# Calculate Total Energy Radiated by Sun During Evolution

• emilykay
In summary, the conversation discusses the evolution of the sun and the change in its internal energy. The question is raised about the total energy that is radiated by the sun, assuming its luminosity is similar to its present state. The individual is seeking help with performing calculations, possibly referencing a study on the first million years of the Sun.

#### emilykay

as the sun evolved it contracted, its internal energy changing fro x to y. what's the total energy radiated, assuming luminosity is comparable with present?

I understand that the rate of change of the internal energy = rate at which energy is radiated away by the star.. but i have been given exact numbers and i don't know what calculations to preform.

any help would be really good. thanks.

Stars, like people, tend to be hot blooded in their youth:
http://arxiv.org/abs/astro-ph/0109051
The first million years of the Sun: A calculation of formation and early evolution of a solar-mass star

Calculating the total energy radiated by the Sun during its evolution can be a complex task, as it involves understanding the changes in the Sun's internal energy, its luminosity, and how these factors have changed over time. However, we can make some approximations based on the available data and equations.

First, we need to determine the change in the Sun's internal energy (ΔU) as it evolved from its initial state (x) to its current state (y). This can be calculated using the equation:

ΔU = ∫ PdV

Where P is the pressure and dV is the change in volume of the Sun during its evolution. This integral can be evaluated using known values for the Sun's mass, radius, and density at different points in its evolution.

Next, we need to determine the luminosity of the Sun at its current state (y). This can be calculated using the Stefan-Boltzmann law:

L = 4πR^2σT^4

Where R is the current radius of the Sun, σ is the Stefan-Boltzmann constant, and T is the current temperature of the Sun. This equation gives us the total energy radiated by the Sun in a given time, which we can then integrate over the entire evolution of the Sun to get the total energy radiated.

However, since we have been given exact numbers, we can make some simplifying assumptions to calculate an approximate value for the total energy radiated by the Sun during its evolution. For example, we can assume that the Sun's luminosity has remained constant throughout its evolution, which is not entirely accurate but can give us a rough estimate. In this case, we can use the luminosity of the Sun at its current state (L) and the age of the Sun (t) to calculate the total energy radiated as:

E = Lt

This calculation will give us the total energy radiated by the Sun from its birth until now. However, it is important to note that this is just an approximation and the actual total energy radiated by the Sun may be significantly different.

In conclusion, calculating the total energy radiated by the Sun during its evolution is a complex task and requires a thorough understanding of the Sun's properties and changes over time. While we can make some approximations, the actual value may vary. It is recommended to use accurate data and equations for a more precise calculation.

## 1. What is the total energy radiated by the sun during its evolution?

The total energy radiated by the sun during its evolution is estimated to be around 3.86 x 10^26 watts. This is equivalent to about 3.828 x 10^33 ergs per second.

## 2. How do scientists calculate the total energy radiated by the sun during its evolution?

Scientists calculate the total energy radiated by the sun during its evolution by using a combination of observational data and mathematical models. They measure the sun's luminosity, temperature, and size, and then use this information to estimate the total energy being emitted by the sun at any given time.

## 3. Has the total energy radiated by the sun remained constant throughout its evolution?

No, the total energy radiated by the sun has not remained constant throughout its evolution. The sun's energy output has gradually increased over time as it continues to burn its fuel and undergo nuclear reactions. It is estimated that the sun's luminosity has increased by about 30% since its formation.

## 4. How long has the sun been radiating energy during its evolution?

The sun has been radiating energy for approximately 4.6 billion years. This is the estimated age of the sun and is based on our understanding of its formation and evolution.

## 5. Are there any factors that could affect the total energy radiated by the sun during its evolution?

Yes, there are several factors that could potentially affect the total energy radiated by the sun during its evolution. These include changes in the sun's internal structure, fluctuations in its magnetic fields, and variations in the amount of fuel available for nuclear reactions. Additionally, external factors such as collisions with other celestial bodies or changes in the sun's orbit could also impact its energy output.