There is this theory, or confirmed fact, that the most far space objects like galaxies are running away because of the space expanding, and the further from us the faster it’s expanding.
So every moment something is not visibile anymore because it’s so distant that it’s speed is greater than the light, and the light it’s shooting towards us can’t ever reach us.
Can someone explain me this theory?
In: Physics
Imagine you have a yard stick. Every minute, the distance between the hashmarks increases by 1%.
This means two hashmarks an inch apart are now 1.01 inches apart.
However, the ends of the stick went from 36″ to 36.36″ apart in that same span of time. Points farther apart are moving apart more quickly because the space between them is itself growing.
On the vast scale of the universe, this means galaxies billions of light years apart are being pushed away from eachother at incredible speed. The expansion is imperceptible across thousands or even millions of light years, but over billions of light years it quickly adds up to exceed the speed of light.
Light emitted from those galaxies today will never reach earth, the space between the two is growing faster than light can cross the gap and it’s just speeding down an ever-faster cosmic treadmill.
This is a confirmed measurement. The more distant a galaxy is, the more space there is between us and the faster they are moving away. For some galaxies, we’ve measured distances that indicate that their relative velocity is larger than C. That means we will never see the light they emit today. We will see light from them for a few million years, because that light left long ago when they were closer. One day, we’ll reach the end of that light beam, and they will go dark.
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