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The benefits of taking GLP-1 agonists seem to outweigh the risks, at least when taken for approved uses, according to an assessment of how the drugs affect 175 conditions

The benefits of taking GLP-1 agonists seem to outweigh the risks, at least when taken for approved uses, according to an assessment of how the drugs affect 175 conditions

Urine is rich in nitrogen, which is important for plant growth, and now scientists have found an efficient way of utilising this to make human wastewater into fertiliser

Supernovae are one of the most useful events in all of astronomy. Scientists can directly measure their power, their spin, and their eventual fallout, whether that’s turning into a black hole or a neutron star in some cases or just a much smaller stellar remnant. One of these events happened around 350 years ago (or around 11,000 years ago from the star’s perspective) in the constellation Cassiopeia. The James Webb Space Telescope recently caught a glimpse of the aftereffects of the explosion, and it happened to shed light (literally) on a familiar area of study – interstellar gas.

The supernova in Cassiopeia ejected a massive amount of X-rays and ultraviolet light into the area surrounding the now-dead star. That energy is now hitting a clump of gas gathered in the interstellar medium about 350 light years from the star. An effect called a “light echo” is created in the process.

A light echo can be thought of as a giant photographer’s bulb. A bright flash (i.e., the energy from the supernova) travels in an ever-extending sphere outwards, gradually illuminating everything in its path, then moving on and leaving the objects it just passed back in darkness. As the material is illuminated, telescopes back on Earth can see this otherwise invisible matter existing in the interstellar medium.

Evolution of the lit-up gas and dust cloud over the course of months.
Credit – STScI YouTube Channel

The Cassiopeia A explosion caused dozens of light echoes, but one in particular caught the attention of astronomers. From our perspective, gas and dust located past the now-dead star have been gradually lit up as the flash from the supernova passes through it, creating a spectacular image.

Spitzer, one of NASA’s great observatories that ended its observations in 2020, examined this same clump of gas and dust back in 2008. Its image was fascinating but not as complete as the one by its successor, JWST.

The image from JWST, admittedly falsely colored since humans can’t see infrared light, is spectacular, both aesthetically and scientifically. It shows a series of “sheets” that are remarkably small for an interstellar structure, measuring only about 400 AU across. They seem to be influenced by interstellar magnetic fields, as video of still images shows them twisting and writhing around.

Image from Spitzer of the dust cloud taken in 2008.
Credit – NASA / JPL-Caltech / Y. Kim (U of Arizona / U of Chicago)

Another feature of the image is described as “knots in wood grain” in a press release from the Webb telescope researchers. It also twists and moves over months as if dragged by some invisible force.

Light echoes can also be seen in the visible light range. However, infrared wavelengths, which are better thought of as the heat emitted from this gas and dust as the light echo passes through it, are more capable of showing the 3D structure as the wavelengths themselves aren’t blocked by the dust as visible light would be.

Consistently taking images over the course of months also provides another advantage. As Armin Rest of the Space Telescope Science Institute puts it, “We have three slices taken at three different times,” comparing the layered result as equivalent to a CT scan commonly used in medicine.

Context for the area of the image in the Cassiopeia
Credit – NASA / ESA / CSA / STScI

While the first picture from these studies might be fantastic, there is plenty of science left to do on these clouds of matter. Future work will continue to watch as the supernova flash-bulb illuminates and darkens different parts of the collected material. Some of that might even be destroyed, as the high-power supernovae that are strong enough to cause infrared light echoes could potentially vaporize some of the matter it hits.

JWST will continue to monitor the evolving situation, but a helping hand is coming. The Nancy Grace Roman Space Telescope, due to launch in 2027, will help scan the sky for evidence of other infrared light echoes. JWST will then follow up with closer observations using its powerful infrared instruments. If we’re lucky, we’ll see plenty more astonishing pictures soon, like the ones released last week.

Learn More:
Webb Space Telescope – NASA’s Webb Reveals Intricate Layers of Interstellar Dust, Gas
UT – A Fast-Moving Star is Colliding With Interstellar gas, Creating a Spectacular bow Shock
UT – Local Interstellar Gas Mapped in 3-D
UT – A Black Hole Has Cleared Out Its Neighbourhood

The post Webb Sees Light Echoes in a Supernova Remnant appeared first on Universe Today.

The video of Day 1 of our “Censorship in the Sciences” conference is up (and down below), and this baby is nearly seven hours long.  Few people have the patience to listen to the first day’s sessions all at 0ne go, but I want to single out a few talks. The first is by Jonathan Rauch, author of The Constitution of Knowledge: A Defense of Truth, an excellent book. His talk begins at 12:01, outlines how knowledge acquisition should work, and is quite eloquent.

Later, the four-member panel on “Examples of Censorship” gives a good account of how ideology has led to suppression of science.  Luana introduces it at 2:43:26 and Lawrence Krauss kicks it off at 2:44:45 via Zoom. His examples are numerous and disturbing—and not just from physics.  He pulls no punches, and even calls out America’s National Academy of Sciences (NAS), the most prestigious honorary organization of scientists in the U.S. It so happened that the NAS President (Marcia McNutt) was in the audience, and heard Krauss call out her organization for identity-based choosing of candidates for a supposedly meritocratic society (see 2:55:45). As Krauss shows, the NAS even admitted this explicitly in a quote from an executive of the organization, and it’s widely admitted by Academy members themselves. (Note that at the end of her later talk, at 4:39:30, President McNutt denies this. accusing Krauss implicitly of ignorance, but her own organization’s stated policies belie her words.)  Finally, Krauss gives evidence that both the NSF and DOE have likewise been captured by ideology in their funding of grants.

If you want to hear about how indigenous peoples are preventing anthropologists and forensic scientists from studying relics likes bones and objects used by Native Americans, Elizabeth Weiss’s short talk in that panel, beginning at 3:23:43,  gives a good idea. She has a new book about these issues.

I heard all the talks, and some of the others engaged me as well, but I’ve just mentioned the ones I enjoyed the most.

Here is the first day’s schedule (from here)

And here’s some of the press as detailed by Heterodox at USC:

Press Coverage

Censorship in the Sciences conference speakers call on peers to organize, defend free speech, writes Jennifer Kabbany in The College Fix.

Rauch’s opening speech highlighted surveys which found that almost half of Americans think that colleges have a negative effect on the country.

“It really is a crisis,” he said, adding a combination of factors are to blame, including students’ emotional fragility, the politicization of hiring, tenure and funding based on ideology, and a newer trend of academic journals refusing to publish findings that allegedly harm some communities.

Kabbany also covered Musa al-Gharbi’s presentation at the conference. Read that article here.

Alice Dreger, managing editor at the Heterodox Academy, wrote a recap on HxA’s Free the Inquiry Substack:

On the issue of censorship of research publication, many speakers at the conference objected to the idea that claims about potential harm to vulnerable populations should be used as a reason to stop, force changes to, or retract research reports. Some raised the question of the harms that arise from alleged-harm-reduction censorship–that is, the harms that arise from stopping valuable research out of fear of harm

In response to a Saturday morning presentation by Nature editor Stavroula Kousta, journalist Jesse Singal, also a speaker at our event, published a critique of some the ideas presented.

Conference organizer and panelist Lee Jussim wrote about the conference (and whether we should just burn academia down).

Panelist Jerry Coyne wrote several dispatches about the conference on his blog Why Evolution is True (which reaches nearly 75,000 readers).

Attendee Zvi Shalem wrote up his take-ways from the conference here.

Panelist Michael Bowen of Free Black Thought reflected on attending conference on his Substack.

Natalya Murakhver wrote about her experience debuting her documentary 15 Days at the conference.

Panel chair Abhishek Saha wrote up excellent Twitter threads (in real time!) detailing conference proceedings. Here is one on the first day of conference.

Is 8 hours of sleep really the right amount for you? Understanding your personal chronotype could be a better way to approach how much time you should spend in bed

There really is a significant mystery in the world of cosmology. This, in my opinion, is a good thing. Such mysteries point in the direction of new physics, or at least a new understanding of the universe. Resolving this mystery – called the Hubble Tension – is a major goal of cosmology. This is a scientific cliffhanger, one which will unfortunately take years or even decades to sort out. Recent studies have now made the Hubble Tension even more dramatic.

The Hubble Tension refers to discrepancies in measuring the rate of expansion of the universe using different models or techniques. We have known since 1929 that the universe is not static, but it is expanding. This was the famous discovery of Edwin Hubble who notice

d that galaxies further from Earth have a greater red-shift, meaning they are moving away from us faster. This can only be explained as an expanding universe – everything (not gravitationally bound) is moving away from everything else. This became known as Hubble’s Law, and the rate of expansion as the Hubble Constant.

Then in 1998 two teams, the Supernova Cosmology Project and the High-Z Supernova Search Team, analyzing data from Type 1a supernovae, found that the expansion rate of the universe is actually accelerating – it is faster now than in the distant past. This discovery won the Nobel Prize in physics in 2011 for  Adam Riess, Saul Perlmutter, and Brian Schmidt. The problem remains, however, that we have no idea what is causing this acceleration, or even any theory about what might have the necessary properties to cause it. This mysterious force was called “dark energy”, and instantly became the dominant form of mass-energy in the universe, making up 68-70% of the universe.

I have seen the Hubble Tension framed in two ways – it is a disconnect between our models of cosmology (what they predict) and measurements of the rate of expansion, or it is a disagreement between different methods of measuring that expansion rate. The two main methods of measuring the expansion rate are using Type 1a supernovae and by measuring the cosmic background radiation. Type 1a supernovae are considered standard candle because they have roughly the same absolute magnitude (brightness). The are white dwarf stars in a binary system that are siphoning off mass from their partner. When they reach a critical point of mass, they go supernova. So every Type 1a goes supernova with the same mass, and therefore the same brightness. If we know an object’s absolute magnitude of brightness, then we can calculate its distance. It was this data that lead to the discovery that the universe is accelerating.

But using our models of physics, we can also calculate the expansion of the universe by looking at the cosmic microwave background (CMB) radiation, which is the glow left over after the Big Bang. This gets cooler as the universe expands, and so we can calculate that expansion by looking at the CMB close to us and farther away. Here is where the Hubble Tension comes in. Using Type 1a supernovae, we calculate the Hubble Constant to be 73 km/s per megaparsec. Using the CMB the calculation is 67 km/s/Mpc. These numbers are not close enough – they are very different.

At first it was thought that perhaps the difference is due to imprecision in our measurements. As we gather more and better data (such as building a more complete sample of Type 1a supernovae), using newer and better instruments, some hoped that perhaps these two numbers would come into alignment. The opposite has happened – newer data has solidified the Hubble Tension.

A recent study, for example, uses the Dark Energy Spectroscopic Instrument (DESI) to make more precise measurements of Type 1a’s in the nearby Coma cluster. This is used to make a more precise calibration of our overall measurements of distance in the universe. With this more precise data, the authors argue that the Hubble Tension should now be considered a “Hubble Crisis” (a term which then metastasized throughout reporting headlines). The bottom line is that there really is a disconnect between theory and measurements.

Even more interesting, another group has used updated Type 1a supernovae data to argue that perhaps dark energy does not have to exist at all. This is their argument: The calculation of the Hubble Constant throughout the universe used to establish an accelerating universe is based on the assumption of isotropy and homogeneity at the scale we are observing. Isotropy means that the universe is essentially the same density no matter which direction you look in, while homogeneity means that every piece of the universe is the same as every other piece. So no matter where you are and which direction you look in, you will observe about the same density of mass and energy. This is obviously not true at small scales, like within a galaxy, so the real question is – at what scale does the universe become isotropic and homogenous? Essentially cosmologists have used the assumption of isotropy and homogeneity at the scale of the observable universe to make their calculations regarding expansion. This is called the lambda CDM model (ΛCDM), where lambda is the cosmological constant and CDM is cold dark matter.

This group, however, argues that this is not true. There are vast gaps with little matter, and matter tends to clump along filaments in the universe. If instead you take into account these variations in the density of matter throughout the universe, you get different results for the Hubble Constant. The primary reason for this is General Relativity. This is part of Einstein’s (highly verified) theory that matter affects spacetime. Where matter is dense, time relatively slows down. This means as we look out into the universe, the light that we see is travelling faster through empty space than it is through space with lots of matter, because that matter is causing time to slow down. So if you measure the expansion rate of the universes it will appear faster in gaps and slower in galaxy clusters. As the universe expands, the gaps expand, meaning the later universe will have more gaps and therefore measure a faster acceleration, while the older universe has smaller gaps and therefore measures a slower expansion. They call this the timescape model.

If the timescape model is true, then the expansion of the universe is not accelerating (it’s just an illusion of our observations and assumptions), and therefore there is no need for dark energy. They further argue that their model is a better fit for the data than ΛCDM (but not by much). We need more and better data to definitively determine which model is correct. They are also not mutually exclusive – timescape may explain some but not all of the observed acceleration, still leaving room for some dark energy.

I find this all fascinating. I will admit I am rooting for timescape. I never liked the concept of dark energy. It was always a placeholder, but also just has properties that are really counter-intuitive. For example, dark energy does not dilute as spacetime expands. This does not mean it is false – the universe can be really counterintuitive to us apes with our very narrow perspectives. I will also follow whatever the data says. But wouldn’t it be exciting if an underdog like timescape overturned a Nobel Prize winning discovery, and for at least a second time in my lifetime radically changed how we think about cosmology. Timescape may also resolve the Hubble Tension to boot.

Whatever the answer turns out to be – clearly there is something wrong with our current cosmology. Resolving this “crisis” will expand our knowledge of the universe.

The post The Hubble Tension Hubbub first appeared on NeuroLogica Blog.

Today’s photos come from mathematician and Hero of Intellectual Freedom Abby Thompson of UC Davis, whose avocation is photographing California tide pools and their invertebrates. Abby’s captions are indented, and you can enlarge her photos by clicking on them.

New year’s tidepool pictures from Dillon Beach in northern California, plus a few older photos.  It’s not that much colder during the winter here- August can be freezing, December delightful.   To see much in December you have to be willing to go out after dark, which is a little spooky, but has the advantage that you often get to see racoons foraging on the rocks.    Sadly the only pictures I get of them look like two red dots (their eyes) on a black background.

As usual I got help with some of the IDs from people on inaturalist.

Schuchertinia milleri (tentative):

This is through a microscope, taken with my iphone.  In the tidepools it appears as a small very pink blob stuck to a rock. These are hydroids, closely related to jellyfish, unlikely as that seems.

Kelp crab:

These crabs are one of the few things you should be cautious about in the tidepools here- they are reported to have a strong bite with their claws (I haven’t tested this), and they’re not shy.

The next four pictures are all nudibranchs. As you can see, their coloration is quite varied, but nevertheless they are all the same species. Keep this in mind for when we get to pictures 7,8 and 9.

Triopha maculata 1:

 

Triopha maculata 2:

 

Triopha maculata 3:

 

Triopha maculata 4:

 

Ok, the next two pictures are two distinct species of nudibranch.    To my eye, the difference in coloration here is a bit more subtle than for the Triophas; H. crassicornis has white “stripes” on the frilly stuff on its back.

Hermissenda opalescens:

Hermissenda crassicornis:

And the next picture is of these two local species of Hermissenda hanging out together.  Not exactly in flagrante (nudibranchs spend an awful lot of their time mating and laying eggs), but still, looking pretty friendly. Maybe Jerry will chime in with some info on delimiting species?  and how exactly it is done, for us non-experts. [JAC: two different forms copulating doesn’t resolve their species status!]

Hermissenda opalescens and Hermissenda crassicornis:

Clam siphons:

There is not enough appreciation of bivalves in the world, except as dinner,  Their siphons can be lovely (I admit this may be in the eye of the beholder).

Coryphella trilineata:

A pretty nudibranch. There are lots of this species at the moment.

Pycnogonid stearnsi:

There are several species of “sea spiders” locally.   They’re small (this one was less than an inch across), and lively.      This is the most common here.

Anthopleura artemisia (Moonglow anemone):

You may remember from earlier pictures that this is another species with many dramatically different color variants.

Camera info:  Mostly Olympus TG-7, in microscope mode, pictures taken from above the water.

Countries like the UK, Spain and Italy rely on gas to step in when renewables can’t produce power, leading to higher energy prices – but a more flexible system could avoid this

The soft metal bismuth may be a wonder material for electronics – particularly because of one surprising behaviour it displays when exposed to magnetic fields

The gut microbiome has tremendous potential for helping us treat, or even prevent, many different conditions - but first, we need to understand it better

Sleeping a solid 8 hours isn't the whole story and the quality of your sleep might matter more. But what does sleep quality mean and how can we measure it?

Even as President Donald Trump is inaugurated today and his pick for HHS Secretary, Robert F. Kennedy, Jr. prepares to face confirmation hearings, there is trouble in "make America healthy" paradise.

The post Trouble in (MAHA) paradise? first appeared on Science-Based Medicine.