Thursday, September 4, 2014

Delta Aquilae is 50 light years away

Aquila, the eagle, is a summer constellation. 
It can be found here in the summer evenings section:

It’s brightest star, alpha aquilae, a/k/a altair, forms one of the corners of the summer triangle.  A huge right triangle seen overhead during summer nights. 
Delta aquilae is at the center of the eagle.  At visual magnitude 3.36 it can be seen with the naked eye in good viewing conditions.



It is 50 light years away. 

Einstein’s theory of special relativity.  Basically states that the speed of light is the same for all observers.  Consider a space ship moving away from us at half the speed of light.  We shine a bright pulse of light into space.  After a year the light has traveled one light year away from us, while the space ship has traveled half a light year.  The pulse of light is half a light year from the ship.  So if the light has only traveled half a light year from the ship, how can its speed relative to the ship be the same?  Speed=distance/time.  So the solution is that the ship has only experienced half the time we have on earth—time has slowed down. 

Consider a photon leaving delta aquilae 50 years ago.  Some of us have experienced 50 years waiting for its arrival today.  But the photon, traveling AT the speed of light experienced no time at all. 

Something to think about for this day.  

Imaging details.
FS 60c @ 254 mm 5.23"/px full size
Chroma Loglow filter
SX H9C, ASA DDM 60 unguided
13 5 minutes, 24x30s, 24x3s
"diffraction spikes" added in processing for emphasis
newport beach, ca

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