Christopher Scott, a space and atmospheric physicist at the University of Reading in the U.K., would know about the bombing raids. Two of his aunts were killed at just 9 and 11 years of age during the London Blitz, Nazi Germany’s eight-month onslaught against the British from September 1940 to May 1941.
Scott, along with Patrick Major with the Department of History, University of Reading, Berkshire, UK, wanted to know the impact of those bombs way up in the atmosphere – something that has never been realized until now. They discovered that shock waves from the bombs briefly weakened the ionosphere, the outermost layer of Earth’s atmosphere, according to Sky News.
The ionosphere – From lightning to bombs
The ionosphere is the ionized part of Earth’s upper atmosphere, from about 60 kilometers (37 miles) to 1,000 kilometers (620 miles) altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere. This region is where auroras are created and where astronauts on board the International Space Station (ISS) live.
The ionosphere is actually a very active part of the planet’s atmosphere. Solar radiation excites gas atoms, forming electrically charged ions. The density and altitude of the electrons, the negatively charged particles in the ionosphere can fluctuate. “The ionosphere is far more variable than can be explained by solar activity,” Scott told Live Science.
Based on his previous research, Scott knew that lightning could enhance the ionosphere. But he wanted to find out if this was because of the explosive energy of lighting or its electrical charge. In order to do this, Scott had to look for well-documented explosions on the ground to compare the historical data with archival data from the Radio Research Centre at Ditton Park near Slough, U.K.
The Radio Research Centre had taken routine measurements of the ionosphere from 1933 to 1996 – “the longest continuous set of ionospheric measurements in the world,” according to the study published Tuesday in the journal Annales Geophysicae.
Referring to the radio stations records, “What they didn’t realize at the time was that the [ionsopheric records] actually contain the signatures of the actual war itself,” Scott said.
The bombing raids over Germany
The researchers originally thought they would analyze the records from the London Blitz, but there is little information surviving about the timing and munitions used for these raids. Also, the German Luftwaffe two-engine planes couldn’t carry the heavier bombs the Allied forces could haul in their four-engine planes.
The German planes could carry about 4,400 pounds of bombs, while the allied air forces could carry bombs like the “Tall Boy” and the “Grand Slam,” respectively weighing 12,000 and 22,000 pounds.
So Scott decided to look at the bombing raids by allied forces over Berlin. Patrick Major, Scott’s colleague was able to supply a database on the bombing of Berlin between 1943 and 1944 as well as direct Scott to other databases. It was also during this time that the staff at the Radio Research Centre at Ditton Park, near Slough, fired a series of shortwave radio pulses 100 kilometers (62 miles) to 300 kilometers (186 miles) into the air.
The ionosphere was shaken
“Echoes from the radio signals bouncing off the ionosphere layers revealed information about their height and electrical intensity, but the scientists had no idea the data they were recording bore a chilling hallmark of the war,” reports Sky News.
The allied bombings over Germany were very intense and shorter – and occurred during the day. Researchers were able to compare the ionosphere data from the Radio Research Station with information concerning 152 large Allied air raids.
Scott said that each raid released the energy of at least 300 lightning strikes, and accounts from survivors attest to the far-reaching power of the bombs. “Residents under the bombs would routinely recall being thrown through the air by the pressure waves of air mines exploding, and window casements and doors would be blown off their hinges,” Major said in a news release.
And in comparing the data and records from the 152 large Allied air raids in Europe, Scott and Major found that the electron concentration in the ionosphere significantly decreased due to the shock waves from the bombs.
“I was able to see an effect in the U.K. ionospheric records from bombing over 1,000 kilometers [620 miles] away,” Scott said. “I was surprised by that.”
“The images of neighborhoods across Europe reduced to rubble due to wartime air raids are a lasting reminder of the destruction that can be caused by man-made explosions,” said Scott. “But the impact of these bombs way up in the Earth’s atmosphere has never been realized until now. It is astonishing to see how the ripples caused by man-made explosions can affect the edge of space.”
But the bottom line to this study is the knowledge that the ionosphere is important because it’s home to technology that is key to human communication, such as satellites that provide information for GPS systems and radio signals that help guide ships and airplanes.
