Ahad's sphere of solar illuminance - the limit of Sun's light domination

[Javid]

First defined: July 2004 by Abdul Ahad
Radius: 11,500 AUs (based on Ahad's flux constant of -6.5 and Sun's absolute magnitude of +4.8)
Volume: 6.4 x 10^12 Cubic AUs
=========================================================

Description:

On any interstellar journey going outward from our solar system, one eventually reaches a point where the total amount of light received from our Sun is exactly matched by the total amount of flux coming from all cosmic sources external to our solar system. The heliocentric distance of that boundary is dubbed the "Ahad radius", and exists at the edge of "Ahad's sphere of solar illuminance", some 11,500 astronomical units (roughly a trillion [10^12] miles) from Earth.

On first definition of this heliocentric boundary, Abdul Ahad wrote:-

"Beyond the outer edges of this theoretical sphere, the feeble currents of light coming from its core (i.e. our own distant Sun) will cease to make any noticeable ripples in the calm waters of the surrounding cosmic ocean..." - July, 2004.

In the context of space exploration, no man-made spacecraft has yet escaped beyond the "Ahad sphere"; Voyager 1 is leading the charge and will reach the AR in just over 3,000 years from now. Voyager 2, Pioneers 10 and 11 will all follow after that.

Full paper:
http://uk.geocities.com/aa_spaceagen...erstellar.html

Commentary on Google:
http://groups-beta.google.com/groups?q=ahad+radius

Regards,
Jav

[Robert-Rowland]

"Ahad radius" can be defined in so many unique and interesting ways:-

- The edge of solar flux prevalence
- Beyond where the Sun no longer rules...
- Where our majestic Sun ceases to be majestic
- The limit of Sol's light domination
- Boundary of equilibrium between solar flux and cosmic background flux
- etc, etc

Interesting concept, but you'd be better off posting to astronomy groups as this BD forum is more mainstream.

R-R

[Nobody_Special]

Interesting chats going on at wikipedia today about this. The night sky constant is pretty neat idea:

when you go outside the Sol System, "The net illumination from all the pinpricks of starry light in the 360-degree celestial sphere around you will then equate to "Ahad's constant" of 1/300th full moon"
As one poster wrote about Ahad's Sphere of Solar Illuminance;

"Thou will be forever seen as the light of inspiration guiding mankind toward thee boundaries marked by the Ahad radius whence returning from universe journeys to the far..." ~ anonymous.

It seems they should keep the ahad radius in Wikipedia for future guidance of mankind

[Nobody_Special]

bunch of co** s***ers deleted it!!! In that case, the Ahad radius should go on Banglapedia

[randomizer]

It is in latest version

Apparent magnitudes of known celestial objects App. Mag. Celestial object:

−26.73 Sun (449,000 times brighter than full moon)
−20 Sun (As seen from Neptune)
−12.6 Full Moon
−8.0 Maximum brightness of an Iridium (satellite) flare
−6.5 Ahad's constant[3]
−6.0 The Crab Supernova (SN 1054) of AD 1054 (6500 light years away)
−4.7 Maximum brightness of Venus and the International Space Station (when the ISS is at its perigee and fully lit by the sun)[4]
−3.9 Faintest objects observable during the day with naked eye
−3.7 Minimum brightness of Venus
−3.0 Maximum brightness of Mars
−2.8 Maximum brightness of Jupiter
−1.9 Maximum brightness of Mercury
−1.47 Brightest star (except for the sun) at visible wavelengths: Sirius
−0.7 Second-brightest star: Canopus
−0.24 Maximum brightness of Saturn
0 The zero point by definition: This used to be Vega
(see references for modern zero point)
3 Faintest stars visible in an urban neighborhood with naked eye
4.6 Maximum brightness of Ganymede
5.5 Maximum brightness of Uranus
6.5 Faintest stars observable with naked eye under perfect conditions
6.7 Maximum brightness of Ceres
7.7 Maximum brightness of Neptune
9.1 Maximum brightness of 10 Hygiea
9.5 Faintest objects visible with binoculars
10.2 Maximum brightness of Iapetus
12.9 Brightest quasar 3C 273 (2.4 Giga-light years away)
13.65 Maximum brightness of Pluto (1,148 times fainter than naked-eye visibility)
18.7 Current opposition brightness of Eris
23 Maximum brightness of Pluto's smallest moons Hydra and Nix
27 Faintest objects observable in visible light with 8m ground-based telescopes
30 Faintest objects observable in visible light with Hubble Space Telescope
35 Sedna at aphelion (900 AU)[5]
38 Faintest objects observable in visible light with planned OWL