So far, our Milky Way Galaxy has only had close calls from gamma ray explosions so large, scientists have suggested, that if they occurred within our galaxy they could potentially trigger mass extinctions on Earth. In 2014, telescopes around the world pointed to our neighboring Andromeda galaxy (above) looking in all wavelengths of light to learn more about a gamma ray burst reported by NASA’s Swift satellite thought to be an explosion from the collision of two neutron stars–the dead cores of massive stars, with the mass of our Sun crushed into the size of a small city.
Welcome to this week’s fix of news of space and science –a random journey from Planet Earth through the Cosmos– that has the capacity to provide clues to our existence and add a much needed cosmic perspective in our current epoch.
One early result of the ongoing Dark Energy Survey is the previously untold story revealed by old, giant RR Lyrae pulsating stars, which tell scientists about the region of space beyond the edge of our Milky Way. In this area nearly devoid of stars–the motion of the RR Lyrae stars hints at the presence of an enormous halo of invisible dark matter, which may provide clues to how our galaxy evolved over the last 12 billion years.
In the Milky Way Galaxy, about three-fourths of the stars are M dwarfs, and the proportion is even higher in elliptical galaxies. But there’s a deadly catch. New research indicates orbiting close to these low-mass stars, prime targets for astronomers in the search for extraterrestrial life, may have lost their window of opportunity at hosting life because of intense heat during their formative years. M dwarfs, also known as red dwarfs, are the smallest type of hydrogen-burning star and are the most common stars and the coolest main-sequence stars in the universe.
Ever since astronomers reached a consensus in the 1980s that invisible “dark matter” binds galaxies together and gravitationally shapes the cosmos — experimentalists have hunted for the elusive nonluminous particles. Without luck. “The nature of dark matter is one of the biggest mysteries in science and we need to use any related new data to tackle it,” says astronomer Avi Loeb at the Harvard-Smithsonian Center for Astrophysics.
“Gaia is measuring the distances of hundreds of millions of objects that are many thousands of light years away, at an accuracy equivalent to measuring the thickness of hair at a distance of more than 2000 kilometers. “These data are one of the backbones of astrophysics, allowing us to forensically analyze our stellar neighborhood, and tackle crucial questions about the origin and future of our Milky Way Galaxy,” says Floor van Leeuwen of the Institute of Astronomy at the University of Cambridge, about the most detailed ever catalog of the stars in a huge swathe of our Milky Way galaxy –the third early data release from the European Space Agency’s Gaia Space Observatory launched in 2013 delivers data for just over 1.8 billion sources. Initial findings include the first optical measurement of the acceleration of the Solar system’s orbit through the Milky Way.
