Don’t let the bright Moon deter you from seeing the one of the best meteor showers of the year.
One of the best meteor showers of 2024 closes out the year this coming weekend. If skies are clear, watch for the Geminid meteors, peaking on the night of Friday into Saturday, December 13-14th.
The Geminids in 2024To be sure, the Geminids have a few strikes against them this year. Not only is it cold outside, but the Moon is near Full, 98% illuminated waxing gibbous at the shower’s max. But don’t despair: the shower hits its maximum at 3:00 Universal Time (UT) on December 14th (10:00 PM EST on the 13th) with a max Zenithal Hourly Rate of 120 meteors per hour. This means the shower will favor western Europe and North America, a plus. The radiant in Gemini near the bright star Castor (Alpha Geminorum) also means that the shower starts to be active in the late evening before local midnight.
The Geminid radiant, looking east on the evening of December 13th. Credit: Stellarium.The source of the Geminids is none other than prolific ‘rock-comet’ 3200 Phaethon. Clearly, something intriguing is going on with this object. On a short 1.4 year orbit, 3200 Phaethon seems to blur the line between asteroid and semi-dormant comet nucleus. Japan wants to send its DESTINY+ mission to 3200 Phaethon in 2028 to get a closer look.
A radio animation of 3200 Phaethon. Credit: Arecibo/NASA/NSFThe Geminids have put on a show since 1862, though they seem to have really taken off in recent decades, surpassing the August Perseids as the best annual meteor shower of the year.
Fighting the MoonThe key to seeing any meteor shower at its best is to find dark skies and a clear, unobstructed horizon. The December Moon sits just a constellation away in Taurus at the shower’s peak… but keep in mind, the shower is also active on the evenings prior to and after the 14th. I plan to select my observing site with this in mind, and block the Moon behind a hill or tree. Early morning predawn observing will put the Moon lower to the horizon.
A sequence of Geminid meteors from 2014. Credit: Mary McIntyre.There’s a reason the Moon is currently so high in the sky: not only is the Moon near the December Solstice and occupying the slot that the Sun will hold in June, but we’re headed towards a once every 18.6-year Major Lunar Standstill of the Moon in 2025.
A Geminid meteor all-sky camera view. Credit: Eliot Herman.Observing and contributing to meteor shower science is as easy as watching, recording what you’re seeing at a designated interval, and reporting that count to the International Meteor Organization (IMO). Keep in mind, several other meteor showers are still active in mid-December, including the November Taurid fireballs and the Ursids, peaking on December 22nd. For imaging, I like to simply automate the process, and set a wide-field DSLR camera running on a tripod with an intervalometer to take timed exposure shots and see what turns up later in post processing. Aim the camera off to one side of the radiant by about 45 to 90 degrees to catch the Geminid meteors in profile.
Don’t miss the 2024 Geminids, as a fine way to round out sky-watching in 2024.
The post Our Strategy to Catch the 2024 Geminid Meteors appeared first on Universe Today.
Meanwhile, in Dobrzyn, Hili is on the alert:
Hili: The Chinese are coming!
A: You must be confused.
Hili: So maybe it’s somebody else.
Hili: Chińczycy idą!
Ja: Chyba ci się coś pomyliło.
Hili: To może jacyś inni.
On BlueSky, Jack Ashby is continuing his observations of the duckbilled platypus:
Perfect #platypus – you can see how they change from swimming to waddling to slithering depending on how deep the water is.#MonotremeMonday #fieldwork #Tasmania #MammalWatching #platypuses #WildOz
— Jack Ashby (@jackdashby.bsky.social) 2024-12-09T08:22:33.461Z
And Ze Frank is exploring how species are named:
Since the nomination of Dr. Jay Bhattacharya for NIH Director, I've been seeing a suggestion from certain contrarian doctors for a a "randomized trial" of study sections vs. a "modified lottery" to determine which grant applications are funded by the NIH. Just what the heck is Dr. Vinay Prasad talking about?
The post Are NIH study sections a waste of time? first appeared on Science-Based Medicine.The standard theory of cosmology is based upon four things: the structure of space and time, matter, dark matter, and dark energy. Of these, dark energy is the one we currently understand the least. Within the standard model, dark energy is part of the structure of space and time as described by general relativity. It is uniform throughout the cosmos and expressed as a parameter known as the cosmological constant. But initial observations from the Dark Energy Spectroscopic Instrument (DESI) suggest the rate of comic expansion may vary over time. If further observations reinforce this, it could open up cosmological models to alternatives to general relativity known as modified gravity.
In a recent paper on the arXiv, the authors look at one version of modified gravity known as Horndeski’s theory. The theory is based upon a generalization of general relativity. Einstein’s original theory was based upon the principle of equivalence, from which he derived a generalized description of spacetime through what is known as a metric tensor. From this, you can derive the equations of motion for objects in a gravitation field, just as Newton’s laws lead to equations of motion for objects under physical and gravitational forces.
General relativity is the simplest model with a metric tensor. Horndeski’s theory is the most general model with a metric tensor and allows for the presence of a uniform scalar field. There are special cases of Horndeski’s theory, such as the Brans-Dicke model and the model of quintessence. Both of these models have been used to describe dark energy in a more general way, as well as dark matter in some cases. While observations of gravitational waves, galactic clustering and cosmic expansion constrain these models to some degree, they don’t entirely rule them out. So far, our data on dark energy isn’t rich enough to distinguish between alternatives.
Comparison between standard model and modified gravity. Credit: Chudaykin and KunzThis latest work looks at the DESI results in the context of Horndeski models, specifically looking at how it might address the time-evolution of cosmic expansion suggested by the DESI data. It found that if the time evolution is taken to be correct, then a modified gravity is a better fit than the standard model. The study goes on to show that Horndeski models only work where the time evolution of the scalar field correlates to the proposed time evolution of dark matter. This rules out some Horndeski models that have been used to explain dark matter.
Overall, the authors argue that the DESI observations make Horndeski’s theory a viable alternative to general relativity. That is, if the data holds up. The Dark Energy Spectroscopic Instrument is still in its early stages, and we don’t yet know what the final results will be. But it is clear that Einstein’s seat on the theoretical throne isn’t entirely assured, and Horndeski’s theory might just be the one to steal the crown.
Reference: Chudaykin, Anton, and Martin Kunz. “Modified gravity interpretation of the evolving dark energy in light of DESI data.” arXiv preprint arXiv:2407.02558 (2024).
The post Observations by DESI Open the Door to Modified Gravity Models appeared first on Universe Today.
Meanwhile, in Dobrzyn, Hili is coming to terms with the inevitable.
Hili: I’m thinking whether to go for a walk.
A: And what is your conclusion?
Hili: It’s not the right season.
Hili: Zastanawiam się, czy iść na spacer.
Ja: I jaki wniosek?
Hili: Niewłaściwa pora roku.
The nature of dark matter has been a hotly debated topic for decades. If it’s a heavy, slow moving particle then it’s just possible that neutrinos may be emitted during interactions with normal matter. A new paper proposes that Jupiter may be the place to watch this happen. It has enough gravity to capture dark matter particles which may be detectable using a water Cherenkov detector. The researchers suggest using a water Cherenkov detector to watch for excess neutrinos coming from the direction of Jupiter with energies between 100 MeV and 5 GeV.
Jupiter is the largest planet in the solar system, large enough to swallow up all the planets and have a little room to spare. It’s composed mainly of hydrogen and helium and is devoid of a solid surface. Of all the planets, Jupiter has a powerful magnetic field and a strong gravitational field. It’s gravitational field is so powerful that, over the years, it has attracted, and even destroyed comets like Shoemaker-Levy 9 back in 1994. Of all the features visible in the planet’s atmosphere, the giant storm known as the Great Red Spot is by far the most prominent.
Image of Jupiter taken by NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) in July 2022 displays striking features of the largest planet in the solar system in infrared light, with brightness indicating high altitudes. One of these features is a jet stream within the large bright band just above Jupiter’s equator, which was the focus of this study. (Credit: NASA, ESA, CSA, STScI, R. Hueso (University of the Basque Country), I. de Pater (University of California, Berkeley), T. Fouchet (Observatory of Paris), L. Fletcher (University of Leicester), M. Wong (University of California, Berkeley), J. DePasquale (STScI))Planets in the solar system would, until now, be the last place to go hunting for dark matter. This mysterious stuff is invisible to all normal detection methods but is thought to make up 27% of the universe, outweighing visible matter at 5% (the majority of remainder made up of dark energy.) As its name suggests, dark matter doesn’t emit, absorb or reflect light making it hard to observe. It’s existence has been inferred from the gravitational effects on galaxies, galaxy clusters and the largest scale structures of the universe. Despite its prominence in the universe, the nature of it remains largely unknown.
Researchers are making progress mapping dark matter, but they don’t know what it is. This is a 3D density map of dark matter in the local universe, with the Milky Way marked by an X. Dots are galaxies, and the arrows indicate the directions of motion derived from the reconstructed gravitational potential of dark matter. Image Credit: Hong et al., doi: 10.3847/1538-4357/abf040.Dark matter is measured in GeV because this is a standard method in high energy physics to express the mass of particles. Until recently attempts to detect dark matter have relied upon experiments where dark matter is scattered with electrons, protons or neutrons in a detector. The interactions cause energy transfers which then reveal he presence of dark matter.
A view of the Large Underground Xenon (LUX) dark matter detector. Shown are photomultiplier tubes that can ferret out single photons of light. Signals from these photons told physicists that they had not yet found Weakly Interacting Massive Particles (WIMPs) Credit: Matthew Kapust / South Dakota Science and Technology AuthorityIn a paper by Sandra Robles from Kings College London and Stephan Meighen-Berger from the University of Melbourne, they propose and calculate the level of annihilating dark matter neutrinos within Jupiter and whether they could be detected using existing neutrino observatories. The team also propose a way to use of water Cherenkov detectors which are designed to detect high-energy particles such as neutrinos or cosmic rays. This is achieved by capturing Cherenkov radiation emitted while they travel through water. To give context to the process, the radiation is optical and occurs when a charged particle moves through a medium like water producing a faint flash of blue light.
The team suggest Jupiter is an ideal location to hunt for dark matter using Cherenkov radiation detectors. It’s low core temperature and significant gravitational attraction will mean it could capture dark matter and retain it. The presence of neutrinos in the direction of Jupiter reveals the capture and annihilation of dark matter. A similar technique is used by observing the Sun.
Source : Extending the Dark Matter Reach of Water Cherenkov Detectors using Jupiter
The post Using Jupiter as a Dark Matter Detector appeared first on Universe Today.
Doctors who profit in any way by normalizing RFK Jr. should be calmly and politely reminded of this at every opportunity for the rest of their careers. They are not entitled to a safe space.
The post Actually Dr. Adam Cifu, It’s Fine to “Attack” Doctors Who Profit By Spreading Pro-RFK Jr. Propaganda first appeared on Science-Based Medicine.Through the Artemis Program, NASA hopes to lay the foundations for a program of “sustained lunar exploration and development.” This will include regular missions to the surface, the creation of infrastructure and habitats, and a long-term human presence. To facilitate this, NASA is teaming up with industry and international partners to develop Human Landing Systems (HLS) that can transport crews to and from the lunar surface and landers that can deliver payloads of equipment, vehicles, and supplies to the lunar surface.
In a recent statement, NASA indicated that it intends to award Blue Origin and SpaceX additional work under their existing contracts to develop landers that will deliver equipment and infrastructure to the lunar surface. NASA also plans to assign demonstration missions to these companies, in addition to design certification reviews, which will validate their concepts. This decision builds on NASA’s earlier request, made in 2023, that the two companies develop cargo versions of their HLS concepts, which are currently in development for the Artemis III, Artemis IV, and Artemis V missions.
Stephen D. Creech, the Assistant Deputy Associate Administrator (Technical) for the Moon to Mars Program Office, explained in the NASA statement:
“NASA is planning for both crewed missions and future services missions to the Moon beyond Artemis V. The Artemis campaign is a collaborative effort with international and industry partners. Having two lunar lander providers with different approaches for crew and cargo landing capability provides mission flexibility while ensuring a regular cadence of Moon landings for continued discovery and scientific opportunity.”
In previous statements issued in April and September of this year, NASA has emphasized the need for vehicles that can accommodate heavy payload deliveries – between 2,000 and 6,000 kg (4,400 and 13,000 pounds) to the Moon to accommodate the Artemis missions. Per the latest, NASA indicates that it plans for at least two heavy payload missions that will deliver elements of the Artemis Base Camp to the Moon. These large cargo landers must have the capacity and capability of landing approximately 12 to 15 metric tons (13 to 16.5 U.S. tons) of heavy cargo on the lunar surface.
The two missions will see SpaceX using a cargo lander version of their Starship to deliver the Habitable Mobility Platform (HMP) – a pressurized rover currently being developed by the Japan Aerospace Exploration Agency (JAXA) – no earlier than 2032 in support of Artemis VII and later missions. Meanwhile, the agency expects Blue Origin to deliver the Lunar Surface Habitat (LSH) element using its Blue Moon lander no earlier than 2033. Said Dr. Lisa Watson-Morgan, program manager for NASA’s Human Landing System:
“Based on current design and development progress for both crew and cargo landers and the Artemis mission schedules for the crew lander versions, NASA assigned a pressurized rover mission for SpaceX and a lunar habitat delivery for Blue Origin. These large cargo lander demonstration missions aim to optimize our NASA and industry technical expertise, resources, and funding as we prepare for the future of deep space exploration.”
SpaceX and Blue Origin will continue to develop their cargo lander concepts and prepare for demonstration missions as part of their NextSTEP Appendix H (Option B) and NextSTEP Appendix P contracts (respectively). NASA plans to issue an initial request for both proposals by early 2025.
Further Reading: NASA
The post NASA has Plans for More Cargo Deliveries to the Moon appeared first on Universe Today.
Telescopes in space have a huge advantage over those on the ground: they can see the universe more clearly. The Earth’s atmosphere, weather conditions, and low-flying satellites don’t obscure their view. But space telescopes have a disadvantage too. They can’t be repaired, at least not since NASA’s Space Shuttle program ended in 2011.
But next-generation telescopes are being planned with robotic servicing missions in mind. And not just in low earth orbit, where the Hubble Space Telescope received repairs and upgrades five times during its lifespan from space shuttle crews. Today’s engineers are preparing for ways to repair telescopes in deep space, including at the Sun-Earth Lagrange point L2.
L2 is the current home of the James Webb Space Telescope (JWST) and ESA’s Gaia mission. In this position, the Earth is kept between the Sun and the telescopes, giving them pristine conditions for observing the universe.
“While neither Gaia nor JWST were explicitly designed to be serviceable, next-generation space telescopes now in development include serviceability in their baseline designs,” write the authors of a new paper from a team at the Grainger College of Engineering, University of Illinois Urbana-Champaign.
Service spacecraft could attach themselves to derelict telescopes, bringing extra fuel, working reaction wheels, or even repairing damaged mirrors and other key components.
But it isn’t an easy task.
Artist’s illustration showing the location of the Sun-Earth Lagrange Points. Credit: NASAThe University of Illinois team, including Professor Siegfried Eggl and Ruthvik Bommena, used Gaia and JWST as test subjects to design a feasible service mission.
“Gaia is like a rotating cylinder with a solar panel. It is encapsulated, so it hasn’t been damaged, but after a decade out there it’s running low on fuel,” said Eggl in a press release. “Ruthvik Bommena designed a novel concept to add a sort of spider-looking attachment that can extend its life without impeding its data collection. Gaia will be decommissioned soon, so there isn’t enough time to reach it, but the James Webb might still be a possibility because it will be operating for several more years and they may decide to prolong its mission.”
JWST’s exposed mirrors have already been struck by micrometeorites multiple times, affecting the quality of its observations.
“We’re trying to stay a step ahead so there is a plan to replace broken mirrors, for example. If we don’t, it’s like buying an expensive sports car, then like throwing it away when it runs out of gas,” says Eggl.
One of the most significant barriers to long-distance servicing missions is designing a trajectory for rendezvous with the target.
“A spacecraft sent to repair or refuel a telescope needs to brake when it reaches it,” Bommena said. “Using the thrusters to slow down would be like pointing a blowtorch at the telescope. You don’t want to do that to a delicate structure like a telescopic mirror. How do we get there without torching the whole thing?”
In addition, the team is working to optimize both fuel efficiency and cost for such a mission.
As Professor Robyn Wollands, another author on the paper explains, “getting there is doable because of some hidden highways in our solar system. We have a trajectory that is optimal for the size of spacecraft needed to repair the JWST,” she said.
These ‘hidden highway’s are geometrically optimal paths that take advantage of orbital mechanics to make rendezvous safe and cost-efficient. The team have developed a new way to calculate and evaluate these optimal paths.
“After we create a map of initial solutions, we use optimal control theory to generate optimal end-to-end trajectories,” said PhD student Alex Pascarella. “Optimal control allows us to find trajectories that depart near Earth, and rendezvous with our space telescope in the least amount of time. The initial sampling of the solution space is fundamental—optimal control problems are notoriously difficult to solve, so we need a decent initial guess to work with.
“The novelty is in how we brought together two separate approaches to trajectory design: dynamical systems theory and optimal control theory,” Pascarella added.
With teams like this one laying the groundwork, the lifespan of space telescopes might be extended long past their original best-before date, and that’s good news for astrophysicists and space programs worldwide.
Learn More:
Alex Pascarella, Ruthvik Bommena, Siegfried Eggl, Robyn Woollands, “Mission design for space telescope servicing at Sun–Earth L2.” Acta Astronautica.
“A mission design for servicing telescopes in space.” EurekAlert.
The post Space Telescopes Could See a Second Life With a Servicing Mission appeared first on Universe Today.
It’s a mere 18 days until Christmas and, of course, the First Day of Coynezaa. Both festivities are marked by an overconsumption of food, and Coynezaa enjoys the advantage of having no religious overtones save encomiums for Professor Ceiling Cat (Emeritus).
Here in Katowice, in southern Poland, the Christmas Market is already in full swing in the town square, and I happened upon it walking back from the Silesian Science Festival (today I registered, tomorrow and Monday I speak). It was exactly what I’d expect a Polish Christmas market to be: full of fun, food, and just a bit of religion in the form of singing angels (not shown). Here are a few holiday snaps I took while crossing the town square.
Yep, here’s where we are:
Katowice has an ancient history, but lacks the charm of other Polish cities for two reasons: it was an industrial hub for mining coal and steel, and, under German occupation, many of its landmarks were wrecked, including the Great Synagogue, shown below next to the City Baths. It was completed in 1900 and razed by the Germans in 1939. And of course most of the Jews were killed or sent away to be murdered.
Photo from public domain, Wikipedia.An old building that remains in the city square:
Here is a monument that I take to be in honor of the local miners. Note the flowers and miner’s lamp at the base:
And everywhere people were having fun and laughing, expecially the kids. This one got a big soap bubble:
But the adults were also having a great time. There are various plastic status behind which you can stick your face to get a photograph. Like these people:
A penguin:
And a train chugging the kids through the market:
But of course people were there to get stuff, too: mostly food. Like these roasted chestnuts:
And look at this inventive and mouth-watering display of lollipops:
And, of curse, gingerbread, a Polish speciality for the holidays:
Very fancy gingerbread. These say “Happy Christmas” in Polish:
Various candies (caramels?), some of them flavored with booze (“piwo” is beer):
And what is a Polish market without sausages?
There were stalls selling non-comestibles, too. This one carried a variety of soaps, including these cat soaps in lavender and lily-of-the-valley (“kot” is “cat” in Polish):
Walking back to my hotel on the shopping street, I saw a big line in front of one shop. It was selling a variety of soft pretzels, and I would have joined the line had it been shorter:
There was a variety, including non-twisted pretzels filled with Nutella. The cinnamon pretzels were nearly sold out:
But below is a store selling the quintessence of Polish baked treats: pączki. Wikipedia describes them:
A pączek is a deep-fried piece of dough shaped into a flattened ball and filled with confiture or other sweet filling. Pączki are usually covered with powdered sugar, icing, glaze, or bits of dried orange zest. A small amount of grain alcohol (traditionally rectified spirit) is added to the dough before cooking; as it evaporates, it prevents the absorption of oil deep into the dough. Pączki are commonly thought of as fluffy but somewhat collapsed, with a bright stripe around them; these features are seen as evidence that the dough was fried in fresh oil.
Although they look like German berliners (bismarcks in North America) or jelly doughnuts, pączki are made from especially rich dough containing eggs, fats, sugar, yeast, and sometimes milk.
(Note that when JFK proclaimed himself “Ich bin ein Berliner” in Germany in June, 1963, his attempt to forge solidarity with the divided people of that city actually meant, in German, “I am a jelly donut.” He should have said “Ich bin Berliner.”)
Believe me; these pastries are superb! The only thing preventing me from trying one or three was that I was full from the ample spread of goodies in the Science Festival’s VIP room, to which I have access as a speaker. But have a look at these puppies! There are four zloty to the dollar, so each large filled pastry is about two bucks.
Happy Christmas from Poland!
Meanwhile, in Dobrzyn, Hili is facing an unpalatable truth
Hili: This is not the right world.
A: We do not have any other.
Most people will think of a dry arid landscape when they think of Mars. When seen from orbit, dry river channels and lake-beds can be seen along with mineral deposits thought to be the created in the presence of liquid water. A team of researches now suggest that liquid carbon dioxide could also explain the features seen. On Earth, a process known as carbon sequestration liquefies CO2 which is buried underground. There are a number of mechanisms that could explain the liquid CO2 underground the researchers suggest.
Mars is often referred to as the ‘red planet’ due to its visual appearance. It’s the fourth planet from the Sun and has been a real focus for exploration and research for decades. The red colour is caused by iron oxide (rust) on its surface which can often be lifted up into the atmosphere by the Martian winds giving stunning pink skies. It’s just over half the size of the Earth, has a thin atmosphere mostly made of carbon dioxide and a surface composed of deserts and volcanoes like Olympus Mons. One of the key focusses of the exploration on Mars has been to establish whether the conditions are suitable for life, have been suitable in the past or whether liquid water exists on the surface.
A full-disk view of Mars, courtesy of VMC. Credit: ESAThe presence of dry riverbeds and lake beds points to a surface that had liquid flowing long ago. Quite what that liquid is has been the cause for debate. Observations of minerals from orbit and from more direct analysis on the surface, suggest that the liquid was just water. However a team of researchers have published a paper in Nature Geoscience that suggests otherwise. They explain that water is only one of two possible liquids that could have existed on ancient Mars. The other is liquid carbon dioxide or CO2. Given the atmospheric conditions it may have been more likely and easier for CO2 in the atmosphere to condense into a liquid than for surface ice to melt into water.
A topographic image of an area of anceint riverbeds on Mars. Created with data from the High-Resolution Stereo Camera on the Mars Express Orbiter. Image Credit: ESA/DLR/FU Berlin http://www.esa.int/spaceinimages/ESA_Multimedia/Copyright_Notice_ImagesIt has been the general consensus that the minerals point to liquid water. The paper suggests that processes like carbon sequestration, liquid CO2 buried underground can alter the composition of minerals even faster than water can. Lead author Michael Hecht, research scientist at MIT’s Haystack Observatory said “Understanding how sufficient liquid water was able to flow on early Mars to explain the morphology and mineralogy we see today is probably the greatest unsettled question of Mars science. There is likely no one right answer, and we are merely suggesting another possible piece of the puzzle.”
Image of the Martian atmosphere and surface obtained by the Viking 1 orbiter in June 1976. (Credit: NASA/Viking 1)The paper explores our current understanding of the Martian atmosphere and combine it with the carbon sequestration research to conclude that the processes do support the evidence and mineralogy seen on Mars. They note however that this proposal does not suggest all Martian surface liquid was CO2 but rather there could have been a combination of the two.
They explain that liquid CO2 on the surface of Mars could exist as a stable surface liquid, as melted CO2 under CO2 ice or in subsurface reservoirs. Which actually took place would have dependent entirely on the distribution of CO2 at the time and the surface conditions too. The paper acknowledges that further testing is required under more realistic Martian conditions to test whether the same processes still occur.
Source : Liquid on Mars was not necessarily all water
The post Other Liquids Could Be Forming Minerals on Mars appeared first on Universe Today.