- #1
Hulse
- 8
- 0
Problem:
I'm trying to do a diagram of the observable universe, and I got bogged down. I drew a circle representing the outer limit, the "surface of last scattering," 78 billion light years in diameter. In the center I put a tiny dot to represent us and the Local Group of galaxies. At two locations on the radius I put dots representing two known galactic clusters together with their "distances now" worked out by using Ned Wright's cosmology calculator. Then I drew two tangent circles, diameters equal to the original circle and labeled each perimeter "surface of last scattering." So the centers of all three circles formed a straight line of diameters. I reasoned that if one could jump in imagination to a tangent point, one would see exactly the same sort of sky one sees now from earth. Further, I reasoned that if the larger universe were closed, one could keep on drawing these tangent circles till they came round in a "band of tangent circles" to meet the original circle. But now I'm get the feeling I did something wrong, but I don't know what.
Can somebody who knows analyze my work, tell me if I made mistakes, show me how I should "diagram the universe," or if it's not diagrammable, tell me why it's not.
Thanks in advance.
I'm trying to do a diagram of the observable universe, and I got bogged down. I drew a circle representing the outer limit, the "surface of last scattering," 78 billion light years in diameter. In the center I put a tiny dot to represent us and the Local Group of galaxies. At two locations on the radius I put dots representing two known galactic clusters together with their "distances now" worked out by using Ned Wright's cosmology calculator. Then I drew two tangent circles, diameters equal to the original circle and labeled each perimeter "surface of last scattering." So the centers of all three circles formed a straight line of diameters. I reasoned that if one could jump in imagination to a tangent point, one would see exactly the same sort of sky one sees now from earth. Further, I reasoned that if the larger universe were closed, one could keep on drawing these tangent circles till they came round in a "band of tangent circles" to meet the original circle. But now I'm get the feeling I did something wrong, but I don't know what.
Can somebody who knows analyze my work, tell me if I made mistakes, show me how I should "diagram the universe," or if it's not diagrammable, tell me why it's not.
Thanks in advance.