Why light from sun takes 8 minutes ?

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In summary, the statement that light takes 8 minutes to reach Earth from the sun means that a photon emitted by the sun takes 8 minutes to reach Earth. This is because light travels extremely fast, but not infinitely fast. Therefore, when we see the sun, we are actually seeing a picture of it that is 8 minutes old. This is similar to how we see rain falling from a cloud, even though the raindrops have been present in the cloud for some time before reaching the ground. The speed of light is not mystical, but a scientific concept that explains why we experience a delay in seeing events that happen far away from us.
  • #1
mkbh_10
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Why is it said that light takes 8 minutes to reach Earth when light from sun is already present in the solar system , what is meant exactly by the statement ?
 
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  • #2
It means that a photon emited by the Sun that hits the Earth at some point in time left the Sun 8 minutes prior to the time it hit.
 
  • #3
if you're at a concert and standing about 330 meters away from the speakers then the sound you are hearing is about 1 second old. this is because sound travels in air at about 330 meters every second.
its a simular situation with light, except it travels much much faster so that normally on Earth we don't notice any delay, it travels 300,000 kilometers per second.
the sun is aprox 150 million kilometers away, so it takes light about 500 seconds to get here or 8 minutes.
essentially when you look at the sun, you see a picture of the sun that is 8 minutes old.
if the sun suddenly stopped shining, you would not know for 8 minutes.
if it then began to shine again, we would not receive the light for 8 minutes.
 
  • #4
but sun doesn't stop shining , the photons are already present around the Earth , sun is burning whether the side on which of Earth i live faces the sun or not , its already there yet we say it takes 8 minutes
 
  • #5
mkbh_10 said:
the photons are already present around the earth
Right; but only becuase the sun was burning 8 minutes ago.
 
  • #6
Photons are like little bullets, so just try to picture someone sitting on the surface of the sun firing off photon bullets at the earth. The sun is ~92,000,000 miles from earth, and the bullets (photons) travel at 186,000 miles per second, so it takes them about 8 minutes to get here from the surface of the sun. Just like if you were to fire a bb gun that shoots bbs at 1000 ft/sec, it would take them 5 sec to hit a target at 5000 ft.
 
  • #7
There is nothing new under the Sun …

mkbh_10 said:
but sun doesn't stop shining , the photons are already present around the Earth , sun is burning whether the side on which of Earth i live faces the sun or not , its already there yet we say it takes 8 minutes

The river is always before us, but the water comes slowly from the mountain.

The present is but a record of the past.

All, all is vanity.
 
  • #8
I'm glad you stuck with your question. There's a depth to these types of questions that makes it sometimes difficult to know where to start the answer. Eventually somebody will click with your question.
mkbh_10 said:
Why is it said that light takes 8 minutes to reach Earth when light from sun is already present in the solar system , what is meant exactly by the statement ?
mkbh_10 said:
but sun doesn't stop shining , the photons are already present around the Earth , sun is burning whether the side on which of Earth i live faces the sun or not , its already there yet we say it takes 8 minutes
Let me ask back:
Why is it said that rain takes about 10 seconds to reach the Earth when rain from a cloud is already present under the cloud?
[...]but the cloud doesn't stop raining, the rain drops are already present at the Earth under the cloud, [...] rain is already there yet we say it takes 10 seconds.

You might notice a problem with my question: "Rain drops are already present at the earth". In this case, you understand that only some of the rain drops are present at the earth. Looking up you know that many others are still on their way following the drops that hit the earth. If we put green dye in the cloud it would take 10 seconds for the green stuff to reach the earth.
As for the sun, although we are drenched in sunlight, only some of it is at the earth. Looking up, fresh sunlight is still coming to us following the light that hit the earth. If we added more green light to the sun it would take 8 minutes for the green stuff to reach the earth.
Back to the cloud: If a hole formed in the cloud, allowing light to come through, the light would be much faster than the rain, but it would still take the smallest fraction of a second to reach the earth.

I think I've noticed the "already present everywhere" statement elsewhere. This seems to be the heart of the confusion. May I recommend reading: http://www.teachersdomain.org/resources/lsps07/sci/phys/energy/lightspeed/index.html. This particular concept of finite speed of light isn't mystical.
 
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  • #9
mkbh_10 said:
Why is it said that light takes 8 minutes to reach Earth when light from sun is already present in the solar system , what is meant exactly by the statement ?

The amount of light emitted by the sun is not constant, it changes continuously. For example, when a sunspot on the surface of the rotating sun rotates into view (as seen from Earth), the total light output drops by a small amount.

On Earth we don't observe the sunspot, or the drop in light output, until 8 minutes later.
 
  • #10
think of it this way... if the sun suddenly exploded, we wouldn't know about it until 8 minutes later.
 

1. How does light travel from the sun to Earth in 8 minutes?

The sun is approximately 93 million miles away from Earth. Light travels at a speed of about 186,282 miles per second, which means it takes around 8 minutes for light to travel from the sun to Earth.

2. Why does it take exactly 8 minutes for light to reach Earth from the sun?

The time it takes for light to reach Earth from the sun is dependent on the distance between the two objects and the speed of light. Since the distance between the sun and Earth is relatively constant, the time it takes for light to travel remains consistent at approximately 8 minutes.

3. How do we know that light takes 8 minutes to reach Earth from the sun?

Scientists use a variety of methods to measure the speed of light and the distance between the sun and Earth. By combining these measurements, we can determine that it takes approximately 8 minutes for light to travel from the sun to Earth.

4. Is 8 minutes the exact amount of time it takes for light from the sun to reach Earth?

While 8 minutes is a close approximation, the actual time it takes for light to reach Earth from the sun can vary slightly due to factors such as the Earth's orbit and the varying distance between the two objects.

5. Can light from the sun ever reach Earth faster or slower than 8 minutes?

No, the speed of light is constant and cannot be changed. Therefore, light will always take approximately 8 minutes to travel from the sun to Earth, regardless of any external factors.

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