Critical Opalescence
A blog about cutting-edge physics

Charismatic Megaparticles Might Hint at Dark Matter, and Much Besides

Out in the cosmos, “dark accelerators” slingshot particles to huge speeds and no one knows why.

At a lecture I went to some years ago, astrophysicist Trevor Weekes compared garden-variety elementary particles to mosquitoes. They are plentiful and easy to find—indeed, they find you. But ultra-high-energy gamma rays, he said, are like elephants. They are fairly rare, but among the greatest of creatures. They often roam in spectacular habitats. Their sheer […]

Is Dark Matter a Glimpse of a Deeper Level of Reality?

Many theoretical physicists speculate that space and time arise from deeper physics. Erik Verlinde goes them one further.

SANTA BARBARA—Two years ago several of my Sci Am colleagues and I had an intense email exchange over a period of weeks, trying to figure out what to make of a new paper by string theorist Erik Verlinde. I don’t think I’ve ever been so flummoxed by physicists’ reactions to a paper. Mathematically it could […]

Particles for Peace: Iranian, Israeli, Turkish, and Arab Physicists Lay Plans for a Joint Particle Accelerator

In the ’50s, CERN united postwar Europe. Can SESAME do the same for the Middle East?

SANTA BARBARA—Physics has always been one of the most globalized of professions. Physicists think of themselves as supranational, rising above national and cultural concerns. They may not always live up to this ideal, but at least they try. I got a glimpse of this as a college student in 1987 when I spent my spring […]

Where Do Space and Time Come From? New Theory Offers Answers, If Only Physicists Can Figure It Out

Vasiliev theory might extend string-theoretic ideas to new settings. But dang, is it hard.

SANTA BARBARA—”Maybe we’re just too dumb,” Nobel laureate physicist David Gross mused in a lecture at Caltech two weeks ago. When someone of his level wonders whether the unification of physics will always be beyond mortal minds, it gets you worried. (He went on to explain why he doesn’t think we are too dumb, though.) […]

The Emperor, Darth Vader and the Ultimate Ultimate Theory of Physics

This physics theory is like Darth Vader: you think it’s the ultimate power, until you meet the Emperor.

PASADENA—The theory is so obscure there’s not a Wikipedia page about it yet. It might be impossible to formulate mathematically. One theoretical physicist calls it the Emperor Palpatine of theories, even more powerful and inscrutable than the Darth Vader theory that he and others have been studying intensively. And yet it has a purity and […]

Could Simple Experiments Reveal the Quantum Nature of Spacetime?

Gravity might muck with the quantum by distorting the uncertainty principle and introducing ambiguities in sequences of cause and effect.

Conventional wisdom has it that putting the words “quantum gravity” and “experiment” in the same sentence is like bringing matter into contact with antimatter. All you get is a big explosion; the two just don’t go together. The distinctively quantum features of gravity only show up in extreme settings such as the belly of a […]

George and John's Excellent Adventures in Quantum Entanglement [Video]

A metaphorical version of John Bell’s famous entanglement.

Simply put, bottomlessly deep: that is the definition of a great discovery in science. From the principle of relativity to evolution by natural selection, the concepts that govern our world are actually not that hard to state. What they mean and what they imply—well, that’s another matter. And so it is with quantum entanglement. One […]

Could a Balloon Fly in Outer Space?

Sure it could. Space is not a perfect vacuum.

Here’s the sort of crazy idea that animates our office conversation at Scientific American. It all started with my colleague Michael Moyer’s joke that a certain politician could build his moon base using a balloon: just capture the hot air and float all the way up. Ha ha, we all know that balloons don’t work […]

Magnetoastrocoolness: How Cosmic Magnetic Fields Shape Planetary Systems

For one thing, they can cause embryonic planets to spiral inward.

AUSTIN, Texas—Astrophysicists have a funny attitude toward magnetic fields. You might say they feel both repelled and attracted. Gravitation is assumed to rule the cosmos, so models typically neglect magnetism, which for most researchers is just as well, because the theory of magnetism has a forbidding reputation. The basic equations are simple enough, solving them […]

Astronomers Catch Black Hole Spitting Out Material

Knots of gas are clocked at a quarter of the speed of light.

AUSTIN, Tex.—One of the great ironies of the universe is that black holes, the ultimate vacuum cleaners, create more of a mess than they clean up. (It is a complaint that many people who finally prevailed on spouses and roommates to clean up after themselves might appreciate.) How is it that, in sucking up surrounding […]

Science Is the 99 Percent

Nobelist Steven Weinberg says the crisis in science funding is part of a general underinvestment in public goods.

AUSTIN—A regular feature of American Astronomical Society conferences is an evening lecture on the state of science funding. Let’s just say it’s not a great date night. There have been happy counterexamples, but usually you spend an hour and a half hearing about the latest budget cuts and walk out of the room in a […]

Melting Glaciers Muck Up Earth’s Gravitational Field

Clever use of gravity data shows that glacial retreat really is a global phenomena.

SINGAPORE—Photographs never quite capture the sparkling blue tint of glacial ice, so when I visited the Perito Moreno glacier in Patagonia on a backpacking trip through South America some years ago, I was happy to get this camera angle: the blue of the Argentine flag gives you a sense of what the blue of the […]

Proving You Are Where You Say You Are

Philandering spouses and students playing hookey, beware: quantum cryptography may make it impossible for you to hide your location.

SINGAPORE—When a speaker brings a tangle of garden hoses, a bottle of water, and a towel to the podium, you know it’s going to be a fun talk. Computer scientist Harry Buhrman of the Centrum Wiksunde & Informatica in Amsterdam recently visited Singapore to help celebrate the fourth anniversary of the Centre for Quantum Technologies. […]

What the World Looks Like, If You Move Backward in Time [Video]

A remarkable film project.

Oops, I said my last post on the recent Foundational Questions Institute conference would be my final one, but I can’t resist just one more. At the conference, Gavin Crooks at Lawrence Berkeley Labs, who studies molecular machines and gave a great talk on how life balances time asymmetry with thermodynamic efficiency, showed this brilliant short […]

How Life Arose on Earth, and How a Singularity Might Bring It Down

Living things are souped-up versions of inorganic geochemical reactions.

COPENHAGEN—It didn’t take long for the recent Foundational Questions Institute conference on the nature of time to delve into the purpose of life. “The purpose of life,” meeting co-organizer and Caltech cosmologist Sean Carroll said in his opening remarks, “is to hydrogenate carbon dioxide.” Well, there you have it. Carroll is one of the most […]

Quantum Cheshire Cat: Even Weirder Than Schrödinger's

A box can contain all the properties of a particle, even though no particle is there.

COPENHAGEN—Just when you thought you’d heard every quantum mystery that was possible, out pops another one. Jeff Tollaksen mentioned it in passing during his talk at the recent Foundation Questions Institute conference. Probably Tollaksen assumed we’d all heard it before. After all, his graduate advisor, Yakir Aharonov—who has made an illustrious career of poking the […]

Free Will and Quantum Clones: How Your Choices Today Affect the Universe at its Origin

Just when you thought the debates over free will couldn’t get any weirder.

COPENHAGEN—The late philosopher Robert Nozick, talking about the deep question of why there is something rather than nothing, quipped: “Someone who proposes a non-strange answer shows he didn’t understand the question.” So, when Scott Aaronson began a talk three weeks ago by saying it would be “the looniest talk I’ve ever given,” it was a […]

Time on the Brain: How You Are Always Living In the Past, and Other Quirks of Perception

Conscious experience lags 80 milliseconds behind actual events.

COPENHAGEN—I always knew we humans have a rather tenuous grip on the concept of time, but I never realized quite how tenuous it was until a couple of weeks ago, when I attended a conference on the nature of time organized by the Foundational Questions Institute. This meeting, even more than FQXi’s previous efforts, was […]

Do Physicists Make the World a Better Place?

Well, I think so, but others are doubtful.

COPENHAGEN—This past week, I’ve been attending the Foundational Questions Institute conference on the nature of time, and in the coming weeks, I hope to share with you some of the mind-blowing things I’ve found out. In the meantime, there’s one question I wanted to put out there for everyone to comment on. On Wednesday, physicist […]

Can Scientists Really Do Anything to Reform Education?

Yes, but it must start with respect for teachers and their needs.

Biologist and biology educator Joanne Manaster has a thought-provoking guest blog post today on what, if anything, scientists can do to help K-12 science education. She quotes English physics teacher Alom Shaha expressing an opinion that I don’t think gets aired enough: If I were trying to be controversial, I’d reply “very little, until they […]

Physicists Simulate the End of Time in a Maryland Lab

So-called plasmons let experimenters explore exotic spacetime geometries in complete safety.

Last September I had an article in Scientific American about what it would mean for time to end—how the world might cease to unfold in a unidirectional sequence of cause and effect. Some processes, for example, could cause time to morph into just another dimension of space. Last week experimenters announced that they have simulated […]

What Would Happen If Earth and Mars Switched Places?

The orbits of the inner planets would go chaotic.

Last Saturday, at a workshop organized by the Foundation Questions Institute, Nobel laureate physicist Gerard ‘t Hooft gave a few informal remarks on the deep nature of reality. Searching for an analogy to the symmetries of basic physics, he asked the attendees to imagine what would happen to our solar system if you suddenly swapped […]

Space Is an Elaborate Illusion

The holographic principle suggests that space emerges from a deeper spaceless reality.

Editor’s Note: This post was initially published May 12 on the World Science Festival’s Web site. My dad took a peculiar pleasure in fitting the maximum amount of stuff into the smallest possible space. Whenever we went on a family trip, he packed our suitcases like a 3-D jigsaw puzzle, ensuring there wasn’t a single […]

Space Shuttle Endeavour Launches Successfully on Its Final Mission

Space shuttle Endeavour soars into space on its 16-day, STS-134 mission to the International Space Station.

Editor’s note: Updated at 12:15 P.M. KENNEDY SPACE CENTER—The space shuttle Endeavour took off on its final flight Monday morning at 8:56 A.M. Eastern time. The takeoff came after a nail-biting final hour as technicians had to do some last-minute repairs to the shuttle’s heat tiles and clouds filled the sky above Cape Canaveral. In […]

Why It Scrubbed

NASA engineers troubleshoot Endeavour’s electrical problems.

KENNEDY SPACE CENTER—When NASA scrubbed the shuttle Endeavour‘s final launch here on Friday, engineers said there was a best-case and a worst-case scenario. Well, guess what: it was the worst case. The trouble began when an electric heater for the hydraulics system failed to turn on. When engineers opened the hatch into the left aft […]

Scrubbed! Space Shuttle Launch Delayed at Least Three Days Due to Electrical Failure

Second-to-last shuttle flight has some glitches.

KENNEDY SPACE CENTER—The shuttle Endeavour suffered a minor but potentially troublesome electrical failure that delayed its launch from Friday to Monday at the earliest. Technicians won’t know for sure until they drain the external fuel tank and get access to the errant unit, a process that will take 24 hours. By Sunday noontime, NASA officials […]

NASA’s shuttle program counts down ’til the end

An excited yet wistful space reporter gets ready for the second-to-last shuttle launch.

KENNEDY SPACE CENTER—If I’d jumped, I could have touched the belly of the Discovery. Of course, I would have then been escorted unceremoniously from the Orbiter Processing Facility. But I was that close. What a strange mix of thrill and melancholy it was to see those heat-shield tiles, the swoop of the delta wing, and […]

Do-It-Yourself Quantum Spooky Action

An experiment that used to fill a basement lab now fits on an endtable.

DRESDEN, Germany—How cool would it be not just to read about the craziness of quantum mechanics, but to see it—even better, do it—for yourself? Several years ago I asked virtuoso experimental physicist Paul Kwiat whether he could develop a simple demonstration anyone could do at home, and he and his undergraduate student Rachel Killmer came […]

Leif Robinson, 1939–2011: A Pioneer of Astronomy Journalism

Nobody knew the night sky, or how to bring it down to earth, like Leif Robinson.

I got the news today that one of the great figures in astronomy journalism and amateur astronomy, Leif Robinson, former editor of Sky & Telescope magazine, died yesterday at 71. Leif served as editor in chief of S&T from 1980 to 2000 and was a regular fixture at gatherings of professional and amateur astronomers alike. […]

Why Don’t Exoplanets Match Astronomers’ Expectations?

A dispatch from the American Astronomical Society meeting.

SEATTLE—The most exhilarating science conference I’ve ever been to took place in San Antonio 15 years ago this week, when planet hunters Geoff Marcy and Paul Butler announced they had found two planets orbiting sunlike stars beyond our solar system. Coming a couple of months after another team, led by Michel Mayor and Didier Queloz, […]

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