¿ 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. 2021 January 18 [2]See Explanation. Clicking on the picture will download the highest resolution version available. The Medulla Nebula Supernova Remnant Image Credit & Copyright: [3]Russell Croman Explanation: What powers this unusual nebula? CTB-1 is the expanding gas shell that was left when a massive star toward the constellation of [4]Cassiopeia exploded about 10,000 years ago. The star likely detonated when it ran out of elements, near its core, that could create [5]stabilizing pressure with [6]nuclear fusion. The resulting [7]supernova remnant, nicknamed the Medulla Nebula for its [8]brain-like shape, still glows in [9]visible light by the heat generated by its collision with confining [10]interstellar gas. Why [11]the nebula also glows in [12]X-ray light, though, [13]remains a mystery. One hypothesis holds that an energetic [14]pulsar was co-created that powers the nebula with a fast outwardly moving wind. Following this lead, a pulsar has [15]recently been found in [16]radio waves that appears to have been expelled by the [17]supernova explosion at over 1000 kilometers per second. Although the [18]Medulla Nebula appears as large as a [19]full moon, it is so faint that it took 130-hours of exposure with two small telescopes in [20]New Mexico, [21]USA, to create the [22]featured image. Tomorrow's picture: moon and planets __________________________________________________________________ [23]< | [24]Archive | [25]Submissions | [26]Index | [27]Search | [28]Calendar | [29]RSS | [30]Education | [31]About APOD | [32]Discuss | [33]> __________________________________________________________________ Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell ([37]UMCP) NASA Official: Phillip Newman [38]Specific rights apply. [39]NASA Web Privacy Policy and Important Notices A service of: [40]ASD at [41]NASA / [42]GSFC & [43]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2101/Medulla_Croman_1200.jpg 3. https://www.rc-astro.com/about.html 4. https://en.wikipedia.org/wiki/Cassiopeia_(constellation) 5. http://large.stanford.edu/courses/2011/ph241/olson1/ 6. https://en.wikipedia.org/wiki/Nuclear_fusion 7. https://imagine.gsfc.nasa.gov/science/objects/supernova_remnants.html 8. https://en.wikipedia.org/wiki/Medulla_oblongata 9. https://science.nasa.gov/ems/09_visiblelight 10. https://apod.nasa.gov/apod/ap130924.html 11. https://ui.adsabs.harvard.edu/abs/2018PASJ...70..110K/abstract 12. https://science.nasa.gov/ems/11_xrays 13. https://www.barkbusters.co.uk/images/articles/7a4120f095480e9f2a2ad2a165d90313.jpg 14. https://en.wikipedia.org/wiki/Pulsar 15. https://ui.adsabs.harvard.edu/abs/2019sros.confE.158K/abstract 16. https://science.nasa.gov/ems/05_radiowaves 17. https://youtu.be/aysiMbgml5g 18. https://www.gxccd.com/art?id=543&cat=1&lang=409 19. https://apod.nasa.gov/apod/ap160201.html 20. https://youtu.be/unghDml5F_4 21. https://en.wikipedia.org/wiki/United_States 22. https://www.rc-astro.com/photo/id1222_big.html 23. https://apod.nasa.gov/apod/ap210117.html 24. https://apod.nasa.gov/apod/archivepix.html 25. https://apod.nasa.gov/apod/lib/apsubmit2015.html 26. https://apod.nasa.gov/apod/lib/aptree.html 27. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 28. https://apod.nasa.gov/apod/calendar/allyears.html 29. https://apod.nasa.gov/apod.rss 30. https://apod.nasa.gov/apod/lib/edlinks.html 31. https://apod.nasa.gov/apod/lib/about_apod.html 32. http://asterisk.apod.com/discuss_apod.php?date=210118 33. https://apod.nasa.gov/apod/ap210119.html 34. http://www.phy.mtu.edu/faculty/Nemiroff.html 35. http://www.phy.mtu.edu/ 36. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 37. http://www.astro.umd.edu/ 38. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 39. https://www.nasa.gov/about/highlights/HP_Privacy.html 40. https://astrophysics.gsfc.nasa.gov/ 41. https://www.nasa.gov/ 42. https://www.nasa.gov/centers/goddard/ 43. http://www.mtu.edu/