Sunspots and Solar Wind
Our sun is incredibly active. It’s made up of the gases hydrogen and helium and the process that it uses to create energy is called nuclear fusion.
The gases are electrically charged and create magnetic forces that are so powerful that they attract and maintain the orbits of all of the planets in our solar system.
The sun’s gases are always moving both inside and outside of the sun. The gases burn, twist, stretch, and tangle the magnetic fields and this process is referred to as the solar activity.
We can’t look at the sun directly with our eyes, but scientists have developed special technologies that let them see the details of what’s happening on the surface of the sun.
The sun has a solar cycle and sometimes the sun is quiet and at other times it is very active. Scientists use the equipment to monitor each of the cycles.
Just outside of the photosphere of the some you can find the atmosphere. This is made up of the solar corona and the chromosphere.
If you look at the sun through special telescopes you would see that the chromosphere is the glowing reddish color at the edge of the sun, while the corona is the large whitish tendrils that are lifted as far as millions of miles.
These are dark areas that appear on the surface of the sun. Their dark shade is due to the fact that they are cooler that the rest of the sun, but they are still around 6,500 degrees F.
The solar wind is the energy of the sun’s corona that is so strong that the sun’s gravity can’t hold it back. It pours off of the sun in every direction at speeds of around 1 million mph/400 km/s.
Sunspot and Solar Wind Statistics:
Sunspots show up as a dark blotch on the sun’s bright surface. Sunspots have two distinct features: a Penumbra, which is the outer section, and the umbra which is the darker middle section.
Scientists don’t know exactly why sunspots happen, but they have made note that they can be smaller in size or as big as 50,000 km in diameter.
Sunspots seem to happen during areas of the sun that experience an increase in magnetic activity. When there is a release of that energy we see solar flares as well as the bigger storms that are called “coronal mass ejections.”
The solar wind occurs when a stream of plasma and particles escapes the sun’s corona. When the temperature of the sun reaches a critical point of 2 million degrees F/1.1 million degrees C, the sun’s gravity can’t keep control of the incredibly fast moving particles and they blast away from the sun.
The sun seems to have an 11-year cycle that gives it periods of time of quiet and then builds up again. This condition can be seen with an increase in the radiation levels and the number of sunspots.
It eventually builds up to the point where the particle matter is ejected. The changes affect the solar wind, velocity, temperature, density, and the sun’s magnetic field.
The intensity of the solar wind differs depending upon how quickly that location is rotating and where on the sun it originates from.
Coronal holes are areas on the sun’s corona that are darker and are associated with magnetic field lines that are “open,” such as those that exist on the poles of the sun.
It’s believed that high-speed solar winds originate from coronal holes. The holes seem to happen at low latitudes of the sun and at the poles and they get bigger when the sun’s activity is at a minimum.
The density and temperature over coronal holes are both low and it also has a weak magnetic field. This leaves the field lines susceptible to open space.
The solar wind velocity over coronal holes can hit speeds as high as 500 mi/800 km per second.Temperatures in the fast solar wind can hit as high as 1 million degrees F/800,000 degrees C.
The solar wind isn’t constant. It might be ejected out and away from the sun but it alternates speed. Magnetic clouds and interacting regions are carried with the wind and this means that the highest winds can quickly catch up with slower speed winds.
The wind speed is its highest over the coronal holes and lowest over the streamers. These changing speeds not only interact with each other but also sweep by the Earth during the rotation of the sun.
The winds hit our Earth’s magnetic field at different speeds and this can result in storms in the magnetosphere of the Earth.
Solar Wind on Planets:
Some think that a better name for solar wind would be “stellar wind,” because other stars outside of our solar system also generate their own wind.
When the solar wind leaves the sun it heads out in every direction. This means that the solar wind has an impact on all of the planets in our solar system.
Those planets that have a magnetic field, such as Earth, are protected from the solar wind damage, however, planets such as Mercury that don’t have a strong atmosphere, are pummeled by it. Mercury’s exosphere is mainly made up of solar wind particles.
If Earth didn’t have our magnetic field, the solar wind wouldn’t have allowed life to flourish on the planet. The field is a kind of shield that goes around our Earth and protects us from the damages of the solar wind by diverting the particles away.
We do see some of the particles that happen to hit the north and south pole. Elements in the atmosphere of the Earth interact with the partiles and create the lovely light show known as aurora.
Planets such as Jupiter, Saturn, Uranus, and Neptune all have magnetic fields. When the solar wind strikes those planets they experience their own aurora at their magnetic poles.
Scientists view the aurora activity of some of the other planets by using an ultraviolet light telescope.
There are a few moons in the solar system such as Neptune’s Triton, that have both active magnetic fields and atmospheres. It’s believed that they also may experience a small aurora from the solar wind.
To see sunspots with any kind of detail, professionals require a land-based and Earth-orbiting telescope. These are special telescopes that make use of projection and filtering techniques for direct views of the sun.
There are some types of filtered cameras that can be used. The sunspot areas require tools such as spectrohelioscopes and spectroscopes. Creating a kind of artificial eclipse gives the view of the sun during rotation as the sunspots move with it.
Looking directly at the sun will cause permanent damage to the naked eye, so for those that aren’t professional astronomers, they can use specially designed protective filters.
You can avoid the filtration by viewing indirectly using a telescope with an eyepiece that projects the image onto a white screen. The white screen viewing also lets you trace the outline of the sunspot(s) as they move.
In 1990, NASA launched the Ulysses spacecraft for the purpose of orbiting through the solar system and passing over the sun’s poles. During two orbits, Ulysses measured the solar wind speed, direction, magnetic field strength, and the composition.
The information sent back from Ulysses provided scientists with an entirely new set of data about the solar wind. The space agency retired Ulysses in 2009.
In 1997, the ACE (Advanced Composition Explorer) satellite was launched and put into orbit between the sun and the Earth at the L1 point. L1 is one of many points in space where the attraction of gravity between the sun and the Earth are equal and opposite.
The L1 point is 1 million mi/1.5 million km from the Earth, heading towards the sun. ACE included a number of technologies that allowed it to monitor solar wind, providing real-time data on the conditions of the solar wind at the spacecraft.
The 2018 Parker Solar Probe is designed to get within 4 million miles of the surface of the sun. It is the first spacecraft of its kind, created to handle the intense radiation and heat face on.
The probe is providing new information on solar activity so that scientists can analyze and possibly predict some of the big space-weather events that can effect life on Earth. This spacecraft is seen as a requirement especially because we have so many technology satellites that could be harmed with damaging space weather.
The mission was named after an S. Chandrasekhar Distinguished Service Professor Emeritus, Department of Astronomy and Astrophysics at the University of Chicago, Eugene Parker.
Parker’s concepts that were proposed in the 1950s are many that were used to understand the stars and how they (including our sun) emit energy.
He coined the name solar wind for the energy that cascades off of the sun and had detailed descriptions about the system of plasmas, energy particles, and magnetic field that are part of it all. This is the first NASA mission ever named after a living individual.
Scientists may have been inspired by NASA’s Parker Solar Probe to try to imitate the solar winds here on Earth. To recreate the intensity of the solar weather a team decided to use an out-of-commission nuclear fusion device in the basement of Imperial College of London.
MAGPIE (the Mega Ampere Generator for Plasma Implosion Experiments) is a full 2-stories and inside it has a box that looks like a collection of huge tubes.
Every so often it jumps into life as it releases a miniature burst of solar wind and its then that the scientists can study its interactions with the a magnetic target.
Although there are other experiments that are similar around the world, the unique situation of MAGPIE is that the scientific team has created a special, scaled-down solar system model so that they can study how magnetic fields and stellar winds interact with each other.
Facts about Sunspots for Kids:
- A sunspot can have a short or long lifetime, existing from a few days and weeks all the way to a few months.
- Sunspots don’t stay in one place, the can travel across the face of the sun.
- The first telescope to observe sunspots was in 1610 AM
- Sunspots have an 11 year cycle, the number increases to the 11thyear and then decreasing.
- In 1890, a scientist, named E. Maunder noticed that the number of sunspots noticeably fell between the years of 1645 and 1715. The name for this period is called the Maunder Minimum.
- An Active Group or sunspot group is where two or more sunspots appear in an area.
- Sunspots happen in a variety of sizes; some are so small you can’t see them when using a telescope, but others are several times bigger than the Earth.
- An average speed of the solar wind as it leaves the sun is 400 km/second.
- The pressure from the solar wind is incredibly powerful and creates a “heliosphere” that goes out as far as Pluto and the Kuiper Belt.
- The area where the heliosphere ends is also the area where the solar wind is subsonic. This is a unique occurrence and is called the termination shock.
- Life on Earth is protected against the solar wind by Earth’s magnetic field.
- When some of the solar wind hits the polar regions of the Earth it creates the auroras.