What is Solar Minimum and its impact on Earth?
The Sun is a yellow dwarf star and is the heart of the solar system. It is a hot ball of glowing gases. The Sun is said to have in a stage of Solar Minimum. What is the solar minimum and its impact on Earth? Let us study in detail.The sun appears mostly same day-in-day-out, year after year. But this is not true. The sun does change. The surface of the sun has sunspots which are strongly magnetized and they crackle with solar flares. The magnetic explosions illuminate Earth with flashes of X-rays and ultraviolet radiation. Therefore, we can say that the sun is a seething mass of activity.
What is Solar Minimum?
Approximately every 11 years, the sun goes through a natural solar cycle. It is marked by the increase and decrease of sunspots.
Let us tell you that the sunspots are visible on the surface of the sun or photosphere as dark blemishes.
According to NASA, the greatest number of sunspots in any given solar cycle is designated as “Solar Maximum” and opposite to it that is the lowest number is designated as “Solar Minimum”. During solar minimum, the intense activity like sunspots and solar flares subside but that does not mean that the sun becomes dull. It’s just simply changing its form.
Note: In 1843, the solar cycle was discovered by Samuel Heinrich Schwabe. He after 17 years of observations noticed a periodic variation in the average of sunspots.
According to NASA, scientists have already predicted about the solar minimum that it was coming because it is a regular aspect of the sun’s cycle. In 2014, the sunspots were peaking and low points beginning in 2019.
About Solar Maximum
As discussed above solar minimum and solar maximum are the two extremes of the Sun’s 11-year activity cycle. When the Sun is at its solar maximum cycle, it has sunspots, solar flares erupt. Skywatchers may see several auroras.
Pesnell told that “at the time of solar minimum we can see the progress of long-lived coronal holes”.
Do you know about coronal holes?
They are vast regions in the atmosphere of the sun where the sun’s magnetic field opens up and allows streams of solar particles to escape the sun as the fast solar wind.
Further Pesnell says that throughout the solar cycle we see these holes, but during solar minimum, they can last for a long time maybe six months or more. From coronal holes when solar wind streams flow can cause space weather effects near Earth when they hit the magnetic field of the Earth.
What is the impact of this phenomenon on Earth?
These effects can cause short-term disturbance of the Earth’s magnetosphere known as geomagnetic storms, auroras and disrupt communications and navigation systems. During solar minimum, the space weather will also affect the upper atmosphere of the Earth on satellites in low Earth orbit changes too.
Basically, the upper atmosphere of the Earth is heated and puffed up by the ultraviolet radiation from the sun. In low Earth orbits, satellites experience friction as they skim through the outskirts of pour atmosphere. This type of friction generates drag, causes the satellite to lose speed over time and eventually fall back to Earth.
No doubt Drag is a good thing for the space junk, natural and manmade particles that floats in the orbit around the earth. It also helps to keep the low Earth orbit clear of debris.
Now let us see what happens during solar minimum. The natural heating capacity mechanism subsides. The upper atmosphere of the Earth cools and to some degree collapse. In fact, space junk tends to hang around, without a normal amount of drag. During solar minimum, various unique space weather effects get stronger.
Also, during solar minimum, a number of galactic cosmic rays that reach the upper atmosphere of Earth increases. Also, the galactic cosmic rays are high energy particles advance toward the solar system by distant supernova explosions and other aggressive events within the galaxy.
The magnetic field of the sun weakens during solar minimum and provides less shielding from these cosmic rays. This can cause an increased threat to astronauts travelling through space.
According to NASA’s Global Climate Change, in the next few decades, we could go into a stage of Grand Solar Minimum. That is the Sun becomes quieter, experiencing much fewer sunspots and giving off less energy. Last time it had occurred between 1650 and 1715 during the Little Ice Age within the Northern Hemisphere of the Earth. It is because when a combination of cooling from volcanic aerosols and low solar activity produced lower surface temperatures.
So we can say that solar minimum brings about several changes to our sun.
Here’s what NASA has to say about ‘solar minimum’ and its impact on Earth
The solar cycle takes place every 11 years when the Sun’s magnetic cycle gets into overdrive. At the height of this cycle, known as “solar maximum”, the Sun’s magnetic poles flip.
With “solar minimum” and “sun lockdown” trending on social media sites and search engines, we wonder if that is really going to mess up with the world, or bring famines and earthquakes. In fact, the solar cycle takes place every 11 years when the Sun’s magnetic cycle ramps up into overdrive. At the height of this cycle, known as “solar maximum”, the Sun’s magnetic poles flip.
NASA, in a recent post, explained the solar cycle and its impact on Earth. “In an effort to understand what affects Earth’s climate, scientists must correctly interpret just how changes on the Sun do and do not change what’s happening on Earth,” the space agency wrote on its page.
Can changes in solar irradiance due to the 11-year solar cycle cause the current change in Earth’s climate?
In a word, no. Scientists agree that the solar cycle and its associated short-term changes in irradiance cannot be the main force driving the changes in Earth’s climate we are currently seeing. For one thing, the Sun’s energy output only changes by up to 0.15 per cent over the course of the cycle, less than what would be needed to force the change in climate that we see, said NASA. Also, scientists have not been able to find convincing evidence that the 11-yr cycle is mirrored in any aspects of the climate beyond the stratosphere – such as surface temperature, rainfall, or wind patterns.
What is the solar cycle and is it connected to Earth’s climate?
The entire Sun from North Pole to South Pole is a giant magnet, but it’s not a simple one. The Sun’s magnetic fields are on the move so that approximately every 11 years the entire field flips, and the north and south magnetic poles switch. Another 11 years and the poles switch back again. In between flips, the total radiation from the Sun — known as total solar irradiance — waxes and wanes in a semi-regular cycle by up to 0.15 per cent.
How to separate the effect of the solar cycle from other possible effects on Earth’s climate?
Unfortunately, one can’t simply take estimates of Earth’s temperature and rainfall all over the globe and know how much of it is affected by changes in the Sun’s total irradiance. Numerous natural and man-made occurrences — from periodic climate fluctuations like El Niño, emissions from volcanoes, and increased greenhouse gases in the atmosphere — affect temperatures and weather patterns too. Instead, scientists must use computer models or statistical analyses to attribute all the changes to all the different influences.
In general, the bigger the effect, the easier it is to get a confident answer. Input into those calculations comes from the measured changes in irradiance from space using instruments like the Total and Spectral solar Irradiance Sensor – 1 (TSIS-1) instrument on the International Space Station.
What about longer-term changes?
While there have only been highly accurate, space-based measurements of solar irradiance since 1979, humans have been recording the solar cycle by monitoring the increase and decrease of magnetically active sunspots — which can be used to estimate longer-term changes in solar irradiance — since the beginning of the 1600s. Prior to that there are indirect measures of solar activity available from ice core and tree ring records.
What is Solar Minimum?
The sun is said to have gone into a state called the ‘solar minimum’ and is about to enter the deepest period of ‘sunshine recession’ as sunspots are virtually not visibly at all.
What is a solar minimum and why is it happening now?
- Sun has a cycle that lasts on average 11 years, and right now we are at the peak of that cycle.
- Every 11 years or so, sunspots fade away, bringing a period of relative calm.
- This is called the solar minimum. And it’s a regular part of the sunspot cycle.
- While intense activity such as sunspots and solar flares subside during solar minimum, that doesn’t mean the sun becomes dull. Solar activity simply changes form.
What about Solar Maximum?
- Solar minima and maxima are the two extremes of the Sun’s 11-year and 400-year activity cycle.
- At a maximum, the Sun is peppered with sunspots, solar flares erupt, and the Sun hurls billion-ton clouds of electrified gas into space.
- Sky watchers may see more auroras, and space agencies must monitor radiation storms for astronaut protection.
- Power outages, satellite malfunctions, communication disruptions, and GPS receiver malfunctions are just a few of the things that can happen during a solar maximum.
What are its effects on Earth?
a) On space weather
- The Solar wind from coronal holes will temporarily create disturbances in the Earth’s magnetosphere, called geomagnetic storms, auroras, and disruptions to communications and navigation systems.
- The space weather during solar minimum will also affect Earth’s upper atmosphere on satellites in low Earth orbit changes.
- This means that the Earth’s upper atmosphere will cool down which is generally heated and puffed up by ultraviolet radiation from the sun.
- However, the heat at the upper atmosphere of our planet helps Earth to drag debris and keep the low Earth orbit clear of manmade space junk.
- Apart from this, the solar minimum will change the space weather significantly which will lead to an increase in the number of galactic cosmic rays that reach Earth’s upper atmosphere.
- These Galactic cosmic rays are high energy particles which are a result of distant supernova explosions and other violent events in the galaxy.
b) On astronauts
- According to NASA the sun’s magnetic field weakens and provides less shielding from these cosmic rays during a solar minimum which will directly increase the threat to astronauts travelling through space.
- This may cause health risks to astronauts travelling through space as the sun’s magnetic field weakens and provides less shielding from these cosmic rays.