A Newly Discovered Clue Finally Revealed Why the Sun Mysteriously Went Dark for 70 Years
This story is a collaboration with biography.com.
Few things seem so immutable Sun– after all, it has been melting hydrogen for five billion years and will continue to do so for about another five billion years. But despite the magnificent presence of our star, the Sun’s magnetic field will experience many solar cycles in just one human lifetime.
These 11-year phases alternate between solar minimums and maximums, characterized by less or more solar activity (sunspots, flares, magnetic fields, etc.), respectively. we live in the moment 25. During the 11-year cycle since astronomers began closely monitoring the Sun’s magnetic activity in 1755.
But there is a mystery at the heart of these seemingly regular solar cycles.
From 1645 to 1715, the Sun experienced a sustained period of low solar activity known as the great solar minimum; Maunder minimum; This phenomenon is named after the English astronomer who discovered it, Edward Walter Maunder. To fully understand this grand minimum, astronomers Data from before the unexpected solar lull is needed. But data is difficult to obtain, given that the first telescope observations of the Sun arrived only a few decades before the Maunder minimum.
Good thing we have a German astronomer Johannes Kepler.
Kepler is best known for his laws of planetary motion (also the name of a very important law). NASA space telescope), but in 2024, scientists at Nagoya University in Japan analyzed Kepler’s observations of sunspots using a camera obscura in 1607, announcing that they believed this reinterpreted piece of data could help astronomers unravel the mysteries of the Maunder minimum.
And given that Kepler initially thought he was witnessing the transit of Mercury, this reinterpretation is certainly needed. The results of the research were published at: Astrophysics Journal Letters.
“Since this recording was not a telescopic observation, it was discussed only in the context of the history of science and was not used for quantitative analyzes of solar cycles in the 17th century,” said Hisashi Hayakawa of Nagoya University, lead author of the study. he said in a press release. “But this is the oldest sunspot sketch so far made by instrumental observation and projection.”
To accurately interpret Kepler’s original findings, Hayakawa and his team needed to narrow down the time period when the observation was made and reconstruct the positions of features on the Sun’s surface (known as heliographic tilt). Previously, astronomers relied on tree ring observations.When the sun is particularly activeSolar winds and solar magnetic field better protect Earth from galactic attack cosmic rays (etched into tree rings as carbon-14). High solar activity means lower carbon-14 (and vice versa), and you can see these changing levels in tree rings.
But trusting Only tree rings to understand solar cycles This comes with some problems, as three separate observations place these cycles (in this case Solar Cycle -13 and -14) into the extremely short, normal, and even extremely long categories. This is where Kepler’s observation comes in, and scientists have discovered that this 417-year observation likely occurred at the tail end of Solar Cycle -13 rather than at the beginning of Solar Cycle -14.
Later telescopic observations also detailed that Kepler’s plot indicated a typical transition from the previous solar cycle, and the team was now able to significantly narrow down the time when this transition occurred (between 1607 and 1610). The final result? During this time the Sun exhibited a typical solar cycle.
“By situating Kepler’s findings within broader reconstructions of solar activity, scientists gain important context for interpreting changes in solar behavior during this important period that marks the transition from regular solar cycles to major solar minimums,” Hayakawa said in a press release. “Kepler’s sunspot records predate the existing telescopic sunspot records from 1610 by several years. His sunspot drawings serve as a testament to his scientific acumen and determination in the face of challenging conditions.” technological restrictions.”
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