About half a century ago, astronomers theorized that the Solar System is situated in a low-density hot gas environment. This hot gas emits soft X-rays that displace the dust in the local interstellar medium (ISM), creating what is known as the Local Hot Bubble (LHB). This theory arose to explain the ubiquitous soft X-ray background (below 0.2 keV) and the lack of dust in our cosmic neighborhood. This theory has faced some challenges over the years, including the discovery that solar wind and neutral atoms interact with the heliosphere, leading to similar emissions of soft X-rays.
Thanks to new research by an international team of scientists led by the Max Planck Institute for Extraterrestrial Physics (MPE), we now have a 3D model of the hot gas in the Solar System’s neighborhood. Using data obtained by the eROSITA All-Sky Survey (eRASS1), they detected large-scale temperature differences in the LHBT that indicate that the LHB must exist, and both it and solar wind interaction contribute to the soft X-ray background. They also revealed an interstellar tunnel that could possibly link the LHB to a larger “superbubble.”
The research was led by Michael C. H. Yeung, a PhD student at the MPE who specializes in the study of high-energy astrophysics. He was joined by colleagues from the MPE, the INAF-Osservatorio Astronomico di Brera, the University of Science and Technology of China, and the Dr. Karl Remeis Observatory. The paper that details their findings, “The SRG/eROSITA diffuse soft X-ray background,” was published on October 29th, 2024, by the journal Astronomy & Astrophysics.
This image shows half of the X-ray sky projected onto a circle with the center of the Milky Way on the left and the galactic plane running horizontally. Credit ©: MPE/J. Sanders/eROSITA consortiumThe eROSITA telescope was launched in 2019 as part of the Russian–German Spektr-RG space observatory. It is the first X-ray observatory to observe the Universe beyond Earth’s geocorona, the outermost region of the Earth’s atmosphere (aka. the exosphere), to avoid contamination by the latter’s high-ultraviolet light. In addition, the eROSITA All-Sky Survey (eRASS1) was timed to coincide with the solar minimum, thus reducing contamination by solar wind charge exchanges.
For their study, the team combined data from the eRASS1 with data from eROSITA’s predecessor, the X-ray telescope ROSAT (short for Röntgensatellit). Also built by the MPE, this telescope complements the eROSITA spectra by detecting X-rays with energies lower than 0.2 keV. The team focused on the LHB located in the western Galactic hemisphere, dividing it into about 2000 regions and analyzing the spectra from each. Their analysis showed a clear temperature difference between the parts of the LHB oriented towards Galactic South (0.12 keV; 1.4 MK) and Galactic North (0.10 keV; 1.2 MK).
According to the authors, this difference could have been caused by supernova explosions that expanded and reheated the Galactic South portion of the LHB in the past few million years. Yeung explained in an MPE press release: “In other words, the eRASS1 data released to the public this year provides the cleanest view of the X-ray sky to date, making it the perfect instrument for studying the LHB.”
In addition to obtaining temperature data from the diffuse X-ray background spectra information, the combined data also provided a 3D structure of the hot gas. In a previous study, Yeung and his colleagues examined eRASS1 spectra data from almost all directions in the western Galactic hemisphere. They concluded that the density of the hot gas in the LHB is relatively uniform. Relying on this previous work, the team generated a new 3D model of the LHB from the measured intensity of X-ray emissions.
A 3D interactive view of the LHB and the solar neighborhood, Credit: MPEThis model shows that the LHB extends farther toward the Galactic poles than expected since the hot gas tends to follow the path of least resistance (away from the Galactic disc). Michael Freyberg, a core author of this work, was a part of the pioneering work in the ROSAT era three decades ago. As he explained:
“This is not surprising, as was already found by the ROSAT survey. What we didn’t know was the existence of an interstellar tunnel towards Centaurus, which carves a gap in the cooler interstellar medium (ISM). This region stands out in stark relief thanks to the much-improved sensitivity of eROSITA and a vastly different surveying strategy compared to ROSAT.”
These latest results suggest the Centaurus tunnel may be a local example of a wider hot ISM network sustained by supernovae and solar wind-ISM interaction across the Galaxy. While astronomers have theorized the existence of the Centaurus tunnel since the 1970s, it has remained difficult to prove until now. The team also compiled a list of known supernova remnants, superbubbles, and dust and used these to create a 3D model of the Solar System’s surroundings. The new model allows astronomers to better understand the key features in the representation.
These include the Canis Major tunnel, which may connect the LHB to the Gum Nebula (the red globe) or the long grey superbubble (GSH238+00+09). Dense molecular clouds, represented in orange, are shown near the surface of the LHB in the direction of the Galactic Center (GC). Recent work suggests these clouds are moving away from the Solar System and likely formed from the condensation of materials swept up during the early formation of the LHB. Said Gabriele Ponti, a co-author of this work:
“Another interesting fact is that the Sun must have entered the LHB a few million years ago, a short time compared to the age of the Sun. It is purely coincidental that the Sun seems to occupy a relatively central position in the LHB as we continuously move through the Milky Way.”
Further Reading: MPE, Astronomy & Astrophysics
The post eROSITA All-Sky Survey Takes the Local Hot Bubble’s Temperature appeared first on Universe Today.
In his new book Abortion in the Age of Unreason: A Doctor’s Account of Caring for Women Before and After Roe v. Wade, a nationally prominent doctor reports the daily challenges of offering and receiving abortion services in a volatile political and social atmosphere. In stories from the front lines–from protecting patients and staff from protesters’ attacks to the dangers to women of restricted access to abortion services, and the pertinent findings of his remote research in Latin America, Hern’s book is strikingly detailed just as it exposes the needs of women and the U.S. national interest. Dr. Hern–an abortion specialist, researcher, scholar, and highly visible public advocate – shows how abortion saves women’s lives given the many risks that arise during pregnancy, more than most people realize. He points to political and national solutions to reverse a reawakened crisis that now threatens democracy. Throughout the book, Dr. Hern shows how the current emergency was largely created by political actors who have exploited and distorted the abortion issue to increase and consolidate their power.
A vital component of women’s health care, the crisis over abortion is not new. Yet the reversal of Roe v. Wade and the steady accumulation of power by America’s right wing has put the issue at a level of urgency and national prominence not seen since the days before legalization. Women’s need for safe abortion services will continue as the struggle to secure their rights intensifies.
Warren M. Hern, M.D., is known to the public through his many appearances on CNN, Rachel Maddow/MSNBC, Sixty Minutes, and in the pages of The Atlantic magazine, The New York Times, Washington Post, and dozens more media. A scientist, Hern wrote about the need for safe abortion services before the 1973 Roe v. Wade decision and was present at the first Supreme Court arguments. In his research and medical work, he pioneered since 1973 the modern safe practice of early and late abortion in his highly influential books and scholarship. A tireless national activist for women’s reproductive rights, he is an adjunct professor of anthropology at the University of Colorado, Boulder, and holds a clinical appointment in obstetrics and gynecology at the University of Colorado medical center. He holds doctorates in medicine and epidemiology. His book is Abortion in the Age of Unreason: A Doctor’s Account of Caring for Women Before and After Roe v. Wade.
Shermer and Hern discuss:
Why women get abortions—2013 study “Understanding Why Women Seek Abortions in the US” (BMC Women’s Health Antonia Biggs, Heather Gould, Diana Greene Foster):
The top three reason categories cited in both studies were: 1) “Having a baby would dramatically change my life” (i.e., interfere with education, employment and ability to take care of existing children and other dependents) (74% in 2004 and 78% in 1987), 2) “I can’t afford a baby now” (e.g., unmarried, student, can’t afford childcare or basic needs) (73% in 2004 and 69% in 1987), and 3) “I don’t want to be a single mother or am having relationship problems” (48% in 2004 and 52% in 1987). A sizeable proportion of women in 2004 and 1987 also reported having completed their childbearing (38% and 28%), not being ready for a/another child (32% and 36%), and not wanting people to know they had sex or became pregnant (25% and 33%)
What about medical problems with the woman or the fetus? Lozier Institute 2024 study:
Worldwide (Guttmacher Institute):
Americans’ Self-ID on Abortion, 2024 (Gallup):
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To end, the week, we have some stunning videos from BBC Earth and other places, depicting the migratory behavior of the red crabs of Christmas Island, a small Australian territory (135 km², pop. 1692 ) near Indonesia: encircled below. Their vernacular name is The Christmas Island red crab, the Latin binomial is Gecarcoidea natalis, and they are endemic to that island and the Cocos (Keeling) Islands in the Indian Ocean.
TUBS, CC BY-SA 3.0, via Wikimedia CommonsThe life cycle of this crustacean is described here, but the videos are more impressive. Here are the basic facts:
The migration starts with the first rainfall of the wet season. This is usually in October or November, but can sometimes be as late as December or January.
Red crabs all over the island leave their homes at the same time and start marching towards the ocean to mate and spawn. Male crabs lead the migration and are joined by females along the way.
The exact timing and speed of the migration is determined by the phase of the moon. Red crabs always spawn before dawn on a receding high-tide during the last quarter of the moon. Incredibly, they know exactly when to leave their burrows to make this lunar date.
However, because crabs wait until the first rainfall to start their trek, they sometimes have to hurry. If the rains arrive close to the optimal spawning date, they will move rapidly. But if the rain comes early they may take their time, stopping to eat and drink on their way to the coast.
If it begins raining too late to make the spawning date, some crabs will stay in their burrows and migrate the following month instead.
And from BBC Earth, narrated by Attenborough. Note that the crabs breathe through gills, which must be kept moist. They live on land, but in moist habitats, but a remnant of their evolutionary origin is their need to go back to the ocean to spawn. Note that they walk sideways.
Note that they mate during the migration, too, so it’s not just females who are drawn to the sea at this time. A similar video, but also showing one of their predators and some of the other dangers they face.
I especially like this video because it shows how the island’s human inhabitants care for and protect the crabs:
After Trump won the election, Laura Helmuth, editor-in-chief of Scientific American, went ballistic on BlueSky (Twitter for progressives). She issued the three posts below, decrying her generation for being “fucking fascists” and telling some of her high-school classmates to “fuck them to the moon and back” (note to editor: “moon” is usually capitalized).
I have to say that this sounds a bit like Helmuth was a bit tipsy, but I won’t blame alcohol for this. After all, if you’re drunk, you’d better stay away from social media! I wrote about these “tweets”, and about Scientific American‘s “progressive” editorial slant, in a piece I posted yesterday. (This is part of a long series of posts I’ve done about her and the magazine.)
At any rate, after what must have been a bunch of pushback, and perhaps realizing that her job was in jeopardy, Helmuth issued an abject response yesterday, to wit:
After making a series of fiercely ideological and political statements on social media in the wake of Trump’s win and being pilloried for doing so, @SciAm editor in chief Laura Helmuth is now back pedaling. She claims she is committed to editorial objectivity. pic.twitter.com/qwTsaiyKLE
— Benjamin Ryan (@benryanwriter) November 7, 2024
Well, I’m trying to be more charitable these days, striving to put myself in my opponents’ shoes and imputing to them the best motives I can think of, but I couldn’t do it this time. And that’s because Helmuth has left a paper trail during her editorship—a paper trail of progressive leftism and wokeness that has demonized many people (including Mendel!) as racists and bigots. Thus I’m not convinced by her assertion that she “respects and values people across the political spectrum.” No, she seems to despise people on the right, and that’s what came out in her first set of tweets above.
Further, what is the “mistake” here? She’s is the editor of a major magazine, for crying out loud, and should know how to control herself. “Shock and confusion” doesn’t, at least to me, excuse her behavior. “Shock,” perhaps, but what is she “confused” about?
Her statement that her unhinged tweets “do not reflect the position of Scientific American or my colleagues,” really means, of course, “Please don’t fire me! I’ll be a good girl from now on,” I doubt, however, that her bosses at Springer really care about her eroding reputation. They probably care more about the bottom line, and I have no idea how the magazine is doing.
The sentence that irked me the most is “I am committed to civil communication and editorial objectivity.” Indeed! The whole magazine has violated both tenets for years. It gave Michael Shermer a pink slip for simply questioning accepted (woke) wisdom in his column, and couldn’t wait to accuse E. O. Wilson of racism, nearly before his body had gone cold. The many biased and slanted columns do not bespeak Helmuth’s commitment to objectivity, and here’s one example that I mentioned yesterday.
After the magazine published its hit piece on E. O. Wilson, accusing him (as well as Mendel and others) of racism, thirty evolutionary biologists and I cobbled together a letter to Scientific American, rebutting the hit piece’s claims and defending Wilson and his legacy (you can see the letter here). Helmuth rejected the letter. She also rejected my personal appeal to “consider an op-ed about how extreme Leftist progressivism is besmirching science itself by distorting the truth? (Example: arguments that sex is not bimodal in humans, but forms a continuum.) I could make a number of arguments like that about biology that, contra McLemore, have truth behind them.” That letter didn’t fly, but Luana Maroja and I turned the idea into a paper for Skeptical Inquirer.
So much for Helmuth’s editorial objectivity!
Unfortunately, the readers are almost unanimously unimpressed by the apology. Go see for yourself, but I’ll put up a few screenshots of responses:
The dividing line between stars and planets is that stars have enough mass to fuse hydrogen into helium to produce their own light, while planets aren’t massive enough to produce core fusion. It’s generally a good way to divide them, except for brown dwarfs. These are bodies with a mass of about 15–80 Jupiters, so they are large enough to fuse deuterium but can’t generate helium. Another way to distinguish planets and stars is how they form. Stars form by the gravitational collapse of gas and dust within a molecular cloud, which allows them to gather mass on a short cosmic timescale. Planets, on the other hand, form by the gradual accumulation of gas and dust within the accretion disk of a young star. But again, that line becomes fuzzy for brown dwarfs.
The problem arises in that, if brown dwarfs form within a molecular cloud like stars, they aren’t massive enough to form quickly. If a cloud of gas and dust has enough mass to collapse under its own weight, it has enough mass to form a full star. But if brown dwarfs form like planets, they would have to accumulate mass incredibly quickly. Simulations of planet formation show it is difficult for a planet to form with a mass of more than a few Jupiters. So what gives? The answer may lie in what are known as Jupiter-mass binary objects, or JuMBOs.
The Orion nebula is a stellar nursery. Credit: NASA, ESA, M. RobbertoJuMBOs are binary objects where each component has a mass between 0.7 and 13 Jupiter masses. If they form like planets, they should be extremely rare, and if they form like binary stars, they should have more mass. Recent observations by the JWST of the Orion nebula cluster discovered 540 free-floating Jupiter mass objects, so-called rogue planets. This was surprising in and of itself, but more surprising was the fact that 42 of them were JuMBOs. Far from being rare, they make up nearly 8% of these rogue objects. So how do they form?
One clue lies in their orbital separation. The components of JuMBOs are most commonly separated by a distance of 28–384 AU. This is similar to that of binary stars with components around the mass of the Sun, which typically are in a range of 50–300 AU. Binary stars are extremely common. More common than single stars like the Sun. The environment of stellar nurseries, such as the Orion nebula, is also extremely intense. Massive stars that form first can blast nearby regions with ionizing radiation. Given how common JuMBOs are, it is likely they began as binary stars, only to have much of their masses blasted away by photo-erosion. Rather than being binary planets, they are the failed remnants of binary stars.
This could also explain why so many rogue planets have super-Jupiter masses. The same intense light that would cause photo-erosion would also tend to push them out of star systems.
Reference: Diamond, Jessica L., and Richard J. Parker. “Formation of Jupiter-Mass Binary Objects through photoerosion of fragmenting cores.” The Astrophysical Journal 975.2 (2024): 204.
The post An Explanation for Rogue Planets. They Were Eroded Down by Hot Stars appeared first on Universe Today.
In 2013, the Food and Agriculture Organization of the United Nations published a report titled Edible Insects: Future Prospects of Insects as Food and Feed.1 Despite being downloaded over seven million times and receiving widespread publicity, the report did not generate much controversy. This was likely because the consumption of insects was seen as an unfamiliar practice associated with developing countries in the tropics, and the idea of incorporating bugs into Western diets was just not taken seriously. However, that perception has been changing recently. Several edible insect products have been declared safe by international and national food safety organizations in Western countries. In response, critical coverage has emerged on social media, claiming that edible insects pose a threat to public health and even to national identities.
Here are a few examples of how some politicians and journalists reacted to the legalization of insects as food:
This aversion has been connected to conspiratorial claims about a shadowy global elite that aims to control the world’s population. The World Economic Forum (Davos) has been singled out, with claims that elites such as heads of state and business leaders want people to eat bugs instead of meat to combat food insecurity.7
The main narratives surrounding these claims include:
Is there any truth to such allegations? These claims are largely false. Since 2021, several insect products have been approved in the European Union as safe for human consumption,9 but there is no mandate forcing citizens to eat them. The safety of these products is ensured through rigorous testing by food safety organizations. Additionally, the move towards including insects in the food supply is motivated by concerns about sustainability and food security, rather than by sanctions against Russia. So, why is there such significant resistance to eating insects?
Why are we reluctant to accept insects as food?The numerous statements by politicians and journalists quoted above, and similar sentiments shared by the public, are primarily rooted10 in two underlying reasons:
Although these are closely related, disgust is the more significant barrier to acceptance of insect consumption. Food neophobia can be mitigated with information about the food item’s nutritional value, safety, and sustainability. Disgust is harder to overcome as it is based on emotion rather than rationality.11 A related reason why insects are not commonly eaten in the Western world is their association with dirt, death, disease, and contamination.
Food Safety and Nutritional ValueThe assumption by Westerners that insects cannot be eaten and are merely survival food in tropical countries is more of a bias than a fact. In tropical regions, over 1,500 insect species are consumed because the local population considers them nutritious, tasty, and easy to procure, rather than solely due to low living standards. In North America and Europe, insects have not been a customary food item primarily because they are not available in sufficient quantities to be considered food. In contrast, in tropical regions, larger insects are available year-round and can be easily harvested due to their tendency to occur in clumped distributions. Insects do occasionally appear in large numbers in temperate zones—for example, in the U.S., the 2024 simultaneous emergence of 13- and 17-year cycle cicadas, which happens only once every 221 years, sparked interest in using them as food.12 Historically, until the mid-1900s insects such as cockchafers were both a common pest and a delicacy in France and Germany.13
To make edible insects available in Western markets, they need to be reared under controlled conditions on farms. For human consumption, species such as mealworms, crickets, and locusts are used, while fly species such as the black soldier fly are used for animal feed because they can be reared on various organic side streams. And there’s an additional benefit: with 30 percent of food and agricultural produce going to waste,14 using these fly species could contribute to a self-sustaining economy. The market for edible insects as animal feed is expected to grow from about $7 billion in 2023 to $116 billion by 2033.15 This growth is being driven by the increasing prices for conventional feed ingredients such as fishmeal and soybean meal, whose sustainability is in question.16 Most insect-based ingredients are used as feed for animals (pets, fish, chickens, and pigs), while insects for human consumption remain a niche market, expected to grow from $650 million in 2023 to over $1 billion by 2033.17
Conspiracy TheoriesConspiracy theories often highlight the perceived food safety risks associated with consuming insects. The European Union requires that any insect intended for food first must be screened by the European Food Safety Authority (EFSA). This rigorous process takes considerable time and thoroughly evaluates all aspects of food safety. While several insect products have been approved, they carry a warning regarding allergies. Individuals allergic to seafood or house dust mites should be cautious due to potential cross-reactivity, as these groups are taxonomically similar to insects. Consequently, this risk must be shown on the product label, along with a clear statement that the product contains insects.
Conspiracy theories also mention the alleged danger of consuming chitin, the material composing the exoskeleton of insects. Chitin can be present in food products containing whole insects, as the processing methods—decontamination, drying, and grinding—do not remove it. However, when insect protein (meal) is used, it is often separated from fats and chitin. Even when chitin is present, it is unlikely to be harmful and may even offer health benefits.18, 19 Insect products are rich in antioxidants and essential minerals such as zinc and iron, which are often deficient in large segments of the human population, and can cause conditions such as anemia.
It is challenging to provide general numbers regarding nutritional value of insects, because they depend on various factors such as the insects’ diet and other biotic and abiotic elements. However, insect products are generally as nutritious as, or even more nutritious than, meat products.20
Are insects the future of food?There are many misconceptions about the use of edible insects, often reinforced by negative associations. Insects provide crucial ecosystem services, such as pollination, valued at over 150 billion U.S. dollars—10 percent of the value of global agricultural production for human consumption.21 Additionally, insects play important roles as decomposers and in the biocontrol of agricultural pests. Many bird species, including chickens, as well as various fish species, naturally consume insects. Non-human primates also eat insects, as do hundreds of millions of people worldwide in tropical regions.22
The publication of the 2013 edition of the Food and Agriculture Organization’s Statistical Yearbook triggered enormous publicity by highlighting the environmental benefits, nutritional value, and safety of using insects as food and feed. This coincided with increasing awareness that changes in our food habits were necessary. Eighty percent of all agricultural land worldwide is used to produce dairy and meat products.23 It is estimated that this land area will not be enough to satisfy the increasing demand for these products due to the growing world population and improving living standards. Additionally, the environmental impact of meat and dairy production is substantial, accounting for about 15 percent of all greenhouse gas emissions and almost two-thirds of all ammonia emissions.24 Water and land use requirements are also very high. Farming edible insects is environmentally better on all fronts, while their nutritional values are similar to those of conventional meats.25
The idea of eating insects is gradually gaining traction in Western countries. Strategies such as targeting more adventurous eaters, incorporating insect ingredients into familiar products, and providing information about food safety, nutrition, and sustainability may help shift public perception and gradually convince more people that insects deserve a place on the menu.26
Resistance to this new food is not unexpected, given that insects have never been considered a regular food ingredient in the West. But if insect products are proven to be safe, nutritious, tasty, and more sustainable than meat, perhaps we should reconsider our food habits?
About the AuthorArnold van Huis is a Professor Emeritus of Tropical Entomology at Wageningen University & Research in the Netherlands. From 1974 to 1979, he worked for the Food and Agriculture Organization of the United Nations (FAO) in Nicaragua. He is the author of over 300 scientific papers and co-author of The Insect Cookbook: Food for a Sustainable Planet (Columbia University Press). In 2014, together with FAO, he organized the first conference, Insects to Feed the World, attended by 450 participants from 45 countries. He is the chief editor of the Journal of Insects as Food and Feed.
References