Lifeboat Foundation

Astronomers have discovered the smallest yet most massive white dwarf star ever seen.

According to a new study published Thursday in the journal Nature, the “very special” star has a mass greater than that of our sun, all packed into a relatively small body, similar in size to our moon. It formed when two less massive white dwarf stars, which spent their lives as a pair orbiting around each other, collided and merged together.

At the end of their lives, the vast majority of stars become white dwarfs, which are essentially smoldering corpses, in addition to being one of the densest objects in the universe alongside black holes and neutron stars. In about 5 billion years, our sun will become a red giant before ultimately suffering the same fate.

Study offers evidence, based on gravitational waves, to show that the total area of a black hole’s event horizon can never decrease.

There are certain rules that even the most extreme objects in the universe must obey. A central law for black holes predicts that the area of their event horizons — the boundary beyond which nothing can ever escape — should never shrink. This law is Hawking’s area theorem, named after physicist Stephen Hawking, who derived the theorem in 1971.

Continue reading “Hawking’s Black Hole Theorem Confirmed Observationally for the First Time” »

A new theory explains the seemingly irreversible arrow of time while yielding insights into entropy, quantum computers, black holes, and the past-future divide.

There are certain rules that even the most extreme objects in the universe must obey. A central law for black holes predicts that the area of their event horizons — the boundary beyond which nothing can ever escape — should never shrink. This law is Hawking’s area theorem, named after physicist Stephen Hawking, who derived the theorem in 1971.

Fifty years later, physicists at MIT and elsewhere have now confirmed Hawking’s area theorem for the first time, using observations of gravitational waves. Their results appear today in Physical Review Letters.

New research shows how the fundamental law of conservation of charge could break down near a black hole.

Singularities, such as those at the centre of black holes, where density becomes infinite, are often said to be places where physics ‘breaks down’. However, this doesn’t mean that ‘anything’ could happen, and physicists are interested in which laws could break down, and how.

Now, a research team from Imperial College London, the Cockcroft Institute and Lancaster University have proposed a way that singularities could violate the law of conservation of charge. Their theory is published in Annalen der Physik.

“In physics, we often say that exceptional discoveries require exceptionally strong evidence.”

Within the space of ten days, LIGO detected gravitational waves that prove black holes can form binaries with neutron stars.

An international group of astronomers has created images with never-before-seen detail of a galaxy cluster with a black hole at its center, traveling at high speed along an intergalactic “road of matter.” The findings also support existing theories of the origins and evolution of the universe.

The concept that roads of thin gas connect clusters of galaxies across the universe has been difficult to prove until recently, because the matter in these ‘roads’ is so sparse it eluded the gaze of even the most sensitive instruments. Following the 2020 discovery of an intergalactic thread of gas at least 50 million light-years long, scientists have now developed images with an unprecedented level of detail of the Northern Clump—a cluster of galaxies found on this thread.

By combining imagery from various sources including CSIRO’s ASKAP radio telescope, SRG/eROSITA, XMM-Newton and Chandra satellites, and DECam optical data, the scientists could make out a large galaxy at the center of the clump, with a black hole at its center.

Mix pair is “elusive missing piece of the family picture of compact object mergers.”

A long time ago, in two galaxies about 900 million light-years away, two black holes each gobbled up their neutron star companions, triggering gravitational waves that finally hit Earth in January 2020.

Discovered by an international team of astrophysicists including Northwestern University researchers, two events — detected just 10 days apart — mark the first-ever detection of a black hole merging with a neutron star. The findings will enable researchers to draw the first conclusions about the origins of these rare binary systems and how often they merge.

Separate collisions of a neutron star and a black hole are detected in a short space of time.