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. 2024 November 29 [2]See Explanation. Clicking on the picture will download the highest resolution version available. Messier 4 Image Credit & [3]Copyright: [4]Steve Crouch Explanation: [5]Messier 4 can be found west of bright red-giant star Antares, alpha star of the constellation Scorpius. [6]M4 itself is only just visible from dark sky locations, even though the globular cluster of 100,000 stars or so is a mere 5,500 light-years away. Still, its proximity to prying telescopic eyes makes it a prime target for astronomical explorations. Recent studies have included Hubble observations of M4's pulsating cepheid variable stars, cooling white dwarf stars, and ancient, pulsar orbiting [7]exoplanet PSR B1620-26 b. This sharp image was captured with a [8]small telescope on planet Earth. At M4's estimated distance it spans about 50 light-years across the core of the globular star cluster. Tomorrow's picture: the climb __________________________________________________________________ [9]< | [10]Archive | [11]Submissions | [12]Index | [13]Search | [14]Calendar | [15]RSS | [16]Education | [17]About APOD | [18]Discuss | [19]> __________________________________________________________________ Authors & editors: [20]Robert Nemiroff ([21]MTU) & [22]Jerry Bonnell ([23]UMCP) NASA Official: Amber Straughn [24]Specific rights apply. [25]NASA Web Privacy Policy and Important Notices A service of: [26]ASD at [27]NASA / [28]GSFC, [29]NASA Science Activation & [30]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2411/m4_STXL16200_RC14_LRGB.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://members.pcug.org.au/~stevec/ 5. https://science.nasa.gov/mission/hubble/science/explore-the-night-sky/hubble-messier-catalog/messier-4/ 6. https://apod.nasa.gov/apod/ap000523.html 7. https://science.nasa.gov/exoplanet-catalog/psr-b1620-26-b/ 8. http://members.pcug.org.au/~stevec/m4_STXL16200_RC14.htm 9. https://apod.nasa.gov/apod/ap241128.html 10. https://apod.nasa.gov/apod/archivepix.html 11. https://apod.nasa.gov/apod/lib/apsubmit2015.html 12. https://apod.nasa.gov/apod/lib/aptree.html 13. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 14. https://apod.nasa.gov/apod/calendar/allyears.html 15. https://apod.nasa.gov/apod.rss 16. https://apod.nasa.gov/apod/lib/edlinks.html 17. https://apod.nasa.gov/apod/lib/about_apod.html 18. http://asterisk.apod.com/discuss_apod.php?date=241129 19. https://apod.nasa.gov/apod/ap241130.html 20. http://www.phy.mtu.edu/faculty/Nemiroff.html 21. http://www.phy.mtu.edu/ 22. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 23. http://www.astro.umd.edu/ 24. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 25. https://www.nasa.gov/about/highlights/HP_Privacy.html 26. https://astrophysics.gsfc.nasa.gov/ 27. https://www.nasa.gov/ 28. https://www.nasa.gov/centers/goddard/ 29. https://science.nasa.gov/learners 30. http://www.mtu.edu/