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Sometimes, when scientists measure things differently, they get different results. Whenever that happens with something as crucial to humanity’s long-term future as the universe’s expansion rate, it can draw much attention. Scientists have thought for decades that there has been such a difference, known as the Hubble Tension, in measurements of the speed at which the universe is expanding. However, a new paper by researchers at the University of Chicago and the Carnegie Institution for Science using data from the James Webb Space Telescope (JWST) suggests that there wasn’t any difference at all.

To understand this more, let’s first look at the Hubble tension. Edwin Hubble, the namesake of the Hubble Space Telescope, JWST’s predecessor, first found the universe was expanding when he looked at the speed at which galaxies travel. He found galaxies that were farther away from us were traveling faster than those nearest to us, and the best answer that we have as to why is that the universe itself is expanding.

It does not do so on a scale that we would notice in our daily lives, but on the scale of the space between galaxies, it is definitely noticeable, and in a number of ways. Historically, there have been two different ways to measure this Hubble Constant, as the rate of expansion is known. One involved studying the Cosmic Microwave Background (CMB), and one involved looking at the speed of galaxies, as Hubble did.

Fraser discusses JWST’s impact on the Hubble Tension before the newest paper was released

Data on the CMB have been consistent and precise for a long time. Studies have shown that it points to an expansion rate of 67.5 kilometers per second per megaparsec. To put that into perspective, the universe adds a little under an hour of highway drive time every second but does so on the scale of 3.2 million light years. Again, that expansion is not noticeable on our own scale, but on the immense scales of the universe, it is very noticeable.

However, calculations of that expansion value differ for the second method of measuring galaxies. Traditionally, the value is higher by about 9% and is estimated at 74 kilometers per second per megaparsec. That measurement is typically done using data from two different kinds of stars in those far and near galaxies – Cepheid variables and “Tip of the Red Giant Branch.” 

Dr. Wendy Freedman, one of the paper’s authors, is an expert in using Cepheid variables to measure the distance of things, so getting a chance to use JWST’s even more precise instrumentation was likely an excellent moment for her and her team. But they didn’t stop there. They added data from another type of star, whose use in calculating distance to an object has recently become more popular. Carbon stars are known for their consistent brightness and wavelengths in near-infrared – exactly the wavelengths JWST was designed to study. Using those known properties, the researchers could calculate redshift and other variables, allowing them to use this new technique to validate their version of the Hubble Constant.

Measuring distance is hard in astronomical terms, as Fraser discusses in this video.

The number they found was much closer to that calculated by the CMB method – 70 kilometers per second per megaparsec, a difference of only 3.5%. That’s within the bounds of estimations for most astronomical calculations, so the authors suggest there might not be a Tension between the two measurements. 

That claim will undoubtedly spark some controversy in the astronomical community, as there are some theories with plenty of proponents to explain the difference in measurements. But, as instruments like JWST provide more and more detailed data and researchers are better able to constrain some of the astronomically large values, one day, we might prove that this existential crisis that has been sitting at the center of cosmology for decades might never have been a thing at all.

Learn More:
University of Chicago – New Webb Telescope data suggests our model of the universe may hold up after all
Freedman et al. – Status Report on the Chicago-Carnegie Hubble Program (CCHP): Three Independent Astrophysical Determinations of the Hubble Constant Using the James Webb Space Telescope
UT – Astronomers Rule Out One Explanation for the Hubble Tension
UT – If Our Part of the Universe is Less Dense, Would That Explain the Hubble Tension?

Lead Image:
Scientists used new data taken by the James Webb Space Telescope to make a new reading of the rate at which the universe is expanding over time, by measuring light from 10 galaxies including the one known as NGC 3972, above.
Credit – Yuval Harpaz, data via JWST

The post Webb Relieves the Hubble Tension appeared first on Universe Today.

Meanwhile, in Dobrzyn, Hili and Szaron are preparing for a debate:

Szaron: What are you doing? Hili: I’m seeking the right position for further discussion.

Szaron: Co ty robisz?
Hili: Szukam właściwej pozycji do dalszej rozmowy.

Solar storms captured the imagination of much of the American public earlier this year when auroras were visible well south of their typical northern areas. As the Sun ramps into another solar cycle, those storms will become more and more common, and the dangers they present to Earth’s infrastructure will continue to increase. Currently, most of our early warning systems only give us a few minutes warning about a potentially destructive impending geomagnetic storm event. So a team of researchers from Sapienza University in Rome and the Italian Space Agency proposed a plan to sail a series of detectors to a point out in space where they could give us an early warning. And they want those detectors to stay on station without rockets.

The mission, known as Helianthus, the official name for a sunflower, was initially described at the 6th International Symposium on Space Sailing in June 2023. In a presentation, the Italian scientists explained the mission objective as providing different alarm levels for geomagnetic storms. But more importantly, the mission design would give humanity 100 minutes of warning for fast-moving solar storms, and a large solar sail would entirely control the mission.

Current warning times for solar storms are only a few minutes at best, as the detectors watching for them are located in Low Earth Orbit. To provide much earlier warning times, Helianthus would place a series of specially designed detectors at a point known as sub-L1 in the Sun/Earth system. While it’s unclear what exactly “sub-L1” means in this context, a typical Sun/Earth Lagrange point is about 1.5 million km toward the Sun—about four times as far away as the Moon is from Earth.

Fraser has a soft spot for solar sails, as he describes here.

Getting there using a solar sail is the hardest part of the Helianthus mission. Most solar sails use photons to push themselves outward in the solar system since the source of those photons is the Sun, which is, by definition, the inner part of the solar system. So, getting to a point closer to the Sun than the Earth and then staying there seems counterintuitive. 

How they will do so is the subject of one of a series of papers from the research team behind the project. Others describe the instrumentation, such as a lightweight coronograph and an x-ray spectrometer, and even structural components, such as the booms used to deploy the solar sails and the membranes those sails would be made of. 

Some of the most interesting research described in these papers shows how Helianthus would hold station at a sub-L1 point while still having its solar sail fully deployed. Instead of using rockets for station-keeping, the mission plans to use a series of electrochromic or liquid-crystal actuators to make approximately four station-keeping maneuvers a year. 

Solar sails have been a concept of awhile – Fraser explains what they do.

Driving the development of most of these systems and methodologies is an interest from the Italian Space Agency to improve workforce development in these areas. As stated in one of the papers, they intend to achieve “challenging national development” regarding solar-sail propulsion. And the geomagnetic storm tracker isn’t their only use-case – the same researchers also planned out an Earth-Mars transfer orbit that uses the same solar propulsion technology.

For now, it’s unclear whether Helianthus has the financial backing to make it to the finish line for actual deployment. While some prototypes of the lightweight instrumentation have been built, there is still a lot of engineering work to do before any such solar-sail mission sees the light of day. If it is to do so, the Italian Space Agency must show how committed they are to that idea.

Learn More:
Boni et al. – Structural response of Helianthus solar sail during attitude maneuvers
Vupetti et al. – ASI Project Helianthus: Solar-Photon Sailcraft for Geostorm Early Warning
UT – Solar Sails Could Reach Mars in Just 26 Days
UT – NASA’s New Solar Sail Has Launched and Will Soon Deploy

Lead Image:
An illustration of the Light Sail 2 craft with its solar sails deployed.
Image Credit: Josh Spradling / The Planetary Society

The post Project Helianthus – a Solar Sail Driven Geomagnetic Storm Tracker appeared first on Universe Today.

Researchers developed a new method known as flash-within-flash Joule heating (FWF) that could transform the synthesis of high-quality solid-state materials, offering a cleaner, faster and more sustainable manufacturing process.

Two scientists discovered a new type of 'whistler,' an electromagnetic wave that carries a substantial amount of lightning energy to the Earth's magnetosphere.

The World Health Organization has declared mpox a public health emergency of international concern – a new variant of the virus has caused an outbreak in Central and West Africa and spread to Sweden

Lightning strikes near Earth give rise to electromagnetic waves called “whistlers” that can carry energy high enough above our planet to pose a risk to satellites and astronauts

Mars rocks that were blasted off the surface of the Red Planet millions of years ago have been traced back to craters where they originated, which could transform our understanding of Mars’s volcanism and evolution

Researchers developed a novel reagent that enhances the precision of drug synthesis. This innovative method introduces a new sulfur fluoride exchange (SuFEx) reagent that allows for highly controlled production of crucial sulfur-based molecules, including sulfinamides, sulfonimidamides and sulfoximines.

There’s a link between Earth’s ocean salinity and its climate. Salinity can have a dramatic effect on the climate of any Earth-like planet orbiting a Sun-like star. But what about exoplanets around M-dwarfs?

Every planet has a measurable albedo, the percentage of starlight it reflects back into space. It’s measured on a scale from 0, which would be a black object that reflects no light, up to 1.00, an object that reflects all light. Since a higher albedo reflects more starlight, it has a cooling effect on an object’s climate. In our Solar System, Saturn’s moon Enceladus has the highest albedo. Enceladus is covered in bright, reflective ice that reflects most of the sunlight that reaches it. (Note that there are different measurements for albedo, and they can be quite different, leading to some confusion.)

Saturn’s moon, Enceladus, is covered in bright ice and is the most reflective object in the Solar System. Image Credit: NASA, ESA, JPL, SSI, Cassini Imaging Team

Mercury has the lowest albedo because it’s covered in mostly dark rock. (Objects like comets can have even lower albedos.)

Earth’s albedo is about 0.3, largely due to our planet’s cloudy atmosphere. The ice in Antarctica, Greenland and the seasonal pack ice in the Arctica also contribute. Earth’s albedo changes throughout the seasons as ice expands and recedes. In short, Earth’s albedo helps regulate the planet’s climate.

The ocean’s salinity levels affect how much sea ice forms and, in turn, affects Earth’s albedo. The more salt there is, the more the freezing point drops, making it harder for ice to form. Higher salinity means less ice, which means the albedo is lower and less sunlight is reflected back into space.

But how would ocean salinity affect exoplanets that orbit stars which are different from our Sun? That’s the question behind new research titled “Climatic Effects of Ocean Salinity on M Dwarf Exoplanets.” The lead author is Kyle Batra from the Department of Earth, Atmospheric, and Planetary Science at Purdue University. Batra is also a member of the NASA Network for Ocean Worlds Exo-oceanography Team.

M Dwarfs are also called red dwarfs, and their light is different from the Sun’s. Plenty of research has been done into ocean salinity and its overall effect on Earth’s climate. According to the authors, research is lacking when it comes to red dwarf exoplanets. “However, how ocean composition impacts climate under different conditions, such as around different types of stars or at different positions within the habitable zone, has not been investigated,” the authors write.

M dwarf exoplanets are particularly important when it comes to the study of exoplanets and their potential habitability. M dwarfs are low-mass stars that have extremely long, stable lifespans. That’s a benefit for potential habitability. M dwarfs are also the most plentiful type of star, so logic says they host the most rocky planets, and observations show us they host few gas giants.

The researchers worked with several key variables in their models, including how instellation changes over a star’s lifetime.

The researchers varied installation and salinity in their model and used the spectra from two well-known stars and two types of planetary oceans. Parameters not specified in this list are fixed at present-day Earth values. Image Credit: Batra et al. 2024

The researchers used an ocean-atmosphere general circulation model (GCM) to investigate how M dwarfs and G-type stars like our Sun respond to ocean salinity. The results show that stars like our Sun respond more dramatically to changes in ocean salinity. “We find that increasing ocean salinity from 20 to 100 g/kg in our model results in non-linear ice reduction and warming on G-star planets, sometimes causing abrupt transitions to different climate states,” they write.

Just as on the real Earth, the G-type star simulations showed that sea ice was restricted to high latitudes and that its coverage decreased as the salinity rose. Coverage went from 19.5% at 35 grams of salt per kg down to 3.5% at 100 grams per kg. That’s a sharp transition.

Transitions were less abrupt on M dwarfs. “Conversely, sea ice on M-dwarf planets responds more gradually and linearly to increasing salinity,” they write.

This figure from the research sums up the effect that ocean salinity has on sea ice. Image Credit: Batra et al. 2024

The researchers also determined how salinity and ice cover affected surface temperatures. On Earth, the average surface temperature rose from 8 Celsius to 14 C as salinity increased from 35 to 100 grams/kg. M-dwarf planets didn’t show a similar rise in surface temperature.

“Moreover, reductions in sea ice on M-dwarf planets are not accompanied by significant surface warming as on G-star planets,” they explain.

Planets in habitable zones around M-dwarfs share another characteristic. Since the habitable zone around an M-dwarf is so much closer to the star than around a Sun-like star, many of the planets are expected to be tidally locked. That affects everything about their climates.

“In this scenario, sea ice is even less coupled to planetary albedo than in our simulations with Earth-like rotation because the ice on the night side would not interact with incoming radiation,” the authors explain.

In a tidally locked scenario, oceanic and atmospheric mixing has more dynamic variables. “Under different rotation and circulation regimes, the climate sensitivity to salinity may, therefore, differ,” the researchers explain. They leave it to future research to investigate those scenarios.

These results are very interesting, but unfortunately, an opportunity to test them against observations won’t arise any time soon because we can’t remotely sense ocean salinity. In fact, we’re not even certain that what seem like exoplanets with oceans do, in fact, have oceans. But at least this work shows what effect ocean salinity can have on the plentiful rocky planets that orbit the galaxy’s M-dwarfs.

“This is an encouraging result that suggests uncertainties regarding exo-ocean salinity are less of a concern for understanding the climates and habitability of M-dwarf planets compared to G-star planets,” they conclude.

The post Ocean Salinity Affects Earth’s Climate. How About on Exoplanets? appeared first on Universe Today.

The asteroid that led to the extinction of the dinosaurs 66 million years ago probably came from the outer solar system.

Although I’m staying away from most of the news, i do follow the election news, and am aware of how Harris has befuddled Trump as Democrats, enthusiastic for a candidate who’s mediocre at best, have taken Harris above the Orange Man in the polls.

As always, I emphasize that I’m a never-Trumper, but I’m probably a not-Harriser, either, as I may vote for a third candidate, or not vote at all, since my state will go Democratic anyway. I also note that Harris is completely avoiding press conferences and interviews, since she’s not at all good on thinking on her feet or speaking intelligibly on the issues. I am baffled for the tremendous Democratic enthusiasm for Harris, but I guess I can understand it as it gives us a way to avoid Trump, who looked as if he was going to win.

But I argue that Harris, despite her promise, did not earn the nomination but simply inherited it, and I’m sad that the person likely to be chosen leader of our country is someone without the smarts and savvy of someone like Gretchen Whitmer, my previous favorite. (n.b. please do not tell me that I MUST vote as doing so won’t help the Democrats, and I will look askance at claims that Kamala Harris is the greatest thing since sliced bread.)

Now that I’ve gotten that off my chest, here are three items I’ve stolen from Nellie Bowles’s weekly news summary at The Free Press, called this week “TGIF: the RayGun goes off.”

→ Kamala is up big: Another week in which Kamala Harris does some high-energy rallies. . . and not much else. The Democratic nominee has so far given no interviews, no press conferences, and is just generally keeping it light on details like, say, how she plans to run the country. And it’s working. The voters are warming to Kamala—or at least the loosely reality-based version of Kamala Harris being put forward by a pliant press. According to The Cook Political Report, Harris now leads or ties Trump in all but one of the seven battleground states. The latest national Emerson poll puts Harris four points ahead on 50 percent to Trump’s 46 percent. Nate Silver’s magic election machine also has Harris ahead, as do the betting markets. Remember how a few months ago every expert and political insider insisted that an obviously over-the-hill Joe Biden was a better candidate than Harris? Or that Biden alone could beat Trump? Me neither.

I am but a passenger in the vibes election. And I am dangerously close to putting in a bet on Kamala.

I’d bet on her winning, at least at this stage of the election. But et’s wait until the candidates debate each other and give interviews and press conferences.

→ Oi, mate, be nice or else! I have some British colleagues and they’re all really nice. Polite, considerate, good manners, hard workers, never cry in public, only slightly concerning drinking habits. Anyway recent headlines out of Blighty have me wondering: Is that just because it’s actually illegal to be a dick over there? After some ugly anti-immigrant riots in the UK, in which real-life people tried to do real-life harm to other real-life people, the big takeaway from the powers that be is that people who are mean on the internet should be put in jail. “Think before you post,” warned prosecutors. Director of Public Prosecutions Stephen Parkinson told Brits: “You may be committing a crime if you repost, repeat or amplify a message which is false, threatening, or stirs up racial / religious hatred.” And one of Britain’s police chiefs even threatened to extradite U.S. citizens who break Britain’s censorship laws—to which the only reasonable response is a big, fat, American middle finger. I can think of no more just war than refighting the American War of Independence, only this time over busybody speech codes and our right to say crazy shit online rather than a tax on tea. Hand me my musket, and fire up Facebook. We’re taking no prisoners.

→ Goodbye, weird kid sports: The Algerian boxer Imane Khelif’s gold medal win highlighted how the IOC is rather squirrely about how they separate the sexes in sports. Is it by what’s listed on your passport? Your testosterone level? What’s coded into your DNA? Whether or not you’re good at math? Who knows! But let’s get real: The Olympics have been playing fast and loose with their standards for quite a while. Skateboarding, speed climbing, BMX racing, and—the newest, dumbest addition—breakdancing all featured as Olympic sports in Paris. I’m not saying these activities don’t require athletic prowess; I’m just saying if the uniform is cargo pants and a sideways hat then maybe it should be part of a different competition than the one Simone Biles participates in. This year, the Australian breakdancer Rachael Gunn, a.k.a. RayGun, participated in the competition, earning herself exactly zero points for her wild display on the break floor. She has a PhD in cultural studies and her thesis was on “Deterritorializing gender in Sydney’s breakdancing scene: A B-girl’s experience of B-boying,” and oh, it showed. After being roundly ridiculed online for her performance Gunn shared the quote, “Don’t be afraid to be different, go out there and represent yourself, you never know where that’s gonna take you.” But sometimes you know exactly where you’re going, like if you sign up for the Olympics as a breakdancer. I commend Raygun for participating and answering the question we all ask ourselves when we watch the Olympics, which is, “I wonder how I would stack up.” Now we know. Breakdancing, and the modern pentathlon that apparently involved laser pistols, will mercifully not be a part of L.A.’s 2028 program.

Okay, one more from Nellie (see also this link from reader Ginger K.):

→ I love my quaint hometown: A referendum in Pittsburgh that would cut all ties with Israel is moving through the legislative process. If it makes it to the ballot, voters will get to choose whether the city charter will be amended to bar “investment or allocation of public funds, including tax exemptions, to entities that conduct business operations with or in the state of Israel.” This is like BDS on crack. If it were to pass, the lights in the city would go out (since we couldn’t do business with Duquesne Light because they do business with Israel) and there would be no more Narcan, a drug manufactured by an Israeli company. Also: There would be no fuel for the city vehicles like patrol cars, nor any vehicles at all, since oil and gas companies and car companies do business with the Jewish state. This sounds like a really promising initiative that will make life in Pittsburgh—a key stakeholder in the war in Gaza—better for all. Also, shout-out to the brave highway blockers in L.A.! If they adopted the Pittsburgh measure, though, they could just take the ambulances away instead of blocking them.

.  .  . and that’s the way it is.

The dramatic dimming of a light source ~ 870 million light years away from Earth confirms the accuracy of a detailed model.

Today, many commercial tools claim to be highly successful at detecting machine-generated text, with up to 99% accuracy, but are these claims too good to be true? RAID, the Robust AI Detection benchmark, which shows that most detectors are easily fooled, setting a new bar for AI detection to clear.

A groundbreaking technology has been unveiled that improves the efficiency of thermoelectric materials, which are key in converting waste heat into electricity, by altering their geometry to resemble an hourglass. Unlike previous research that solely depended on the material properties of thermoelectric substances, this new approach is expected to have widespread applications in thermoelectric power generation.

A new study assessed the feasibility of recovering phosphorus from municipal wastewater as an alternative sustainable source of this non-renewable mineral.

Microscope images could be obtained much more quickly -- rather than one pixel at a time -- thanks to a new imaging method for neutral atomic beam microscopes. It could ultimately lead to engineers and scientists getting faster results when they are scanning samples.

Microscope images could be obtained much more quickly -- rather than one pixel at a time -- thanks to a new imaging method for neutral atomic beam microscopes. It could ultimately lead to engineers and scientists getting faster results when they are scanning samples.

New research using a decommissioned section of the beam pipe from the Large Hadron Collider (LHC) at CERN has bought scientists closer than ever before to test whether magnetic monopoles exist. Scientists have revealed the most stringent constraints yet on the existence of magnetic monopoles, pushing the boundaries of what is known about these elusive particles.

Researchers have found a better method to recycle polyurethane foam from items like mattresses: They are not only able to break down PUR and separate the two main components -- they can do it in one go. This is great news for the budding industry that aims to chemically recover the original components of the material -- making their products cheaper and better.