Think of it this way. Even the Sun has a heart that beats. Only, each of its beats—that is, a “solar cycle”—lasts 11 long years.
During this time, its interior goes through changes, changes that manifest in the number of “sunspots”—pockets of cooler areas on the Sun, with intense magnetic fields poking out of them, and which appear as dark blobs on the solar disc.
Typically, throughout this period, its pulse fluctuates. When it’s faint, the sunspots wane. When it leaps into a canter, there’s a burst of sunspots.
But 15 years from now, what’ll happen is a departure from routine. During the solar cycle, extending from 2030 to 2040, it’ll experience “irregularities” in its heart beat, and its level of activity will plummet by 60 percent.
A lot of publications have interpreted this to mean that the Sun will slip into a funk, and that this will trigger the dawn of a Little Ice Age on Earth. The entire planet will be iced over à la “The Day After Tomorrow” (2004).
But that’s not true, writes Phil Patton at Bad Astronomy. Reason: the drop is in the Sun’s level of magnetic activity, not in its output of heat and light.
The last time something of this nature took place was roughly 300 years ago, between 1645 and 1715. During that 70-year-period, known as the “Maunder Minimum,” there was a steep decline in sunspots. The Sun was nearly blank.
Yes, that period did coincide with a string of cruel winters. On the night of January 6, 1709, the whole of Europe was gripped by a bone-chilling freeze, not encountered in the last 500 years.
Be that as it may, the cold snap of the 17th and 18th centuries wasn’t brought on by the Sun’s so-called slumber alone. There were many other factors.
Even so, the summers were like ordinary summers. Only, winters were far colder than usual. Events like the “polar vortex” (an enormous whirlpool of very cold, dense air, which sits over the polar region during winters), traveling far south, down to the U.S. and Europe, might have been more common.
In the future, if at all, there’s any cooling effect of the Sun, it’ll be subsumed by a much more robust heating trend due to global warming.
h/t: BAD ASTRONOMY