What is the Maunder Minimum?

Named after English astronomer Edward W. Maunder (1851-1928), the Maunder Minimum was a period of extremely low sunspot activity that lasted from 1645 to 1715. Maunder discovered this solar event by researching old records.

What are some other sunspot minimums and maximums?

Below is a list of notable sunspot activity changes dating back to 1000 C.E. Some of the names for these maximums and minimums come from their discoverers,

Why do sunspots appear dark?

Sunspots are a slightly cooler temperature (about 2,000 degrees Fahrenheit [1,100 degrees Celsius] cooler) than their surrounding photospheric gas, and so in the bright back-lighting, sunspots appear dark. Do not be fooled, though; a sunspot is still many thousands of degrees, and the amount of electromagnetic energy that courses through sunspots is tremendous.

including German astronomer Gustav Spörer (1822-1895), English meteorologist John Dalton (1766-1844), English astronomer Edward W. Maunder (1851-1928), and Swiss astronomer Johann Rudolf Wolf (1816-1893).

Sunspot Activity 1000 c.e. to Present

Years (c.e.)


1010 to 1050

Oort Minimum

1100 to 1250

Medieval Maximum

1280 to 1340

Wolf Minimum

1420 to 1530

Spörer Minimum

1645 to 1715

Maunder Minimum

1790 to 1820

Dalton Minimum

1950 to Present

Modern Maximum

What is the Wolf Number?

Swiss astronomer Johann Rudolf Wolf (1816-1893) devised a system for counting sunspots in 1848. The Wolf Number is named in his honor. Astronomers count sunspots from various observation points across the globe, then average those counts to come up with the official Wolf Number for that period.

What happens to the Sun every 22 years?

The sunspot activity on the Sun is related to the magnetic field change the Sun goes through. Every 22 years, the Sun's magnetic field completely reverses. Magnetic north becomes magnetic south and vice versa. Other than having something to do with sunspot activity, astronomers do not believe that this flipping affects our weather in any way.

What is a solar prominence?

Prominences are high-density streams of solar gas projecting outward from the Sun's surface (photosphere) into the inner part of the corona. They can be more than 100,000 miles long and can maintain their shapes for days, weeks, or even months before breaking down.

What were the Great Solar Storms of 1989?

In March 1989 solar activity became much more active than usual, creating solar storms that sent out high energy particles into the Earth's ionosphere. The storms had adverse effects on communications and weather satellites, and also resulted in spectacular aurorae that reached as far south as Mexico. The storms also affected power grids in some areas. Most notably, six million people in Quebec, Canada, experienced a blackout when circuit breakers and fuses overloaded. More recently, an even bigger solar storm occurred on Halloween 2003, mostly affecting Sweden with power outages and damaging 28 satellites, two of which were complete losses.

What is a coronal mass ejection?

A coronal mass ejection is a huge blob of solar material—usually highly energetic plasma—that is thrown outward into space in a huge solar surface explosion. Coronal mass ejections are associated with solar flares, but the two phenomena do not always occur together. When coronal mass ejections reach the space near Earth, artificial satellites can be damaged by the sudden electromagnetic surge caused by the flux of these charged particles.

What is a solar flare?

Solar flares are sudden, powerful explosions on the surface of the Sun. They usually occur when large, powerful sunspots have their magnetic fields too tightly twisted and torqued by the hot, swirling plasma in the Sun. The magnetic field lines unwind and break suddenly, and the matter and energy that had been contained rushes outward from the Sun. Solar flares can be many thousands of miles long, and they can contain far more energy than all of the energy consumption of all of human history on Earth.

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