Universe Today

June 19, 2023June 19, 2023 by Andy Tomaswick

Even Though They’re Bigger, Generation 2 Starlinks are Fainter than Gen 1

We’ve filed plenty of reports here at UT warning about the potential impact of Starlink and similar satellites on the field of astronomy. We’ve gone so far as to point out that the granddaddy of space-based telescopes – Hubble – has already had some of its images tarnished by passing Starlink satellites. However, SpaceX has been aware of the problem and is working to limit their product’s brightness. The recently launched Gen2 satellites seem to have made a significant step forward – research from a team of amateur astronomers finds that the new Gen2 Starlinks are more than 10x fainter than previous Gen1 iterations.

June 18, 2023June 18, 2023 by Matt Williams

Astronomers See the Same Supernova Four Times Thanks to a Gravitational Lens

A gravitational lens caused by a galaxy in the foreground leading to an "Einstein Cross." Credit: NASA/ESA/STScI

Measuring cosmic distances is challenging, and astronomers rely on multiple methods and tools to do it – collectively referred to as the Cosmic Distance Ladder. One particularly crucial tool is Type Ia supernovae, which occur in binary systems where one star (a white dwarf) consumes matter from a companion (often a red giant) until it reaches the Chandrasekhar Limit and collapses under its own mass. As these stars blow off their outer layers in a massive explosion, they temporarily outshine everything in the background.

In a recent study, an international team of researchers led by Ariel Goobar of the Oskar Klein Centre at Stockholm University discovered an unusual Type Ia supernova, SN Zwicky (SN 2022qmx). In an unusual twist, the team observed an “Einstein Cross,” an unusual phenomenon predicted by Einstein’s Theory of General Relativity where the presence of a gravitational lens in the foreground amplifies light from a distant object. This was a major accomplishment for the team since it involved observing two very rare astronomical events that happened to coincide.

June 17, 2023June 11, 2023 by Paul M. Sutter

The Best Particle Collider in the World? The Sun

A look inside ALICE at the Large Hadron Collider. ALICE is one of the LHC's four particle detectors. Image: CERN/LHC

Recently astronomers caught a strange mystery: extremely high-energy particles spitting out of the surface of the Sun when it was relatively calm. Now a team of theorists have proposed a simple solution to the mystery. We just have to look a little bit under the surface.

June 17, 2023June 17, 2023 by Scott Alan Johnston

We Could See the Glint off Giant Cities on Alien Worlds

How large would an extraterrestrial city have to be for current telescopes to see it? Would it need to be a planet-sized metropolis like Star Wars’ Coruscant? Or could we see an alien equivalent of Earth’s own largest urban areas, like New York City or Tokyo?

A recent preprint by Bhavesh Jaiswal of the Indian Institute of Science suggests that, in fact, we could see cities a mere fraction of that size, using a feature of light known as specular reflection.

June 17, 2023June 17, 2023 by Brian Koberlein

JWST is Powerful Enough to See a Variety of Biosignatures in Exoplanets

Spectra of an exoplanet atmosphere. Credit: NASA, ESA, CSA, STScI

The best hope for finding life on another world isn’t listening for coded messages or traveling to distant stars, it’s detecting the chemical signs of life in exoplanet atmospheres. This long hoped-for achievement is often thought to be beyond our current observatories, but a new study argues that the James Webb Space Telescope (JWST) could pull it off.

June 16, 2023June 11, 2023 by Paul M. Sutter

The Hidden Benefits of Large Science Projects

Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during the survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos. Credit: NSF/DES/NOIRLab/DOE/FNAL/AURA/University of Alaska Anchorage/

Large astronomical projects like the Dark Energy Survey and the James Webb Space Telescope provide innumerable benefits to society, like technological spin-offs, national prestige, and a way to satisfy our common human curiosity.

June 16, 2023June 17, 2023 by Laurence Tognetti

This Hot Jupiter is Leaving a Swirling Tail of Helium in its Wake

Image from the computer simulation of HAT-P-32 b (bright dot left of star) leaving a trail of helium during its 2.2-day, clockwise orbit (dashed line). (Credit: M. MacLeod (Harvard-Smithsonian Center for Astrophysics) and A. Oklopčić (Anton Pannekoek Institute for Astronomy, University of Amsterdam)

In a recent study published in Science Advances, a team of researchers commissioned the Hobby-Eberly Telescope (HET), which is designed to study exoplanetary atmospheres, to examine how a “hot Jupiter” exoplanet is losing its helium atmosphere as it orbits its parent star, leaving tails of helium that extend approximately 25 times the diameter of the planet itself.

June 16, 2023June 16, 2023 by Evan Gough

Earth Might Have Formed in Just a Few Million Years

Planets form by accreting material from a protoplanetary disk. New research suggests it can happen quickly, and that Earth may have formed in only a few million years. Credit: NASA/NASA/JPL-Caltech

Earth formed about 4.6 billion years ago. That simplistic statement is common, and it’s a good starting point for understanding our planet and our Solar System. But, obviously, Earth didn’t form all at once. The process played out for some period of time, and the usual number given is about 100 million years.

New research suggests that Earth formed more quickly than that in only a few million years.

June 15, 2023June 15, 2023 by Matt Williams

Pulsars Could Help Map the Black Hole at the Center of the Milky Way

The Atacama Large Millimeter/submillimeter Array (ALMA) looked at Sagittarius A*, (image of Sag A* by the EHT Collaboration) to study something bright in the region around Sag A*. Credit: ESO/José Francisco Salgado.

The Theory of General Relativity (GR), proposed by Einstein over a century ago, remains one of the most well-known scientific postulates of all time. This theory, which explains how spacetime curvature is altered in the presence of massive objects, remains the cornerstone of our most widely-accepted cosmological models. This should come as no surprise since GR has been verified nine ways from Sunday and under the most extreme conditions imaginable. In particular, scientists have mounted several observation campaigns to test GR using Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way.

Last year, the Event Horizon Telescope (EHT) – an international consortium of astronomers and observatories – announced they had taken the first images of Sag A*, which came just two years after the release of the first-ever images of an SMBH (M87). In 2014, the European members of the EHT launched another initiative known as BlackHoleCam to gain a better understanding of SMBHs using a combination of radio imaging, pulsar observations, astrometry, and GR. In a recent paper, the BHC initiative described how they tested GR by observing pulsars orbiting Sgr A*.

June 15, 2023June 15, 2023 by Carolyn Collins Petersen

A Planet So Hot Its Atmosphere Contains the Raw Material for Rocks

An artist's impression of WASP-76b, a planet with an atmosphere so hot it vaporizes metals. Courtesy: International Gemini Observatory/NOIRLab/NSF/AURA/J. da Silva/Spaceengine/M. Zamani

In the annals of “strange new worlds”, the ultra-hot Jupiter planet WASP-76b ranks right up there as a very unusual place. There’s no surface, but it does have a massive, hot atmosphere. Temperatures average a raging 2000 C and rise up to 2400 C in one hemisphere. That’s hot enough for mineral and rock-forming elements like calcium, nickel, and magnesium to get vaporized and float around in that thick blanket of air. Not only that, but iron probably rains down through the clouds.