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What is Solar Cycle 25?

Topics Covered: Awareness in space.

What is Solar Cycle 25?


Context:

Scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA) have announced their predictions about the new solar cycle, called Solar Cycle 25, which they believe has begun.

Key findings:

  • The solar minimum for Solar Cycle 25 occurred in December 2019.
  • Scientists predict a solar maximum (middle of the solar cycle) will be reached by July 2025.
  • This solar cycle will be as strong as the last solar cycle, which was a “below-average cycle” but not without risks.

But first, What is a solar cycle?

The Sun is a huge ball of electrically-charged hot gas. This charged gas moves, generating a powerful magnetic field. This magnetic field goes through a cycle, called the solar cycle.

Every 11 years or so, the Sun’s magnetic field completely flips. This means that the Sun’s north and south poles switch places. Then it takes about another 11 years for the Sun’s north and south poles to flip back again.

So far, astronomers have documented 24 such cycles, the last one ended in 2019.

How do scientists track solar activity?

Scientists track a solar cycle by using sunspots.

The beginning of a solar cycle is typically characterised by only a few sunspots and is therefore referred to as a solar minimum.

 What is solar minimum and maximum?

One way to track the solar cycle is by counting the number of sunspots.

  • The beginning of a solar cycle is a solar minimum, or when the Sun has the least sunspots. Over time, solar activity—and the number of sunspots—increases.
  • The middle of the solar cycle is the solar maximum, or when the Sun has the most sunspots. As the cycle ends, it fades back to the solar minimum and then a new cycle begins.

Impacts of Solar Cycle on Earth:

  • Solar eruptions can cause lights in the sky, called aurora, or impact radio communications. Extreme eruptions can even affect electricity grids on Earth.
  • Solar activity can affect satellite electronics and limit their lifetime.
  • Radiation can be dangerous for astronauts who do work on the outside of the International Space Station.

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Prelims Link:

  1. What are solar flares?
  2. What are sunspots?
  3. How solar flares affect earth’s magnetic field?
  4. What is sun’s 11 year cycle?
  5. What is solar minimum?

Sources: Indian Express.