Parents
Spouse
Children
Siblings
1887
Sep 28
| 1887 • Heinrich Hertz discovers the photoelectric effect on the production and reception of electromagnetic (EM) waves (radio). This was an important step towards the understanding of the quantum nature of light. |
1915
Oct 6
Age: 28y
|
marriageJohn Sampson Bagnall Seattle, King, Washington, USA ⇓ 1 Source ⇓ |
| 1915 • Lassen Peak, one of the Cascade Volcanoes in California, erupts, sending an ash plume 30,000 feet in the air and devastating the nearby area with pyroclastic flows and lahars. It is the last volcano to erupt in the contiguous United States until the 1980 eruption of Mount St. Helens. |
about
Age: 31y
1919
Age: 31y
|
birth of childJohn Bagnall Jr. 2 Sources ⇓ |
| 1919 • The United States Army sends a convoy across the continental U.S., starting in Washington, D.C., to assess the possibility of crossing North America by road. This crossing takes many months to complete, because the building of the U.S. Highway System has not commenced. |
1920
Age: 32y
| 1920 • Mexican Revolution: Álvaro Obregón's troops enter Mexico City. |
1971
Feb 20
Age: 83y
| 1971 • Mars probe program: Mars 2 is launched by the Soviet Union. |