Relative speeds also cannot exceed the speed of light. Since there’s no absolute reference frame, if this were possible it would be no different than exceeding the speed of light on “absolute” terms. Once you get up to speeds where this would matter, funny dilation effects that I’m too dumb to understand would prevent this.
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treesquid@lemmy.world 5 days ago
In the same way that two cars driving away from each other at 60 mph have relative speeds of 120 mph with regard to each other, yes. Everything in the universe moving away from everything else and sometimes at relative speeds that exceed the speed of light. Nothing is exceeding the speed of light in absolute terms.
Luna@ani.social 4 days ago
childOfMagenta@jlai.lu 4 days ago
Cars are not driving away from each other at more than the speed of light. The road is stretching faster than the speed of light.
plutopos@lemmy.zip 4 days ago
Yeah, but wouldn’t this lead to the cars perceiving each other as moving faster than light?
Objection@lemmy.ml 4 days ago
That’s intuitive but actually completely wrong. There is no “absolute” reference frame, and nothing can move faster than light in any relative reference frame.
The only thing that gets around that is the expansion of space itself. It’s not that the objects are moving away from each other, it’s that the distance between them is expanding, causing them to become farther apart.
The best analogy is to picture an ant crawling on the surface of an expanding balloon. If the balloon keeps expanding fast enough forever, the ant won’t be able to make it from point A to point B. It’s not really that the ant is moving away from point B, it’s just that the distance is expanding faster than it can move.
Rooster326@programming.dev 4 days ago
Okay but the ant can still only go at the speed of ant.
Allero@lemmy.today 4 days ago
Exactly! That’s why we have a concept of observable universe.
As the universe expands (think of it not as ants moving, but more space created between ants), at some distance away from us it starts doing so faster than light.
The light, however, can only travel at, well, the speed of light. As such, we will never see or reach anything that is beyond this light speed horizon. And as the expansion of the universe speeds up, more and more objects that we can still observe will disappear beyond this point.