Sunspots turned out to be areas of cooler zones on the surface of the sun. These spots are about one-third cooler than the rest of the surface and are protected by magnetic fields that stop the heat from being transmitted into the zone.
The magnetic field is formed from underneath the sun's surface, but is able to project itself outside through the surface and all the way to the corona of the sun. The sun has the largest effect on the climate that we enjoy on Earth. Without it there would be no light, resulting in no growth, since our climate largely relies on the sun to provide the energy needed for photosynthesis. Sunspots were first noticed to affect the Earth when scientists realized that increased activity with sunspots creates increased interference with magnetic instruments on the surface of the earth.
As scientists looked further into this phenomenon, they noticed that near the sunspot, hotter areas of the sun would react with the magnetic field outside the sunspot and create a solar flare. Solar flares project a host of things, including x-rays and energy particles rushing toward the Earth's atmosphere in the form of a geomagnetic storm. The first most noticeable effect of sunspots on our climate were the northern and southern lights, otherwise known as the aurora.
With sunspots come an increase in ultraviolet rays that emit from the outer ring of the sunspots toward Earth.
This increase in UV rays affects chemistry of the outer atmosphere and the energy balance of Earth. The idea that sunspots affect Earth's climate is still largely debated, but it is believed that the increase of sunspots on the surface of the sun can reduce the amount of energy and light distributed to Earth.
This decrease in energy can result in colder weather and even "mini ice ages" on parts of Earth that are farther from the equator. Therefore during sunspot maximums, the Earth will see an increase in the Northern and Southern Lights and a possible disruption in radio transmissions and power grids. The storms can even change polarity in satellites which can damage sophisticated electronics. Therefore scientists will often times preposition satellites to a different orientation to protect them from increased solar radiation when a strong solar flare or coronal mass ejection has occurred.
The Solar Cycle: Sunspots increase and decrease through an average cycle of 11 years. Dating back to , we have experienced 23 full solar cycles where the number of sunspots have gone from a minimum, to a maximum and back to the next minimum, through approximate 11 year cycles.
We are now well into the 24th cycle. Daily observations of sunspots began in at the Zurich, Switzerland observatory.
One interesting aspect of solar cycles is that the sun went through a period of near zero sunspot activity from about to This period of sunspot minima is called the Maunder Minimum. So how much does the solar output affect Earth's climate?
There is debate within the scientific community how much solar activity can, or does affect Earth's climate. There is research which shows evidence that Earth's climate is sensitive to very weak changes in the Sun's energy output over time frames of 10s and s of years. Times of maximum sunspot activity are associated with a very slight increase in the energy output from the sun.
Ultraviolet radiation increases dramatically during high sunspot activity, which can have a large effect on the Earth's atmosphere. The converse is true during minimum sunspot activity. But trying to filter the influence of the Sun's energy output and its effect on our climate with the "noise" created by a complex interaction between our atmosphere, land and oceans can be difficult.
For example, there is research which shows that the Maunder Minimum not only occurred during a time with a decided lack of sunspot activity, but also coincided with a multi-decade episode of large volcanic eruptions. Large volcanic eruptions are known to hinder incoming solar radiation. Finally, there is also evidence that some of the major ice ages Earth has experienced were caused by Earth being deviated from its average Indeed Earth has tilted anywhere from near 22 degrees to But overall when examining Earth on a global scale, and over long periods of time, it is certain that the solar energy output does have an affect on Earth's climate.
However there will always be a question to the degree of affect due to terrestrial and oceanic interactions on Earth. But the fall in Solar activity was too small to account for the temperature drop, which has since been attributed to volcanic eruptions. Solar activity picked up during the 20th century, reaching a peak in the cycle that ran from to , before falling away to a very weak cycle in Because changes in Solar activity are important to spacecraft and to radio communications, there is a Solar Cycle Prediction Panel who meet to pool the available evidence.
Experts there are currently predicting the next cycle, which will run to , will be similar to the last one. The extreme weather events of that year provided a glimpse into the future. They gave examples of what even average years will look like after another decade of steadily worsening global warming. Solar physics is an active area of research. Apart from its importance to us, the Sun is a playground for the high-energy physics of plasmas governed by powerful magnetic, nuclear and fluid-dynamical forces.
The Solar cycle is driven by a dynamo coupling kinetic, magnetic and electrical energy. Read more: Explainer: how does our sun shine?
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