Astronomy Archives

April 4, 2023April 4, 2023 by Scott Alan Johnston

A Stellar Explosion Mimicked the End of the Death Star

In 1997, George Lucas released the special edition remaster of his Star Wars trilogy, making changes to the special effects that both delighted and divided fans worldwide (did Han shoot first?). Among the myriad additions was a visually spectacular ring-shaped shockwave emanating from the exploding Death Star, and Alderaan too. Star Trek fans will delightedly point out that this particular special effect had previously been used in the 1991 film Star Trek VI: The Undiscovered Country, in which the Klingon moon Praxis explodes, giving the effect its name: the Praxis ring. Hollywood lore suggests Lucas was so impressed with the effect in that film that he added it to Star Wars too.

Praxis rings look cool on the silver screen, but we all know explosions in space are supposed to be spherical. With no preference for up, down, left, or right, the material blown off an exploding star should push outward in all directions.

Except when it doesn’t. A paper published at the end of March described the flattest explosion ever observed, with a disc of material ejecting out from the core along one plane, just like the Praxis effect.

April 3, 2023April 3, 2023 by Matt Williams

Astronomers Think They've Found One of the Biggest Black Holes Ever Seen

Artist's impression of an ultramassive black hole (UBH). Credit: ESA/Hubble/DSS/Nick Risinger/N. Bartmann

In 1931, Indian-American physicist Subrahmanyan Chandrasekhar proposed a resolution to Einstein’s Theory of General Relativity that postulated the existence of black holes. By 1972, astronomers obtained the first conclusive evidence that these objects existed in our Universe. Observations of quasars and the center of the Milky Way also revealed that most massive galaxies have supermassive black holes (SMBHs) at their cores. Since then, the study of black holes has revealed that these objects vary in size and mass, ranging from micro black holes (MBHs) and intermediate black holes (IMBHs) to SMBHs.

Using astronomical simulations and a technique known as Gravitational Lensing, an international team of astrophysicists detected what could be the largest black hole ever observed. This ultramassive black hole (UMBH) has a mass roughly 30 billion times that of our Sun and is located near the center of the Abell 1201 galaxy cluster, roughly 2.7 billion light-years from Earth. This is the first time a black hole has been found using Gravitational Lensing, and it could enable studies that look farther into space to find black holes and deepen our understanding of their size and scale.

March 31, 2023March 30, 2023 by Carolyn Collins Petersen

Now We Know How a Solar Storm Took Out a Fleet of Starlinks

A view of an auroral storm from the ISS. Aurorae are one effect of solar storms like the one that took out 39 Starlink satellites in 2022. Credit: NASA/ESA/Tim Peake — A view of an auroral storm from the ISS. Credit: NASA/ESA/Tim Peake

On March 23rd, sky observers marveled at a gorgeous display of northern and southern lights. It was reminder that when our Sun gets active, it can spark a phenomenon called “space weather.” Aurorae are among the most benign effects of this phenomenon.

March 30, 2023April 2, 2023 by Matt Williams

Gravitational Waves From Colliding Neutron Stars Matched to a Fast Radio Burst

Artist’s impression of a fast radio burst traveling through space and reaching Earth. Credit: ESO/M. Kornmesser

Fast Radio Bursts (FRBs) were first detected in 2007 (the Lorimer Burst) and have remained one of the most mysterious astronomical phenomena ever since. These bright radio pulses generally last a few milliseconds and are never heard from again (except in the rare case of Repeating FRBs). And then you have Gravitational Waves (GW), a phenomenon predicted by General Relativity that was first detected on September 14th, 2015. Together, these two phenomena have led to a revolution in astronomy where events are detected regularly and provide fresh insight into other cosmic mysteries.

In a new study led by the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav), an Australian-American team of researchers has revealed that FRBs and GWs may be connected. According to their study, which recently appeared in the journal Nature Astronomy, the team noted a potential coincidence between a binary neutron star merger and a bright non-repeating FRB. If confirmed, their results could confirm what astronomers have expected for some time – that FRBs are caused by a variety of astronomical events.

March 28, 2023March 28, 2023 by Matt Williams

Moons Orbiting Rogue Planets Could be Habitable

An artist's conception of a potentially-habitable exomoon. It seems reasonable that exoplanets have exomoons, and now we're going to look for them. Credit: NASA

When looking for signs of life beyond the Solar System, astrobiologists are confined to looking for life as we understand it. For the most part, that means looking for rocky planets that orbit within their star’s circumsolar habitable zone (HZ), the distance at which liquid water can exist on its surface. In the coming years, next-generation telescopes and instruments will allow astronomers to characterize exoplanet atmospheres like never before. When that happens, they will look for the chemical signatures we associate with life, like nitrogen, oxygen, carbon dioxide, methane, and ammonia.

However, astrobiologists have theorized that life could exist in the outer Solar System beneath the surfaces of icy moons like Europa, Callisto, Titan, and other “Ocean Worlds.” Because of this, there is no shortage of astrobiologists who think that the search for extraterrestrial life should include exomoons, including those that orbit free-floating planets (FFPs). In a recent study, researchers led by the Max Planck Institute for Extraterrestrial Physics (MPE) determined the necessary properties that allow moons orbiting FFPs to retain enough liquid water to support life.

March 27, 2023March 27, 2023 by Alan Boyle

Beads of Lunar Glass Boost Hopes for Using the Moon’s Water

Glass beads from the moon — Chinese researchers detected water trapped within beads of glass created by lunar impacts. (Credit: He et al., IGG /CAS)

Beads of glass could become a key source of water for future crewed settlements on the moon, researchers say.

That claim is based on an assessment of the water contained within a sampling of glassy beads that were created over the course of millennia by cosmic impacts on the moon, and ended up being brought back to Earth in 2020 by China’s Chang’e-5 sample return mission.

A spectroscopic analysis determined that the beads contained more water than the researchers expected based on past studies. They surmised that interactions between hydrogen ions in the solar wind and oxygen-bearing materials in lunar soil created H₂O molecules that could be trapped within the glass — and then diffused under the right conditions.

Based on an extrapolation of such findings, the research team — headed by scientists from the Chinese Academy of Sciences — estimates that glass beads in lunar soil may contain up to 270 trillion kilograms (595 trillion pounds, or 71 trillion gallons) of water.

“We propose that impact glass beads in lunar soils are a prime water reservoir candidate able to drive the lunar surface water cycle,” the researchers report in Nature Geoscience.

March 26, 2023March 26, 2023 by Scott Alan Johnston

Asteroid Ryugu Contains Niacin (aka Vitamin B3)

In December 2020, JAXA’s Hayabusa2 spacecraft delivered a pristine sample of otherworldly dust and rock from asteroid Ryugu to Earth. Scientists have since had the opportunity to study the sample, and announced last week that the asteroid contains organic molecules important for life. In particular, they discovered Niacin, otherwise known as vitamin B3, and Uracil, one of the four core components of ribonucleic acid (RNA).

March 24, 2023March 24, 2023 by Evan Gough

A Rogue Earth and Neptune Might Have Been Found in Older Data

An artist's illustration of a rogue planet, dark and mysterious. Image Credit: NASA

Scientists have found what appear to be rogue planets hidden in old survey data. Their results are starting to define the poorly-understood rogue planet population. In the near future, the Nancy Grace Roman Space Telescope will conduct a search for more free-floating planets, and the team of researchers developed some methods that will aid that search.

March 23, 2023March 23, 2023 by Matt Williams

Hypervelocity Stars Teach us About Black Holes and Supernovae

An artist's conception of a hypervelocity star that has escaped the Milky Way. Credit: NASA

Hypervelocity stars (HVS) certainly live up to their name, traveling thousands of kilometers per second or a fraction of the speed of light (relativistic speeds). These speed demons are thought to be the result of galactic or black hole mergers, globular clusters kicking out members, or binary pairs where one star is kicked out when the other goes supernova. Occasionally, these stars are fast enough to escape our galaxy and (in some cases) take their planetary systems along for the ride. This could have drastic implications for our theories of how life could be distributed throughout the cosmos (aka. panspermia theory).

There are thousands of these stars in our galaxy, and tracking them has become the task of cutting-edge astrometry missions (like the ESA’s Gaia Observatory). In previous research, astronomers suggested that these stars could be used to determine the mass of the Milky Way. In a recent study from Leiden University in the Netherlands, Ph.D. candidate Fraser Evans showed how data on HVS could be used to probe the mysteries of the most extreme objects in our Universe – supermassive black holes (SMBHs) and the violent supernovae of massive stars.

March 23, 2023March 23, 2023 by Evan Gough

The Discovery of a Hot Neptune that Shouldn’t Exist

exoplanet hot jupiter transiting its star — This artist’s impression shows an ultra-hot exoplanet as it is about to transit in front of its host star. Credit: ESO

1800 light-years away, an unlikely survivor orbits an aged star. This rare planet is called a hot Neptune, and it’s one of only a small handful of hot Neptunes astronomers have found. Hot Neptunes are so close to their stars that the overpowering stellar radiation should’ve stripped away their atmospheres, leaving only a planetary core behind.

But this planet held onto its atmosphere somehow.