On Aug. 18, 1868, a French astronomer named Pierre Jules César Janssen found helium whereas observing a complete photo voltaic eclipse in India.
Through the eclipse, Janssen was utilizing a spectroscope to have a look at the spectrum of sunshine emitted by the sun. This device permits scientists to find out what parts they’re . Whereas observing photo voltaic prominences through the eclipse, Janssen seen a shiny yellow line that did not correspond to any parts that was not but found on Earth.
Within the months that adopted, English astronomer Norman Lockyer independently noticed the identical spectral line and concluded that it got here from a beforehand unknown factor, which was named helium after Helios, the Greek god of the solar.
13 years later, the Italian physicist Luigi Palmieri discovered the primary proof of helium on Earth, within the lava of Mount Vesuvius.
Why it mattered
The detection of helium through the 1868 eclipse was the primary time spectroscopy revealed a component in an astronomical object that had not but been found on Earth, and highlights why spectroscopy is one among astronomy’s strongest instruments.
Like each different factor on the periodic desk, helium has innumerable functions, together with some which can be particularly necessary to house and spaceflight. Scientists finally discovered that helium is the second-most considerable factor within the universe (after hydrogen). And the fusion of hydrogen into helium is the method that powers stars like our solar. Helium gasoline is often used to pressurize and purge rocket propellant programs, and liquid helium is commonly used to chill delicate scientific devices on spacecraft.
