Tabby's Star is arguably the most mysterious – and controversial – star in our galaxy. Observed by NASA's Kepler space telescope, the star shot to fame when citizen scientists studying the mission's data noticed the star dim and flicker dramatically between 2011 and 2013. Hypotheses about this weird behavior abound, but not a single one seems to fully explain what's going on.
Astronomers are constantly uncovering the "most distant," "most massive" or "most energetic" objects in our universe, but today, researchers have announced the discovery of a truly monstrous structure consisting of a ring of galaxies around 5 billion light-years across. The galactic ring, which was revealed by 9 gamma-ray bursts (GRBs), is located 7 billion light-years away and spans an area of the sky more than 70 times the diameter of a full moon.
After three years of construction, the world's most sensitive dark matter experiment is online, and scientists report that the detector is operating as designed. The XENON1T detector hasn't found any dark matter particles yet, but it has carried out a 30-day science run, and project scientists are optimistic about the future. "The best result on dark matter so far! … and we have just started!" the XENON1T team said in a statement.