Expansion factor in light distance measurements

[gone_fishin]

Hi all I'm new here and really enjoy the atmosphere so I joined after seeing the nice discussions and really open thought. <br /><br />I have a question that has always bugged me when I hear the vast precise measurements of distant objects thrown about. <br /><br />The universe is observed to be expanding. Light travels across the expanding universe to our perspective viewpoint. The distance to get here increases because of this expansion over time. The gravitational forces the light encounters distorts the path of the light increasing its journey even more.<br /><br />Now imagine an extreme example. The light from say a galaxy in Hubble's deep space probe image. We say the measurement is so many billions of light years. The characteristics of the universal expansion are unknown, as in what we measure now may be a lot less expansion than billions of years ago. Also the light may have been bent (increasing its journey) from countless unseen gravity fields (black holes, dark matter etc).<br />The light we see from our nearest stars only had to travel through a small fraction of universal expansion time in comparison.<br /><br />The light year is a constant I know but if we don't know the variables are we really giving an accurate distance as relates to the object and our viewpoint?<br />

 

[why06]

Usually these images are not distorted...<br /><br />But when they are only a small fraction is distorted and the object blocking the light will eventally move out the way. This i how we notice planets i other solar systems.<br /><br />In th case of a black hole many times the light that would normally not intersect the hole will instead veer around it and head in our direction.<br />So that the we can tell of the lost in energy form the light, but can still see the object.<br /><br /><br /><font color="yellow"> Welcome to SDC <img src="/images/icons/smile.gif" /></font> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[alkalin]

Welcome to the board. Or should I say the universe. <br /><br /><font color="yellow">The universe is observed to be expanding.</font><br /><br />Well, actually, it is not observed to be expanding. Due to the red shift seen in the distant universe we assume expansion to explain the red shift seen there. There are other possibilities such as the Wolf effect.<br /><br />And there are several factors in determining distance other than red shift. There is luminosity or brightness of distant objects that must be considered along with an angle of reference that very powerful telescopes can give us.<br /><br />I would caution that a lot of the thinking behind the issues you have brought up involve logic in math, and guess what, there is no math that explains the universe. A lot of it is imagination.<br />