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Nano-immunotherapy developed to improve lung cancer treatment

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:19am
Researchers have developed a new nanomedicine therapy that delivers anticancer drugs to lung cancer cells and enhances the immune system's ability to fight cancer. The team showed promising results for the new therapy in cancer cells in the lab and in mouse lung tumor models, with potential applications for improving care and outcomes for patients with tumors that have failed to respond to traditional immunotherapy.
Categories: Science

Researchers use large language models to help robots navigate

Computers and Math from Science Daily Feed - Fri, 06/14/2024 - 11:19am
A technique can plan a trajectory for a robot using only language-based inputs. While it can't outperform vision-based approaches, it could be useful in settings that lack visual data to use for training.
Categories: Science

Researchers use large language models to help robots navigate

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:19am
A technique can plan a trajectory for a robot using only language-based inputs. While it can't outperform vision-based approaches, it could be useful in settings that lack visual data to use for training.
Categories: Science

New approach to identifying altermagnetic materials

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:19am
An international team has discovered a spectrum characteristic of an altermagnetic material with X-ray magnetic circular dichroism.
Categories: Science

High-precision measurements challenge our understanding of Cepheids

Space and time from Science Daily Feed - Fri, 06/14/2024 - 11:19am
Scientists have clocked the speed of Cepheid stars -- 'standard candles' that help us measure the size of the universe -- with unprecedented precision, offering exciting new insights about them.
Categories: Science

A liquid crystal source of photon pairs

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:19am
Spontaneous parametric down-conversion (SPDC), as a source of entangled photons, is of great interest for quantum physics and quantum technology, but so far it could be only implemented in solids. Researchers have demonstrated, for the first time, SPDC in a liquid crystal. The results open a path to a new generation of quantum sources: efficient and electric-field tunable.
Categories: Science

Strengthener for graphene

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:19am
Layers of carbon atoms in a honeycomb array are a true supermaterial: their unusually high conductivity and favorable mechanical properties could further the development of bendable electronics, new batteries, and innovative composite materials for aeronautics and space flight. However, the development of elastic and tough films remains a challenge. A research team has now introduced a method to overcome this hurdle: they linked graphene nanolayers via 'extendable' bridging structures.
Categories: Science

Self-assembling and disassembling swarm molecular robots via DNA molecular controller

Computers and Math from Science Daily Feed - Fri, 06/14/2024 - 11:18am
Researchers have succeeded in developing a DNA-based molecular controller. Crucially, this controller enables the autonomous assembly and disassembly of molecular robots, as opposed to manually directing it.
Categories: Science

Self-assembling and disassembling swarm molecular robots via DNA molecular controller

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:18am
Researchers have succeeded in developing a DNA-based molecular controller. Crucially, this controller enables the autonomous assembly and disassembly of molecular robots, as opposed to manually directing it.
Categories: Science

Concrete-nitrogen mix may provide major health and environment benefits

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:18am
Adding nitrogen to concrete could significantly reduce the amount of greenhouse gases created by the construction industry.
Categories: Science

Synthetic data holds the key to determining best statewide transit investments

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:18am
Synthetically generated population data can reveal the equity impacts of distributing transportation resources and funding across diverse regions, according to new research.
Categories: Science

Novel insights into fluorescent 'dark states' illuminate ways forward for improved imaging

Matter and energy from Science Daily Feed - Fri, 06/14/2024 - 11:18am
Scientists address decades-long problem in the field of single-molecule fluorescence resonance energy transfer, paving the way for more accurate experiments.
Categories: Science

Hungry Heart

Why Evolution is True Feed - Fri, 06/14/2024 - 10:00am

How about some Friday music? I’m not as huge a fan of The Boss as many, but this one song from 1980, which he wrote and performed, is enough to make me an admirer. (I also love “Blinded by the Light”.)

The opening chords (including the introductory drumroll) are simply fantastic, and I also like the the lyrics: a guy leaves his wife and family because he’s dissatisfied, but is still hungering for love. It’s not a happy message, but one that rings true. The first verse is great:

Got a wife and kids in Baltimore, JackI went out for a ride and I never went back;Like a river that don’t know where it’s flowingI took a wrong turn and I just kept going

According to Wikipedia, “Hungry Heart” reached #5 on the Billboard charts in 1980, but was later voted “Song of the Year” in a Rolling Stone readers’ poll.  Wikipedia adds this:

John Lennon, on the day of his murder in December 1980, said he thought “Hungry Heart” was “a great record” and even compared it to his single “(Just Like) Starting Over“, which was actually released three days after “Hungry Heart”.

Here’s the best “live” performance I can find, though it may well be lip synched; the original recording is here.

Categories: Science

Echoes of Flares from the Milky Way’s Supermassive Black Hole

Universe Today Feed - Fri, 06/14/2024 - 9:55am

The supermassive black hole at the heart of our Milky Way Galaxy is a quiet monster. However, Sagittarius A* (or Sgr A* for short) is not totally dormant. Occasionally it gobbles down a blob of molecular gas or even a star and then suffers a bit of indigestion. That emits x-ray flares to surrounding space.

Sgr A* is the closest supermassive black hole to Earth, at a distance of 26,000 light-years. Studying the nearby environment is tough due to the black hole’s intense gravitational pull. It distorts the view of nearby objects, making them difficult to observe. However, there are ways to do it by looking at the effect of its flares on nearby molecular clouds. Astronomers recently found the centuries-old echoes of previously unknown flares that occurred long before there were telescopes to observe them. Those echoes indicate that Sgr A* eats fairly often.

Two researchers from Michigan State University—Grace Sanger-Johnson and Jack Uteg—studied the flares and their light-echoes in detail. What they found shows activity at Sgr A* in the very distant past when Sgr A* ingested material. X-ray emissions from that activity traveled for hundreds of years from Sgr A* to bounce off of and brighten a nearby molecular cloud. That created a light echo that traveled another roughly 26,000 years before reaching Earth. So, when Uteg and Sanger studied these flares and light echoes, they were literally looking into the past.

Astronomers do know about outbursts from Sgr A* from other observations. Here’s a view from NASA’s Imaging X-ray Polarimetry Explorer and Chandra X-ray Observatory. The combination of IXPE and Chandra data helped researchers determine that the X-ray light identified in the molecular clouds originated from Sagittarius A* during an outburst approximately 200 years ago. Credits: IXPE: NASA/MSFC/F. Marin et al; Chandra: NASA/CXC/SAO; Image Processing: L.Frattare, J.Major & K.Arcand Searching for Sgr A* X-ray Flares with NuSTAR

Sanger-Johnson analyzed ten years’ worth of data looking for X-ray flares generated by Sgr A*’s eating habits. During the search, she found evidence for nine more such outbursts.

The flares are typically quite dramatic. Because they’re so bright, they provide astronomers a chance to study the immediate environment around the black hole. The data Sanger-Johnson studied came from the NuSTAR mission. It zeroes in on high-energy X-ray and gamma-ray emissions. These typically come from active regions in the hearts of galaxies, supernova explosions, and other active events.

The data Sanger-Johnson collected and analyzed is now a database of flares from Sgr A. “We hope that by building up this bank of data on Sgr A flares, we and other astronomers can analyze the properties of these X-ray flares and infer the physical conditions inside the extreme environment of the supermassive black hole,” Sanger-Johnson said.

Tracking the Echoes of Flares

While Sanger-Johnson was working with the NuSTAR data, undergraduate researcher Jack Uteg studied the activity around the black hole. He analyzed 20 years of data about a giant molecular cloud called “the Bridge”. The data came from observations made by NuSTAR and the European Space Agency’s XMM-Newton observatory. The Bridge lies close to Sgr A* and normally wouldn’t give off its own light.

So, astronomers took notice when it brightened up in X-rays, according to Uteg, who is constructing a timeline of Sgr A‘s past outbursts. “The brightness we see is most likely the delayed reflection of past X-ray outbursts from Sgr A,” he said. “We first observed an increase in luminosity around 2008. Then, for the next 12 years, X-ray signals from the Bridge continued to increase until it hit peak brightness in 2020.”

Uteg’s work helped astronomers determine that Sgr A* was about five orders of magnitude brighter in X-rays than it is now. That brightening indicates our central supermassive black hole had probably cannibalized a nearby gas cloud. And, the brightness revealed other properties, according to Uteg. “One of the main reasons we care about this cloud getting brighter is that it lets us constrain how bright the Sgr A* outburst was in the past,” he said.

What Those Light-echoes from Sgr A* Reveal

Thanks to Sanger-Brown and Uteg’s work, astronomers have another way around the difficulties of observing around black holes. “Both flares and fireworks light up the darkness and help us observe things we wouldn’t normally be able to,” she said. “That’s why astronomers need to know when and where these flares occur, so they can study the black hole’s environment using that light.”

Astronomers know that the black hole does gobble up nearby material on a variable basis, but these findings help them constrain how often it happens and how the resulting flares affect the nearby neighborhood. Many questions remain about how often these flares occur and have happened in the past, according to MSU assistant professor Shuo Zhang, who acted as team lead for these two studies.

“This is the first time that we have constructed a 24-year-long variability for a molecular cloud surrounding our supermassive black hole that has reached its peak X-ray luminosity,” Zhang said. “It allows us to tell the past activity of Sgr A* from about 200 years ago. Our research team at MSU will continue this ‘astroarchaeology game’ to further unravel the mysteries of the Milky Way’s center.”

These results of the MSU team’s work were presented at the summer 2024 meeting of the American Astronomical Society.

For More Information

‘Flares’ and ‘Echoes’ from the Milky Way’s Monster Black Hole

About NuStar

About XMM-Newton

The post Echoes of Flares from the Milky Way’s Supermassive Black Hole appeared first on Universe Today.

Categories: Science

Hybrid design could make nuclear fusion reactors more efficient

New Scientist Feed - Fri, 06/14/2024 - 9:19am
Two types of fusion reactor called tokamaks and stellarators both have drawbacks – but a new design combining parts from both could offer the best of both worlds
Categories: Science

Did rock art spread from one place or was it invented many times?

New Scientist Feed - Fri, 06/14/2024 - 9:00am
Rock art is a truly global phenomenon, with discoveries of cave paintings and etchings on every continent that ancient humans inhabited – but how many times was it invented over human history?
Categories: Science

Richard Dawkins talks with Ayaan Hirsi Ali about why she’s a Christian and what she really believes

Why Evolution is True Feed - Fri, 06/14/2024 - 7:50am

I watch few videos and listen to few podcasts, but this is one I recommend highly.

As most of us know, Ayaan Hirsi Ali declared recently that she had given up atheism and had become a Christian. In the Unherd article to which I linked, she argued that her belief rested largely on seeing Christianity as a bulwark against sinister forces, like Islam and Chinese Communism, out to destroy Western civilization. As she said in that article:

So, what changed? Why do I call myself a Christian now?

Part of the answer is global. Western civilisation is under threat from three different but related forces: the resurgence of great-power authoritarianism and expansionism in the forms of the Chinese Communist Party and Vladimir Putin’s Russia; the rise of global Islamism, which threatens to mobilise a vast population against the West; and the viral spread of woke ideology, which is eating into the moral fibre of the next generation.

We endeavour to fend off these threats with modern, secular tools: military, economic, diplomatic and technological efforts to defeat, bribe, persuade, appease or surveil. And yet, with every round of conflict, we find ourselves losing ground. We are either running out of money, with our national debt in the tens of trillions of dollars, or we are losing our lead in the technological race with China.

But we can’t fight off these formidable forces unless we can answer the question: what is it that unites us? The response that “God is dead!” seems insufficient. So, too, does the attempt to find solace in “the rules-based liberal international order”. The only credible answer, I believe, lies in our desire to uphold the legacy of the Judeo-Christian tradition.

This, of course, left some questions, most notably this: Does Hirsi Ali really believe the tenets of Christianity—for example the divinity and Resurrection of Jesus—or did she accept it on the basis of its salubrious effects on society? In the 70-minute discussion below between atheist Richard Dawkins and newly-formed Christian Hirsi Ali, that question is answered, but we also learn that Hirsi Ali came to Christianity for reasons beyond its effects on society. In fact, we learn that she became a Christian mainly because of its effects on her own well being.

First, the YouTube notes, apparently written by Richard:

Ayaan Hirsi Ali is a hero, a staunch fighter against the violent intolerance and bossy control freakery of Islamism. She is also a personal friend of whom I am very fond. When she recently announced her conversion to Christianity, I assumed that she must be no more than a political Christian, regarding Christianity as a bulwark against Islam. I have some sympathy with the view that if you must have a religion at all, Christianity is hugely better than the leading alternative. In Hilaire Belloc’s words, “Always keep a-hold of Nurse for fear of finding something worse.”

I agreed to have a public conversation with her in New York, in which I was all prepared to emphasize the distinction between a political Christian and a true believing Christian, who actually thinks Jesus was born of a virgin and rose from the dead. I think the distinction is a really important one. I don’t think a political Christian is a real Christian, any more than the kind of cultural Christian I am myself.

When we met on the stage at the Dissident Dialogues meeting in New York, I was wrongfooted when Ayaan began with a personal statement which seemed to suggest that she really is a believing Christian, not just a political Christian. Well, her form of words was “I choose to believe.” I’m not sure what to make of that. Anyways, see what you think; here is the recording of our New York meeting.

The upshot is that their disagreement is almost entirely about faith versus fact. Richard sees Christianity, and theism in general, as an empirical hypothesis—one of great importance if it were true.  But, like me, he sees little evidence for the tenets of Christianity, or for the existence of a God, and that there is also not inconsiderable evidence against the tenets of Christianity.

Hirsi Ali, on the other hand, accepted Christianity since it helped her in a time of crisis, because she sees it as having filled the “spiritual void” that was inside her during a period of mental instability.  She then became a real, believing Christian because of that, but also because she chose to believe the message of Christianity, which she sees as one of love and acceptance. And with the acceptance of that message came the acceptance of Christian tenets like the divinity and resurrection of Jesus, the virginity of Mary, and so on. (She’s not sure if there’s a soul that survives us after death.)  These are things that, she says repeatedly, she chooses to believe because they helped her personally. The empirical truth of these tenets she takes as a “different plane of perception,” which I construe as “a different way of knowing”. It is a subjective, emotional way of knowing, not all that different from the “other way of knowing” of people like the Māori.

Over and over again, Richard tries to draw the conversation back to the issue of what is empirically true—that is, what nearly all reasonable people would agree what really exists in the universe if were they given the evidence.  As a scientist, Richard is truth-based, always looking for the relevant empirical evidence. In contrast, Hirsi Ali looks within and sees whether the message and tenets of Christianity comport not only with what not only soothes her, but also seems “wise.” I’ll give a brief conclusion before the video, which I urge you to watch, but indented below are a few notes I made while watching the video.

Here are a few notes I took during the discussion. I’ve indented them, but they’re my own words:

In 2024, Hirsi Ali says she experienced a personal crisis, involving anxiety, depression, and self-loathing. It got to the point that didn’t want to live any more. She started self-medicating and consulting psychiatrists, seeing these potential remedies as “evidence-based science”. But nothing worked until one therapist diagnosed her with “spiritual bankruptcy”.  So Hirsi Ali started praying because she “had absolutely nothing to lose”.  She then immediately felt “connected to something higher and greater than herself.” That was Christianity, and she considered her discovery of it a “miracle.” She goes on to say that her conversion is hard to explain, but she is writing a book about it.

Dawkins responds by asserting that a “Christian has to believe in something“, and wonders what, exactly, does she believe about Christianity: did Jesus rise from the dead, was he the son of God and son of a virgin, and so on?  She responds that these tenets of Christianity “make sense and are wise.” And so she no longer mocks faith, but argues says that people with faith have something that atheists don’t have. (My response: yes, they have faith: belief in what consoles them regardless of its truth.) Judging by the applause, the audience seems to be sympathetic with Hirsi Ali’s view of the salubrious nature of religion.

The difference between the two is summarized in Hirsi Ali’s statement,  “I choose to accept the story of Jesus Christ”, and that that belief rests on a “different ways of perception.” It is “her choice”.

She adds that the message of Western civilization is “essentially Christian”, something that is often told to atheists to silence them: “The whole basis for our culture (and your morality)”, they tell us, “is Christianity.” I find this a debatable assertion, since the whole basis of Judaism is not Christianity, and essentially there is no difference in moral values between Jews and Christians. (Islam, however, is a different matter. I would have asked Hirsi Ali if she thought that Jews, who don’t accept Jesus as the son of God, are doomed and will go to hell. Further, the Enlightenment was a rejection of Christian authoritarianism, so can you praise something because its rejection led to better things?

You have to hand it to Richard. He pulls no punches with Hirsi Ali, saying that the whole Christian story of original sin and our salvation through belief in Jesus is  “obvious nonsense” and “theological bullshit”.  Christianity, he says, is obsessed with sin. But you also have to hand it to Hirsi Ali for standing by her guns (even though I disagree with her): she responds that “Christianity is obsessed with love.” (Loud applause follows; the audience are clearly, as Dennett might have said, “Believers in belief.”)  I’m not sure, further, having watched American Christians, whether in general they’re “obsessed with love”.

Richard again says that if you’re a Christian, you have to accept its empirical assertions along with its moral messages; in his words, “You have to take the whole package”.  Ayaan responds again why she believes that Jesus rose from the dead. . . “it is a matter of choice.” She compares Dawkins being moved by art and music to her being moved by religion, though I disagree with this comparison, for nobody asks whether art and music are “true”, only whether they move you or not.

Hirsi Ali apparently thinks that others should accept Christianity, too, so it isn’t simply a personal choice for her, but one that she thinks others should make to both improve their own mental health and Western society. She is no proselytizer, but does argue that others should become Christians, too. I certainly can’t, for I can’t force myself to believe something that I’ve rejected after long thought, and does Hirsi Ali think that children should be brought up believing Christianity is true? (This question isn’t answered.)

Dawkins clarifies that he sees the hypothesis of theism as a scientific hypothesis, and an important one, but one for which there is no evidence. Hirsi Ali says that, religion, contrary to atheism, “offers you something.”  Richard says that yes, faith offers you something comforting, but “that doesn’t make it true.”  Hirsi Ali then advances the recent argument that evidence for God lies in the observation that “there is something rather than nothing” in the universe. To that I’d add that that is a fallacious argument, but even if it did point to a Creator, it wouldn’t for a minute point to the Christian God.

My Take (after hearing it all): This is a very good and civil argument between two smart and thoughtful people, but in the end they epitomize two different ways of perceiving truth. Richard instantiates the scientific approach: you believe in something in proportion to the amount of evidence supporting it. Ayaan epitomizes the “other ways of knowing”: if you feel something is true, and especially if your belief make you feel better, then that is evidence that it is true.

It’s clear, as you’d see if you read my book Faith versus Fact, that I agree with Richard. You can believe what you want, and are welcome to believe what makes you feel better, but subjective “truth” is no way to ascertain what really exists in the universe. Some religious beliefs may help you, and some may help society, but that is also true of secular humanism, and I see secular humanism as a non-divisive guide for conduct that doesn’t rest on superstition.  Almost by definition, secular humanism is not divisive.

And, as northern Europe and Scandinavia show us, a society doesn’t have to accept the tenets of Christianity to be a good and moral society. Data tell us that the religiosity of a country (or of U.S. states) is negatively correlated with the well-being and happiness of its inhabitants. I don’t see how you can ascribe that to Christianity, much religion in general.

Although the audience and the moderator, who says he’s a Christian, appear to be “believers in belief”, I must disagree with Hirsi Ali’s claim that what she subjectively perceives to be true IS true, and that atheism is dangerous to society. Atheism is simply the absence of belief in the supernatural, and of course people want to have a “meaning and purpose” for their lives. Yet, as I’ve argued, “meaning and purpose” are delineated post facto—after people find what makes them feel good and fulfilled. (See my 2018 post when I asked readers what they see as the meaning and purpose of their lives. Virtually nobody named religion as one of those sources.) Steve Pinker has argued, in my view convincingly, that the moral improvement of society in the last 400 years or so has involved the rejection of religion (Christianity existed well before the moral improvement that Pinker discusses). You’ll have to read his two big books (Better Angels and Enlightenment Now) to see his argument in full. (The subtitle of the second book is “The Case for Readson, Humanism, Science, and Progress.”) I recommend those books to everyone. Yes, they’re long, and are criticized by those misguided souls who think there’s been no moral or material progress of humanity, but I think they’re excellent and on the mark.

In the end, I think Hirsi Ali makes as good a case for Christianity as can be made. But Richard shows, to me at least, that her case is weak, as it’s based on delusions and superstitions that made her feel good and, that she thinks, will make others also feel good while at the same time staving off the forces of nescience and authoritarianism.

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

I invite readers to take an hour and listen to the video below.  And then weigh in in the comments. Do we need people to be religious to stave off anti-Western values and to improve their mental health? Did the Enlightenment and secular humanism really come from Christianity, as Hirsi Ali says, or was it a reaction against Christianity, as Dawkins claims?  Do we need Christianity as THE faith that will fill society’s moral vacuum (if there is one)? And is there really a moral vacuum now, compared to say, five hundred years ago?

Updates: First, I just discovered that Hirsi Ali now has her own Substack site, called “Restoration” (she’s not the only author). If you want to follow her intellectual and spiritual journey, click on the link, though at $75 per year it’s pricier than many other such sites.

And I couldn’t resist adding this quote from the eminent nonbeliever H. L. Mencken.  What if a religion dictates something that you think is immoral? Chritianity certainly does, at least for liberal humanists (see “Catholicism”):

Categories: Science

Warp Drives Could Generate Gravitational Waves

Universe Today Feed - Fri, 06/14/2024 - 7:09am

Will future humans use warp drives to explore the cosmos? We’re in no position to eliminate the possibility. But if our distant descendants ever do, it won’t involve dilithium crystals, and Scottish accents will have evaporated into history by then.

Warp drives have their roots in one of the most popular science fiction franchises ever, but they do have a scientific basis. A new paper examines the science behind them and asks if a warp drive containment failure would emit detectable gravitational waves.

The paper is titled “What no one has seen before: gravitational waveforms from warp drive collapse.” The authors are Katy Clough, Tim Dietrich, and Sebastian Khan, physicists from institutions in the UK and Germany.

There’s room for warp drives in General Relativity, and Mexican physicist Miguel Alcubierre described how they could theoretically work in 1994. He’s well-known in space and physics circles for his Alcubierre Drive.

Everyone knows that no object can travel faster than the speed of light. But warp drives may offer a workaround. By warping spacetime itself, a spacecraft with a warp drive wouldn’t be breaking the faster-than-light (FTL) rule.

“Despite originating in science fiction, warp drives have a concrete description in general relativity, with Alcubierre first proposing a spacetime metric that supported faster-than-light travel,” the authors write.

There are clear scientific barriers to actually making a warp drive. But it’s possible to simulate how one would work and how they may be detectable via gravitational waves in the event of a failure. Warp drives distort spacetime itself, just like binary mergers of compact objects like black holes and neutron stars. It’s theoretically possible that they emit a gravitational wave signal in the same vein as mergers. “To search for such signals and to correctly identify them in the measured data, it is important to understand their phenomenology and properties,” the authors explain.

It begins with understanding how warp drives might work, and for that, we have to delve deeply into physics.

“The principle idea behind a warp drive is that instead of exceeding the speed of light directly in a local reference frame, which would violate Lorentz invariance, a “warp bubble” could traverse distances faster than the speed of light (as measured by some distant observer) by contracting spacetime in front of it and expanding spacetime behind it,” the paper states.

The first barrier is that warp drives require a Null Energy Condition (NEC). Physics states that a region of space cannot have a negative energy density. There are theoretical workarounds for that, but for now, none of them are practical.

“Other issues with the warp drive metric include the potential for closed time-like curves and, from a more practical perspective, the difficulties for those in the ship in controlling and deactivating the bubble,” the authors explain. This is because there would be no way for the crew to send signals to the front of the ship. It’s difficult for events inside the bubble to influence events outside the warp bubble, as this paper explains.

“From the perspective of simulating the warp drive dynamically, the key challenge is stability,” the authors explain. Equations show that the Alcubierre Drive can initiate a warp bubble using the Einstein Equation, but no known equations can sustain it. “There is (to our knowledge) no known equation of state that would maintain the warp drive metric in a stable configuration over time. Therefore, whilst one can require that initially, the warp bubble is constant, it will quickly evolve away from that state, and, in most cases, the warp fluid and spacetime deformations will disperse or collapse into a central point.”

Though instability is a prime obstacle to warp drives, it’s also what could make them detectable. If an Alcubierre Drive achieves a constant velocity, it’s not detectable. It generates no gravitational waves and has no ADM mass. ADM stands for Arnowitt–Deser—Misner, named for three physicists. I’ll leave it to curious readers to read more about ADM mass.

But the warp drive is only undetectable if it’s constant and stable. Once it breaks down, accelerates or decelerates, it could be detectable. In their work, the authors allow the warp drive bubble to collapse. “Physically, this could be related to a breakdown in the containment field that the post-warp civilization (presumably) uses to support the warp bubble against collapse,” they write.

In their formulations, the nature of the ship itself isn’t important. Only the warp bubble and the warp fluid inside are significant.

The researchers simulated the breakdown of the warp bubble. They found that the collapse generated gravitational waves with characteristics different from those generated by mergers. “The signal comes as a burst, initially having no gravitational wave content, followed by an oscillatory period with a characteristic frequency of order 1/[R],” they write. “Overall, the signal is very distinct from the typical compact binary coalescences observed by gravitational wave detectors and more similar to events like the collapse of an unstable neutron star or the head-on collision of two black holes.”

The authors point out that though the warp drive creates a GW signal, it’s outside the frequency range of our current ground-based detectors. “Proposals for higher frequency detectors have been made, so in the future, one may be able to put bounds on the existence of such signals,” they write.

The ship itself could also send some type of multimessenger signal, but it’s difficult to know how the ship’s matter would interact with regular matter. “Since we do not know the type of matter used to construct the warp ship, we do not know whether it would interact (apart from gravitationally) with normal matter as it propagates through the Universe,” the researchers explain.

This is a fun thought experiment. It’s possible that some type of workaround to FTL travel will exist one day in the distant future. If it does, it may be related to a better understanding of dark matter and dark energy. If any ETIs exist, they may be in a position to exploit fundamental knowledge of the Universe that we don’t yet possess.

If they’ve figured out how to construct and use a warp drive, even with all of its seeming impossibilities, their activities might create gravitational waves that our future observatories could detect, even in other galaxies. But for now, it’s all theoretical.

“We caution that the waveforms obtained are likely to be highly specific to the model employed, which has several known theoretical problems, as discussed in the Introduction,” the authors write in their conclusion. “Further work would be required to understand how generic the signatures are and properly characterize their detectability.”

Without a doubt, some curious physicists will continue to work on this.

The post Warp Drives Could Generate Gravitational Waves appeared first on Universe Today.

Categories: Science

Readers’ wildlife photos

Why Evolution is True Feed - Fri, 06/14/2024 - 6:15am

Thanks to readers who sent in their photos. Today we have ecologist Susan Harrison‘s batch of photos of Arctic seabirds. Her captions and IDs are indented, and you can enlarge the photos by clicking on them.

Visit to an Arctic seabird island

On a May trip to the Arctic regions of Finland and Norway, one of the highlights was a visit to the seabird colony on Hornoya, a tiny island in the Barents Sea that is home to something like 80,000 nesting birds.

Hornoya is reached by a 15-minute boat ride from Vardo, a small town where Norwegian dried fish were for many centuries traded for Russian grain, and where an infamous series of 17th-century witch trials took place.  Despite its age, Vardo lacks historic buildings since the retreating Germans leveled it in 1944. Vardo now gets by on fishing, ecotourism, and a radar antenna array that may possibly be listening to Russian submarines in nearby Murmansk.

Vardo with a Yellow-Billed Loon (Gavia adamsii), found only in the high Arctic, floating in the foreground:

Yellow-Billed Loon closeup:

Black-Legged Kittiwake (Rissa tridactyla) nests festooning Vardo buildings:

Common Murres (Uria aalge) on the water, and the Hornoya Island tour boat returning to Vardo:

Common Murres circling Hornoya Island and nesting on its cliffs:

Common Murre closeup:

Razorbills (Alca torda) mating and nesting:

European Shags (Gulosus aristotelis) courting and nesting:

Atlantic Puffins (Fratercula arctica) socializing and nesting:

Birdwatchers waiting for the return boat to Vardo:

Categories: Science

UK election: How can the next government get climate goals on track?

New Scientist Feed - Fri, 06/14/2024 - 6:00am
The UK’s journey to net zero has stalled – whoever wins the 4 July election will need to get it moving again, but many climate scientists are frustrated with what the main parties are offering
Categories: Science

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