Sun’s activity in 18th century was similar to that now


Counting sunspots over time helps in knowing the activity of our star but the two indices used by scientists disagree on dates prior to 1885. Now an international team of researchers has tried to standardise the historical results and has discovered that, contrary to what one may think, the solar activity of our times is very similar to that of other times, such as the Enlightenment.

Scientists have been counting sunspots since 1610 with small telescopes. Thus it has been verified that the Sun's activity increases every eleven years, according to the interval in the growth of the number of darker and colder spots in comparison with the rest of its surface. The more spots that appear, the more luminous the surrounding areas are, and our star shines brighter.

Nonetheless, the eleven-year cycles do not always have the same intensity. The more intense peaks of the Sun's luminosity were produced in the 20th century, which experts have called the 'modern maximum'. However, an international team of scientists has reviewed the historical data and has verified that there were also elevated values in other periods.

"It has been a huge surprise to observe that in the 18th century the levels of the Sun's activity were practically the same as they are now," points out José M. Vaquero, researcher at the University of Extremadura (Spain) and co-author of the research, a review of the number of sunspots recorded in the last 400 years.

The results, published in the journal Space Science Reviews, also reveals that in other periods the opposite occurred, such as the Maunder minimum (1645-1715), when the sunspots practically disappeared and solar activity was drastically reduced.

International sunspot number. Image credit: Royal Observatory of Belgium/SILSO graphics

"A proper estimate of the past and present activity of the Sun, our main source of light and heat, is crucial in understanding numerous phenomena that occur on Earth, especially to rule out the role of the Sun in global warming," says Vaquero, "but we come up against the problem that two indices or ways of calculating historical solar activity exist, and their data does not coincide when describing what happened before the 20th century".

Discrepancy between European and American indices

The first index is the 'International Sunspot Number' or Wolf number, thought up by the Swiss astronomer Rudolf Wolf in 1849. It is currently the method followed by the Royal Observatory of Belgium, aided by a network of more than a hundred other astronomical observatories, the majority amateur. The second version is the 'Group Sunspot Number', and was created by US scientists Douglas V. Hoyt and K.H. Schatten in 1998.

Unfortunately these two series only coincide in the more recent period, from approximately 1885 onwards," points out Vaquero. "In the previous periods, the US index shows a much lower level of solar activity than the European one, and this causes confusion and contradictions when the number of sunspots is used in modern research regarding the solar dynamo or the solar forcing on the Earth's climate system, for example".

The historical study of sunspots has led to the detection of several errors in the two versions. Their authors, from centres such as the Royal Observatory of Belgium, Stanford University and the US National Solar Observatory, have also been able to correct some of the detected incidents.

To carry out this research, Spain has provided information from the catalogue of sunspots from the Observatory of the University of Valencia, created between 1920 and 1928 before its fire, and data from the Astronomical Observatory of Madrid recorded between 1876 and 1986.

Source: AgenciaSinc


Featured image credit: Royal Observatory of Belgium/SILSO graphics

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  1. TSI has not been down. TSI has been right up there. In fact it peaked for the second time this cycle way above the solar constant while sunspot numbers were mediocre. The TSI has just taken a dive below the solar constant this month. First time in long time it’s been below the solar average. A recent study showed that narrow band x rays, infra red, visible light has been steadily increasing each and every year no matter what the sunspot totals are.

  2. Global Conning: Temperature Data Cooked in “Biggest Science Scandal Ever”
    What do you get when you combine copious amounts of government grant money, layers of dishonesty, the heat of environmental activism, a few dollops of ambition, and a glaze of science in a political pressure cooker?

    It’s a recipe for enriching a few, impoverishing most, and serving up bad policy all around.

    If you’ve ever wondered why you’re buried in snow but keep hearing about how we’ve experienced “officially, the second warmest year on record” (when we’re not being told it could be the warmest year on record), know that “officially” relates to the pronouncements of officials, and “official temperature records” have been “systematically ‘adjusted’ to show the Earth as having warmed much more than the actual data justified.”
    Global warming or cooling is simply being used an excuse for big government to grow even bigger and take control of the lives of EVERYONE on the planet. The goal is to control every aspect of a person’s life by implementing tons of regulations to control global warming or cooling
    Best wishes,


    1. Dear Alex, your so right its same with instead of drilling for oil in poor war torn in drought countries there should be drilling for water. Funding war is the biggest “work to make a kill industry”, is making earning an honest living look like a continued death sentence especially when those in top power & money control put all stakes up on all we buy or sell or try to save for.
      Also as for climate issues, It’s “what I call the Emperor’s New Clothes Theory!” Where does the carbon credit money really go to? To the big paid Fossil Fuel Corps etc..
      If you interested in spot on day to day up dates of Earth, Climate Change, Space Weather & Astronomy go to (www.suspiciousobservers.org)
      Earth has away of panning things out with or without our control or help and even pollution.
      Have we forgotten what happened when the last Roman Empire fell and what happened to the Earths life patterns that lead up to it and followed?
      Have fun exploring the differences as long as the Earth still spins and the Sun still shines, we still live on a planet that is constantly changing and yet it is still the third Rock from the Sun and that will never change, unless something out of the blue knocks us off out of orbit. 🙂 Good comment cheers from Dina. NZ

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