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. 2023 June 29 [2]The illustration shows the beams from pulsars around the image and a pair of merging black holes on the upper left. A grid depicting the warping of spacetime by passing gravitational waves spreads across the image center. Please see the explanation for more detailed information. A Message from the Gravitational Universe Illustration Credit: [3]NANOGrav Physics Frontier Center; Text: [4]Natalia Lewandowska ([5]SUNY Oswego) Explanation: Monitoring 68 [6]pulsars with very large [7]radio telescopes, the [8]North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has uncovered evidence for the [9]gravitational wave (GW) [10]background by [11]carefully measuring slight shifts in the arrival times of pulses. [12]These shifts are correlated between different [13]pulsars in a way that indicates that they are caused by GWs. This [14]GW background is likely due to hundreds of thousands or even millions of [15]supermassive black hole binaries. Teams in [16]Europe, [17]Asia and [18]Australia have also independently reported their results today. Previously, the [19]LIGO and [20]Virgo detectors have detected higher-frequency GWs from the [21]merging of individual [22]pairs of massive orbiting objects, such as stellar-mass [23]black holes. The featured illustration highlights this [24]spacetime-shaking result by depicting two orbiting [25]supermassive black holes and several of the [26]pulsars that would [27]appear to have slight timing shifts. The imprint these [28]GWs make on spacetime itself is illustrated by a [29]distorted grid. Open Science: [30]Browse 3,000+ codes in the Astrophysics Source Code Library Tomorrow's picture: asteroid day __________________________________________________________________ [31]< | [32]Archive | [33]Submissions | [34]Index | [35]Search | [36]Calendar | [37]RSS | [38]Education | [39]About APOD | [40]Discuss | [41]> __________________________________________________________________ Authors & editors: [42]Robert Nemiroff ([43]MTU) & [44]Jerry Bonnell ([45]UMCP) NASA Official: Phillip Newman [46]Specific rights apply. [47]NASA Web Privacy Policy and Important Notices A service of: [48]ASD at [49]NASA / [50]GSFC, [51]NASA Science Activation & [52]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2306/Gwb_Nanograv_3000_annotated.jpg 3. https://nanograv.org/ 4. https://www.oswego.edu/physics/natalia-lewandowska 5. https://www.oswego.edu/physics/ 6. https://en.wikipedia.org/wiki/Pulsar 7. https://en.wikipedia.org/wiki/Radio_telescope 8. https://nanograv.org/science/overview 9. https://nanograv.org/science/topics/low-frequency-gravitational-waves 10. https://en.wikipedia.org/wiki/Gravitational_wave_background 11. https://nanograv.org/news/15yrRelease 12. https://www.seti.org/press-release/nanogravs-15-year-journey-reveals-cosmic-hum 13. https://apod.nasa.gov/apod/ap220821.html 14. https://astrobites.org/2018/01/29/hunting-for-gravitational-waves-from-spinning-neutron-stars/ 15. https://apod.nasa.gov/apod/ap181203.html 16. https://en.wikipedia.org/wiki/Europe 17. https://en.wikipedia.org/wiki/Asia 18. https://en.wikipedia.org/wiki/Australia 19. https://www.aps.org/publications/apsnews/201710/virgo.cfm 20. https://en.wikipedia.org/wiki/Virgo_interferometer 21. https://apod.nasa.gov/apod/ap210411.html 22. https://apod.nasa.gov/apod/ap211207.html 23. https://solarsystem.nasa.gov/news/1068/10-questions-you-might-have-about-black-holes/ 24. https://en.wikipedia.org/wiki/Spacetime 25. https://astronomy.swin.edu.au/cosmos/s/supermassive+black+hole 26. https://www.atnf.csiro.au/outreach/education/everyone/pulsars/index.html 27. https://images.fineartamerica.com/images/artworkimages/mediumlarge/3/cat-looking-surprised-peering-over-the-edge-of-the-picture-john-daniels.jpg 28. https://youtu.be/4GbWfNHtHRg 29. https://youtu.be/R7V3koyL7Mc 30. https://ascl.net/code/all 31. https://apod.nasa.gov/apod/ap230628.html 32. https://apod.nasa.gov/apod/archivepix.html 33. https://apod.nasa.gov/apod/lib/apsubmit2015.html 34. https://apod.nasa.gov/apod/lib/aptree.html 35. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 36. https://apod.nasa.gov/apod/calendar/allyears.html 37. https://apod.nasa.gov/apod.rss 38. https://apod.nasa.gov/apod/lib/edlinks.html 39. https://apod.nasa.gov/apod/lib/about_apod.html 40. https://asterisk.apod.com/discuss_apod.php?date=230629 41. https://apod.nasa.gov/apod/ap230630.html 42. http://www.phy.mtu.edu/faculty/Nemiroff.html 43. http://www.phy.mtu.edu/ 44. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 45. http://www.astro.umd.edu/ 46. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 47. https://www.nasa.gov/about/highlights/HP_Privacy.html 48. https://astrophysics.gsfc.nasa.gov/ 49. https://www.nasa.gov/ 50. https://www.nasa.gov/centers/goddard/ 51. https://science.nasa.gov/learners 52. http://www.mtu.edu/