The origin of the mysterious Magellanic Stream was discovered by astronomers using NASA’s Hubble Space Telescope. The giant ribbon of gas has been a mystery to astronomers for 40 years.
The Large and Small Magellanic Clouds are at the head of the stream, which stretches almost halfway around the Milky Way galaxy. It was first discovered by radio telescopes in the early 1970s.
Since then, NASA notes that astronomers have wondered if the gas stream comes from one or both of the satellite galaxies. But now Hubble is here to clear up.
A team of astronomers using Hubble found that most of the gas was taken from the Small Magellanic Cloud about two billion years ago. However, a second region of the stream also came from the Large Magellanic Cloud, but that happened more recently.
The source of the Magellanic Stream was uncovered using Hubble’s Cosmic Origins Spectograph, which measures the amount of heavy elements in any given cosmic object.
In this case, it was used to measure elements like sulfur and oxygen at six locations along the massive gas ribbon. A low amount of the elements was discovered along most of the stream, matching levels found in the Small Magellanic Cloud about two billion years ago. But the team also found a much higher level of sulfur closest to the Magellanic Clouds.
The Huffington Post notes that Andrew J. Fox of the Space Telescope Science Institute led the study. He explained that the inner region of the gas stream was similar in composition to the Large Magellanic Cloud, indicating that portion of the stream was ripped out more recently.
The Magellanic Clouds still have their gas and are still forming stars, unlike other satellite galaxies of the Milky Way. But more and more they are feeling the gravity of the Milky Way, which causes their gas to be ripped away. The stream may eventually settle onto the Milky Way’s disk, allowing for the birth of more stars.
But for now, it’s enough for scientists to finally know the origin of the Magellanic Stream.
[Image via NASA]