- Joined
- Jun 18, 2011
- Messages
- 168
I took astronomy, too 
I don't think it was needed to explain the following, but it might help.
The time it takes for light to reach the Earth from a 12 billion year old star is dependent upon how far away that star is and the speed of light. If it is 2 billion light years away, then the light would take 2 billion years to reach us. NOW the star has been shining for 12 billion years, so we ARE seeing 2 billion year old light from that star unless we get closer to that star (EVEN IF THE EARTH IS ONLY 6,000 YEARS OLD.)
Here is a scenario in which case we can not see the star:
The star is 12 billion years old, but it is 14 billion light years away. However because of the expansion rate of the universe we can see stars much older than that as their light becomes stretched out (redshifted) and thus from our perception on Earth due to special relativity the light takes much longer to reach us. Therefore, we have even detected light from stars like Earendel which was created just 900 million years after the big bang or at a distance of 28 billion light years from us. The universe is expanding so fast that when the light from this old star was emitted it was only 4 billion light years from Earth.
What Riot said was correct, but did prove anything. When he said that the planet existed for 6,000 years he added unneeded information to his word problem. Again, understand that the planets age has nothing to do with light hitting it. Light waves are constant (in basic physics), so light is going to be hitting the planet if it exists.
I don't think it was needed to explain the following, but it might help.
The time it takes for light to reach the Earth from a 12 billion year old star is dependent upon how far away that star is and the speed of light. If it is 2 billion light years away, then the light would take 2 billion years to reach us. NOW the star has been shining for 12 billion years, so we ARE seeing 2 billion year old light from that star unless we get closer to that star (EVEN IF THE EARTH IS ONLY 6,000 YEARS OLD.)
Here is a scenario in which case we can not see the star:
The star is 12 billion years old, but it is 14 billion light years away. However because of the expansion rate of the universe we can see stars much older than that as their light becomes stretched out (redshifted) and thus from our perception on Earth due to special relativity the light takes much longer to reach us. Therefore, we have even detected light from stars like Earendel which was created just 900 million years after the big bang or at a distance of 28 billion light years from us. The universe is expanding so fast that when the light from this old star was emitted it was only 4 billion light years from Earth.
What Riot said was correct, but did prove anything. When he said that the planet existed for 6,000 years he added unneeded information to his word problem. Again, understand that the planets age has nothing to do with light hitting it. Light waves are constant (in basic physics), so light is going to be hitting the planet if it exists.
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