The best road to progress is freedom's road. - JFK
Texas
Click on the thumbnail image to jump to the desired order of length magnitude: top-left is 1e6m, lower-right is 1e17m. (Image description)
Largest circle with yellow arrow indicates one light year from Sun; Cat's Eye Nebula on left and Barnard 68 in middle are depicted in front of Comet 1910 A1's orbit. Click image for larger view, details and links to other scales.
7.5 Pm — 50,000 AU — Possible outer boundary of Oort cloud (other estimates are 75,000 to 125,000 or even 189,000 AU (1.6, 2, and 3 light years, respectively))
^Michael Szpir (May–June 2001). "Bart Bok's Black Blobs". American Scientist. Archived from the original on 2003-06-29. Retrieved 2008-11-19. Bok globules such as Barnard 68 are only about half a light-year across and weigh in at about two solar masses
References
Reed, Darren S.; Balick, Bruce; Hajian, Arsen R.; Klayton, Tracy L.; Giovanardi, Stefano; Casertano, Stefano; Panagia, Nino; Terzian, Yervant (1999). "Hubble Space Telescope Measurements of the Expansion of NGC 6543: Parallax Distance and Nebular Evolution". Astronomical Journal118 (5): 2430–2441. arXiv:astro-ph/9907313. Bibcode:1999AJ....118.2430R. doi:10.1086/301091.