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. 2025 August 13 [2]A bright nebula occupies the center of the frame. The nebula is complex but roughly tan in the center and red around the edges. In the center are four bright blue stars. Please see the explanation for more detailed information. Trapezium: In the Heart of Orion Image Credit: Data: [3]Hubble Legacy Archive, Processing: [4]Robert Gendler Explanation: What lies in the heart of Orion? Trapezium: four bright stars, that can be found near the center of [5]this sharp cosmic portrait. Gathered within a region about 1.5 light-years in radius, these stars dominate the core of the dense [6]Orion Nebula Star Cluster. [7]Ultraviolet ionizing radiation from the [8]Trapezium stars, mostly from the brightest star [9]Theta-1 Orionis C powers the complex star forming region's entire visible glow. About three million years old, the Orion Nebula Cluster was even more [10]compact in its younger years and a [11]dynamical study indicates that [12]runaway stellar collisions at an earlier age may have formed a black hole with more than 100 times the mass of [13]the Sun. The presence of a [14]black hole within the cluster could explain the observed high velocities of the [15]Trapezium stars. The Orion Nebula's distance of some 1,500 [16]light-years make it one of the [17]closest candidate black holes to Earth. Tomorrow's picture: when the Sky is serene and the Moon absent __________________________________________________________________ [18]< | [19]Archive | [20]Submissions | [21]Index | [22]Search | [23]Calendar | [24]RSS | [25]Education | [26]About APOD | [27]Discuss | [28]> __________________________________________________________________ Authors & editors: [29]Robert Nemiroff ([30]MTU) & [31]Jerry Bonnell ([32]UMCP) NASA Official: Amber Straughn [33]Specific rights apply. [34]NASA Web Privacy, [35]Accessibility, [36]Notices; A service of: [37]ASD at [38]NASA / [39]GSFC, [40]NASA Science Activation & [41]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2508/OrionTrapezium_HubbleGendler_4000.jpg 3. http://hla.stsci.edu/ 4. http://www.robgendlerastropics.com/ 5. http://www.robgendlerastropics.com/TrapMosaic-HST-Gendler.html 6. https://apod.nasa.gov/apod/ap241104.html 7. https://science.nasa.gov/ems/10_ultravioletwaves 8. https://en.wikipedia.org/wiki/Trapezium_Cluster 9. http://stars.astro.illinois.edu/sow/theta1ori.html 10. https://ih1.redbubble.net/image.1754337954.2361/raf,360x360,075,t,fafafa:ca443f4786.jpg 11. https://ui.adsabs.harvard.edu/abs/2012ApJ...757...37S/abstract 12. https://skyandtelescope.org/astronomy-news/a-black-hole-in-orion/ 13. https://science.nasa.gov/sun/ 14. https://apod.nasa.gov/apod/ap141026.html 15. https://apod.nasa.gov/apod/ap170321.html 16. https://spaceplace.nasa.gov/light-year/ 17. https://en.wikipedia.org/wiki/List_of_nearest_black_holes 18. https://apod.nasa.gov/apod/ap250812.html 19. https://apod.nasa.gov/apod/archivepix.html 20. https://apod.nasa.gov/apod/lib/apsubmit2015.html 21. https://apod.nasa.gov/apod/lib/aptree.html 22. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 23. https://apod.nasa.gov/apod/calendar/allyears.html 24. https://apod.com/feed.rss 25. https://apod.nasa.gov/apod/lib/edlinks.html 26. https://apod.nasa.gov/apod/lib/about_apod.html 27. https://asterisk.apod.com/discuss_apod.php?date=250813 28. https://apod.nasa.gov/apod/ap250814.html 29. http://www.phy.mtu.edu/faculty/Nemiroff.html 30. http://www.phy.mtu.edu/ 31. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 32. http://www.astro.umd.edu/ 33. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 34. https://www.nasa.gov/about/highlights/HP_Privacy.html 35. https://www.nasa.gov/general/accessibility/ 36. https://www.nasa.gov/privacy/ 37. https://astrophysics.gsfc.nasa.gov/ 38. https://www.nasa.gov/ 39. https://www.nasa.gov/centers/goddard/ 40. https://science.nasa.gov/learners 41. http://www.mtu.edu/