We can see things moving faster than light
Physics Girl・12 minutes read
Light from distant galaxies takes longer to reach us due to the universe's expansion, resulting in galaxies being farther away than expected, with some moving away faster than the speed of light but still visible through a complex path.
Insights
- Light from distant galaxies can take billions of years to reach us, but due to the universe's expansion, they are much farther away than the time it took for their light to travel.
- The expansion of the universe causes galaxies to move away from us at speeds exceeding that of light, making it impossible to observe them as they are now, only as they were when the light began its journey.
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Recent questions
How does the expansion of the universe affect the distance light travels?
The expansion of the universe causes space between objects to increase, impacting the distance light can travel. This phenomenon is why light from galaxies can take billions of years to reach us, even though the actual distance is much greater due to the ongoing expansion of space.
Why are galaxies moving away from us at speeds faster than light?
Galaxies are receding from us, with 97% of them moving faster than the speed of light. This is primarily due to the expansion of space in the universe, which causes objects to move away from each other at velocities that exceed the speed of light.
How does the expansion of space impact the visibility of objects moving faster than light speed?
Objects moving away from us faster than the speed of light will never be seen as they are in the present moment. Instead, we observe them as they were when the light left them, as the light takes a significant amount of time to reach us due to the expansion of space.
Why do galaxies that are moving faster than light speed eventually become visible to us?
Despite galaxies moving faster than the speed of light, their light eventually reaches us due to the expansion of space. The light follows a complex path through the expanding universe, allowing us to observe these galaxies even though they are receding from us at velocities exceeding the speed of light.
How does the expansion of the universe impact the size of the observable universe?
The observable universe is larger than the expected 13.8 billion light years due to the expansion of the universe. This expansion causes the space between objects to increase, affecting the distance light can travel and leading to a larger observable universe than initially anticipated.
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Summary
00:00
Galaxies' Light Travel and Universe Expansion
- Light from a galaxy took 25,000 years to reach us, making it 25,000 light years away.
- Another galaxy's light took 13.4 billion years to reach us, but it's actually 32 billion light years away.
- The galaxy GNZ11, discovered in 2016, took 13.4 billion years for light to reach us, but it's now 32 billion light years away due to the universe's expansion.
- The universe's expansion causes space between objects to increase, affecting the distance light travels.
- The observable universe is larger than the 13.8 billion light years expected due to the universe's expansion.
- Galaxies are receding from us, with 97% moving faster than the speed of light due to space expansion.
- Objects moving away from us faster than light speed will never be seen as they are now, only as they were when the light left them.
- Light from galaxies moving faster than light speed eventually reaches us due to the expansion of space, following a complex path.
