A yellow streak led from the sun to helium

At 10:42:10 a.m. local time on August 18, 1868, English astronomer Norman Pogson saw Madras Observatory In Machilipatnam, India, during a solar eclipse something is strange. He noticed an unfamiliar yellow line flashing on his instrument as he looked at the sun’s hot atmosphere, called the corona.

Normally it would be obscured by all the sunlight itself, but in the darkened India the halo sat like a graceful halo of light around the eclipsed sphere. The corona has a size of 1 million Kelvin, and this temperature extreme produces very bright light, allowing the chemical elements in the atmosphere to be identified in the light spectrum.

Pogson saw a bright yellow line in the spectrum of the aura that he had not seen before. He informed the local officer and continued his “normal” search for asteroids. Three months later, he discovered 107 Camillas, one of the largest asteroids in the Milky Way. A nice find, but it could also be a novelty, as it turned out.

They were expecting metal

The yellow line heralded the discovery of the first noble gas from the periodic table, which was eventually attributed to Englishman Norman Lockyer and Frenchman Pierre Jansen. They named it helium, after the Greek word for sun, Helios. suffix -day It was added because they were expecting a metal, but after helium was discovered on Earth by Scottish chemist William Ramsay in 1895, it turned out to be a noble gas. But the name did not change again.

Helium one amazing literally item. It has the lowest melting and boiling points, respectively -272.2 and -268.9 degrees Celsius. It is an inert gas, which means that it does not enter into chemical reactions. Additionally, helium is a by-product of the radioactive decay of uranium and thorium. By measuring the ratio of helium to uranium or thorium, you can date fossils, minerals, and rocks.

low gravity

The search for helium is now back on track, 155 years after its discovery. The demand for the colorless noble gas is enormous. In the universe, helium makes up 25% of matter. Although large supplies of helium were found in 2016 at Lake Rua in Tanzania, only 0.0005 percent of our atmosphere is composed of helium. Because of Earth’s relatively low gravity, our atmosphere doesn’t hold helium well, and it flies off into space.

Shame, because helium has many useful applications. Because of its low boiling point, helium works well as a coolant for processes that require very low temperatures, such as nuclear power generation or for cooling superconducting electromagnets in MRI scanners. Another application is gas lift. Since helium is much lighter than air and also non-flammable, it is used in weather balloons and airships so that they float. In addition, it is added to divers’ oxygen cylinders, because pure oxygen becomes toxic at high pressure; Helium prevents this.