The fabric of spacetime is roiling with vibrating quantum fields, known as the vacuum energy. It’s right there, everywhere we look. Could we ever get anything out of it?
We can even calculate the strength of this vacuum energy. When we apply the rules of quantum mechanics to determine how much the fields vibrate in isolation, we get…infinity. That’s right, there’s an infinite amount of energy filling every bit of spacetime. That’s because there’s no limit to the amount of vibrations that these fields can have. Small vibrations, medium vibrations, and big vibrations are all happening in every quantum field simultaneously.
Wait, wait…how can the fields have infinite energy but still have more energy to produce particles? To answer this question we can turn to a clever experiment designed by the Dutch physicist Hendrik Casimir.
If you take two metal plates and stick them really, really close together, the quantum fields between those plates must behave in a certain way. The wavelengths of their vibrations must fit perfectly between the plates, just like the vibrations on a guitar string have to fit their wavelengths to the length of the string. In the quantum case, there are still an infinite number of vibrations between the plates, but there are not as many infinite vibrations between the plates as there are outside the plates.
Using some clever bits of mathematics, we can subtract the two kinds of infinities and arrive at a finite number. This means that there really are more quantum vibrations outside the two plates than there are inside the place. This leads to the conclusion that the quantum fields outside the plates push the two plates together, something called the Casimir effect. We can measure this effect and verify that the quantum fields actually do exist.
All this theory and experiment results in a startling conclusion. All the physics of the world, every interaction, every process, and action, takes place on a stage filled with an infinite amount of vacuum energy. As weird as this picture is, it’s the result of decades of investigation into quantum theory.
Right now, we have no way of accessing this energy and doing anything useful with it. That’s because it is the lowest energy state of the universe. To get work done, you have to have differences in energy, you need to pull energy from one place, transform it, and put it somewhere else. We can’t pull from the vacuum energy because there’s nowhere lower for the vacuum energy to go. It’s like trying to get an elevator to go beyond the lowest level in a building – it stops at the ground floor because there are no more floors beneath it.
When it comes to the Casimir effect, we had to put energy into the system to arrange the plates together in the first place. When the plates start moving, we’re simply getting back the energy that we put in, with no net gain of energy production.
There are many ideas in the science fiction universe that propose using vacuum energy to power a starship or other advanced kind of propulsion. While those ideas run counter to established physics, we must admit that we do not fully understand all of physics…especially the vacuum energy. The biggest clue that we’re doing something wrong has to do not with subatomic scales, but with cosmic.
In the late 1990’s astronomers discovered that the expansion of the universe is accelerating. The simplest explanation for this accelerated expansion is the vacuum energy of the universe. But because we can measure the expansion rate, we can use that to estimate the total amount of vacuum energy, and we get around 6 x 10^-10 Jules in every cubic meter of space.
That’s…not infinity. So we have a problem. On one hand, we have a set of subatomic calculations, predictions, and measurements that tell us that there’s an infinite amount of vacuum energy. On the other hand, we have a cosmic measurement that tells us that the amount of vacuum energy is really, really small.
What’s going on? We have no idea. It’s one of the greatest unsolved problems in modern physics. If we want to find a way to exploit the vacuum energy, then first we have to understand what it truly is. Whatever we find there will involve new kinds of physics, and who knows what new physics will unlock for us.
The post Could We Ever Harness Quantum Vacuum Energy? appeared first on Universe Today.
Comet Tsuchinshan-ATLAS may be one to watch for at dawn late next month.
If predictions and prognostications hold true, a decent comet could grace dawn skies in late September into early October. We’re talking about Comet C/2023 A3 Tsuchinshan-ATLAS, discovered early last year. Early signs suggest it could be the best comet of 2024… if it survives until perihelion.
The DiscoveryThe comet was discovered jointly by the Tsuchinshan (Purple Mountain) observatory in China and the ATLAS (Asteroid Terrestrial-impact Last Alert System) sky survey on January 9th, 2023. Later ‘pre-discovery’ images date back to 2022. The comet was discovered 7.2 Astronomical Units (AU) out in the outer solar system, beyond the orbit of Jupiter. This always a good sign in terms of how the comet will behave on approach.
The orbit of Comet Tsuchinshan-ATLAS. Credit: NASA/JPL.Early estimates put the orbital period for the comet at 80,000 years. Later refinements on the orbit now puts it at millions of years, possibly due for ejection post perihelion. This means that C/2023 A3 Tsuchinshan-ATLAS is likely a first-time visitor from the Oort Cloud, and should be dynamically new. This another plus and always a good thing in terms of activity.
Following the Comet Through FallThe path of the comet seems to hang stationary in the constellation Sextans through September, as it is headed towards us as seen from our vantage point in space. The comet is on a high 139º inclination retrograde orbit about the Sun. Perihelion 0.39 AU from the Sun interior to the orbital aphelion distance of Mercury occurs on September 27th, and the closest Earth approach for the comet occurs on October 12th, at 0.472 AU (70.6 million kilometers) distant.
Southern hemisphere observers may get a short look at the comet starting in mid-September. The best show for folks up north begins in the last week of September into the first week of October, when the comet sits about 10 degrees above the eastern horizon in the dawn. The slim waning crescent Moon will pair with the comet on the mornings of September 30th and October 1st.
Looking to the southwest on the morning of October 1st. Credit: Starry Night.Said Moon is headed towards an annular solar eclipse on October 2nd. Lucky observers along the path crossing the southern tip of South America might just see the comet along with Venus during annular phases, if (a big ‘if’ to be sure) it exceeds expectations and reaches negative magnitudes.
The comet versus the October 2nd annular eclipse. Credit: Starry Night.We’ll also get a look at Comet Tsuchinshan-ATLAS courtesy of the joint solar observing SOHO mission, as it transits the LASCO C3 field of view from October 7th to the 10th. From there, the comet will transition to the evening sky in late October, as it fades back down into binocular visibility range and heads back out of the solar system, perhaps to never return again.
The comet versus SOHO’s LASCO C3 imager. Credit: Starry Night. Dazzle, or Fizzle?It has been a roller coaster ride for the comet in 2024. How bright will Comet Tsuchinshan-ATLAS be at perihelion? The comet seemed to be under-performing in terms of brightness in early 2024, suggesting a breakup and a ‘fizzle’ could be imminent. As of writing this, the comet is back up on the expected light curve at magnitude +8. Comets often neglect to read predictions, and can fail to measure up to expectations… we all remember ISON in 2013. On the plus side, remember F3 NEOWISE in 2020, which actually exceeded anticipations? One factor will aid the visibility of comet Tsuchinshan-ATLAS right around Earth approach: its brightness may be helped a bit by an effect known as forward scattering. And of course, all bets are off in terms of brightness in the event of a well-placed outburst.
“A3 (Tsuchinshan-ATLAS) is now sort of on the brightening line to get mostly as bright like predicted, although my own projection shows it peaking more like magnitude +4 to +5 because the trend line is a bit south of the optimum line…” astrophotographer Eliot Herman told Universe Today. “So it will not be (naked eye) visible at brightest, but…it will be a fine telescopic comet (or ‘camera comet’) kind of like P1 Nishimura. That is what I am thinking unless it shatters or splits. I think it is going to fall short of imagination, which is about the norm for comets.”
Here’s a Month-by-Month look at Comet Tsuchinshan-ATLAS:
September7-Flips over to the dawn sky
27-Reaches perihelion
28-Crosses into the constellation Leo
The projected and observed (black dots) light curve for Comet Tsuchinshan-ATLAS. Credit: Seiichi Yoshida’s Weekly Information About Bright Comets. October1-The waning crescent Moon sits 11º from the comet
2-The Comet is 18º from the Sun during an annular solar eclipse
4-Crosses into the constellation Virgo
7-Crosses into SOHO’s LASCO C3 field of view
8-Crosses the ecliptic plane northward
9-Passes 3º from the Sun
10-Exits SOHO’s LASCO C3 field of view
11-Flips over to the dusk sky
12-Passes closest to the Earth
14-Crosses the celestial equator northward, and makes an edge-on, orbital plane crossing
15-Photo-Op: Passes 1º from +9th magnitude Comet 13 Olbers
15-Crosses into the constellation Serpens Caput
16-Passes just over 1º from the globular cluster Messier 5
19-Crosses into the constellation Ophiuchus
20-Passes near the +3.8 magnitude star Lambda Ophiuchi (Marfik)
29-Passes between the +3rd magnitude stars Cebalrai and Gamma Ophiuchi
November1- Passes near the +3.9 magnitude star 67 Ophiuchi
10-Passes into the constellation Serpens Cauda
20-Passes very near (occults) the +4.6 magnitude star Alya
25-Passes into the constellation Aquila
26-Crosses the Celestial Equator southward
In December into early 2025, the comet drops back below +10th magnitude.
Comet A3 Tsuchinshan-ATLAS from July 25th. Image credit: Eliot Herman.Keep in mind, like deep-sky targets, all of that precious quoted magnitude for a comet is ‘smeared out’ over an apparent surface area. We usually think of the naked eye cutoff for stars under a good dark sky is +6, but a comet generally won’t reach naked eye visibility until about +3 magnitude or so. This is also usually the point at which a given comet becomes bright enough to capture along with foreground objects, always a photogenic sight.
Good luck and clear skies on your quest to see comet Tsuchinshan-ATLAS, on what is very probably its one-time only visit to the inner solar system.
The post Comet Tsuchinshan-ATLAS Set to Perform This Fall appeared first on Universe Today.
We’re suffering from a power cut in Hoedspruit, and, as I’ve left the park and am resting here just a day before traveling on, I’ll have to type fast to get this finished before my computer loses its battery power. So here are a few things I saw on my last evening and morning game drives in Manyolete.
Please click on all photos to enlarge them.
First, a shot I’ve wanted to get for a while: a magnificent male Greater Kudu (Tragelaphus strepsiceros) with his spiral horns.
Finally I was able to photograph what I think is one of the most beautiful birds in Africa, the Lilac-breasted roller (Coracias caudatus). It’s widespread through SE Africa, and both males and females have these stunning colors: it’s not sexually dimorphic.
And a male impala with its curved horns:
After nearly 1.5 hours of searching, our guide/driver Dan, following rhino tracks and droppings, made a rare spotting: a large male Southern White Rhinoceros (Ceratotherium simum simum). It grazed peacefully as we sat silently in our vehicle nearby.
From Wikipedia:
The southern white rhinoceros is one of largest and heaviest land animals in the world. It has an immense body and large head, a short neck and broad chest. Females weigh around 1,600–1,700 kg (3,530–3,750 lb) and males around 2,000–2,300 kg (4,410–5,070 lb), with specimens of up to 3,600 kilograms (7,940 lb) considered reliable, and larger sizes up to 4,500 kg (9,920 lb) claimed but not verified.
They can weigh FOUR TONS!
Reduced to between 20 and 50 animals in South Africa in the 19th century by big-game hunting, the population has now recovered to about 18,000 individuals, and some are being bred for release into the wild. Because of poaching to get its horns—used in traditional Chinese medicine—it’s considered “near threatened.” What a crime to kill one of these creatures to get its horns for worthless medicinal purposes!
Notice the birds (oxpeckers) cleaning the beast of parasites like ticks and fleas:
We were excited to get this rare sighting, one of the “Big Five” animals that everyone wants to tick off their mental list.
I wrote Martim for an identification of the oxpeckers, and here’s part of his reply:
Well done both for such a good view of your target lilac-breasted roller and also for seeing all the members of a bird family at the same time. And for the big five of course.
You have the two species making the family Buphagidae on the same rhino. The Yellow-billed Oxpecker (Buphagus africanus), further in the back, and the Red-billed Oxpecker (B. erythrorynchus).
Some info from Birds of the World (Cornell)
“The oxpeckers are lanky brown passerines that feed on ectoparasites and wounds found on large African mammals. Although elephants and some antelope species will not tolerate them, these birds can often be seen foraging on the other large African megafauna, using their long stiffened tails for support as woodpeckers do while climbing trees. All aspects of their lives are entangled with their mobile large-mammal habitats. Oxpeckers spend the entire day on their hosts, feeding, sunbathing, and snoozing. They even defecate off the side of their perch, and sometimes take a drink at the waterhole while still gripping their hosts’ legs. While breeding, which they often perform cooperatively, they even make their nests out of mammal hair and dung.”
Regarding beautiful birds not so difficult to see, you can now set your sights on the African Paradise-Flycatcher (male). It should be around your camp.
Well, of course I had to look up the African Paradise-Flycatcher (Terpsiphone viridis), and here’s a photo from Wikipedia (this is the male; the species is sexually dimorphic).
Hannah Rooke, CC BY-SA 3.0, via Wikimedia CommonsBelow are the stumpy two horns of this rhino. This is explained by the rangers having previously anesthetized the animals to remove its horns, making it worthless for poaching. Yes, the procedure deprives the circumcised beast of a weapon and an adaptive feature, but that’s more than compensated for by saving the animal from poaching (rhino horns are the object of most South African poaching). Unfortunately, as you see, the horns grow back, though slowly:
At the “sunupper” stop for coffee, we halted by a “dam”: a large pool of water. A herd of Blue Wildebeest came by, drank together rapidly, and then quickly moved off. I suspect they’re wary because they’re hunted by many predators. As Wikipedia notes, “They are a major prey item for lions, cheetahs, leopards, African wild dogs, hyenas, and Nile crocodiles.”
Rhino droppings. They are black—in contrast to elephant droppings, which are brown.
Dan told us that these are wildebeest tracks:
A female elephant and her baby in a matriarchal herd we came upon. This was fairly close to the lodge (about 2 miles away), so I suspect that this is our swimming pool herd. (Elephants cover a lot of distance.)
And, just at the end of our morning trip, I completed my sighting of all the “Big Five” animals by coming across an African Buffalo (Syncerus caffer). This is an old male (probably about 20, says Dan), and the horns have grown together. From Wikipedia:
A characteristic feature of the horns of adult male African buffalo (southern and eastern populations) is that the bases come very close together, forming a shield referred to as a “boss”. From the base, the horns diverge downwards, then smoothly curve upwards and outwards and in some cases inwards and or backwards. In large bulls, the distance between the ends of the horns can reach upwards of one metre (the record being 64.5 inches 164 cm). The horns form fully when the animal reaches the age of 5 or 6 years old, but the bosses do not become “hard” until it reaches the age of 8 to 9 years old.
These older males, expelled from their herd (they are social) are called “dagga boys“, and are testy and dangerous. I heard that a ranger was recently seriously injured but not killed by one of these; the bull had to be shot by another ranger.
Note the oxpeckers, busy cleaning and eating:
You don’t want to mess with these!
Dan pouring coffee at our stop. He’s showing his characteristic humor, and was always laughing. He was a fantastic guide, and much enhanced our trip with his ability to spot animals, his knowledge, and his affability.
Dan has worked as a guide for many years (8 at Manyeleti), and apparently has seven weeks on the job—working 7 days a week from 4 a.m. to about 10 p.m.—and then five weeks off when he can visit his family in a nearby village (he lives in the camp while working). He told me that he was married and had TWELVE children.
Sadly, I had to leave Manyelete after five days. It’s not cheap to stay at such a place, but I considered the dosh very well spent. Never again, I think, will I get to see a place like this—so dry and barren in winter yet so full of life.
As I waited to be picked up and driven to the gate, the herd of 23 elephants came again to the swimming pool for a drink: the matriarch, a few males, and the rest females or babies. I sat by the water and watched them, fascinated and enchanted as they entwined their trunks for bonding, occasionally bellowed, and filled their bellies with pool water, sometimes squirting it over their bodies. These are highly intelligent social animals and I need to learn more about them.
I could have watched them for hours, but I felt a tap on my back. “I thought I’d find you here”, said Dan, who was carrying my luggage. He knows that I love all of Ceiling Cat’s creatures.
The departure was abrupt, and Rosemary met me at the gate to drive me to my lodgings at Hoedspruit. I’ll be here today, where I’ll go to visit a couple of local villages to help distribute donated food (Rosemary works with them). Tomorrow I’ll begin two one-day trips to the Blyde River Canyon, reputedly one of Africa’s most beautiful sights. Then on to Kruger Park for five days. More pictures will be coming, but there may be a hiatus as I travel about.
********
Jerry’s “Big Ten”:
I think the “Big Five” list, comprising the animals most difficult to kill by spear or gun, is too restrictive, so I’ve expanded it to ten animals. The first five below are the Big Five.
Jerry’s “Big Ten”:
Elephant
Rhino
Leopard
Lion
African buffalo
Giraffe
Cheetah
Kudu
Nyala
and, of course, the African Warthog, of which Ozy is one specimen.
Lagniappe photos (the power was just restored):
The herd of slephants at the pool; I was watching them when Dan gently told me it was time to leave. Note that they come in all sizes (look at the cute baby!) but only two sexes.
A panorama of the swimming pool; note that there are also elephants at the big pond in the distance. Click to enlarge:
The matriarch splashing her body with water to cool off:
The eye of the elephant:
Back in Hoedspruit, which counts as civilization though it’s small. For dinner I ordered a quarter bunny with mutton (medium spicy) to go. Photo by Rosemary.
Onward and upward!
It’s interesting to follow the scientific exploration of a new clinical entity in real time. It reveals a lot about how medical science works, and how scientists nibble away at complex problems. This is partly why I have been closely following the story of long COVID as it has unfolded over the last few years. I also see patients with long COVID […]
The post More on Long COVID first appeared on Science-Based Medicine.Meanwhile, in Dobrzyn, Hili is demanding. She is a cat, after all.
Hili: Where are you going?
A: To the shop.
Hili: Buy three cans of this new pâté.
Hili: Gdzie idziesz?
Ja: Do sklepu.
Hili: Kup trzy puszki tego nowego pasztetu.
In 1977, astronomers received a powerful, peculiar radio signal from the direction of the constellation Sagittarius. Its frequency was the same as neutral hydrogen, and astronomers had speculated that any ETIs attempting to communicate would naturally use this frequency. Now the signal, named the Wow! Signal has become lore in the SETI world.
But what was it?
Beginning in the 1970s, the Ohio State University Big Ear radio telescope was used in the university’s Search for Extraterrestrial Intelligence (SETI) program, which ran from 1973 to 1995. This program is the longest-running SETI program in history.
In 1977, Big Ear detected a peculiar signal that’s taken on a life of its own: the Wow! Signal. The Wow! Signal was a strong narrowband radio signal right near the frequency of neutral hydrogen. The Big Ear telescope is long gone now, but the effort to understand what the signal is lives on.
The signal lasted the full 72-second window in which Big Ear was able to observe it. A few days later, astronomer Jerry R. Ehman was looking over the data when he saw the signal on a computer printout. Astronomers had never seen anything like it, and he wrote “Wow!” beside it, and the name has stuck ever since.
The Wow! signal from 1977 as discovered by astronomer Jerry R. Ehman. Image via Big Ear Radio Observatory and North American AstroPhysical Observatory (NAAPO).The signal has another name: 6EQUJ5. This has been interpreted as a message hidden in the signal, but it really represents how the signal’s intensity varied over time.
This image is a plot of the Wow! signal’s intensity versus time. Image Credit: By Maxrossomachin – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=16197844The signal generated a lot of excitement. Some thought it was extraterrestrial in origin, some thought it could come from some type of human-generated interference, and some thought it could be from an unexplained natural phenomenon.
New research shows that the Wow! Signal has an entirely natural explanation.
The research is “Arecibo Wow! I: An Astrophysical Explanation for the Wow! Signal.” The lead author is Abel Méndez from the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo. It’s available at the pre-print server arxiv.org.
Arecibo Wow! is a new effort based on an archival study of data from the now-defunct Arecibo Radio Telescope from 2017 to 2020. The observations from Arecibo are similar to those from Big Ear but “are more sensitive, have better temporal resolution, and include polarization measurements,” according to the authors.
“Our latest observations, made between February and May 2020, have revealed similar narrowband signals near the hydrogen line, though less intense than the original Wow! Signal,” said Méndez.
Arecibo detected signals similar to the Wow! signal but with some differences. They’re far less intense and come from multiple locations. The authors say these signals are easily explained by an astrophysical phenomenon and that the original Wow! signal is, too.
“We hypothesize that the Wow! Signal was caused by sudden brightening from stimulated emission of the hydrogen line due to a strong transient radiation source, such as a magnetar flare or a soft gamma repeater (SGR),” the researchers write. Those events are rare and rely on precise conditions and alignments. They can cause clouds of hydrogen to brighten considerably for seconds or even minutes.
This simple schematic shows how the Wow! Signal was generated and detected. A radiative source such as a magnetar or a soft gamma repeater is positioned behind a cloud of cold neutral hydrogen. Energy from the source stimulates emission from the HI cloud, which brightens abruptly and is observable from Earth. Image Credit: Méndez et al. 2024.The researchers say that what Big Ear saw in 1977 was the transient brightening of one of several H1 (neutral hydrogen) clouds in the telescope’s line of sight. The 1977 signal was similar to what Arecibo saw in many respects. “The only difference between the signals observed in Arecibo and the Wow! Signal is their brightness. It is precisely the similarity between these spectra that suggests a mechanism for the origin of the mysterious signal,” the authors write.
These signals are rare because the spatial alignment between source, cloud, and observer is rare. The rarity of alignment explains why detections are so rare.
The researchers were able to identify the clouds responsible for the signal but not the source. Their results suggest that the source is much more distant than the clouds that produce the hydrogen signal. “Given the detectability of the clouds as demonstrated in our data, this insight could enable precise location of the signal’s origin and permit continuous monitoring for subsequent events,” the researchers explain.
The Wow! Signal was originally interpreted as a technosignature by many. By explaining where the signal came from, this research outlines a new source of false positives.
“Our hypothesis explains all observed properties of the Wow! Signal, proposes a new source of false positives in technosignature searches, and suggests that the Wow! Signal could be the first recorded event of an astronomical maser flare in the hydrogen line,” the authors explain in their conclusion.
The post The Wow! Signal Deciphered. It Was Hydrogen All Along. appeared first on Universe Today.
What’s wrong with boys and men these days?
Boys and men are struggling. Profound economic and social changes of recent decades have many losing ground in the classroom, the workplace, and in the family. While the lives of women have changed, the lives of many men have remained the same or even worsened. Our attitudes, our institutions, and our laws have failed to keep up. Conservative and progressive politicians, mired in their own ideological warfare, fail to provide thoughtful solutions.
The father of three sons, a journalist, and the founding president of the American Institute for Boys and Men, Richard V. Reeves has spent twenty-five years worrying about boys both at home and work. His book, Of Boys and Men, along with his American Institute for Boys and Men, tackles the complex and urgent crisis of boyhood and manhood. Reeves looks at the structural challenges that face boys and men and offers fresh and innovative solutions that turn the page on the corrosive narrative that plagues this issue. Of Boys and Men argues that helping the other half of society does not mean giving up on the ideal of gender equality.
Reeves says that gender equality is not a zero-sum game. We can do more for boys and men without doing less for women and girls. We can be passionate about women’s rights, and compassionate towards the struggles of boys and men. Of course there remain many gender gaps where women and girls remain at a disadvantage, especially in terms of pay, senior positions of leadership, access to venture capital, and so on. But in advanced economies, there are also gender gaps where boys and men have now fallen behind, especially if they are Black or from a lower-income background.
Richard Reeves is the founding president of the American Institute for Boys and Men. Before founding AIBM in 2023, Reeves was a Senior Fellow at the Brookings Institution where he focused on policies related to economic inequality, racial justice, social mobility, and boys and men. Reeves is the author of several books, including Of Boys and Men: Why the Modern Male is Struggling, Why it Matters, and What to do About It and Dream Hoarders: How the American Upper Class Is Leaving Everyone Else in the Dust, Why That is a Problem, and What to do About It. Inspired by his own experiences as a father and policy expert, Richard founded the American Institute for Boys and Men to bring awareness to the challenges facing boys and men today and to develop evidence-based solutions. In June, philanthropist Melinda French Gates announced she will be donating over $1B over the next two years to support women’s rights, and one of the recipients was the American Institute for Boys and Men founded by Richard Reeves to the tune of $20 million.
Shermer and Reeves discuss:
However:
“In a zero-sum political environment, merely drawing attention to the problems of boys and men can be seen as somehow downplaying the ongoing challenges facing girls and women. This is why Democrats, in particular, are so reluctant to directly address male issues. That is a recipe for bad politics…”
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