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 March 7 [2]See Explanation. Clicking on the picture will download the highest resolution version available. Planetary Nebula Abell 7 Image Credit: Image Credit & [3]Copyright: [4]Vikas Chander Explanation: Very faint planetary nebula Abell 7 is about 1,800 light-years distant. It lies just south of Orion in planet Earth's skies toward the constellation [5]Lepus, The Hare. Surrounded by Milky Way stars and near the line-of-sight to distant background galaxies its [6]generally simple spherical shape, about 8 light-years in diameter, is revealed in this deep telescopic image. Within the cosmic cloud are beautiful and complex structures though, enhanced by the use of long exposures and [7]narrowband filters that capture emission from hydrogen, sulfur, and oxygen atoms. Otherwise Abell 7 would be much too faint to be appreciated [8]by eye. A [9]planetary nebula represents a very brief final phase in stellar evolution that our own Sun will experience 5 billion [10]years hence, as the nebula's central, once sun-like star shrugs off its outer layers. Abell 7 itself is estimated to be 20,000 years old. But its central star, seen here as a [11]fading white dwarf, is some 10 billion years old. Tomorrow's picture: light-weekend __________________________________________________________________ [12]< | [13]Archive | [14]Submissions | [15]Index | [16]Search | [17]Calendar | [18]RSS | [19]Education | [20]About APOD | [21]Discuss | [22]> __________________________________________________________________ Authors & editors: [23]Robert Nemiroff ([24]MTU) & [25]Jerry Bonnell ([26]UMCP) NASA Official: Amber Straughn [27]Specific rights apply. [28]NASA Web Privacy Policy and Important Notices A service of: [29]ASD at [30]NASA / [31]GSFC, [32]NASA Science Activation & [33]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2503/Abell7_VChander4096.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.instagram.com/vikaschanderastrophotography/ 5. http://www.allthesky.com/constellations/big/lepus28vm-b.jpg 6. http://arxiv.org/abs/1210.6226 7. https://apod.nasa.gov/apod/ap111013.html 8. https://apod.nasa.gov/apod/ap100506.html 9. http://en.wikipedia.org/wiki/Planetary_nebula 10. http://www.futuretimeline.net/beyond.htm 11. https://www.nasa.gov/feature/goddard/2019/citizen-scientist-finds-ancient-white-dwarf-star-encircled-by-puzzling-rings 12. https://apod.nasa.gov/apod/ap250306.html 13. https://apod.nasa.gov/apod/archivepix.html 14. https://apod.nasa.gov/apod/lib/apsubmit2015.html 15. https://apod.nasa.gov/apod/lib/aptree.html 16. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 17. https://apod.nasa.gov/apod/calendar/allyears.html 18. https://apod.nasa.gov/apod.rss 19. https://apod.nasa.gov/apod/lib/edlinks.html 20. https://apod.nasa.gov/apod/lib/about_apod.html 21. http://asterisk.apod.com/discuss_apod.php?date=250307 22. https://apod.nasa.gov/apod/ap250308.html 23. http://www.phy.mtu.edu/faculty/Nemiroff.html 24. http://www.phy.mtu.edu/ 25. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 26. http://www.astro.umd.edu/ 27. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 28. https://www.nasa.gov/about/highlights/HP_Privacy.html 29. https://astrophysics.gsfc.nasa.gov/ 30. https://www.nasa.gov/ 31. https://www.nasa.gov/centers/goddard/ 32. https://science.nasa.gov/learners 33. http://www.mtu.edu/