When you buy through links on our articles, Future and its syndication partners may earn a commission.Illustration of the separation of the SWCX foreground emission from the cosmic X-ray sky, for the Western Galactic hemisphere. The stripe patterns visible in the SWCX image result from temporal variations in foreground emission combined with eROSITA’s scanning geometry. | Credit: MPEAstronomers have, for the first time, spotted the “breath of the solar system.” The finding comes in the form of X-ray emissions generated when the electrically charged solar wind slams into both Earth’s atmosphere and the bubble that surrounds our solar system, the heliosphere.This phenomenon, known as “solar wind charge exchange,” was observed by the eROSITA space telescope, allowing a team of scientists to create a map of the sky in so-called “soft X-rays.” This X-ray glow is radiated when the heavy ions of the solar wind, like carbon and oxygen, grab an electron from neutral atoms in either our outer atmosphere or the heliosphere.AdvertisementAdvertisementSolar wind charge exchange had previously been considered interference or background noise interfering with astronomers’ attempts to measure the density and temperature of plasma in distant galaxies and galaxy clusters. By producing the clearest map to date of soft X-rays, this team has further validated the phenomenon as a fascinating area of study in its own right.Reconstruction of how the diffuse X-ray sky should have appeared to eROSITA from May to October 2021. At any given moment, eROSITA has observed only a 1° wide field along its scanning direction, which is indicated by a cyan curve. Each 360° scan took 4 hours and was done approximately perpendicularly to the direction of the Sun, which is located in the overexposed moving region. | Credit: K. Dennerl, J. Sanders, H. Brunner & the eSASS team (MPE); E. Churazov, M. Gilfanov (IKI)Launched by Russia’s space agency Roscosmos on July 13, 2019, eROSITA currently sits at a gravitationally stable point between Earth and the sun known as Lagrange Point 2. This point, also known simply as L2, is located 932,000 miles (1.5 million kilometers) from Earth. From the vantage point of L2, the X-ray spacecraft was able to gather the data that informed this soft X-ray map by scanning the sky four times between 2019 and 2021.”We were interested in studying the Milky Way’s X-ray emission, particularly the circumgalactic medium, which should extend into a large sphere of plasma around our galaxy,” Gabriele Ponti, team member and an astronomer with the Brera Astronomical Observatory said in a statement translated from Italian. “Analyzing the eROSITA data, we noticed significant and unexpected variations in this diffuse radiation.”We realized that they couldn’t come from distant galactic structures, which are constant, but must be linked to a phenomenon much closer to us: the charge exchange of the solar wind.”AdvertisementAdvertisementTeam member and Max Planck Institute researcher Konrad Denneri pointed out that the …
