Astro Blog

By Science Advisor, AAAS.  Excerpt: ...The rate of cosmic expansion, known as the Hubble constant, is so important for cosmologists that the disagreement among researchers over its value has its own name: the Hubble tension. Astronomers measure it one way, using stars or supernovae with predictable brightness. Cosmologists have another way, studying ripples in the echo of the Big Bang and winding the clock forward to today. The two techniques have become increasingly precise, but they steadfastly disagree with each other. A third method is needed to  break the deadlock  . That may come through the magic of gravitational lensing, which can cause a supernova—a star exploding at the end of its life—to appear to explode again and again. If a supernova is situated behind a large mass, such as a galaxy or cluster of galaxies, then as its light passes by the mass, its gravity bends the light along different paths, producing multiple images that show the explosion at different ti...

By Caryl-Sue Micalizio , Eos/AGU.  Excerpt: The  awe-inducing Vera C. Rubin Observatory  does not blink. From its sky-high altitude in the Chilean Andes, Rubin will image every point in the skies over the Southern Hemisphere 800 times over a 10-year period. The observatory is already issuing astronomers 800,000 alerts a night and eventually might send 10  million  a night. “The whole field of astronomy is about to be completely revolutionized by this dataset,” says astronomer Sarah Greenstreet in Kimberly Cartier’s beautiful, breathless introduction to the observatory, “ Small, Faint, or Fast, Rubin Will Find It .” So what is Rubin going to find? Asteroids . ...astronomers think Rubin might find 4 million more. Comets . Rubin’s unblinking eye will help astronomers trace comets and other trans-Neptunian objects in the icy reaches of the outer solar system. Planet 9 . “This is the survey that will determine whether Planet 9 is real or not,” says astronomer Meghan ...