China and Russia quietly conducted experiments this year aimed at manipulating the Earth’s atmosphere.

In June, scientists from the two countries jointly performed five tests that some have speculated to be military related, and detailed their results in Earth and Planetary Physics last week.

The experiments involved heating the ionosphere, which is an upper, electrically charged layer of the planet’s atmosphere. At Russia’s Sura Ionospheric Heating Facility (SURA) in Vasilsursk, a powerful transmitter was used to pump radio energy into the ionized plasma that characterizes this layer, some 310 miles above the town.

Russia's SURA facility. Image: Wikimedia Commons

Once the ionosphere was stimulated, sensors aboard the China Seismo‐Electromagnetic Satellite (CSES) Zhangheng-1 recorded observations from orbit.

“There’s a lot of hype but we’ve done all of these things for years,” Dennis Papadopoulos, a professor of physics at the University of Maryland, told Motherboard.

“What was done is nothing exciting, except for sending the message that Russia and China are interested [in this space],” Papadopoulos, who has conducted similar research in the US but was not part of these experiments, added.

Most of the tests did not cause plasma disturbances, the study notes.

However, one test on June 7 reportedly created an electric spike across 49,000 square miles, “with 10 times more negatively charged subatomic particles than surrounding regions,” according to the Hong Kong newspaper South China Morning Post.

The study claims another test increased the temperature of ionized gas in a select area by 212 degrees Fahrenheit.