kottke.org

...is a weblog about the liberal arts 2.0 edited by Jason Kottke since March 1998 (archives). You can read about me and kottke.org here. If you've got questions, concerns, or interesting links, send them along.

Personal light cones

When I was born 35.2 years ago, a light cone started expanding away from Earth out into the rest of the universe (Minkowski space-temporally speaking, of course). Thanks to updates from Matt Webb's fancy RSS tool, I know that my personal light cone is about to envelop the Zeta Herculis binary star system, located 35.2 light years from Earth in the constellation Hercules.

With a mass some 50 percent greater than the Sun, however, and beginning its evolution toward gianthood (its core hydrogen fusion likely shut down), Zeta Her A is 6 times more luminous than the Sun with a radius 2.5 times as large. Nevertheless, the star gives a good idea of what the Sun would look like from a great distance, in Zeta Her's case 35 light years. The companion (Zeta Her B), a cooler class G (G7) hydrogen-fusing dwarf with a luminosity only 65 percent that of the Sun and a mass about 85 percent solar, orbits with a period of 34.5 years at a mean distance of 15 Astronomical Units (over 50 percent farther than Saturn is from the Sun). A rather high eccentricity takes the two as far apart as 21 AU and as close as 8 AU.

Hercules is of course named for the Greek hero, Heracles. Next up is Delta Trianguli, another binary star system, in about two months.

By Jason Kottke    Dec 2, 2008 at 05:09 pm    Jason Kottke   light   Matt Webb   space   time   universe

kottke.org, quickly...

The best way to get a sense of what kottke.org is all about is to head to the front page or check out some random entries from the archives. Follow kottke.org via RSS or Twitter.

Want to share your something special with kottke.org's readers? Sponsor the RSS feed for a week!

Looking for work?

See more on the Job Board.

Recommended sites

David Archer    Matthew Paul Thomas    Rebecky    greg.org    jimr(ay)    evhead    panopticist    strange maps    Nivi    Type for you.    Airbag    Ikeepadiary    The Pop!Tech Blog    Eater    tremble.com    Frumination    Personism    NYT Science    Idle Words    The Laboratorium