail about 327 million kilometers from Earth. At right, 2I/Borisov appears shortly after perihelion, it's closest approach to Sun. Borisov's closest approach to our fair planet, a distance of about 290 million kilometers, will come on December 28. Even though Hubble's sharp images don't resolve the comet's nucleus, they do lead to estimates of less than 1 kilometer for its diameter. Tomorrow's picture: cloudy day __________________________________________________________________ [11]< | [12]Archive | [13]Submissions | [14]Index | [15]Search | [16]Calendar | [17]RSS | [18]Education | [19]About APOD | [20]Discuss | [21]> __________________________________________________________________ Authors & editors: [22]Robert Nemiroff ([23]MTU) & [24]Jerry Bonnell ([25]UMCP) NASA Official: Phillip Newman [26]Specific rights apply. [27]NASA Web Privacy Policy and Important Notices A service of: [28]ASD at [29]NASA / [30]GSFC & [31]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/1912/borisovStsci1826.jpg 3. https://www.nasa.gov/ 4. http://www.spacetelescope.org/ 5. http://www2.ess.ucla.edu/~jewitt/David_Jewitt.html 6. http://www.ess.ucla.edu/ 7. https://apod.nasa.gov/apod/ap191018.html 8. https://en.wikipedia.org/wiki/2I/Borisov 9. https://hubblesite.org/contents/news-releases/2019/news-2019-61 10. https://hubblesite.org/contents/media/videos/2019/53/1244-Video 11. https://apod.nasa.gov/apod/ap191213.html 12. https://apod.nasa.gov/apod/archivepix.html 13. https://apod.nasa.gov/apod/lib/apsubmit2015.html 14. https://apod.nasa.gov/apod/lib/aptree.html 15. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 16. https://apod.nasa.gov/apod/calendar/allyears.html 17. https://apod.nasa.gov/apod.rss 18. https://apod.nasa.gov/apod/lib/edlinks.html 19. https://apod.nasa.gov/apod/lib/about_apod.html 20. http://asterisk.apod.com/discuss_apod.php?date=191214 21. https://apod.nasa.gov/apod/ap191215.html 22. http://www.phy.mtu.edu/faculty/Nemiroff.html 23. http://www.phy.mtu.edu/ 24. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 25. http://www.astro.umd.edu/ 26. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 27. https://www.nasa.gov/about/highlights/HP_Privacy.html 28. https://astrophysics.gsfc.nasa.gov/ 29. https://www.nasa.gov/ 30. https://www.nasa.gov/centers/goddard/ 31. http://www.mtu.edu/