> What's the term for a giant cloud of dust and gas in outer space?And the answer: a nebula. Photo courtesy: NASA/JPL-Caltech/University of Colorado.A nebula is a giantcloud of dust and gases, mostly hydrogen and helium. According to NASA, "somenebulae come from the gas and dust thrown out by the explosion of a dying star,such as a supernova. Other nebulae are regions where new stars are beginning toform."Coming from the Greek word for "cloud," these fittingly named nebulae arelargely invisible to the naked eye, yet are ubiquitous in our universe. TheMilky Way, our galaxy, is filled with nebulae of all different shapes and sizes.The Orion Nebula is one of the most visible, and has been observed for thousandsof years. In fact, the Maya of Central America called it "the fire of creation." Almost every part of the lifecycle of a star can be seen in a nebula. Thesegaseous clouds are so closely intertwined with the life of stars that it isimpossible to understand our universe without them. Recent advances intelescopic and infrared technology allow astronomers to peer inside thesegaseous clouds to uncover new, striking truths about the nature of stars in ouruniverse. Infrared detectors work with concentrations of heat and density. These detectorscan penetrate a seemingly dark, cold congregation of a nebulae to source signsof increased heat and temperature – oftentimes indicating that a new star isbeing born. Eventually, the center of the gravity in the nebula grows strongenough to ignite fusion, and a star is born (no, it's not Lady Gaga). Did you know? At the dawn of the universe, around 13.8 billion years ago, the Big Bang gaveway to an expanse of pure energy. Over the course of 300,000 years, the energycooled to form hydrogen and helium gas, lacking solid matter. This means thatthe entire universe was once one enormous nebula! Take a trip through a nebula with the video below.