उचित दूरी कैलकुलेटर
ब्रह्मांडीय उचित (प्रॉपर) दूरी की गणना करें।
Proper Distance
428.0000 Mpc
Proper Distance vs Comoving Distance
सूत्र
Proper Distance
The proper distance is the physical distance between two objects at a particular moment in cosmic time.
Relation
d_proper = a(t) * d_comoving
At the present epoch a = 1, so proper distance equals comoving distance. In the past (a < 1) the physical distance was smaller.
हल किया गया उदाहरण
A galaxy with comoving distance 428 Mpc observed at the present epoch (a = 1).
- 01d_proper = a(t) * d_comoving
- 02d_proper = 1.0 * 428
- 03d_proper = 428 Mpc ≈ 1396 Mly
अक्सर पूछे जाने वाले प्रश्न
What is the scale factor?
The scale factor a(t) describes how distances in the universe have changed over time. By convention a = 1 today; at the Big Bang a = 0.
When would I use a scale factor other than 1?
To find the physical distance at an earlier epoch. For instance, at redshift z the scale factor was a = 1 / (1 + z).
Is the proper distance directly observable?
Not directly. We infer it from redshift and a cosmological model. What we observe is the luminosity distance or angular-diameter distance.