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From the ancient Counter-Earth to the modern many-worlds interpretation, physicist Paul Halpern's guide explores the rich science of multiverses. Makers of blockbusters, take note

Our galaxy is filled with magnetic fields. They come not just from stars and planets, but from dusty stellar nurseries and the diffuse hydrogen gas of interstellar space. We’ve long known of this galactic magnetic field, but mapping it in detail has posed a challenge. Now a new study gives us a detailed 3-dimensional map of these fields, with a few surprises.

Magnetic fields don’t emit light on their own, so we can’t simply scan the sky with optical telescopes to see where they are. Instead, we must look for ways in which magnetic fields cause charged particles to emit light, or how distant light is affected by interstellar gas within the magnetic field.

For objects such as stars and planets, we mostly map their magnetic fields by charged particles. Ions can become trapped by magnetic field lines, spiraling along them as they emit light. It’s how we first mapped the magnetic field of Jupiter, and how we can study the magnetic fields of the accretion disks of black holes. But galactic magnetic fields are much weaker and diffuse. While charged particles can spiral along galactic magnetic fields, the light they emit is often too faint for us to detect. So instead we use a trick of polarized light.

Polarized light is light where its waves oscillate in a particular direction, rather than randomly in various directions. It’s often used in things like polarized sunglasses, which filter out light scattered off shiny objects, and water, which helps to eliminate glare. There are lots of things in space that emit polarized light, such as pulsars and matter within accretion disks. Radio telescopes in particular can detect the polarization of this light, which gives astronomers more information than they’d otherwise have.

One of the properties of polarized light is that different frequencies move through ionized gas at slightly different speeds. This gives a beam of polarized light and effective rotation depending on how much ionized gas it travels through. Since ionized gas is caught by magnetic fields, we can map the magnetic fields by looking at the polarization of various light sources.

White lines show the complex structure of magnetic fields in our galaxy. Credit: Doi, et al

This has been done before, and it has given us a rough map of magnetic fields in our galaxy. What these studies found was that the magnetic fields of the Milky Way tend to fall uniformly along the disk shape of the galaxy. This new study took this one step further. Using data from the Gaia spacecraft, the team had a detailed map of the distribution of stars and nebulae in the local region of our galaxy. They then combined this with polarization observations of the Sagittarius spiral arm. Together this gave them a detailed 3-dimensional magnetic field map of the region.

They found that the magnetic fields aren’t uniform, and don’t simply lie along the galactic plane. Even within the diffuse regions of interstellar space galactic magnetic fields can take complex forms. Many of their field lines diverge significantly from the galactic plane. They also found that these galactic magnetic fields can strongly interact with stellar nurseries, penetrating them and affecting the motion of gas and dust. This could explain how some stellar nurseries have regions of star formation that could not have formed from gravity alone.

As we capture a more detailed view of magnetic fields, we will better understand how they interact with the galaxy as a whole. They not only affect the formation of new stars but could impact the structure of galaxies and how they evolve over time.

Reference: Doi, Yasuo, et al. “Tomographic Imaging of the Sagittarius Spiral Arm’s Magnetic Field Structure.” The Astrophysical Journal 961.1 (2024): 13.

The post Astronomers Have Mapped the Milky Way's Magnetic Fields in 3D appeared first on Universe Today.

Reader Muffy sent in this photo showing the tracks of animal that she disturbed while cross-country skiing. Your job is to guess the type of animal AND the species.  Muffy will reveal it it the comments towards the end of the day, so put up your guesses now:

AlphaGeometry scores almost as well as the best students on geometry questions from the International Mathematical Olympiad

A conventional computer must be fully assembled before it can run, but an experimental DNA computer solves problems through the very act of putting itself together

With anaesthetics and brain organoids, we are finally testing the idea that quantum effects explain consciousness – and the early results suggest this long-derided idea may have been misconstrued

With anaesthetics and brain organoids, we are finally testing the idea that quantum effects explain consciousness – and the early results suggest this long-derided idea may have been misconstrued

The new Jesus and Mo strip, called “tragic,” came with the caption, “It’s okay, they had muesli for breakfast.”

I’m not sure about this one, save that the boys leave their McDonald’s cups and french-fry package on the bench after they leave. Is that the licensed immoral behavior?

Perhaps readers can explain. . .

Two readers sent me this 44-minute video posted by Tom Gross, showing Emily Hand, a 9-year-old girl kidnapped by Hamas, comforting her father Thomas, an Irishman, as he’s interviewed by Piers Morgan. (Hand’s wife died of cancer, and Thoma’s ex-wife, who served as Emily’s stepmother, was killed by Hamas.) It’s ineffably moving to see young Emily stroke her father’s face, wiping the tears from his eyes as he recounts the family’s ordeal.

You may remember Thomas Hand saying, when he thought his daughter was dead in Gaza, that her death was probably for the best, for her fate would have been worse had she been taken alive:  he imagined what Hamas would do to Emily.(A clip from that interview is at 11:42.) I’m sure he feels differently now! But he did have to explain to Emily, after she returned, that her stepmother was dead.

My friend said this:

You have to watch this—it’s insanely powerful. I’m crying.  He just lays it all out. Makes me want to move to Israel and help. . .

Towards the end, Thomas Hand gets very angry and calls Western university students “idiots”. . . and he mentions Harvard.

Here are Tom Gross’s notes:

Thomas Hand, the Irish-born father of Emily Hand who was released after 50 days in Hamas hell, gave an in-depth interview yesterday evening to Piers Morgan on Britain’s TalkTV. Emily was 8 when she was kidnapped and turned 9 in captivity.

One viewer said: “How she wiped her father’s tears, caressed and cared for him when he started to cry in the interview. Melted my heart.”

Also of note is when Thomas Hand says ignorant critics of Israel in the West “don’t know a thing” and have “no idea what they are talking about”.

Hand is no conservative: he brought up Emily on a kibbutz because he liked its socialist atmosphere. As for Emily’s kidnapping during a sleepover and the attack on the kibbutz, you’ll have to listen to the interview.

Three bits are worth noting: about 30 minutes in, Thomas explains how he told Emily that her stepmother/caretaker was dead. (See especially from 31:15 on.)

At 32:25, the discussion turns to politics, Israel’s response, and how the West has reacted. Thomas gets quite exercised, especially when he gets to the accusation that Israel is an “apartheid state.”

At 43:00, Piers asks Thomas to ask Emily (in Hebrew) how she felt when she saw her father again after her release.

A final word from me: of the roughly 200 people taken hostage by Hamas, from several countries, about 136 remain in Gaza. That there is no world outcry about this; that the UN hasn’t condemned Hamas for this; and that the Court of Justice in the Hague is not putting Hamas on trial for real genocide, including taking civilian hostages, firing rockets into Israel, swearing to keep attacking Israel until all the Jews are dead (as specified in its charter) and many other terroristic war crimes—all of this should bring deep shame to the West

As with many YouTube videos, this one is periodically interrupted with annoying advertisements.  Nothing is immune from being monetized these days.

Today we have photos by Friend of the Site Greg Mayer, who sent these in when the photo well was about to run dry. Greg’s captions are indented, and you can enlarge the photos by clicking on them. This is part 1 of 2.

Southern trees: what’s on them?

One of the things you notice in heading south are the changes in the plants and animals you see. One of the most striking things you notice is the abundance of epiphytes– plants growing on plants– which are much commoner in the southern US than in the north. Epiphytes of all sorts, and often large ones– bromeliads, vines, strangler figs, etc.– are a typical characteristic of tropical forests, but there are a fair number in subtropical Florida. The following pictures are from Jacksonville, in northern Florida.

Among the first “southern” things you notice, even while driving, is Spanish moss (Tillandsia usneoides, in the bromeliad family) dripping off of trees; while driving south I first noticed it in southern Georgia. Unfortunately, there were none where I walked around to take these photos! But there were other air plants– which is what Spanish moss is. Here’s one, another species of Tillandsia, in a lime tree (Citrus sp.).

Tillandsia sp., Jacksonville, FL, January 9, 2024.

Air plants have no roots, consisting instead of twisted leaves clinging to other plants and surfaces; they get water and nutrients from the air and the rain. They are not parasitical in the usual sense– they don’t “feed” upon their host– but they are what are known as “support parasites”: their host holds them up, and gets them exposed to sunlight. Some support parasites can be inimical to the host, weighing it down and intercepting sunlight and rain; a friend here in Florida told me that a lot of Spanish moss will kill a tree.

Though the lime tree had no Spanish moss, it was not doing well, and epiphytes (mostly lichens) were abundant on the moribund parts of the tree; compare the left side, with leaves, vs. the nearly barren right side.

Lime tree, Jacksonville, FL, January 9, 2024.

A live oak (Quercus sp., I think) with lots of epiphytes was also not doing well. Notice the few bunches of live leaves higher in the tree; the ground below it was covered with broken-off, epiphyte-encrusted, branches. [Edit by GCM: The clumps of live leaves in the tree below are probably mistletoe, an epiphytic parasite, not leaves of the oak. Also the oak is probably not a live oak. See the comments for further details. My thanks to readers Dennis Howard Schneider,  j a higginbotham, bruce morgan, and debi!]

Live oak (Quercus sp., ?), Jacksonville, FL, January 9, 2024.

The most common epiphytes here are lichens. I won’t even venture an opinion on what species occur here, but there were differences in growth form indicating to me that several species were present. Here’s a wispy kind I found on branches.

Wispy lichen, Jacksonville, FL, January 9, 2024.

Nearby on the same branches could be found a lichen with a more “structured” form, with “chimneys”.

Lichen, Jacksonville, FL, January 9, 2024.

Lichens also grew on trunks; this is the same live oak as shown above.

Lichens on trunk, Jacksonville, FL, January 9, 2024.

A common sight in Florida is a palm whose trunk is covered with ferns. The ferns on this one are modestly dense– I’ve seen much denser. I think the tree is one of the twelve native palms of Florida– perhaps cabbage palm. (IDs from readers on this or other plants would be appreciated!)

Epiphytic ferns on palm trunk, Jacksonville, FL, January 9, 2024.

On this palm, moss is growing on the trunk, and we can see some epiphytic vines dangling.

Epiphytic moss on palm trunk, Jacksonville, FL, January 9, 2024.

Finally, neither trees nor epiphytes, and, in fact, not even plants, a couple of fungi on the lawn.

Mushrooms, Jacksonville, FL, January 9, 2024.

Fermented food such as artisan cheeses or kimchi made with unpasteurised milk or starter cultures that haven't been properly screened can contain antibiotic-resistant bacteria

A new study finds that hospital measures to limit the spread of COVID-19 worked, and we probably should keep them.

The post Hospital Measures Prevented COVID Transmission first appeared on Science-Based Medicine.

Black holes can be difficult to study, so researchers have made a powerful quantum vortex in a tank of superfluid helium that acts as a simulation of a black hole

Researchers estimate that 17,000 baby elephant seals have died from avian flu in Argentina and it is likely that the virus is spreading among marine mammals

Solar power is a booming industry right now as we all strive to run our lives with minimum carbon footprint. Solar is a relatively easy way to get clean electricity but of course we are limited to the hours then Sun is above the horizon. Solar panels in space have been muted before but the costs and technology to transmit power to Earth is prohibitive. An alternative approach has been explored by a team of engineers who have been looking at the possibility of deploying giant reflectors into space.

They are a familiar site on houses these days, panels of crystalline-silicon that convert light into electricity. Solar panels have to be positioned carefully to maximise incoming sunlight and thus maximise electricity generation. If a way could be found to increase the amount of time a solar panel was in sunlight then of course they would be more useful to us. In 1993, a 20metre Russian space mirror known as Znamya-2 was unfurled to demonstrate that sunlight could be reflected down to Earth. 

The concept to use reflectors in space to prolong the time that solar panels are illuminated is a far simpler and cheaper solution to some sort of solar power station in space. Arguably one of the key times in the day when power is needed is at night so being able to extend the hours of sunlight seems like a great concept. It’s not a new idea though as Hermann Oberth suggested it back in 1929 when he visualised giant reflectors in space, reflecting light down to areas that need it. 

A paper recently published explores the reality of the concept and shows how the vision of Oberth may now be achievable. It should be noted that the idea is designed to target sunlight onto solar farms rather than individual homes. The technology is now available and materials suitable to be able to create, launch and deploy large solar reflectors into space. Once deployed, an orbiting reflector could be angled to direct sunlight onto a solar farm as it passes over, extending the ‘day’ and increasing electricity generation.

The reflectors which are proposed to be hexagonal with sides 250 metres long would likely be deployed into orbits at an altitude of about 900km. This would illuminate an area approximately 10km across and extend generation time by around 20 minutes either side of dusk and dawn. 

Concerns that these would destroy the night are likely to be unfounded due to the planned approach to target solar farms away from inhabited areas.  The reflectors would not be visible ot the naked eye unless you happened to be standing near a solar farm at the time it was beign illuminated and astronomical observations protected by angling the reflectors when not in use. 

It is likely to be some years before such a project became reality but it is nice to see engineers and scientists looking at ways to enhance the generatin of clean energy in a way that promotes protection of our planets natural resources but also limits negative impacts on human activity.

Source : Reflectors in space could make solar farms on Earth work for longer every day

The post Reflectors in Space Could Make Solar Power More Effective appeared first on Universe Today.

Welcome to a Hump Day (“Ngày bướu” in Vietnamese): Wednesday, January 17, 2024. This will be a curtailed post, as PCC(E) is travelling.

Readers are welcome to mark notable events, births, or deaths on this by consulting the January 17 Wikipedia page.

Meanwhile in Dobrzyn, Hili is a wise cat:

Hili: I have a feeling that the world has gone crazy. A: Is it visible from your place as well? 

In Polish:

Hili: Mam wrażenie, że świat zwariował.
Ja: Z twojego miejsca też to widać?

*******************

From Stacy:

 

Just like a book can't be judged by its cover, a material can't always be judged by its surface. But, for an elusive conjectured class of materials, physicists have now shown that the surface previously thought to be 'featureless' holds an unmistakable signature that could lead to the first definitive observation.

Chemists have mapped how proton-coupled electron transfers happen at the surface of an electrode. Their results could help researchers design more efficient fuel cells, batteries, or other energy technologies.

On hot days, Alpine ibex increase their activity at nighttime to avoid the heat – but this might increase the risk of predation by wolves

Men's navigational skills slightly trump women's, but it probably comes down to their upbringing, rather than it being an evolutionary trait