The universe is awash in gravitational waves. The collisions of massive objects such as black holes and neutron stars generate many of them. Now astronomers are wondering about the environments where these catastrophic events occur. It turns out they might need to look at quasars.
Continue reading “Want to Find Colliding Black Holes? Check the Disks Around Quasars”A Black Hole Switched On in the Blink of an Eye
In 2019, a team of astronomers led by Dr. Samantha Oates of the University of Birmingham discovered one of the most powerful transients ever seen – where astronomical objects change their brightness over a short period. Oates and her colleagues found this object, known as J221951-484240 (or J221951), using the Ultra-Violet and Optical Telescope (UVOT) on NASA’s Neil Gehrels Swift Observatory while searching for the source of a gravitational wave (GW) that was thought to be caused by two massive objects merging in our galaxy.
Multiple follow-up observations were made using the UVOT and Swift’s other instruments – the Burst Alert Telescope (BAT) and X-Ray Telescope (XRT), the Hubble Space Telescope, the South African Large Telescope (SALT), the Wide-field Infrared Survey Explorer (WISE), the ESO’s Very Large Telescope (VLT), the Australia Telescope Compact Array (ATCA), and more. The combined observations and spectra revealed that the source was a supermassive black hole (SMBH) in a distant galaxy that mysteriously “switched on,” becoming one of the most dramatic bursts of brightness ever seen with a black hole.
Continue reading “A Black Hole Switched On in the Blink of an Eye”Ancient Stars Somehow Survived Close to the Center of the Milky Way
The core of our Milky Way Galaxy draws astronomers’ attention like moths to a flame. That’s because there’s a lot going on there. Not only is there a supermassive black hole, but also populations of very ancient red giant stars that swarm the center. Most of them date back at least to the formation of the Galaxy.
Continue reading “Ancient Stars Somehow Survived Close to the Center of the Milky Way”A Neutron Star is Unwinding a Companion Star
Close binary stars play several important roles in astronomy. For example, Type Ia supernovae, used to measure galactic distances, occur when a neutron star in a binary system reaches critical mass. These stars are also the source of x-ray binaries and microquasars, which help astronomers understand supermassive black holes and active galactic nuclei. But the evolutionary process of close binaries is still not entirely understood. That’s changing thanks in part to a new discovery of a close binary in its intermediate stage.
Continue reading “A Neutron Star is Unwinding a Companion Star”A Planet has Whipped Up Spiral Arms Around a Young Star
When you hear the phrase “spiral arms” you probably think of galaxies. Lots of galaxies have bright arcs of stars that spiral away from their center, including our Milky Way. But not all galaxies have spiral arms, and galaxies aren’t the only celestial objects with spiral arms. About a third of protoplanetary disks around young stars have spiral arms, and we now think we know why.
Continue reading “A Planet has Whipped Up Spiral Arms Around a Young Star”JWST Sees the Most Distant Active Supermassive Black Hole
As astronomers push our views of the Universe further back in time, their telescopes keep uncovering surprises. That’s the case with a supermassive black hole in CEERS 1019, a distant very early galaxy.
Continue reading “JWST Sees the Most Distant Active Supermassive Black Hole”Astronomers Scan the Skies for Nanosecond Pulses of Light From Interstellar Civilizations
In 2015, Russian-Israeli billionaire Yuri Milner and his non-profit organization, Breakthrough Initiatives, launched the largest Search for Extraterrestrial Intelligence (SETI) project. Known as Breakthrough Listen, this SETI effort relies on the most powerful radio telescopes in the world and advanced analytics to search for potential evidence of technological activity (aka. “technosignatures”). The ten-year project will survey the one million stars closest to Earth, the center of our galaxy, the entire galactic plane, and the 100 galaxies closest to the Milky Way.
In 2018, they partnered with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) Collaboration, a ground-based system of gamma-ray telescopes operating at the Fred Lawrence Whipple Observatory (FLWO) atop Mt. Hopkins in southern Arizona. In a recent paper, the VERITAS Collaboration shared the results of the first year of their search for “optical technosignatures” (from 2019 to 2020). Their results are a vital proof of concept demonstrating how future searches for extraterrestrial civilizations can incorporate optical pulses into their technosignature catalog.
Continue reading “Astronomers Scan the Skies for Nanosecond Pulses of Light From Interstellar Civilizations”Supernovae are the Source of Dust in Early Galaxies
Every now and then there’s an interesting discovery that helps us fill in a gap in our understanding of the universe. In the case of this latest discovery, we now have confirmation of a process we’ve long assumed, but have had little direct evidence for. It all has to do with cosmic dust.
Continue reading “Supernovae are the Source of Dust in Early Galaxies”Venus has Clouds of Concentrated Sulfuric Acid, but Life Could Still Survive
The surface of Venus is like a scene from Dante’s Inferno – “Abandon all hope, ye who enter here!” and so forth. The temperature is hot enough to melt lead, the air pressure is almost one hundred times that of Earth’s at sea level, and there are clouds of sulfuric acid rain to boot! But roughly 48 to 60 km (30 to 37.3 mi) above the surface, the temperatures are much cooler, and the air pressure is roughly equal to Earth’s at sea level. As such, scientists have speculated that life could exist above the cloud deck (possibly in the form of microbes) as it does on Earth.
Unfortunately, these clouds are not composed of water but of concentrated sulfuric acid, making the likelihood that life could survive among them doubtful. However, a new study led by scientists from the Massachusetts Institute of Technology (MIT) reveals that the basic building blocks of life (nucleic acid bases) are stable in concentrated sulfuric acid. These findings indicate that Venus’ atmosphere could support the complex chemistry needed for life to survive, which could have profound implications in the search for habitable planets and extraterrestrial life.
Continue reading “Venus has Clouds of Concentrated Sulfuric Acid, but Life Could Still Survive”A Practical Use for Space Power: Beaming Energy to Probes on Venus
A few weeks ago, a team of scientists from Caltech announced that they had successfully transmitted energy from an orbiting satellite down to Earth. It wasn’t a lot of energy, but it showed that it was possible.
Eventually, we might be able to beam energy from solar satellites down to Earth, making solar energy available almost anywhere and helping combat climate change. But there’s another potential use: powering surface probes on Venus.
Continue reading “A Practical Use for Space Power: Beaming Energy to Probes on Venus”