Universe Today

July 10, 2023July 10, 2023 by Matt Williams

A Black Hole Switched On in the Blink of an Eye

This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. This thin disc of rotating material consists of the leftovers of a Sun-like star which was ripped apart by the tidal forces of the black hole. Shocks in the colliding debris as well as heat generated in accretion led to a burst of light, resembling a supernova explosion. Credit: ESO, ESA/Hubble, M. Kornmesser

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.

July 10, 2023July 11, 2023 by Carolyn Collins Petersen

Ancient Stars Somehow Survived Close to the Center of the Milky Way

The center of the Milky Way as seen from Chile. The core contains very old stars that date back to early in cosmic history. Credit: ESO/P.Horalek CC by 4.0.

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.

July 10, 2023July 10, 2023 by Brian Koberlein

A Neutron Star is Unwinding a Companion Star

Artist impression of a star being stripped by its companion. Credit: Elisa Schösser

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.

July 9, 2023July 9, 2023 by Brian Koberlein

A Planet has Whipped Up Spiral Arms Around a Young Star

Three protoplanetary disks captured by ESO’s Very Large Telescope. Credit: ESO

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.

July 8, 2023July 8, 2023 by Carolyn Collins Petersen

JWST Sees the Most Distant Active Supermassive Black Hole

A zoomed-in view of images captured by the James Webb Space Telescope in near-infrared light for the Cosmic Evolution Early Release Science (CEERS) Survey. A galaxy assembling itself JWST found in this view has the most distant supermassive black hole seen to date.Credit: NASA, ESA, CSA, Steve Finkelstein (UT Austin), Micaela Bagley (UT Austin), Rebecca Larson (UT Austin). — A zoomed-in view of images captured by the James Webb Space Telescope in near-infrared light for the Cosmic Evolution Early Release Science (CEERS) Survey. A galaxy assembling itself JWST found in this view has the most distant supermassive black hole seen to date. Credit: NASA, ESA, CSA, Steve Finkelstein (UT Austin), Micaela Bagley (UT Austin), Rebecca Larson (UT Austin).

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.

July 8, 2023July 8, 2023 by Matt Williams

Astronomers Scan the Skies for Nanosecond Pulses of Light From Interstellar Civilizations

Artist’s impression of Green Bank Telescope connected to a machine learning network. Credit: Breakthrough Listen/Danielle Futselaar.

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.

July 8, 2023July 8, 2023 by Brian Koberlein

Supernovae are the Source of Dust in Early Galaxies

Images of SN 2004et and SN 2017eaw. Credit: NASA, ESA, CSA, Ori Fox (STScI), Melissa Shahbandeh (STScI), Alyssa Pagan (STScI)

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.

July 7, 2023July 7, 2023 by Matt Williams

Venus has Clouds of Concentrated Sulfuric Acid, but Life Could Still Survive

Image from NASA's Mariner 10 spacecraft in February 1974 as it traveled away from Venus. (Credit: NASA/JPL-Caltech)

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.

July 7, 2023July 7, 2023 by Evan Gough

A Practical Use for Space Power: Beaming Energy to Probes on Venus

The first color pictures taken of the surface of Venus by the Venera-13 space probe. Credit: NASA — The first color pictures taken of the surface of Venus by the Venera-13 space probe. The Venera 13 probe lasted only 127 minutes before succumbing to Venus's extreme surface environment. Part of building a longer-lasting Venus lander is figuring out how to power it. Credit: NASA

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.

July 7, 2023July 7, 2023 by Brian Koberlein

Astronomers Map out the Radio Waves Coming From Large Satellite Constellations

Illustration Starlink satellites over LOFAR. Credit: Daniëlle Futselaar

Satellite internet constellations such as Starlink have the potential to make connect nearly the entire world. Starlink already provides internet access to remote areas long excluded by the internet revolution, and other projects such as OneWeb and Project Kuiper are in the works. But there are side effects to creating a massive array of low-orbit satellites, and one of them is the potentially serious effect on astronomy.