The spiral arms of the Milky Way galaxy may stretch farther out into space than previously known, according to a team of astronomers who have made precise distance measurements using data from two telescopes orbiting high above Earth's atmosphere.
The researchers, led by Italian Ph.D. student Beatrice Vaia, took advantage of rare, powerful gamma-ray bursts in distant galaxies. As X-rays from those bursts traveled through the Milky Way, some of the light bounced off dust clouds, creating rings that could be measured with unusual precision.
The team used data from NASA's Chandra and the European Space Agency's XMM-Newton to make their measurements. The dust cloud in the most distant arm of the Milky Way was estimated to be about 3,500 light-years wide, according to the data collected.
The recent breakthrough with studying gamma-ray bursts could have massive implications on how we conceptualize our home within the universe. The differences are small, but any revision of these distances is important because they are so fundamental for understanding our galaxy.
Astronomers have been aware of the Milky Way's arms for at least a century, but mapping them has always been difficult since Earth is positioned inside one of them. The technique used by the researchers is not hampered by Earth's position inside the galaxy.
However, the technique has its limitations. Suitable gamma-ray bursts are rare, and researchers have found only a handful over the past 25 years that were bright enough and positioned in a way that allowed them to measure the Milky Way's spiral arms.
The researchers will continue to be on the lookout for more suitable gamma-ray bursts, which will allow them to refine their measurements and gain a deeper understanding of the Milky Way's structure.
