Ages ago in its youth, Mars appeared much like Earth. It was a warm planet with lakes, rivers, and vast seas. It had a thick atmosphere with clouds and rain. One major difference is that the atmosphere was rich with carbon dioxide instead of oxygen. Then about 3.5 billion years ago much of the atmosphere disappeared, and we haven’t understood how. A new study in Science Advances suggests that the waters of Mars may have been the key, and much of the ancient atmosphere may be locked in the surface of the red planet.
The authors center their paper on a clay mineral known as smectite. On Earth smectite is produced through tectonic activity. As tectonic plates are uplifted they can drag material from the mantle to the surface, some of which is this kind of clay. One characteristic of smectite is that it’s full of little folds. Nooks and crannies if you will, that can trap carbon dioxide for billions of years. In an earlier study the team demonstrated how smectite on Earth helped prevent our world from becoming a greenhouse planet by pulling carbon dioxide out of our early atmosphere. It’s a process still going on today. Mars doesn’t experience tectonic activity, but smectite can be found all over Mars, and the authors wondered if it might solve the mystery of the Martian atmosphere.
The processes that captured the Martian atmosphere. Credit: Murray & Jagoutz
The challenge was to figure out how so much smectite formed on Mars. Rather than uplifting tectonic plates it is a series of chemical reactions. The authors suggest that water on Mars seeped through olivine, a magnesium iron silicate common on Earth, Mars, and even asteroids. The iron in olivine would bind with the water’s oxygen and release hydrogen. This hydrogen would then react with carbon dioxide to form methane. Over time this process would transform the olivine into smectite, which would trap methane and carbon dioxide. Based on their calculations the team argues that 80% of the ancient atmosphere is now trapped in the Martian clay, leaving the thin atmosphere we see today.
If this model is true, it could be a boon for future Martian explorers. Not only will there be plenty of water found beneath the surface, there will also be large quantities of methane. The solution to the problems of water and fuel could be right under the feet of those first explorers, trapped in the nooks and crannies of common clay.
I’ve often stated that planets come in a wide range of sizes but rarely do I find myself stating they come in a wide range of shapes too! The discovery of WASP-107b is a case in point since this planet is the size of Jupiter but only a tenth of its mass. But there’s more… Using the James Webb Space Telescope a team of astronomers have accurately identified that the planet has an east-west asymmetry in its atmosphere, in other words, it’s lopsided. It is tidally locked to the star and on one side, the atmosphere seems to be inflated compared to the other.
Planets orbiting other stars are known as exoplanets. WASP-107b is one such planet in orbit about a star 200 light years away in the constellation of Virgo. The first exoplanet detection was confirmed in 1992 and since then over 5,000 alien planets have been identified. A multitude of different techniques are used to hunt them down from searching for dips in light from distant stars to analysing the spectra of a star. A wide variety of planet systems have been found from Earth-like possibly habitable planets to great big gas giants like Jupiter. With the new generation of space telescopes like the JWST it is now possible to study the atmosphere of exoplanets to learn even more about them.
Artist impression of the James Webb Space Telescope
A team of astronomers from the University of Arizona have been using the JWST with an international group of researchers to study WASP-107b. They discovered the east-west asymmetry of the planet as it passed in front of its host star just like the Moon does during a solar eclipse.
The shape of the planet is an atmospheric phenomenon but of course when it comes to gas giants like Jupiter that’s pretty much referring to the planet itself. It’s not just a physical asymmetry though as there are temperature and cloud property differences between the eastern and western hemisphere. It’s now important to explore the asymmetry observed to learn more about the dynamics of the planet and whether it’s a unique phenomenon.
“Icy and Rocky Worlds” is a new exoplanet infographic by Slovak artist and space enthusiast Martin Vargic. It’s available as a wall poster at his website. Image Credit and Copyright: Martin Vargic
One element of the planet which is cause for investigation and likely cause is that it’s tidally locked to the star. The force of gravity from the star and the force of gravity on the planet have acted upon each other to lock one face of the planet to the star. This means one hemisphere is constantly illuminated and warmed by the star while the other hemisphere is permanently night! Tidal locking is not unique to WASP-107b though so if this is the cause then the asymmetry should be common.
To make their finding, the team used a technique known as transmission spectroscopy. In this technique, observations are made of the starlight as it passes through the atmosphere of the planet during transit events. As the light passes through atmospheric gasses, the presence of different gasses interacts with the light in different ways that can be seen during spectral analyses.
What does make WASP-107b unique is low gravity and low density giving rise an atmosphere that is somewhat over-inflated compared to other alien worlds of this mass. This is the first time such an asymmetry has been seen so it will be interesting to see how unique this fascinating world really is.
Venus is often described as a hellscape. The surface temperature breaches the melting point of lead, and though its atmosphere is dominated by carbon dioxide, it contains enough sulfuric acid to satisfy the comparison with Hades.
But conditions throughout Venus’ ample atmosphere aren’t uniform. There are locations where some of life’s building blocks could resist the planet’s inhospitable nature.
Among the rocky planets, Venus has by far the largest atmosphere by volume. So, while its surface is inhospitable, its atmosphere has regions that are the most Earth-like of anywhere else in the Solar System. Scientists have wondered if life could survive in parts of the planet’s upper atmosphere, and the discovery of the potential biomarker phosphine (though it was later disproved) generated more interest.
Some research suggests that life could exist within Venus’ voluminous clouds. Image Credit: Abreu et al. 2024.
One reason Venus keeps coming up in discussions around habitability is that it’s accessible, whereas exoplanets aren’t. Venus is easily reached, and we currently have one orbiter in place, the Japanese Akatsuki spacecraft. Three other missions to Venus are planned for the mid-2030s: NASA’s Veritas and DAVINCI and the ESA’s EnVision.
Nobody is convinced we’ll find life on Venus. But the planet can teach us a lot about chemistry and biology and their limits.
In new research, a team of scientists tested different building blocks under Venus-like conditions to see if they can withstand the planet’s perilous nature. The research is “Simple lipids form stable higher-order structures in concentrated sulfuric acid.” The lead author is Daniel Duzdevich from the Department of Chemistry at the University of Chicago. The paper is in pre-print now and has been submitted to the journal Astrobiology.
Venus’ surface isn’t a candidate for habitability. But regions in its atmosphere may be. The issue is that much of Venus’ sulfuric acid is concentrated in discrete clouds rather than diffused throughout its atmosphere.
“The Venusian surface is sterilizing, but the cloud deck includes regions with temperatures and pressures conventionally considered compatible with life. However, the Venusian clouds are thought to consist of concentrated sulfuric acid,” the authors explain.
Cloud structure in the Venusian atmosphere in 2016, revealed by observations in the two ultraviolet bands by Akatsuki. Credit: Kevin M. Gill
They wanted to test if any of life’s “fundamental features” could withstand Venus’ challenging environment. Can any of life’s chemistry resist sulfuric acid?
“Organic chemistry in concentrated sulfuric acid is rarely studied yet surprisingly rich, with recent work supporting the notion that complex organic molecules, including amino acids and nucleobases can be stable in this unusual solvent,” the authors write.
If simple organic molecules can remain stable in sulfuric acid, it’s an interesting observation in favour of life. But it takes more complexity than that, and that’s what this research focuses on.
“One fundamental feature of life is cellularity: the differentiation of “inside” (the contents of a cell, including information, molecules, and all their interactions) and “outside” (the environment), in addition to a mechanism for communication and exchange between the two,” Duzdevich and his co-researchers write.
The researchers focused on lipids, the membranes that define cells. Lipids are the foundation of cellular structure, not only as membranes between cells but also as membranes that create distinct parts of the interior of cells. “The cell membrane is especially important in extreme environments because it must help maintain the homeostasis of the intracellular environment against otherwise harsh external conditions,” the authors write.
The researchers performed lab experiments to determine whether lipids can withstand Venus’ harsh environment. They asked two questions: Can simple lipids resist decomposition by sulfuric acid, and can the lipids form stable higher-order structures like they do in cells?
The researchers placed masses of lipids in vials and exposed them to different concentrations of sulfuric acid and measured each vial at specific intervals. Their results show that some lipids can survive exposure to the acid and even form structures.
This figure from the research shows the vesicle-like structures that formed after concentrated sulfuric acid was added to solid lipids. Each panel is a different region of the same sample taken on the same day. Subsequent images showed that the structures remained intact even after seven days. Image Credit: Duzdevich et al. 2024.
Interested readers can explore the detailed chemistry for themselves.
In summary, the results suggest that stable membranes can form and persist in the presence of sulfuric acid. Life uses water as a solvent because it’s a polar molecule, can form networks of hydrogen bonds, has a high heat capacity, and, of course, is abundant on Earth. But it’s not abundant everywhere.
Critically, this study shows that some aspects of the chemistry of life don’t require water as a solvent. Instead, they can tolerate and use sulfuric acid as a solvent. “Here, we show the unexpected stability of complex membranous structures in another polar solvent: concentrated sulfuric acid,” the authors write.
What does this mean for exoplanet habitability and astrobiology?
“Concentrated sulfuric acid as a planetary solvent could be widespread on exoplanets, either on exo-Venuses or on other rocky planets that are desiccated as a result of the stellar activity of their host star,” the researchers explain.
And, of course, sulfuric acid is present in large amounts at Venus.
“Concentrated sulfuric acid is also present in our immediate planetary vicinity as a dominant liquid in the clouds of Venus, further emphasizing its importance for planetary science, planetary habitability, and astrobiology,” the authors write.
The question of whether life could somehow survive in Venus’ clouds is one that won’t go away. We’re new at the astrobiology game, and we’re simply not in a position to rule things out. It might seem far-fetched, but science is an evidence game, and evidence can be surprising.
This study doesn’t present evidence that can answer the question—big questions like this are answered incrementally—but it does present an intriguing result.
“By demonstrating the stability of lipid membranes in this aggressive solvent, we have taken a significant step forward in exploring the potential habitability of the concentrated sulfuric acid cloud environment on Venus,” the authors conclude.
The reason we call dark matter dark isn’t because it’s some shadowy material. It’s because dark matter doesn’t interact with light. The difference is subtle, but important. Regular matter can be dark because it absorbs light. It’s why, for example, we can see the shadow of molecular clouds against the scattered stars of the Milky Way. This is possible because light and matter have a way to connect. Light is an electromagnetic wave, and atoms contain electrically charged electrons and protons, so matter can emit, absorb and scatter light. Dark matter isn’t electrically charged. It has no way to connect with light, and so when light and dark matter meet up they simply pass through each other.
All of our observations suggest that dark matter and light only have gravity in common. When dark matter is clustered around a galaxy, for example, its gravitational tug can deflect light. Because of this we can map the distribution of dark matter in the Universe by observing how light is gravitationally lensed around it. We also know that dark and regular matter interact gravitationally. The tug of dark matter causes galaxies to gather together into superclusters. But an unanswered question is whether dark and regular matter only interact gravitationally. If an atom and dark matter particle intersected, would they really just pass through each other?
Since we haven’t directly observed dark matter particles we can only speculate, but most dark matter models argue that gravity is the only common link with light and regular matter. Dark and regular matter clump around each other, but they don’t collide and merge like interstellar clouds. But a new study suggests the two do interact, which could reveal subtle aspects of the mysterious stuff.
The study looks at six ultrafaint dwarf galaxies, or UFDs. They are satellite galaxies near the Milky Way that seem to have far fewer stars than their mass would suggest. This is because they are mostly made of dark matter. If regular and dark matter only interact gravitationally, then the distribution of stars in these small galaxies should follow a certain pattern. If dark and regular matter interact directly, then this distribution will be skewed.
To test this the team ran computer simulations of both scenarios. They found that in the non-interacting model the distribution of stars should become more dense in the center of the UFDs and more diffuse at the edges. In the interacting model the stellar distribution should be more uniform. When they compared these models with observations of the six galaxies, they found the interacting model was a slightly better fit.
So it seems dark and regular matter interact in ways beyond their gravitational tugs. There isn’t enough data to pin down the exact nature of the interaction, but the fact there is any interaction at all is a surprise. It means that our traditional models of dark matter are at least partly wrong. It may also point the way toward new methods of detecting dark matter directly. In time we may finally solve the mystery of this dark, but not entirely invisible, material.
We have known that water ice exists on the Moon since 1998. These large deposits are found in the permanently shadowed craters around the polar region. The challenge is how to get it since shadowed craters are not the best place for solar powered vehicles to operate. A team of engineers have identified a design for an ice-mining vehicle powered by americium-241. With a half-life of 432 years, this element is an ideal power source for a vehicle to operate in the dark for several decades.
Ice in the polar regions of the Moon is of vital importance for our future space explorations, not just lunar visits but as we stretch our legs in the Solar System. Its thought to be ancient material deposited by comets or formed by interactions with solar wind. It is expensive to take materials to the Moon so harvesting on site is far more efficient. Ice on the Moon can provide drinking water, oxygen for breaking and even hydrogen for rocket fuel. Surveys suggest something in the region of 600 billion kilograms of ice deposited at the lunar poles.
Exposed water ice (green or blue dots) in lunar polar regions and temperature. Credit: Shuai Li
The challenge facing future lunar harvesting missions is that operations in the permanently shadowed regions (or PSRs as they have been called) cannot be powered by solar panels as is often the case. The environment is cold too, in the region of 40K, that’s -233?C and at those temperatures special power considerations are required.
A team of researchers have been exploring the use of Radioisotope Power Systems (RPS) to provide thermal and electrical power systems. These power systems have been used before during deep space missions for example Voyager and New Horizons. They work by generating electricity using the heat that is released from the natural decay of a radioactive isotope usually plutonium-238.
Artist rendition of Voyager 1 entering interstellar space. (Credit: NASA/JPL-Caltech)
The team led by Marzio Mazzotti from the University of Leicester have explored an ice-mining rover using power generated by the radio activate decay fo Americium-241. It has a half-life of 432 years which means it takes 432 years for half of a sample of Americium to decay. During this time, half of the atoms in the substance will transform into a different element. Using this power source will provide a stable power supply for an ice-mining rover in the darkness of the lunar polar craters for decades.
Apollo 17 commander Eugene Cernan with the lunar rover in December 1972, in the moon’s Taurus-Littrow valley. Credit: NASA
Using a radioisotope power system is not new however the team came upon the idea that the excess heat that is not used can be used to thermally mine ice from samples of lunar material. The rover would be fitted with a sublimation plate that would turn any ice deposits into a gas which would be collected in a cold trap.
The team developed a model of its Thermal Management System and tested it for icy regolith (the fine dusty lunar surface) material with a water ice content of 0-10 vol %. Their simulations showed that it is possible to mine ice using thermal techniques in the PSR of the Moon using an RPS (I had to really concentrate writing that sentence!) powered lunar rover.
It’s no secret that spending extended periods in space takes a toll on the human body. For years, NASA and other space agencies have been researching the effects of microgravity on humans, animals, and plants aboard the International Space Station (ISS). So far, the research has shown that being in space for long periods leads to muscle atrophy, bone density loss, changes in vision, gene expression, and psychological issues. Knowing these effects and how to mitigate them is essential given our future space exploration goals, which include long-duration missions to the Moon, Mars, and beyond.
However, according to a recent experiment led by researchers at Johns Hopkins University and supported by NASA’s Johnson Space Center, it appears that heart tissues “really don’t fare well in space” either. The experiment consisted of 48 samples of human bioengineered heart tissue being sent to the ISS for 30 days. As they indicate in their paper, the experiment demonstrates that exposure to microgravity weakens heart tissue and weakens its ability to maintain rhythmic beats. These results indicate that additional measures must be taken to ensure humans can maintain their cardiovascular health in space.
Heart tissues within one of the launch-ready chambers. Credit: Jonathan Tsui
Previous research has shown that astronauts returning to Earth from the ISS suffer from a myriad of health effects consistent with certain age-related conditions, including reduced heart muscle function and irregular heartbeats (arrhythmias), most of which will dissipate over time. However, none of this research has addressed what happens at the cellular and molecular level. To learn more about these effects and how to mitigate them, Kim and his colleagues sent an automated “heart-on-a-chip” platform to the ISS for study.
To create this payload, the team relied on human-induced pluripotent stem cells (iPSCs), which can become many types of cells, to produce cardiomyocytes (heart muscle cells). These resulting tissues were placed in a miniaturized bioengineered tissue chip designed to mimic the environment of an adult human heart. The chips would then collect data on how the tissues would rhythmically contract, imitating how the heart beats. One set of biochips was launched aboard the SpaceX CRS-20 mission to the ISS in March 2020, while another was kept on Earth as a control group.
Once on the ISS, astronaut Jessica Meir tended the experiment, changing the liquid nutrients surrounding the tissues once each week while preserving tissue samples at specific intervals so gene readout and imaging analyses could be conducted upon their return to Earth. Meanwhile, the experiment sent real-time data back to Earth every 30 minutes (for 10 seconds at a time) on the tissue samples’ contractions and any irregular beating patterns (arrhythmias).
“An incredible amount of cutting-edge technology in the areas of stem cell and tissue engineering, biosensors and bioelectronics, and microfabrication went into ensuring the viability of these tissues in space,” said Kim in a recent Hub news release.
When the tissue chambers returned to Earth, he and his colleagues continued to maintain and collect data from the samples to see if there was any change in their abilities to contract. In addition to losing strength, the muscle tissues developed arrhythmias, consistent with age-related heart conditions. In a healthy human heart, the time between beats is about a second, whereas the tissue samples lasted nearly five times as long – though they returned to nearly normal once returned to Earth.
The team further found that the tissue cell’s protein bundles that help them contract (sarcomeres) were shorter and more disordered than those of the control group, another symptom of heart disease. What’s more, the mitochondria in the tissue samples grew larger and rounder and lost the characteristic folds that help them produce and use energy. Lastly, the gene readout in the tissues showed increased gene production related to inflammation and an imbalance of free radicals and antioxidants (oxidative stress).
This is not only consistent with age-related heart disease but also consistently demonstrated in astronauts’ post-flight checks. The team says these findings expand our scientific knowledge of microgravity’s potential effects on human health in space and could also advance the study of heart muscle aging and therapeutics on Earth. In 2023, Kim’s lab followed up on this experiment by sending a second batch of tissue samples to the ISS to test drugs that could help protect heart muscles from the effects of microgravity and help people maintain heart function as they age.
Meanwhile, the team continues to improve its tissue-on-a-chip system and has teamed up with NASA’s Space Radiation Laboratory to study the effects of space radiation on heart muscles. These tests will assess the threat solar and cosmic rays pose to cardiovascular health beyond Low Earth Orbit (LEO), where Earth’s magnetic field protects against most space radiation.
Now is the time to catch Comet A3-Tsuchinshan-ATLAS at dawn.
The window is now open. If skies are clear, set your alarm heading into this weekend to see Comet C/2023 A3 Tsuchinshan-ATLAS at dawn. We’re already seeing great views of the comet this week from southern observers and astronauts aboard the International Space Station. The visibility window is now even creeping up to the southern tier latitudes of the contiguous United States (CONUS). If fortune favors us, the comet could hit an easy naked eye magnitude +2 by next week, and forward scattering could even boost this into negative magnitudes… the rare term ‘daytime comet’ is even getting kicked around a bit in cometwatching circles.
But the span to see this comet will be brief indeed. For most northern hemisphere observers, the comet will be a bashful one, never reaching much more than 10 degrees above the eastern horizon about 45 minutes before sunrise on the week centered around September 29th.
Exposures of Comet A3 against the brightening dawn. Credit: Chris Schur
The Story of Comet A3 Tsuchinshan-ATLAS Thus Far
We wrote about prospects for this comet for Universe Today previously just last month. China’s Tsuchinshan (Purple Mountain) observatory and the automated ATLAS (Asteroid Terrestrial impact Last Alert System) survey discovered the comet on January 9th, 2023. I’ve seen the name abbreviated to simply ‘Comet A3’ or ‘Comet T-ATLAS’ in discussions on keystroke-conservative social media.
Likely a first-time visitor to the inner solar system from the distant Oort Cloud, the comet is on an orbit measured in millions of years. This may also be the one and only appearance of the comet in the inner solar system. That’s a good thing, in terms of dynamics and activity, as the comet may have never experienced the heat of the inner solar system in the past. The comet could well head towards permanent ejection from the solar system after perihelion.
Key dates coming right up include when the comet reaches perihelion this coming Friday on September 27th at 0.391 Astronomical Units (AU, 36.4 million miles or 58.6 million kilometers) from the Sun, just interior to Mercury’s aphelion point. The comet then makes its closest Earth approach on October 12th, at 0.556 AU distant.
Comet A3 Tsuchinshan-ATLAS will become more difficult to catch after October 7th, as it heads in to the Solar Heliospheric Observatory’s (SOHO) LASCO C3 field of view and approaches less than 15 degrees elongation from the Sun. The comet makes a second evening reappearance mid-month, which will most likely be less than favorable as it heads away from us and back out of the inner solar system. We could, however, see something interesting in late October (if the comet survives perihelion) as the tail precedes ahead of the outbound comet.
Chris Schur caught the comet from Payson, Arizona (with a narrow 10 minute window!) on the morning of September 23rd. Credit: Chris Schur.
How the Comet is Performing Now
The comet seemed to be headed towards the long rolls of ‘great comets that weren’t’ this past summer, as it stalled at +10th magnitude. Now, the trend seems to have shifted, as the comet is over-performing versus expectations. As of writing this, the comet stands at +3rd magnitude and is rapidly brightening.
We’re already seeing signs of two tails (one dust and one ion) forming in this week’s images of the comet. Forward scattering may help boost the visibility of the comet next week, as all those dust particles reach a maximum illumination angle as seen from our Earthly vantage point in early October. The comet’s orbit passes edge-on from our vantage point on October 14th. The comet will seem to hang stationary low in the dawn next week, as it loops towards us, and then crosses between the Earth and the Sun.
Comet T-ATLAS as imaged from Tivoli Farm, Namibia on September 22nd (note the fan of the comet’s second tail off to the left). Credit: Gerald Rhemann.
How to See the Comet
The October apparition will be a tricky one for sure. A good strategy is to use binoculars and start sweeping low to the eastern horizon about an hour before local sunrise. The +1st magnitude star Regulus (Alpha Leonis) will make a good ‘guide star’ to find the comet. The star will be about an outstretched hand’s width to the observer’s lower right. The comet pairs with the slim waning crescent Moon on the morning of September 30th, making for a grand photo-op. That same Moon is headed towards an annular solar eclipse on October 2nd.
The view on the morning of September 30th. Credit: Starry Night Edu Software.
Clouded out? We feel your frustration here in eastern Tennessee, as clouds from approaching hurricane Helene move inland this coming weekend. Astronomer Gianluca Masi will also carry the comet live on the evening of October 9th.
Comet C/2023 A3 Tsuchinshan-ATLAS from September 24th. Credit: The Virtual Telescope Project.
“It (Comet T-ATLAS) survived and so far, it looks brighter than expected.” Astrophotographer Eliot Herman told Universe Today. “I still don’t think it will be amazing when it can be seen when dark enough… I am thinking maybe March 2013 Comet (C/2011 L4) PanSTARRS level – which was visible to the eye and pretty nice with a camera.”
We can only hope for a bright comet as depicted by astronomer Charles Piazzi Smyth’s painting of the Great Daytime Comet of 1843:
Astronauts aboard the International Space Station already caught the comet from their vantage point in low Earth orbit this week. NASA astronaut Matthew Dominick produced this fine animation:
Comet A3 Tsuchinshan-ATLAS is teasing us with the recent memories of two other dawn comets. Remember P1 McNaught in 2006-2007 and W3 Lovejoy in 2011-2012? Both beat the odds, and went on to become fine comets, ahead of expectations.
Comet McNaught imaged from Villa Alemana, Chile in January 2007. Credit: Garcia Ruben/Wikimedia Commons/Public Domain.
As always with comets, a caveat is in order: several factors will conspire against your cometary quest. First: as noted, the comet will appear very low to the horizon. This means it will fight against the thick murk of the atmosphere and the brightening twilight sky. Secondly, comets are intrinsically dark objects, with a low surface brightness or albedo… remember Rosetta’s views of Comet 67P Churumov-Gerasimenko? Lastly, like deep sky objects, all of that precious magnitude gets dispersed over an apparent surface area. This makes a +2 magnitude comet much fainter looking versus a +2nd magnitude star. During F3 NEOWISE’s 2020 apparition, I could juuuust start to convince myself that it was naked eye when it reached around +1st magnitude.
Comet C/2023 A3 (Tsuchinshan-ATLAS) is finally here ! ???I captured this image this morning at 09:22 UTC from @LCOAstro in Atacama desert in Chile ?? The view was absolutely spectacular ! The clouds were constantly moving just above the horizon, but we got really lucky when the… pic.twitter.com/AoClHkatFr
We had two recent comets perform very similar to Comet A3 Tsuchinshan-ATLAS. In 2020, Comet F3 NEOWISE became a fine naked eye comet at dawn, wowing early morning observers. On the flip side, 2023’s Comet P1 Nishimura flirted with naked eye brightness, but never really became a general crowd pleaser.
Clear skies on your hunt this coming week, to see what’s most likely to be the best comet of 2024.
