You have two observers, moving directly opposite each other.
Each has a flashlight pointing back at the other.
The speed of the light from those torched is the same for both observers.
(Instead the light would be red-shifted.)
Add a third observer, stationary to one and moving towards the other. As the third observer passes that observer, the speed of light from their flashlight never changes. (Instead it would go from being blue shifted to red shifted.)
whotookkarl@lemmy.dbzer0.com 3 days ago
When sailing boats pushed for speed they ended up hitting an unexpected speed barrier. As you increase velocity the break wave created by the bow of the ship elongates until the length of the ship is at 1 wavelength, then the hull drag prevents further acceleration. For a 50 meter ship it’s about 17 knots. You can get much faster lifting the boat from the water as you gain speed with an underwater wing, the current max speed was set 47 years ago at ~276 knots. But that’s only because they can remove the hull from the high drag environment and is extremely dangerous to attempt to break. The speed of light is nothing like that because spacetime itself can stretch and squish, I just wanted to talk about boats for a bit.
cannedtuna@lemmy.world 2 days ago
Still very interesting
icelimit@lemmy.ml 2 days ago
So you’re saying, we need to lift the spaceship out from space/time.
Sylvartas@lemmy.dbzer0.com 2 days ago
I’m not even mad because now I get why and how these competition multihull boats basically fly above water while keeping like 1% of the boat in water
anomnom@sh.itjust.works 2 days ago
Those ones are reaching a new speed limit as well, the cavitation around the hydrofoil starts at a certain speed/angle and stalls the foil, which then abruptly drops the hull back into the water.
I’ve been wondering how long before the equivalent of variable swept wings will be added to the cup boats.
kuberoot@discuss.tchncs.de 1 day ago
I love this because this feels like something the 10th doctor would say to confused daleks while stalling
NocturnalMorning@lemmy.world 1 day ago
I don’t like being deceived John! Tell me more about boats!