# What is the relationship between solar radiation intensity and lunar phases?

• charlie05
In summary, the intensity of solar radiation at a location where the full moon is visible can be calculated using the Earth's distance from the sun and the moon's distance from the Earth. This is based on the inverse square law, where intensity decreases with the square of the distance. Using the values for RE, RM, and IE, we can calculate the intensity at this location to be approximately 1353 W/m^2.
charlie05

## Homework Statement

What is the intensity of solar radiation in a place where is the full moon ?

I know luminosity of the Sun and Earth's distance from the Sun RE and Moon´s distance from the Earth RM. Trajectory of Earth and Moon are circular.

## Homework Equations

distance of the site from the sun is d = RE + RM

## The Attempt at a Solution

Radiation intensity decreases with the square of the distance.

charlie05 said:

## Homework Statement

What is the intensity of solar radiation in a place where is the full moon ?

I know luminosity of the Sun and Earth's distance from the Sun RE and Moon´s distance from the Earth RM. Trajectory of Earth and Moon are circular.

## Homework Equations

distance of the site from the sun is d = RE + RM

## The Attempt at a Solution

Radiation intensity decreases with the square of the distance.
Sorry, your problem statement didn't translate very well. Is there a diagram associated with this question? Are they asking what is the intensity of sunlight at the combined distance Re + Rm? As if you were on the Moon and the Earth was nearly between the Moon and the Sun?

sorry for my bad English :-(
I think - full Moon - position is Sun - Earth - Moon
in full Moon - Earth is between the Sun and Moon ...and distance between the Sun and the Moon is the sum of Earth's distance from the Sun RE and Moon´s distance from the Earth RM. At this distance I have to calculate solar radiation intensity.

charlie05 said:
sorry for my bad English :-(
I think - full Moon - position is Sun - Earth - Moon
in full Moon - Earth is between the Sun and Moon ...and distance between the Sun and the Moon is the sum of Earth's distance from the Sun RE and Moon´s distance from the Earth RM. At this distance I have to calculate solar radiation intensity.
Okay, makes sense.

So it sounds like you have all the information you need to do the calculation. You said you have the radiant intensity at the Earth's surface, right? And you know the intensity decreases with the square of the distance. So can you show us how you would calculate the lower intensity when you add in the extra distance to the Moon?

I know only luminosity of Sun...3,827.10 26 W...but maybe I do not to calculate from this information...
but I think, I can find the radiant intensity at the Earth's surface in some tables... IE = 1360 W/m2

IE/IM = RE2 / ( RE + RM )2

charlie05 said:
IE = 1360 W/m2
That looks about right -- I always remember that it's about 1kW/m^2 at the Earth.
charlie05 said:
IE/IM = RE2 / ( RE + RM )2
That doesn't look quite right to me. Remember that the intensity is proportional to the inverse of the square of the distance. Intensity gets lower the farther away you get...

conversely... :-)
IM/IE = RE2 / ( RE + RM )2

charlie05 said:
conversely... :-)
IM/IE = RE2 / ( RE + RM )2
Yeah, that looks better. What answer do you get? Can you show your work?

charlie05
RE = 150.106 km
RM = 384.103 km
IE = 1360 W/m2

IM = 1353 W/m2 ?

charlie05 said:
RE = 150.106 km
RM = 384.103 km
IE = 1360 W/m2

IM = 1353 W/m2 ?
Looks good to me. Do you have a way to check the answer? Is the value of the intensity at the Earth a standard value that you got from your class or textbook?

value on Earth I found my physical tables..solar irradiance

berkeman
thank you very much for your help :-)

berkeman

## 1. What is the intensity of solar radiation?

The intensity of solar radiation refers to the amount of energy from the sun that reaches a particular area on Earth's surface. It is measured in watts per square meter (W/m²) and varies depending on factors such as time of day, location, and atmospheric conditions.

## 2. How is the intensity of solar radiation measured?

The intensity of solar radiation is typically measured using a device called a pyranometer, which is specifically designed to measure the amount of solar radiation received on a horizontal surface. Other instruments, such as radiometers and spectroradiometers, can also be used to measure the intensity of solar radiation at different wavelengths.

## 3. What factors affect the intensity of solar radiation?

The intensity of solar radiation is affected by several factors, including the angle of incidence (the angle at which the sun's rays hit the Earth's surface), the Earth's rotation and tilt, the Earth's distance from the sun, and atmospheric conditions such as clouds, dust, and pollutants.

## 4. How does the intensity of solar radiation impact the Earth?

The intensity of solar radiation plays a crucial role in shaping Earth's climate and weather patterns. It is responsible for driving processes such as the water cycle, wind patterns, and ocean currents. It also provides the energy necessary for photosynthesis, which is essential for the growth of plants and ultimately all life on Earth.

## 5. How can we use the intensity of solar radiation?

The intensity of solar radiation can be harnessed and converted into various forms of energy, such as electricity and heat. Solar panels, for example, use photovoltaic cells to convert sunlight into electricity, while solar thermal systems use sunlight to heat water or other fluids for use in homes or industries. The use of solar energy can reduce our dependence on fossil fuels and help mitigate the negative impacts of climate change.

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