Milky Way Fortified with Calcium

Like milk,our Milky Way Galaxy and the restof the universe is fortified withcalcium, the stuff of strong bones.In fact, the cosmos contains 50 percent more calcium than previously thought, anew study suggests.

Calcium isa soft metal and the fifth most abundant element in Earth'scrust. Organisms depend on it for chemical assistance with musclecontraction, bones and tooth structure, bloodclotting, fluid balance in cells, regulating the heartbeatand other processes.

Explosionsof massive stars produce and eject lots of heavy elements into space. Thebuilding blocks of new stars, planets and life are released duringthe final moments of these supernovablasts [video].Iron that aids in producing our redblood cells and the calcium that hardens our bones are made up of atomsthat come from these violent outbursts.

Auniversal X-ray

Stellarmatter ejected from these explosions form swirls of hot gases that surroundgalaxies. The calcium atoms in the hot gas emit X-rays with a specificwavelength, which can be detected with instruments aboard ESA'sXMM-Newton X-ray observatory.

"The amountof X-rayradiation at that wavelength is related to the real amount of calcium,"said Jelle de Plaa, a researcher at the SRON Netherlands Institute for SpaceResearch.

De Plaa andcolleagues looked to distant clusters of galaxies--containing20 to 30 percent of visible matter--to measure the amount of calcium.

"Inclusters, a lot of the supernova products end up in the hot gas," De Plaa told "Clusters are in many ways the big cities of the universe."

Theresearchers compared the amounts of the products expected from theoreticalmodels of supernovae with measurements from XMM-Newton X-ray observatory within22 galaxyclusters. The observed amounts for seven elements--oxygen, neon, silicon,sulfur, argon, iron and nickel--jibed with theoretical predictions, but thecalcium did not match up.

"Since we checked that there was nothing wrong with ourmeasurements, we concluded that the supernova model (theoretical) must be underpredicting the calcium abundance," De Plaa said.

Got calcium?

Supernovaeexplosions happen in every corner of the universe, but their influences can befelt down on Earth. 

"If certain types of supernovae indeed produce more calcium,then this means that there must be more calcium in the universe compared to thepredictions from the supernova models," De Plaa said. "Then this is not onlytrue for clusters, but also for our solarsystem and everything that lives in it, because we are mostly made of thesame supernova products."

The studyis detailed in a forthcoming issue of the journal Astronomy &Astrophysics

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Sara Goudarzi
Sara Goudarzi is a Brooklyn writer and poet and covers all that piques her curiosity, from cosmology to climate change to the intersection of art and science. Sara holds an M.A. from New York University, Arthur L. Carter Journalism Institute, and an M.S. from Rutgers University. She teaches writing at NYU and is at work on a first novel in which literature is garnished with science.