4 ms·
I read the article but didn't watch the videos yet, but I'm curious as to what would be needed to make this a 3D map. That is, I'm assuming this 2D map records
by hn_throwaway_99 2mo ago
I read the article but didn't watch the videos yet, but I'm curious as to what would be needed to make this a 3D map. That is, I'm assuming this 2D map records the position of all of these objects in the sky, but not the distance from Earth. But I thought that calculating the distance of objects is relatively straightforward, e.g. you hear all the time "Galaxy X is 2 billion lightyears away" or whatever. Would it just be really computationally expensive to calculate the distance to all of the 4 billion objects identified in the map?
- LeBit 2mo agoI think it is 2D because the universe is not that thick?
- jbritton 2mo agoI will add that it is said the universe is flat, but that does not mean 2d flat. Flat is a mathematical construct, which means parallel lines stay parallel and triangle angles sum to 180 degrees. So it is 3d flat at least as far as we can observe.
- LeBit 2mo agoI was mistaken. Our solar system is flat. Galaxies are mostly flat. But the universe is not flat. Galaxies are all over the place. So, I was mistaken. But, just to be clear: I am not a flat earther! Flat is relative here. The thickness of our galaxy is not measured in kilometers ofc. It is just that within the same units , solar systems and galaxies are flat relative to their length.
- soulofmischief 2mo agoThere are a lot of unknowns and processes that must be undone, which often require an unknown basis. Red shift, moving bodies, gravitational lensing and other processes distort light along its journey. Sometimes we don't know the exact magnitude of a star, etc. Spectroscopy helps a lot but is limited by the fidelity of our datasets.
- epistasis 2mo agoThey do this mostly with spectroscopy, breaking out the light by frequency. The longer the light has been travelling, the more frequency shifts into redder frequencies, because the universe is continually expanding. But those distances are all built on top of the cosmic distance ladder (Terence Tao explaining on 3blue1brown) https://youtu.be/YdOXS_9_P4U?is=jbkFbwWKgbn3yOjq https://youtu.be/YdOXS_9_P4U?is=jbkFbwWKgbn3yOjq Maps like DESI add the 3d distances. https://www.desi.lbl.gov/education-outreach/interactive-visualizations/ https://www.desi.lbl.gov/education-outreach/interactive-visu...
- fluoridation 2mo agoCelestia might be what you're looking for.