The CHIME telescope has made its first standalone detection of the glow of hydrogen from when the universe was about five billion years old, paving the way for new studies of cosmic expansion and dark energy.

With a global ocean of liquid water below a thick crust of ice, Saturn’s moon Enceladus is one of the most promising places to search for life beyond Earth. A new study suggests the moon itself may aid in that search by making some ocean compounds easier for future spacecraft to detect. 

The vacuum is not always so empty. “When we talk about a vacuum in cosmology, we do not mean completely devoid of energy,” explains David Wands, Professor at the Institute of Cosmology & Gravitation at the University of Portsmouth. “A vacuum is rather a state in which a field sits at a minimum of its energy. The true vacuum is the lowest possible minimum, but there can also be local minima, which we call false vacua.” We can picture this as a landscape made up of valleys of different depths: the true vacuum is the deepest one, while the others are false vacua. Something sitting in one of these depressions can remain “trapped” there even if, somewhere else, a lower-energy state exists. This is exactly what can happen to quantum fields, fundamental physical objects that permeate the Universe. A classical field is something that has a value at every position in space, like a magnetic field, whose strength changes from point to point. Quantum fields behave in a similar way, and their excitations appear as particles. In a new study published in JCAP, Robson Christie, Jaewoo Joo, Greg Kaplanek, Vincent Vennin and David Wands used a simplified model to investigate what determines which vacuum a field may end up in within an expanding Universe.

Researchers tested a "sunflower" antenna layout on AAVS3, a full-scale prototype station built for the SKA-Low radio telescope. Computer simulations predicted the layout would lose sensitivity directly overhead at around 125 MHz. Real sky observations confirmed this loss and traced the problem to the layout's repeating geometry. As a result, the Observatory decided not to adopt the design for the telescope's final configuration and selected a modified layout instead.