The atmosphere, a thin veil of molecules enveloping Earth, reaches about 20 miles (32 kilometers) above the planet's surface.

If so, they could make the leap to an expanding Universe and the possibility that somewhere out there, farther than they can see, are others like them. The era of star formation is at an end.

Could time itself actually explain our universe's expansion? Our current cosmological model—known as lambda cold dark matter, ...

Permafrost, a frozen layer rich in organic matter, is degrading due to rising temperatures. By the end of the century, researchers predict significant thawing, releasing carbon into the atmosphere.