The stronger the gravity/acceleration the slower the time.
We know from Einstein that my clock and your clock will not run at the same rate. Time (or rate of our clocks) depends on acceleration and/or gravity. If my clock accelerates and/or is in a strong gravitational field then it will run slower than your clock. So time is relative. Quran 22.47 compares time of Earth with time at Paradise/Hell (1 day vs 1000 years); while Quran 70.4 compares time on Earth with time in wormholes (1 day vs 50,000 years).
The Quran says that when angels travel they experience different time than ours:
[Quran 70.4] The angels and the Spirit ascend to Him in a day, the measure of which is fifty thousand years.
Here angels will experience 1 day while humans will measure it as 50,000 years (time vs. time and not time vs. distance as the other lunar verse). This can happen if:

Angels accelerate to relativistic speeds.

Angels are in a strong gravitational field.
1) Outside gravitational fields: This agrees with Einstein’s theory of special relativity, which says that a faster moving object appears to experience slower time. Moslems use Einstein’s theory of special relativity with the following verse in the Quran to check whether those angels really accelerate up to the speed of light or not. Given this time difference (time dilation) we can calculate the speed at which that object traveled. We can verify if those angels really accelerate up to the speed of light, as claimed by Moslems, or not. Outside gravitational fields this speed turned out to be 99.99999999999981% of the speed of light:
(Where ∆t_{o} is the time measured for a mover by a mover; ∆t is the time measured for a mover by a stationary frame; v is the velocity of the mover relative to the stationary observer):
∆t_{o} is the time experienced by angels (1 day).
∆t is the time as measured by humans (50,000 lunar years x12 lunar months/lunar year x 27.321661 days/lunar month).
v is the velocity of angels in this case (which we intend to calculate and then compare to the known speed of light).
c is the nominal speed of light 299792.458 km/s.
From the above equation we can solve for the unknown velocity:
This time dilation (time difference) shows that angels indeed accelerate to relativistic speeds; outside gravitational fields this is the same speed calculated from the previous lunar verse also outside gravitational fields.
We cannot calculate our local speed of light from this time dilation however we can calculate at what percentage of the speed of light those angels are traveling relative to an observer on Earth. By this we can compare a time dilation (50,000 years vs. one day) with a speed (12000 Lunar Orbits/Earth Day). We can do this by translating both of them to a common speed in km/sec. Outside gravitational fields 50,000 years vs. one day shows angels traveling at 12000 Lunar Orbits/Earth Day; it is the same speed in km/sec.
2) Inside gravitational fields: This time dilation shows angels crossing a wormhole (معراج) at a few meters/sec.
This is a picture of a wormhole. The Quran says that angels use these wormholes to reach any place in the universe. An observer outside gravitational fields sees those angels passing by him at 99.99999…% of the speed of light (relativistic speeds, very close to the local speed of light), that is at 299792.457999…km/s. But when those angels enter the gravitational field of a wormhole this observer still sees those angels entering the wormhole at 99.99999…% of the speed of light however that would no longer be at 299792.457999…km/s. This is because in the presence of gravity the speed of light becomes relative. If he sees the speed of light in a wormhole at 10 meters/sec, for example, then he would see those angels traveling at only 9.999999…meters/sec, flapping their wings in slow motion, reddish in color and very dim (and in turn they would see him in fast motion, bluish in color and very bright).
A smaller time dilation (say 100 or 1000 years vs. one day) can also occur if we stand on Earth and angels stand on a neutron star (or resist their fall into a neutron star; gravitational time dilation). This makes their velocity relative to us to be zero (and not 299792.457999… km/s). But naturally occurring wormholes connect distant black holes; however at a lower time dilation (100 or 1000 years vs. one day) the two entrances of the wormhole cannot connect; hence a wormhole cannot form. So with the time dilation stated in the Quran (50,000 years vs. 1 day) and the fact that angels are moving then those angels have to be crossing a wormhole. The neutron star or any other scenario cannot do. Learn more: Wormholes