Every day we benefit from the Sun’s consistent nature.
The sun rises and sets, and our globe is bathed in its constant and sustaining energy.
Life’s very existence depends upon the light that Earth receives, and the well-balanced
parameters of the Sun’s size, temperature, distance, and mass, all of them very important
to the Sun-Earth relationship.
First, the in terms of its physical size, the Sun is by far the largest object in the
Solar System.
The Sun is approximately 10 times wider than Jupiter and over 100 times wider than Earth.
Its volume could contain around one million Earths.
The Sun is also a massive object.
If you were to add together all of the mass for every object in our Solar System--the
terrestrial planets, the Gas Giants, the dwarf planets, all of their moons, asteroids, the
comets--the Sun by itself would still be far more massive.
In fact, the Sun contains 99.866% of all the mass in our Solar System.
Being the most massive object the Sun acts as a “gravity anchor” holding all the
planets and dwarf planets and objects in their respective orbits.
From our perspective on Earth, the Sun appears as a bright yellow disk.
The part of the Sun that we can see shining so brightly is called the photosphere.
This layer is often described as the visible surface of the Sun, because it is the outermost
opaque layer, restricting our view of the Sun’s deeper layers.
Now while we use the term “surface,” we’re not saying the Sun is solid, rather the Sun
is composed primarily of hydrogen and some helium in a very highly-energized state of
matter called a plasma.
The photosphere has a temperature of 10,000 degrees F and radiates dominantly visible
light.
If you were to take a picture of the Sun, your picture would show a yellowish and mostly
featureless ball.
(But remember don’t look directly at the Sun without special protection.)
The Sun emits all colors of visible light -- reds, oranges, yellows, greens, blues,
and violets.
If all of these colors were equally emitted, the Sun would appear a bright white.
But instead, the Sun appears a yellow because the peak wavelengths of its output comes from
the yellow range.
The spectrum of sunlight that Earth receives is finely tuned for life to thrive.
The Sun’s visible light output peaks in the yellow-green range of wavelengths.
The Solar Spectrum effectively covers the major wavelengths needed for photosynthesis.
This absorption of specific wavelengths of sunlight powers the critical, life-sustaining
process of our planet.
Earth would not be able to support humanity and the abundance of all the other life, if
this single process of photosynthesis did not function and proceed at its effective
level.
Keep in mind, the visible light you are seeing is only a small portion of the full spectrum
given off by the Sun.
Visible light is only a particular radiation energy range in the full electromagnetic spectrum.
Every day we encounter and even use many of the other energy ranges, from listening to
the radio, to popping popcorn in a microwave oven, to the infrared motion sensors in our
houses, or having an X-ray image taken of a broken a bone.
The Sun actually gives off varying amounts of all these energies.
The amount of energy that Earth receives from the Sun is approximately 1400 Watts per square
meter on our surface.
It is so consistent that it is referred to as the “solar constant.”
Aspects of the Sun’s design can be seen in its consistent nature: both in its role
as a gravitational anchor for the Solar System including Earth’s stable orbit, but also
in its role as the constant source of Earth’s life-sustaining energy.
But the Sun is not silent.
It has a dynamic nature as well.
And the Sun’s dynamic nature provides a view of its complexity and design.
The surface of the Sun is constantly churning like a pot of boiling water, large columns
of matter rise from the hot interior while cooler regions sink back down.
This convective motion creates granulation, an effect seen at small scales within the
photosphere where cell-like structures—or granule--form with hot matter surrounded by
cooler boundaries.
While we are usually only aware of the Sun’s consistency from day-to-day, the Sun actually
teems with activity from sunspots to massive eruptions.
Sunspots are large dark regions on the Sun’s surface.
They form due to the Sun’s intense magnetic field.
The disturbances causes the surface material in that region to slightly cool and appear
darker in contrast to the rest photosphere material.
The interior of a sunspot is still extremely hot--only a few thousand degrees cooler than
the rest of the surroundings.
The number of visible sunspots fluctuates through a solar cycle.
This cycle follows an 11-year oscillation from a period of low activity--called a solar
minimum--through a period of high-activity--called a solar maximum--and back then back to the
minimum.
During a solar maximum there can be hundreds of sunspots.
And sunspots are often the precursors to a variety of other active features.
Outbursts of hot, gaseous material can occur from the magnetically disturbed sunspot regions,
extending thousands of miles above the surface, forming prominences, filaments, coronal loops,
coronal streamers and even coronal mass ejections.
These larger outward extending features occur above the photosphere, in the Sun’s less
dense upper atmosphere.
Prominences and filaments are two features mainly seen within the chromosphere, and essentially
they’re the same feature seen either face-on or at an angle.
Prominences can appear as dramatic bursts of material looping off the side of the Sun.
The looping path that the material takes follows a strongly distorted portion of the magnetic
field.
Similarly structured to prominences, coronal loops are even larger extensions of heated
material that follow magnetic field lines extending out into the Sun’s atmospheric
layer called the Corona.
Amazingly, this outer atmospheric layer reaches temperatures of 1 to 2 million K, being superheated
by the solar wind and the magnetic storms.
Sometimes we use the term “space weather” to describe various fluctuations and changes
in space, especially that affect us here on Earth.
Most of these fluctuations originate from the active nature of the Sun.
The mechanism that drives the occurrence of space weather events is a feature known as
the solar wind.
While the space within our Solar System is nearly a vacuum, there is a continuous flow
of particles streaming outward from the Sun and this forms what we call the “solar wind,”
a continuous wind of particles that travels at the incredible speed 1 to 2 million mph.
However, episodes of extreme space weather occur whenever coronal mass ejection--or CME
events-occurs on the Sun.
CMEs are concentrated bursts of highly energized matter that is ejected from the Sun in these
eruptions of solar flares.
If such an event happens in the direction towards Earth, then we are showered with literally
hundreds of millions of tons of charged particles.
Though the Sun can be wildly active, can cause extreme space weather conditions, its dynamic
nature actually helps to demonstrate just how privileged our planet really is.
We live day-to-day with very little noticeable impacts into our lives.
And some of the most observable consequences to this intense solar activity, are the beautiful
auroral lights that dance across the skies near Earth’s polar region, remnants of the
massive solar eruptions that were safely deflected by Earth’s magnetic field.
Yet, these few particles that were caught spiral down and interact with atoms in our
Ionosphere releasing emissions of visible light.
Earth’s protective layers of safety were designed in concert with the Sun’s nature
to supply what is needed for humanity’s existence.