As concerns rise about global warming and climate change impacting our planet in negative ways in the future, scientists say that the sun is expected to be unusually cool by around 2050. In what is called the “grand minimum,” the sun will be at a particularly low point during its usually steady 11-year cycle.

Essentially, the sun has a core that is like a heart that races at some times and rests at others, and at its high point the sun’s core forces more magnetic loops to throw out more radiation and generate more sunspots. But at its quietest the sun’s surfaces calms down a great bit and ejects less energy, and scientists are trying to understand these cycles better.

One of these periods back in the 17th century, called the “Maunder Minimum,” caused the Thames river in England to freeze over, and much of the Baltic Sea to be covered in ice.

Physicist Dan Lubin at the Universoty of California San Diego is trying to figure out just how much dimmer the sun will get, and if it will at all compare to that historical incident. He is also trying to figure out exactly when it is likely to take place.

The study has been published in the journal Astrophysical Journal Letters, and it estimates the sun is likely to be 7 percent cooler than a standard minimum inits cycle.