though not as drastically different in composition as you might assume. Earth's atmosphere is composed of 78% nitrogen gas (N2) and 21% oxygen gas (O2). The final 1% is a mix of argon, carbon ...

Scientists found that volcanic eruptions triggered short-lived oxygen spikes before Earth's air became breathable.

plus trace amounts of other gases. The atmosphere has four layers. The troposphere is the layer closest to the surface of the Earth. Next is the stratosphere, which is where commercial airplanes fly.

In a phone interview with The Guardian on Feb. 19, Kuljeet Grewal explained the effects of greenhouse gas emissions in the Earth’s atmosphere.

“Xenon is a noble gas which, being chemically inert and having nine isotopes, is an ideal element to reveal the xenon isotopic composition in the Earth’s primary atmosphere. This also makes it an ...

This article was originally published with the title “ The Earth in the Sun's Atmosphere ” in Scientific American Magazine Vol. 201 No. 4 (October 1959), p. 64 doi:10.1038 ...