The Cosmic Horizon: Exploring the Oldest Light Ever

In summary, the oldest light we can see from the universe is from 300,000 years after the big bang. However, we cannot see beyond our cosmic horizon because light travels at a finite speed and the universe has a finite age. This is also why the universe is expanding, leading to the existence of multiple horizons in cosmology. The rate of expansion over time determines the distance to the cosmic horizon, and there are different types of horizons in cosmology.
  • #1
yazanhomsi
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Hello everyone,

Questions keep on rushing through my mind. If we can see light from 300,000 years after the big bang (THE OLDEST LIGHT EVER) then why can't we see beyond our cosmic horizon? We are seeing the oldest light ever... then why do we have a cosmic horizon?
 
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  • #2
Because light travels at a finite speed and the universe has a finite age.

There was light before the CMB, but we cannot see it because the universe was opaque and that light scattered.
 
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  • #3
Orodruin said:
Because light travels at a finite speed and the universe has a finite age.

There was light before the CMB, but we cannot see it because the universe was opaque and that light scattered.
And the universe is expanding as well is that correct? So that's why we have a cosmic horizon?
 
  • #4
yazanhomsi said:
And the universe is expanding as well is that correct? So that's why we have a cosmic horizon?
The rate of expansion over time determines the distance to the cosmic horizon.
 
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  • #5
Note that there are several different horizons in cosmology, see https://en.wikipedia.org/wiki/Cosmological_horizon
The particle horizon would be there even if the universe was not expanding, but had a finite age. If you want specific answers you will need to specify which horizon you are talking about.
 
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  • #6
Chalnoth said:
The rate of expansion over time determines the distance to the cosmic horizon.
Alright got it
 
  • #7
Orodruin said:
Note that there are several different horizons in cosmology, see https://en.wikipedia.org/wiki/Cosmological_horizon
The particle horizon would be there even if the universe was not expanding, but had a finite age. If you want specific answers you will need to specify which horizon you are talking about.
Yeah thanks a lot. I get it now.
 

Related to The Cosmic Horizon: Exploring the Oldest Light Ever

1. What is the cosmic horizon and why is it important to explore?

The cosmic horizon refers to the boundary of the observable universe, beyond which light and information cannot reach us due to the expansion of space. It is important to explore because it allows us to understand the origins and evolution of our universe, and provides insight into the fundamental laws of physics.

2. How can we see the oldest light in the universe?

The oldest light in the universe, also known as the cosmic microwave background (CMB), can be seen through observations using specialized telescopes and satellites. This light is the leftover radiation from the Big Bang and has been traveling through the universe for over 13 billion years, making it the oldest light we can observe.

3. What information can we learn from studying the cosmic horizon?

Studying the cosmic horizon can provide us with valuable information about the composition, age, and structure of the universe. It can also help us understand the expansion of the universe and the distribution of matter and energy within it. Additionally, studying the cosmic horizon can give us insights into the early stages of the universe, such as the formation of galaxies and the first stars.

4. How does exploring the cosmic horizon contribute to our understanding of dark matter and dark energy?

The cosmic horizon plays a crucial role in our understanding of dark matter and dark energy. By studying the CMB and its fluctuations, we can gather information about the amount and distribution of dark matter in the universe. Additionally, the expansion of the universe as seen through the cosmic horizon can help us understand the effects of dark energy on the evolution of the universe.

5. What technological advancements have allowed us to explore the cosmic horizon?

The development of specialized telescopes and satellites, such as the Planck and WMAP satellites, have allowed scientists to observe and study the cosmic horizon in detail. Advancements in data analysis techniques and computing power have also played a crucial role in our ability to explore and understand the oldest light in the universe.

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