Be Safe When Observing the Sun
The stellar solar is a beautiful place to visit, but it can also be a scary one. That’s why you should always be safe when observing the sun, whether through binoculars or a telescope.
The solar atmosphere is composed of three layers: the chromosphere, radiative zone and convective zone. These layers are often hidden from view, but can be seen with special equipment during a total eclipse of the sun.
The Sun’s Core
The Sun’s core is the hottest part of the star, where nuclear fusion reactions occur. It is also the source of energy that makes it possible for us to live on Earth.
The core is made up of billions and billions of hydrogen atoms, the lightest element in the universe. When the immense pressure and heat from inside the core pushes them together, they fuse into helium.
As a result, the energy released during this process is responsible for the majority of solar radiation. This includes gamma-ray photons, neutrinos, and positrons.
The energy produced by this nuclear fusion also balances outward pressure that could lead to an explosion if the star wasn’t contained. As the solar hydrogen nears its end, this outward pressure will no longer be there to oppose the inward force of gravity. This will trigger the fusing of heavier elements, including carbon, nitrogen and oxygen, into the central core. This will give the Sun a main-sequence lifetime of around 10 billion years.
The Sun’s Radiative Zone
The Sun’s radiatal zone is the layer that transfers energy from the superhot interior to the cooler outer layers. The region begins just outside the Sun’s core and extends to about 0.7 radii from the surface.
It is one of the most important parts of the stellar solar system. The radiational zone transfers energy from the core by way of thermal radiation, which travels at an extremely slow rate – it may take millions of years for photons to make their way through the layer.
The radiant zone contains a thick layer of ionized gases surrounded by an insulating shell of molten hydrogen and helium. These dense materials are bombarded by gamma rays generated from nuclear fusion reactions in the Sun’s core. These rays produce photons of light that travel from the core to the radiative zone, where they are absorbed by particles and then released by other ions. This process continues over and over again.
The Sun’s Convective Zone
The Sun’s convective zone is the outermost layer of the solar interior. It extends from a depth of 200,000 km down to the visible surface and is where convection takes place.
In the convective zone, hot plasma from near the center of the sun rises and cools at the surface before sinking back down through the convection zone again. This cycle of hot and cold gas in the convection zone is what gives the Sun its convective motions.
It also makes the surface of the Sun constantly oscillate. This is called seismicity and it can be likened to earthquakes on Earth.
This is because the convective zone is very unstable and constantly disrupts the other layers of the Sun. The amplitude and pattern of these disturbances is what causes the oscillations.
The Sun’s Corona
The Sun’s outermost layer is called the corona. It stretches out to hundreds of solar radii (about the distance between Earth and the Sun) and is not visible from the surface.
The corona consists of plasma (i.e., a gas of charged particles) and has a temperature from 1 to 3 million kelvin (about 10 to 12 times hotter than the photosphere).
It also contains much higher levels of ionization, especially for heavier elements like iron. This ionization is the mechanism by which the solar corona is heated by wave energy from the Sun’s magnetic field and/or magnetohydrodynamic waves from below.
The question of how this heating occurs has occupied astronomers for more than 50 years, with a variety of theories proposed. The most popular are wave heating and magnetic reconnection. But recent data from Hinode and SOHO have shown that oscillations of whole loops and localized Doppler shifts of UV spectral lines are also present. These data may explain the heating problem or at least provide a clue.