Astronomy and Planetary Science Thread

Mentions not only the proposed Lyra mission to 'Oumuamua, but also an ESA 'rapid response' mission.

It is an opportunity to study an interstellar object without having to travel interstellar distances.

In the news
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This article is by the author of the related scientific paper.

The accelerated expansion of the present universe, believed to be driven by a mysterious dark energy, is one of the greatest puzzles in our understanding of the cosmos. The standard model of cosmology called Lambda-CDM, explains this expansion as a cosmological constant in Einstein's field equations. However, the cosmological constant itself lacks a complete theoretical understanding, particularly regarding its very small positive value.

In my work, I propose another model to explain the present accelerated expansion of the universe. Unlike existing models, this does not require any form of dark energy or modified gravity approaches. However, there is a price to pay: we need a partner anti-universe whose time flow is oppositely related to our universe.

There are strong arguments supporting this concept. From a quantum theory perspective, it is natural for the universe to be created in pairs. Recently, Boyle et al proposed that the universe does not spontaneously violate CPT (Charge, Parity, and Time reversal symmetry), but rather, the universe after the Big Bang is the CPT image of the universe before it, pointing towards a partner anti-universe.

Related paper:

I have always wondered about the origin of Dark Energy, but this new model could explain why the Universe is expanding at an ever faster rate than it was before. It could also explain the Multiverse theory as well.
Astronomers have captured what appears to be a snapshot of a massive collision of giant asteroids in Beta Pictoris, a neighboring star system known for its early age and tumultuous planet-forming activity.

The observations spotlight the volatile processes that shape star systems like our own, offering a unique glimpse into the primordial stages of planetary formation.

Heavy Bombardment phase 2

Also in the news
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Looks like Beta Pictoris is going through it's very own Heavy Bombardment phase like what our Solar System did millions of years ago
The Earth’s inner core has been slowing down since 2008, the first time this has happened since we have had the capacity to measure it. This could eventually affect the whole planet’s rotation, lengthening our days, but if there are effects big enough for us to notice, they are more likely to be on the geomagnetic field.

Some of this slower movement will eventually be transferred to the surface, making for longer days. However, Vidale says this will be “very hard to notice, on the order of a thousandth of a second, almost lost in the noise of the churning oceans and atmosphere."

The Earth’s gravitational field is caused by movements in the outer, not inner, core. Nevertheless, there may be some interaction, and the observed change may relate to unexplained phenomena like the way the magnetic field has sometimes reversed direction.

Related paper:

Is this a sign that the Earth's magnetic field could be about to flip? Though not instantly, it will probably take several thousand years or so to complete the transition from the north to the south magnetic pole.
An international team of astronomers reports the discovery of a new Earth-sized exoplanet that orbits an ultracool dwarf star located just 54.6 light years away. The newfound alien world, designated SPECULOOS-3 b, is slightly smaller but much hotter than our planet. The finding was reported in a paper published May 15 in the journal Nature Astronomy.

”We present the SPECULOOS project's detection of an Earth-sized planet in a 17-hour orbit around an ultracool dwarf of M6.5 spectral type located 16.8 parsecs away," the researchers wrote in the paper.

According to the paper, SPECULOOS-3 b has a radius of approximately 0.977 Earth radii and orbits its host star every 17.28 hours. The planet's equilibrium temperature was estimated to be about 553 K.

In concluding remarks, the authors of the paper underline that high irradiation of SPECULOOS-3 b, combined with the infrared luminosity and Jupiter-like size of its host make it one of the most promising rocky exoplanets to investigate with the James Webb Space Telescope (JWST) in order to conduct a detailed emission spectroscopy characterization.

Related paper:

Preserved inside an ancient rock that fell to Earth from space and was recovered in 2018, an international team of scientists have now identified traces of material that, they say, must have originated in the protoplanetary disk, back when the Solar System was young.

Related paper:

Thanks to the efforts of a citizen science project called Backyard Worlds: Planet 9 and a team of astronomers from around the country, a rare hypervelocity L subdwarf star has been found racing through the Milky Way. More remarkably, this star may be on a trajectory that causes it to leave the Milky Way altogether. The research, led by University of California San Diego Professor of Astronomy and Astrophysics Adam Burgasser, was presented today at a press conference during the 244th national meeting of the American Astronomical Society (AAS) in Madison, Wisconsin.

The star, charmingly named CWISE J124909+362116.0 (“J1249+36”), was first noticed by some of the over 80,000 citizen science volunteers participating in the Backyard Worlds: Planet 9 project, who comb through enormous reams of data collected over the past 14 years by NASA's Wide-field Infrared Survey Explorer (WISE) mission. This project capitalizes on the keen ability of humans, who are evolutionarily programmed to look for patterns and spot anomalies in a way that is unmatched by computer technology. Volunteers tag moving objects in data files and when enough volunteers tag the same object, astronomers investigate.

Using the James Webb Space Telescope (JWST), astronomers from the Space Telescope Science Institute (STScI) have discovered a new supernova. Designated SN 2023adsy, the newfound stellar explosion is the most distant Type Ia supernova so far detected. The finding was detailed in a research paper published June 7 on the pre-print server arXiv.

Related paper:

In late 2019, the previously unremarkable galaxy SDSS1335+0728 suddenly started shining brighter than ever before. To understand why, astronomers have used data from several space and ground-based observatories, including the European Southern Observatory's Very Large Telescope (ESO's VLT), to track how the galaxy's brightness has varied. In a study out today, they conclude that they are witnessing changes never seen before in a galaxy—likely the result of the sudden awakening of the massive black hole at its core.

"[This] process (...) has never been observed before," Hernández García says. Previous studies reported inactive galaxies becoming active after several years, but this is the first time the process itself—the awakening of the black hole—has been observed in real time. Ricci, who is also affiliated with the Kavli Institute for Astronomy and Astrophysics at Peking University, China, adds, "This is something that could happen also to our own Sgr A*, the massive black hole (...) located at the center of our galaxy," but it is unclear how likely this is to happen.

Related paper:

Related video:

'Atmospheric lensing' - that is, using the earth's atmosphere as a telescope lens.

The original paper:

Here's his YouTube channel, BTW:


A compact source, G0.02467–0.0727, was detected in Atacama Large Millimeter/submillimeter Array 3 mm observations in continuum and very broad line emission. The continuum emission has a spectral index α ≈ 3.3, suggesting that the emission is from dust. The line emission is detected in several transitions of CS, SO, and SO 2 and exhibits a line width FWHM ≈ 160 km s ⁻¹ . The line profile appears Gaussian. The emission is weakly spatially resolved, coming from an area on the sky ≲1″ in diameter (≲10 ⁴ au at the distance of the Galactic center, GC). The centroid velocity is v LSR ≈ 40–50 km s ⁻¹ , which is consistent with a location in the GC. With multiple SO lines detected, and assuming local thermodynamic equilibrium (LTE) conditions, the gas temperature is T LTE = 13 K, which is colder than seen in typical GC clouds, though we cannot rule out low-density, subthermally excited, warmer gas. Despite the high velocity dispersion, no emission is observed from SiO, suggesting that there are no strong (≳10 km s ⁻¹ ) shocks in the molecular gas. There are no detections at other wavelengths, including X-ray, infrared, and radio. We consider several explanations for the millimeter ultra-broad-line object (MUBLO), including protostellar outflow, explosive outflow, a collapsing cloud, an evolved star, a stellar merger, a high-velocity compact cloud, an intermediate-mass black hole, and a background galaxy. Most of these conceptual models are either inconsistent with the data or do not fully explain them. The MUBLO is, at present, an observationally unique object.

Photographing faint objects close to bright stars is incredibly difficult. Yet, by combining data from ESA's Gaia space telescope with ESO's GRAVITY instrument on the ground, scientists managed just that. They took the first pictures of so far unseen dim companions of eight luminous stars. The technique unlocks the tantalizing possibility to capture images of planets orbiting close to their host stars.

Thanks to GRAVITY's uniquely sharp and sensitive eye, the team caught the light signal of all eight predicted companions, seven of which were previously unknown. Three of the companions are very small and faint stars, while the other five are brown dwarfs. These are celestial objects in between planets and stars: more massive than the heaviest of planets but lighter and fainter than the lightest of stars.

Surprisingly, two of the brown dwarfs turned out to be less luminous than one would expect given their size and age. A possible explanation for this could be that the dwarfs themselves have an even smaller companion.

Related paper:

A peculiar cluster of stars swirling around the violent center of the Milky Way could become "immortal" by continuously capturing and destroying dark matter particles in their cores, a new study suggests.

Using computer simulations of stellar evolution, researchers found that dark matter particles captured by these stars' gravity may frequently collide with and "annihilate" each other inside the star, transforming into ordinary particles while releasing a significant amount of energy.

This additional energy source could maintain the star's stability and potentially make it immortal, even after its regular supply of nuclear fuel has run dry, the researchers suggest.

"The innermost stars of our Galaxy, the S-cluster stars, show a series of properties that [are] not found anywhere else: It is not clear how they got so close to the center, where the environment is thought to be rather hostile to star formation," John explained. "They also seem to be much younger than what would be expected if the stars had moved there from somewhere else. Additionally, it seems like there are unexpectedly many heavy stars."

"More precise observations of the S-cluster stars will provide us with more information about these stars and ongoing processes," John said. "This will show if the observations are consistent with our simulations, or if other explanations of their unusual properties become more favorable."

Paper is direct linked to in the article.
A small team of astronomers affiliated with several institutions in Japan, working with a pair of colleagues in the U.S., has solved the mystery of the unusually smooth aurora that appeared in the Arctic sky in December of 2022.

Related paper:

Astronomers have discovered three potential “super-Earth” exoplanets orbiting a relatively nearby orange dwarf star. This groundbreaking find was made by an international team of researchers led by Dr Shweta Dalal from the University of Exeter.

The exoplanets are orbiting Star HD 48498, located approximately 55 light-years from Earth. These planets revolve around their host star in 7, 38, and 151 Earth days, respectively. Notably, the outermost exoplanet candidate resides in the habitable zone of its host star, where conditions could allow liquid water to exist without boiling or freezing. This region, often referred to as the Goldilocks zone, is considered ideal for potentially supporting life.

The research revealed three planetary candidates with minimum masses ranging from 5 to 11 times that of Earth. The team suggests that the proximity of the star, combined with the outermost planet’s favourable orbit, makes this system a promising target for future high-contrast direct imaging and high-resolution spectroscopic studies.

Related paper:

Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have conducted molecular line observations of a protostellar system known as VLA 1623. Results of the observational campaign, published June 18 on the pre-print server arXiv, yield new information regarding stellar mass and origin of this system.

Related paper:

Our ability to detect such asteroids hasn’t really improved in recent times, in fact the loss of Arecibo probably had a negative impact on such detections. The US has made little progress in this area, and the rest of the world well best not ask.

Two large asteroids will safely pass Earth this week, a rare occurrence perfectly timed to commemorate this year's Asteroid Day. Neither poses any risk to our planet, but one of them was only discovered a week ago, highlighting the need to continue improving our ability to detect potentially hazardous objects in our cosmic neighbourhood.
Black holes and other finds


space bricks

Dryas event

A happy tune
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Who knew Earth’s upper atmosphere was like alphabet soup?

NASA’s Global-scale Observations of the Limb and Disk (GOLD) mission has revealed unexpected C- and X-shaped formations in an electrified layer of gas high above our heads called the ionosphere.

While these alphabetical shapes have been observed before, GOLD sees them more clearly than other instruments have and is now finding them where and when scientists didn’t expect. Their surprise appearances prove that we have more to learn about the ionosphere and its effects on communication and navigation signals that pass through it.

Researchers may have solved one lingering mystery behind the world’s oldest known mechanical computer using a combination of statistical analysis, techniques used to examine spacetime ripples, and a little bit of holiday season downtime.

“Previous studies had suggested that the calendar ring was likely to have tracked the lunar calendar, but the dual techniques we’ve applied in this piece of work greatly increase the likelihood that this was the case,” Bayley added.

Paper is linked to in the article.

And, thanks to the Juno probe's Jovian Infrared Auroral Mapper (JIRAM) imaging Jupiter and its surrounding environment, we now know a lot more about what a gloriously hot mess Io is.

Related paper:

A new study from scientists at Stanford University and Washington University in St. Louis (WUSL) provides evidence of a new explanation.

Unlike planet Earth, the Moon no longer generates a global magnetic field to protect it from the Sun's charged particles. This means that when solar winds collide with the lunar surface, they turn the rock darker over time due to chemical reactions.

That said, some pockets on the Moon appear to be protected by mini magnetic fields.

So far, every light-shaded lunar swirl scientists have found coincides with one of these local magnetic fields. And yet not all rocks within them are reflective, nor do all magnetic fields on the Moon contain swirls.

So what on Earth (or, rather, on the Moon) is going on?

Paper is directly linked to in the article.
Here’s how to find it in the sky.

The first recorded sighting of the T CrB nova was more than 800 years ago, in autumn 1217, when a man named Burchard, abbot of Ursberg, Germany, noted his observance of “a faint star that for a time shone with great light.”

The T CrB nova was last seen from Earth in 1946. Its behavior over the past decade appears strikingly similar to observed behavior in a similar timeframe leading up to the 1946 eruption. If the pattern continues, some researchers say, the nova event could occur by September 2024.

What should stargazers look for? The Northern Crown is a horseshoe-shaped curve of stars west of the Hercules constellation, ideally spotted on clear nights. It can be identified by locating the two brightest stars in the Northern Hemisphere – Arcturus and Vega – and tracking a straight line from one to the other, which will lead skywatchers to Hercules and the Corona Borealis.

The outburst will be brief. Once it erupts, it will be visible to the naked eye for a little less than a week – but Hounsell is confident it will be quite a sight to see.

Here’s all the professional telescopes to observe it.

Hays is the project scientist for NASA’s Fermi Gamma-ray Space Telescope, which has made gamma-ray observations from low Earth orbit since 2008. Fermi is poised to observe T CrB when the nova eruption is detected, along with other space-based missions including NASA’s James Webb Space Telescope, Neil Gehrels Swift Observatory, IXPE (Imaging X-ray Polarimetry Explorer), NuSTAR (Nuclear Spectroscopic Telescope Array), NICER (Neutron star Interior Composition Explorer), and the European Space Agency’s INTEGRAL (Extreme Universe Surveyor). Numerous ground-based radio telescopes and optical imagers, including the National Radio Astronomy Observatory’s Very Large Array in New Mexico, also will take part. Collectively, the various telescopes and instruments will capture data across the visible and non-visible light spectrum.

I can see clearly now

Star drive

Moon-to-Mars architecture papers

What to do on Mars

The Moon

Solar events

Space nearby

Stars living and dead


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