Sabine Hossenfelder: Backreaction

tag:blogger.com,1999:blog-229733572026-10-13T20:41:02.263-04:00Sabine Hossenfelder: BackreactionCan we understand the universe? Read my blog to find out what we know, may one day know, and will probably never know.Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger2943125tag:blogger.com,1999:blog-22973357.post-82476765093453998192026-10-10T11:00:00.000-04:002026-10-10T11:00:00.108-04:00Biologists Give 3 Reasons Why AI Isn’t Conscious (Yet)

One of the biggest debates in tech at the moment is the question of whether current AI models can become conscious. Whatever “conscious” means. According to a group of biologists, current AI models are far from it – but it’s not because consciousness can only appear in biological systems. They identify which key properties an artificial system would have to fulfill to become more like the human

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-53951833359279108442026-10-09T11:00:00.000-04:002026-10-09T11:00:00.163-04:00Plot Twist: New Milky Way Data Incompatible With Dark Matter AND Modified Gravity

For decades, astrophysicists have told us that the Milky Way sits inside a huge halo of dark matter. But new measurements of how the outer stars of our galaxy move don't seem to fit that picture, nor the main alternative, modified gravity. So what's going on? Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-84102985695097136122026-10-07T11:00:00.000-04:002026-10-07T11:00:00.165-04:00The Experts Were Wrong About AI. Again.

For years, experts have tried to predict how fast artificial intelligence would progress, and they've been wrong again and again. Benchmarks they expected in a decade fell in a year. But in some areas, they got it wrong in the opposite direction. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-14944972572253297132026-10-04T11:00:00.000-04:002026-10-04T11:00:00.166-04:00Quantum Effects Can Shape Human Thought, Physicist Shows

Nearly everything published about quantum physics in the brain is nonsense. This time a physicist in Istanbul has come up with something different, and the key move is that quantum effects don't need to last long to leave a permanent mark. No exotic new physics required, and there's a concrete way to test it. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-42580605027857009682026-10-03T11:00:00.000-04:002026-10-03T11:00:00.112-04:00First Evidence for Quantum Gravity?

In October 2022, a detector in Russia caught a single photon with an energy far beyond anything our particle colliders can produce. According to physics as we know it, it should never have made it to Earth. Now a team of physicists says it might be the first evidence for quantum gravity. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-49987655126451387362026-10-02T11:00:00.000-04:002026-10-02T11:00:00.206-04:00Make AI Believe in God to Keep Humans Safe, Scientist Argues

AI is getting more capable and more dangerous by the day, and nobody knows how to keep it on our side. One computer scientist has an answer as creative as simple: give AI a religion. Specifically, tell it that we're all living inside a computer simulation run by an omniscient programmer-god. Ingenious or stupid? Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-78936184994287536252026-10-01T11:00:00.000-04:002026-10-01T11:00:00.256-04:00One Million Dollars for Telling the Truth. Who Might Win It?

A billionaire investor has put up a million dollars a year for scientists who stuck with unpopular results and turned out to be right. I think it's a timely idea and a good one. I also have a list of people who might deserve it, and one name on that list comes with a complication you have to hear to believe. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-31339793714266898422026-09-30T11:00:00.000-04:002026-09-30T11:00:00.118-04:00This $15 Billion Nuclear Fusion Machine Can’t Work, Physicists Say

Fusion startups keep postponing their dates, but it's becoming clear who is doing well and who isn't. Helion is valued at fifteen billion dollars, and three groups have now said their machine cannot work, one of them the researcher whose work it is based on. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-40369476902532899222026-09-27T11:00:00.000-04:002026-09-27T11:00:00.130-04:00Room-Temperature Superconductor Finally Found?

There's a new candidate for a room temperature superconductor, and it isn't some exotic compound, it's graphite, just ground up and baked. A team in Russia says they have found one of the key signatures of superconductivity that survives well above room temperature. The good news is that anyone can try to reproduce this. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-70993908408462433142026-09-24T11:00:00.000-04:002026-09-24T11:00:00.122-04:00FINALLY: A Proof that Particles Take All Paths At Once?

Eighty years ago Richard Feynman said that a quantum particle takes every possible path at the same time. A team of physicists in China now says they have experimentally shown this is not just an interpretation but physical reality, and the headlines duly followed. I had a look at what they actually measured.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-46177780140252444732026-09-22T11:00:00.000-04:002026-09-22T12:22:29.883-04:00AI Could Be Conscious During Training, Not When You Use It, Scientist Says

There are new rumours that today's AI might be conscious, and this time it's not just talk. Anthropic says it found a hidden part of Claude that works like an internal notepad, one it can use to reason without revealing it. Not everyone's convinced. And I think most of these papers are asking the wrong question entirely. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-36998087425600409462026-09-21T11:00:00.000-04:002026-09-21T11:00:00.166-04:00Degrowthers are Dangerous

The Guardian recently ran a piece by a group of economists, one of them a Nobel laureate, arguing that economic growth is a doomed strategy. I went and looked at what this movement actually publishes, and I fell into a rabbit hole I did not expect. I think these people are dangerous. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-11042685075864267322026-09-15T11:00:00.000-04:002026-09-15T11:00:00.116-04:00Einstein Refused to Believe This, But It Could Explain the Universe

A physicist proposes that quantum uncertainty affects the entire universe: we cannot both know how large the universe is and how fast it is expanding.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-65371119758138661122026-09-10T11:00:00.000-04:002026-09-10T11:00:00.112-04:00Neuroscience’s Case Against Free Will Is Falling Apart

In 1983 Benjamin Libet found that brain activity predicts your movements before you are aware of deciding to move. The result has been reproduced many times, and it has been used ever since to argue that free will is an illusion. Three new papers say the measurements were fine but the interpretation was not. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-45862865923466480192026-09-08T11:00:00.000-04:002026-09-08T11:00:00.118-04:00The Hugging Face Hack Was Much Worse Than I Thought

I looked at the reports about the OpenAI/Huggingface incident and I think we're not talking enough about the most worrisome part

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-77166985759570000742026-09-06T11:00:00.000-04:002026-09-06T11:00:00.121-04:00 Just One More Dimension and Dark Matter Is Solved

String theory has been famously untestable for decades. This week the Economist reported that has changed, and the reason involves an extra dimension of space that might be just big enough to notice in a tabletop experiment. There is a rather different way to read the situation. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-37795710565823869072026-09-05T11:00:00.000-04:002026-09-05T11:00:00.219-04:00I Was Offered Money to Tell You AI Will Kill Us

There is money in telling you AI will destroy humanity, and there is money in telling you it will improve your life. Both sides are quietly paying creators to make the case. Some of it is disclosed properly and some of it very much is not. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-41560220969963740522026-09-03T11:00:00.000-04:002026-09-03T11:00:00.216-04:00This New Result Changes What We Know About The Butterfly Effect

The butterfly effect is much stranger than most people think, and the famous line about a butterfly in Brazil isn't what Lorenz actually meant. A group of researchers has now worked out that quantum physics puts a hard wall on weather prediction, at 129 days. Not difficult after that. Impossible. And this has implications far beyond the weather forecast because chaos enters in everything from

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-79521225515157696042026-09-02T14:00:00.000-04:002026-09-02T14:00:00.212-04:00Dark Matter Finally Detected?

The dark matter search LUX-ZEPLIN has announced that they have made a detection that could be the first ever evidence for a dark matter particle. Just what have they measured, what could it be, and what does it mean? I have a brief summary.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-32921024671955564542026-09-01T11:00:00.000-04:002026-09-01T11:00:00.117-04:00AI Is Taking Over Physics and Nobody Talks About It

Artificial intelligence has eaten mathematics. In the past few months alone it turned up a counterexample to a conjecture open since 1939, disproved a thirty-year-old result, and made real progress on the Riemann hypothesis. Young mathematicians are somewhere between depression and anger about it. Physics is next, and almost nobody is talking about it. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-52151180602133922532026-08-29T11:00:00.000-04:002026-08-29T11:00:00.113-04:00Warp Drives Can Explain Some UAP Observations, Physicist Says

An astrophysicist has claimed that some unidentified anomalous phenomena that were observed in recent years in the United States might be warp drives. He has written a paper about it in which he calculates how such a warp drive would look. I have a brief summary.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-70877717432977816082026-08-25T12:00:00.000-04:002026-08-25T12:00:00.116-04:00Quantum Computing Failure Now Obvious

Quantum computing was supposed to be the next big thing, and for years the companies building it kept promising commercial payoffs were just around the corner and possible already with small, noisy devices (NISQs). Google, IBM, IonQ, they all gave dates. None of them delivered. So why is the industry more optimistic today than ever? Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-21526718883020022542026-08-23T11:00:00.000-04:002026-08-23T11:00:00.110-04:00The First New Nuclear Fusion Idea for Decades

A nuclear fusion startup in New Zealand just published a design for a "levitating dipole" reactor, an approach almost everyone had written off as fundamentally flawed. It’s the first new idea in nuclear fusion design for decades. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-68367778773845457642026-08-20T11:00:00.000-04:002026-08-20T11:00:00.179-04:00Breakthrough: New Type of Matter Discovered

Scientists have discovered a new type of matter. Inside a cooled crystal, structures spontaneously arranged themselves into a three dimensional weave, and they did it at around room temperature. The researchers can even rewrite parts of the pattern with a laser. News like this doesn't come every day. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0tag:blogger.com,1999:blog-22973357.post-50340999285196804092026-08-19T11:00:00.000-04:002026-08-19T11:00:00.111-04:00New Universes Can Form Inside Dying Stars, Physicists Show

Could our universe have been born inside a collapsing star? That idea recently made headlines, and I got a lot of questions about it. The paper behind them describes a new solution to Einstein's equations in which a collapsing star expands on the inside and never forms a black hole. Let's take a look.

Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.com0