{"next":"2026-03-12","photo":{"source":"nasa","date":"2026-03-11","cid":"bafkreia62grwmn4gjep5yxqlcx2ovvcfsrun77jw5mqu2d6c3fwhhslgne","title":"CG 4: The Globule and the Galaxy","explanation":"Is this a cosmic monster ready to devour an unsuspecting galaxy? Thankfully, that is not the case. The red “monster” shown in the featured image is Cometary Globule CG 4, 1,300 light-years away in the Constellation Puppis. CG 4 is a molecular cloud, where hydrogen becomes cold enough to form molecules that can be brought together by gravity to create stars. The shape of CG 4 resembles that of a comet, but its head is 1.5 light-year in diameter and its tail is 8 light-years long; for comparison, the distance from the Earth to the sun is only 8 light-minutes. Astronomers believe that the tail of a cometary globule could have been shaped by a nearby supernova explosion or by irradiation from hot, massive stars. Indeed, CG 4 and other nearby globules point away from the Vela Supernova Remnant, at the center of the Gum Nebula. The edge-on spiral galaxy, ESO 257-19, is more than a hundred million light-years beyond CG 4, and is completely safe from the “monster”.","imageUrl":"https://apod.nasa.gov/apod/image/2603/cg4.jpg","thumbUrl":"https://apod.nasa.gov/apod/image/2603/cg4_1024.jpg","mediaType":"image","credit":"William Vrbasso","sourceUrl":"https://apod.nasa.gov/apod/ap260311.html","placeholder":false,"fetchedAt":"2026-05-19T04:34:10Z"},"prev":"2026-03-10","source":"nasa"}