Earth

The meteoroid broke apart around 9 a.m. Tuesday over Valley City, a half-hour south of Cleveland, after it sped through the atmosphere at about 45,000 miles (72,420 kilometers) per hour. It caused a sonic boom that rattled buildings and caused fears of an explosion.

From unknown supermassive black hole discoveries to the new evidence that two million years ago supernova debris showered Earth — there is no shortage of…

The United Nations conference on climate change kicked off in Paris this week, and on Monday, President Obama addressed America's role as a major emitter…