The Milky Way’s signature gas halo spins at a relative speed of its host disk, according to a NASA-funded study. It was earlier surmised that the host gas reservoir surrounding the galaxy’s disk remained motionless. But astronomers from the College of Literature, Science and the Arts at the University of Michigan discovered otherwise. The study was published in the Astrophysical Journal.
Scientists sourced archival data from the XMM-Newton, a European Space Agency (ESA) telescope. Astronomers used motion—which causes a shift in light’s wavelength—to exhibit the spinning gas halo in concert with the Milky Way’s disk. The halo whirls at 400,000 mph, the disk 540,000 mph.
“The rotation of the hot halo is an incredible clue to how the Milky Way formed. It tells us that this hot atmosphere is the original source of a lot of the matter in the disk,” said Edmund Hodges-Kluck, co-research scientist for the study.
This new knowledge will assist scientists’ efforts in trying to understand the genesis of the Milky Way and its eventual terminus. The visibility of the Milky Way is slowly disappearing. In fact, 80 percent of North America can longer view it. Western Europe, however, is most affected by a phenomenon known as light pollution; Spain, Scotland, Sweden, Norway, and Austria are, nonetheless, still dark enough to witness the galaxy.
Light pollution is present in other areas around the world. South Korea, Italy, and Saudi Arabia experience the most light pollution, whereas Germany and India have the blackest skies. The International Dark-Sky Association (IDA), though, says that light pollution is reversible. Energy-efficient light bulbs and drawing blinds at night to keep interior light from seeping out are ways to reduce added light pollution.
The association also advises to only use light when requisite. Instead, the organization suggests turning off lights when not being used and installing motion detectors and timers to avoid artificial lighting; cutoff lighting is also encouraged.
Light pollution obfuscates the night skies, but moreover, it interferes with the body’s circadian rhythm, which controls sleep patterns.