July 16, 2024

A massive dark hole also referred to as a coronal hole, has formed on the surface of the sun and is hurling strong, swift radiation streams—also known as solar wind—directly towards Earth, posing what looks to be a new challenge for astronomers.

Scientists report that the temporary gap’s size and orientation—wider than 60 Earths—remain unprecedented at this stage of the solar cycle.

A coronal hole, a massive dark patch on the sun, first emerged close to its equator on December 2. Within a day, it had expanded to a maximum width of almost 497,000 miles (800,000 kilometers), according to Spaceweather. The large hole in the sun has been aimed straight at Earth since December 4.

First, experts said that this latest hole could produce a moderate (G2) geomagnetic storm, which can result in radio blackouts and potentially cause powerful auroral displays over the next few days.

However, the solar wind did not get as strong as predicted, so the storm that resulted has only been weak (G1) thus far, according to Spaceweather.com. However, there are formation of auroras at high latitudes.

Although the exact duration for the hole to vanish from the sun is unknown, prior observations indicate that coronal holes have persisted for longer than one solar rotation (27 days), according to NOAA data. The hole, however, will soon rotate away from Earth.

coronal hole in the sun

What is a Coronal Hole?

The dark patches in the corona, the outermost region of the sun’s atmosphere, are known as coronal holes, which are areas of open magnetic fields. 

In contrast to the surrounding regions of the corona, they have lower temperatures and densities, which makes them appear dark in optical and X-ray images. 

Some coronal holes are so large that they occupy about 25% of the solar surface. 

Scientists are still unsure of the exact cause of coronal holes, despite NASA’s Skylab being the first to detect them in the early 1970s.

Although they can occur at any point in the solar cycle, which is the roughly 11-year cycle that the sun’s magnetic field goes through, they are most frequently seen in the cycle’s declining phase.  

The current solar cycle, numbered 25, started in 2019 and is expected to continue until about 2030. 

Coronal Hole Effects on Humans

The idea that solar flares are entirely safe has not won over everyone. The field of science known as “heliobiology” is devoted to examining the relationships between solar activity and human health. Some researchers contend that the link can be negative.

According to one study, modifications to the solar and geomagnetic environments may result in a range of health problems, such as:

  • Blood flow alterations
  • Cardiac arrhythmia
  • Cardiovascular disease
  • Epileptic seizures
  • Increased blood pressure
  • Increased incidence of myocardial infarction-related death

What Causes the Coronal Hole In the Sun?

Scientists do not really know where coronal holes originate, according to Dean Pesnell, a project scientist for NASA’s Solar Dynamics Observatory, who spoke with NPR.

He stated, “There are those who assert that they are the remnants of ancient sunspots.”

According to other scientists, it happens during times of high solar activity when the magnetic fields collide, combine, and split.

Daniel Verscharen, University College London associate professor of space plasma physics, stated in March that coronal holes are places where fast solar wind is propelled into space.

“Fast solar wind has speeds of about 700km or 800km per second and is thus almost twice as fast as the average solar wind.”

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