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The End of the “End of Science”

Question: Can science give us a precise image of the universe?

David Albert: Oh, I see what you're saying. Look, that is -- throughout most of the 20th century, what was widely considered to be the lesson of quantum mechanics, what was widely considered to be the upshot, the deep upshot of our scientific investigations of subatomic particles, was precisely that: the thought that science was going to ultimately give us a picture of the world all the way to the bottom, which we were going to be able to carry around in our heads -- okay? -- which we were going to be able to understand in the way we understand billiard balls colliding with one another or something like that. It's widely been thought to be the upshot of quantum mechanics that those expectations of science have now been exposed as quaint and naïve and old-fashioned, and moreover as presumptuous, okay? Who were we to think, with these brains evolved for very different purposes of hunting and gathering and so forth, that there was going to be this kind of intelligible, mechanical model of the world that we were going to be able to get our heads around, okay?

And indeed, the response to this measurement problem throughout most of the 20th century was precisely that: look, this is where our scientific imagination gives out in its attempt to penetrate the world. We have encountered for the first time ever the ultimate limits of the capacity of the scientific project to penetrate into the foundations of the world. We're not going to get farther than this; we should be thankful enough that we have a good mechanism for predicting the behaviors of these particles, and so on and so forth. That was very much the consensus throughout most of the 20th century. And if students were to raise their hands and say, gee, how can you be so sure of this? I mean, have people tried to make these modifications, blah blah blah? -- those students would be referred to a number of famous so-called no-go theorems or no hidden variable theorems, the most famous of which for most of the century was one due to the mathematician John von Neumann.

And it wasn't until rather late in the century that attention began to be focused on the fact that these theorems and these arguments that we couldn't do better than this were hasty, were premature; that the theorems, especially the von Neumann theorem, was just a very flawed theorem. The mathematics was completely correct, but the presumptions that he started with were much too restrictive. There was no reason to be persuaded that those assumptions were true. And since then, mostly over the past 25 years, enormous progress has been made, okay, in actually proposing ways to tinker with these fundamental equations in such a way as to solve this problem, in such a way as indeed to provide us with precisely the sort of thoroughly intelligible mechanical picture of what was going on that was said for most of the 20th century to be quaint and outmoded and immature and so on and so forth.

So yeah, you're right: throughout most of the 20th century the reaction was, the lesson to take from this is that there are limits to the capacity of the human scientific imagination to penetrate the mysteries of nature; and the mature thing to do, the grownup thing to do, is to accept these limits. It isn't until recently that it's become clear that these pronouncements were enormously premature. Who knows if we're going to finish the scientific project or not? Who knows if we're every going to get to the bottom of it? But there is this really interesting episode in the 20th century where it was thought that we had. And it's now becoming clearer and clearer that the announcements of the death of this project, after Mark Twain, were greatly exaggerated.

Throughout much of the 20th century, quantum mechanics seemed to kill the idea that human beings could develop an "intelligible, mechanical model of the world." But today, the search for a "simple" model of the physical world is alive and well.

The “new normal” paradox: What COVID-19 has revealed about higher education

Higher education faces challenges that are unlike any other industry. What path will ASU, and universities like ASU, take in a post-COVID world?

Photo: Luis Robayo/AFP via Getty Images
Sponsored by Charles Koch Foundation
  • Everywhere you turn, the idea that coronavirus has brought on a "new normal" is present and true. But for higher education, COVID-19 exposes a long list of pernicious old problems more than it presents new problems.
  • It was widely known, yet ignored, that digital instruction must be embraced. When combined with traditional, in-person teaching, it can enhance student learning outcomes at scale.
  • COVID-19 has forced institutions to understand that far too many higher education outcomes are determined by a student's family income, and in the context of COVID-19 this means that lower-income students, first-generation students and students of color will be disproportionately afflicted.
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What if Middle-earth was in Pakistan?

Iranian Tolkien scholar finds intriguing parallels between subcontinental geography and famous map of Middle-earth.

Image: Mohammad Reza Kamali, reproduced with kind permission
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  • J.R.R. Tolkien hinted that his stories are set in a really ancient version of Europe.
  • But a fantasy realm can be inspired by a variety of places; and perhaps so is Tolkien's world.
  • These intriguing similarities with Asian topography show that it may be time to 'decolonise' Middle-earth.
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Giant whale sharks have teeth on their eyeballs

The ocean's largest shark relies on vision more than previously believed.

Photo by Koichi Kamoshida/Getty Images
Surprising Science
  • Japanese researchers discovered that the whale shark has "tiny teeth"—dermal denticles—protecting its eyes from abrasion.
  • They also found the shark is able to retract its eyeball into the eye socket.
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NASA releases first sounds ever captured on Mars

On Friday, NASA's InSight Mars lander captured and transmitted historic audio from the red planet.

NASA
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  • The audio captured by the lander is of Martian winds blowing at an estimated 10 to 15 mph.
  • It was taken by the InSight Mars lander, which is designed to help scientists learn more about the formation of rocky planets, and possibly discover liquid water on Mars.
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A massive star has mysteriously vanished, confusing astronomers

A gigantic star makes off during an eight-year gap in observations.

Image source: ESO/L. Calçada
Surprising Science
  • The massive star in the Kinsman Dwarf Galaxy seems to have disappeared between 2011 and 2019.
  • It's likely that it erupted, but could it have collapsed into a black hole without a supernova?
  • Maybe it's still there, but much less luminous and/or covered by dust.

A "very massive star" in the Kinman Dwarf galaxy caught the attention of astronomers in the early years of the 2000s: It seemed to be reaching a late-ish chapter in its life story and offered a rare chance to observe the death of a large star in a region low in metallicity. However, by the time scientists had the chance to turn the European Southern Observatory's (ESO) Very Large Telescope (VLT) in Paranal, Chile back around to it in 2019 — it's not a slow-turner, just an in-demand device — it was utterly gone without a trace. But how?

The two leading theories about what happened are that either it's still there, still erupting its way through its death throes, with less luminosity and perhaps obscured by dust, or it just up and collapsed into a black hole without going through a supernova stage. "If true, this would be the first direct detection of such a monster star ending its life in this manner," says Andrew Allan of Trinity College Dublin, Ireland, leader of the observation team whose study is published in Monthly Notices of the Royal Astronomical Society.

So, em...

Between astronomers' last look in 2011 and 2019 is a large enough interval of time for something to happen. Not that 2001 (when it was first observed) or 2019 have much meaning, since we're always watching the past out there and the Kinman Dwarf Galaxy is 75 million light years away. We often think of cosmic events as slow-moving phenomena because so often their follow-on effects are massive and unfold to us over time. But things happen just as fast big as small. The number of things that happened in the first 10 millionth of a trillionth of a trillionth of a trillionth of a second after the Big Bang, for example, is insane.

In any event, the Kinsman Dwarf Galaxy, or PHL 293B, is far way, too far for astronomers to directly observe its stars. Their presence can be inferred from spectroscopic signatures — specifically, PHL 293B between 2001 and 2011 consistently featured strong signatures of hydrogen that indicated the presence of a massive "luminous blue variable" (LBV) star about 2.5 times more brilliant than our Sun. Astronomers suspect that some very large stars may spend their final years as LBVs.

Though LBVs are known to experience radical shifts in spectra and brightness, they reliably leave specific traces that help confirm their ongoing presence. In 2019 the hydrogen signatures, and such traces, were gone. Allan says, "It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion."

The Kinsman Dwarf Galaxy, or PHL 293B, is one of the most metal-poor galaxies known. Explosive, massive, Wolf-Rayet stars are seldom seen in such environments — NASA refers to such stars as those that "live fast, die hard." Red supergiants are also rare to low Z environments. The now-missing star was looked to as a rare opportunity to observe a massive star's late stages in such an environment.

Celestial sleuthing

In August 2019, the team pointed the four eight-meter telescopes of ESO's ESPRESSO array simultaneously toward the LBV's former location: nothing. They also gave the VLT's X-shooter instrument a shot a few months later: also nothing.

Still pursuing the missing star, the scientists acquired access to older data for comparison to what they already felt they knew. "The ESO Science Archive Facility enabled us to find and use data of the same object obtained in 2002 and 2009," says Andrea Mehner, an ESO staff member who worked on the study. "The comparison of the 2002 high-resolution UVES spectra with our observations obtained in 2019 with ESO's newest high-resolution spectrograph ESPRESSO was especially revealing, from both an astronomical and an instrumentation point of view."

Examination of this data suggested that the LBV may have indeed been winding up to a grand final sometime after 2011.

Team member Jose Groh, also of Trinity College, says "We may have detected one of the most massive stars of the local Universe going gently into the night. Our discovery would not have been made without using the powerful ESO 8-meter telescopes, their unique instrumentation, and the prompt access to those capabilities following the recent agreement of Ireland to join ESO."

Combining the 2019 data with contemporaneous Hubble Space Telescope (HST) imagery leaves the authors of the reports with the sense that "the LBV was in an eruptive state at least between 2001 and 2011, which then ended, and may have been followed by a collapse into a massive BH without the production of an SN. This scenario is consistent with the available HST and ground-based photometry."

Or...

A star collapsing into a black hole without a supernova would be a rare event, and that argues against the idea. The paper also notes that we may simply have missed the star's supernova during the eight-year observation gap.

LBVs are known to be highly unstable, so the star dropping to a state of less luminosity or producing a dust cover would be much more in the realm of expected behavior.

Says the paper: "A combination of a slightly reduced luminosity and a thick dusty shell could result in the star being obscured. While the lack of variability between the 2009 and 2019 near-infrared continuum from our X-shooter spectra eliminates the possibility of formation of hot dust (⪆1500 K), mid-infrared observations are necessary to rule out a slowly expanding cooler dust shell."

The authors of the report are pretty confident the star experienced a dramatic eruption after 2011. Beyond that, though:

"Based on our observations and models, we suggest that PHL 293B hosted an LBV with an eruption that ended sometime after 2011. This could have been followed by
(1) a surviving star or
(2) a collapse of the LBV to a BH [black hole] without the production of a bright SN, but possibly with a weak transient."

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