Quasars are the actively feeding supermassive black holes at the hearts of galaxies and can contain millions or even billions of times the mass of the Sun. It's believed they're the source of some of the highest energy cosmic rays detected. But there are also microquasars, where a star and black hole orbit one another. Material from the star accretes around the black hole, and the magnetic fields form jets that can also hurl cosmic rays with similar energies.
Continue reading
When a star like the Sun dies, it puffs away its outer layers, leaving behind its glowing core. Without fusion to keep it heated, the white dwarf slowly cools down over billions of years. Astronomers have discovered that 6% of massive white dwarfs pause their cooling for up to 10 billion years, providing a stable habitable zone for any planets nearby. This gives life a long time to develop under extremely stable conditions.
Continue reading
Astronomers have announced the discovery of a new asteroid with a non-zero chance of striking the Earth on December 22, 2032. Designated 2024 YR4, the space rock measures between 40 m and 100 m across, which would create regional damage if it struck the Earth. Initial observations estimate it has a 99% chance of passing the Earth safely but a 1% chance of hitting, which gives it a Level 3 designation on the Torino Impact Hazard Scale.
Continue reading
At the largest scales, the Universe is expected to be isotropic and homogeneous. No matter where you go, things will look roughly the same, with no preference for rotation direction. Researchers have proposed a way to test this "mirror symmetry" hypothesis using the mergers of black holes. When black holes collide, they release gravitational waves that can be polarized, either right- or left-handed. After studying 47 mergers, they found that symmetry is preserved.
Continue reading
The Einstein Probe is a collaboration between Europa and China and was designed to detect flashes of low-energy X-rays, so-called "soft X-rays." Recently, the Probe automatically detected a 17-minute-long flash in brightness, known as a fast X-ray transient. Other astronomers made follow-on observations and confirmed that it was a blast of radiation that happened when the Universe was just over a billion years old: a gamma-ray burst near the dawn of time.
Continue reading