THE SUN: AWESOME AND ACTIVE
Boston University PHOTON
An average-size yellow star, just like billions of others in the universe
Center of the solar system, Earth orbits around it
Formed about 4.6 billion years ago
The sun has a mass of 2x1030 kg or 330,000 Earths, thatís 99.8% of the mass in the solar system.
ēThe Sun is the source of all of the energy on Earth.
ēThe amount of energy that reaches Earth from the Sun in one second is enough energy to meet Massachusettsí current energy needs for 32,655,294 years!!!*
ēAbout half the energy that hits the Earth is absorbed and used to heat the planet.
ēYou can feel this energy in the form of heat on your skin on a sunny day.
ē*figure based on data from California Energy Commision:
Energy is produced in the Sunís core through a process known as nuclear fusion.
Nuclear fusion is when nuclei of one kind of element combine to make a new nucleus in that requires less energy to hold it together. This difference in energy is spit out as a result of the reaction.
The Sunís nuclear fusion occurs when four hydrogen nuclei combine to make helium and release energy.
This type of reaction canít happen just anywhere, it can only happen at incredibly high temperatures and pressures like those found in stars, somewhere around 23 million degrees!!
4 Hydrogen nuclei
1 Helium nucleus
We know how much energy the Sun emits by measuring the amount of energy that reaches Earth.
The Sun consumes 660 million tons of hydrogen releasing 100 billion megatons of energy per second! Thatís the same energy as 20 billion Hydrogen bombs every second!
Based on the amount of hydrogen the Sun consumes per second and the mass of the Sun, we estimate its lifetime to be 50 billion years.
Nuclear Fusion Hydrogen Bombó50 megatons
Layers of the Sun
the core of the sun alone is the size of 13 Earths!
2. Radiative Zone
energy from the core radiates through this part of the Sun
3. Convective Layer
convection cells move energy through this part of the Sun