dontmakelemonad3 t1_j1gxnrt wrote on December 24, 2022 at 6:43 AM

Reply to comment by Shadowkiller00 in Did you know it will still take 46 billion years to cross the universe at the speed of light? 65 mph = 4.8 * 10^17 years! by NotAndroid545

>you would basically never reach the other side traveling at light speed

I'm neither a mathematician nor a physicist, but I don't think that's entirely correct. Although the observable universe would be expanding, it would be expanding both in front of you and behind you. This would mean that regardless of how slow your going, the proportion of distance you cover would be constantly increasing, and you would inevitably be able to get to the other side.

Shadowkiller00 t1_j1h7oyw wrote on December 24, 2022 at 9:00 AM

That is technically correct. There's a YouTube video about it by... minutephysics, I think, that points it out. But practically speaking, if you said you wanted to travel across the 93 billion light year universe at the speed of light, ignoring other aspects of special relativity, it would take far longer than 93 billion years.

dontmakelemonad3 t1_j1l4130 wrote on December 25, 2022 at 6:26 AM

Gotcha. When you said "basically never" I thought you were describing some kind of behavior of constantly approaching but never crossing. To me, if we're already talking about a length of time as comically large as 93 billion years, then contextually I would consider no finite length of time to be "basically never," even if we're talking about an amount of time tens or hundreds of orders of magnitude greater than 93 billion.