# Finding loss of sun's mass given the energy density delivered.

• texan14
In summary, the energy density from the sun at the surface of the Earth is 1300 J/m2s. To calculate the mass loss of the sun in one year, the equation ΔE = Δmc2 can be used, where ΔE is the change in energy, Δm is the change in mass, and c is the speed of light. However, since the Earth is about 1.49 x 1011 m from the sun, the distance must also be taken into account. Therefore, the equation KE = (γ-1)mc2 can be used, where KE is the kinetic energy, γ is the Lorentz factor, m is the mass, and c is the speed of light.
texan14

## Homework Statement

The energy density (energy per unit area per unit time) arriving from the sun at the surface of the Earth is 1300 J/m2s. Calculate the mass loss of the sun in one year. (The Earth is about 1.49 x 1011 m from the sun.)

ΔE = Δmc2

KE = (γ-1)mc2

## The Attempt at a Solution

I'm not sure how to calculate the loss of energy density from the sun as a function of distance. I feel like it can't be as easy as plugging the energy into E=mc2

Hint: You're not given an energy; you're given an energy density.

## 1. How do scientists determine the loss of the sun's mass from energy density?

Scientists use the famous equation E=mc², where E represents energy, m represents mass, and c represents the speed of light. By measuring the energy density delivered by the sun and plugging it into this equation, they can calculate the loss of mass.

## 2. Can energy density be measured accurately?

Yes, energy density can be measured using various methods such as spectroscopy, which involves analyzing the light emitted by the sun. Scientists can also use data from satellites and other instruments to calculate the energy density delivered by the sun.

## 3. How does the loss of the sun's mass affect its size?

The loss of the sun's mass over time does not significantly affect its size. The sun's mass is so vast that even a small loss of mass due to energy density is negligible in terms of its overall size.

## 4. Is the sun's mass constantly decreasing due to energy density?

Yes, the sun's mass is constantly decreasing due to energy density, as it is constantly releasing energy through nuclear fusion. However, this decrease is very small and will not significantly impact the sun's lifespan.

## 5. How does the sun's loss of mass affect its gravitational pull?

The sun's loss of mass does not significantly affect its gravitational pull. Gravitational pull is determined by the mass and distance between two objects, so even a small loss of mass will not have a noticeable impact on the sun's gravitational pull.

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