Context: The Sun is currently on its downtime mode known as Solar Minimum.
More about the news:
- Some reports also suggest that we have already crossed 100 days in the year 2020 with usually low sunspots.
About Solar Minimum
- The sun rays do not shine upon us with the same intensity all the time.
- Association with Solar Cycle and Sunspots:
- The brightness of the Sun varies over the period, predictably after every 11 years, which marks the end of a solar cycle.
- During this time, very few sunspots appear on the surface of the Sun.
- Association with the magnetic field of Sun
- The sunspot cycle is believed to be controlled by the Sun's magnetic field.
- Also all the other activities of the Sun are influenced by its magnetic field.
- Measuring activity of the Sun
- It is mostly measured by sunspots.
- During the midpoint of the solar cycle, the activity of the Sun increases. That means increment in events of flareups and sunspots.
Impact of solar minimum on the Earth
- Solar minimum does not mean that the Sun will stop shinning and this event will have any major impact on the life here on the Earth.
- NASA’s team has clarified that there is no impending ice age to be caused by an expected reduction in the sun’s energy output in the next several decades.
- The change in the flow of energy is a natural phenomenon. However the Sun's activity rarely dips to lower levels, which is called as Grand Solar Minimum.
- The last Grand Solar Minimum was in the late 1600s. This drop in the temperature was linked with a rise in the volcanic eruption.
- In this period, sunspot activity had come to a halt on the Sun, a phenomenon referred to as the Maunder minimum.
- However contemporary challenges are completely different as apart from the Sun's heat, several other factors affect the global temperatures on the Earth that include global warming caused due to greenhouse gas emissions.
Colder areas on the Sun’s surface
Sunspots are areas that appear dark on the surface of the Sun. They appear dark because they are cooler than other parts of the Sun’s surface.
The temperature of a sunspot is still very hot around 6,500 degrees Fahrenheit.
Why are sunspots relatively cool?
- It’s because they form in areas where magnetic fields are particularly strong.
- These magnetic fields are so strong that they keep some of the heat within the Sun from reaching the surface.
Sunspots originate deep within the Sun and become visible when they pop out.
Sunspots occur in pairs, with a leader and a follower.
Mechanism of generation
- Given the high temperatures in the Sun, matter exists there in the form of plasma, where the electrons are stripped away from the nuclei.
- The Sun is made of hot ionized plasma whose motions generate magnetic fields in the solar interior by harnessing the energy of the plasma flows.
- This mechanism is known as the solar dynamo mechanism (or magnetohydrodynamic dynamo mechanism).
- It is a process by which kinetic energy of plasma motions is converted to magnetic energy, which generates the magnetized sunspots, giving rise to the solar cycle.
The reversal in magnetic field in the Sun and the association with SunSpots
- Because of the nature of the solar dynamo, the part of its magnetic field that gives rise to sunspots reverses direction when it moves from one solar cycle to another.
- This can be inferred by observing when the relative orientation of the sunspot pairs flip.
About Solar cycles
The number of Sunspots is not constant but shows a minimum and then rises up to a maximum and then falls again in what is called the solar cycle.
So far, astronomers have documented 24 such cycles, the last one ended in 2019.
The number of the Sunspots waxes and wanes in cycles that last 11 years approximately. We are currently at the minimum of one such cycle.
Origin of solar flares and coronal mass ejections from Sunspots:The Sun appears to be sedated and constant from a large distance. However, huge solar flares and coronal mass ejections spew material from its surface into outer space.
Importance of the Sun
- The Sun is the center of the universe for all the planets revolve around it, including the Earth.
- Without the Sun's heat and light, Earth would be a lifeless ball coated with ice.
- Sunlight keeps the seas warm, it is responsible for the change in the weather pattern, and helps in the growth of the green plants, which further provides food and oxygen to other living beings.