Why Bother with Ordinary Fireworks When You Can Have Black Hole Fireworks?

Black holes might be explosions occuring in extremely slow motion, says theoretical physicist Carlo Rovelli.

Theoretical physicist Carlo Rovelli, one of the creators of loop quantum gravity, and his collaborator Hal Haggard have just come out with a new paper on black holes. Ever attuned to puns, Rovelli calls it the “fireworks” model, alluding to the firewall argument that has consumed black-hole theorists over the past two years. As if […]

Gravitational Waves Reveal the Universe before the Big Bang: An Interview with Physicist Gabriele Veneziano

The BICEP2 discovery of primordial gravitational waves was premature, but got theorists wondering about what came before the big bang.

It’s not usually put like this, but the discovery of primordial gravitational waves two weeks ago has given us our first direct glimpse of a period before the big bang. [The discovery was later retracted, but I’ll keep this post here to show why theorists at the time found it so exciting.] The term “big […]

How to Build Your Own Quantum Entanglement Experiment, Part 2 (of 2)

The cheapest and easiest way to do the famous Einstein-Podolsky-Rosen experiment.

In my last post, I scrounged the parts for a very crude, but very cool, experiment you can do in your basement to demonstrate quantum entanglement. To my knowledge, it’s the cheapest and simplest such experiment ever done. It doesn’t give publishable results, but, to appropriate a line from Samuel Johnson, a homebrew entanglement experiment […]

How to Build Your Own Quantum Entanglement Experiment, Part 1 (of 2)

The cheapest and easiest way to do the famous Einstein-Podolsky-Rosen experiment.

Quantum-entanglement experiments are not exactly something you can buy in the science kit aisle at Toys ’R Us. The cheapest kit I know of is a marvel of miniaturization, but still costs 20,000 euros. In the past month, though, I’ve put together a crude version for just a few hundred dollars. It’s unbelievably simple—so simple […]

How to Build the World's Simplest Particle Detector

Foil tray, plastic tumbler, and rubbing alcohol make for a simple cloud chamber, without any dry ice.

In about 10 minutes, using stuff you probably already have lying around your house, you can watch atomic nuclei and elementary particles for yourself using a diffusion cloud chamber—a rudimentary particle detector. There are lots of websites and YouTube videos giving step-by-step instructions to build such a chamber, but all require some component that’s hard […]

How Do You Count Parallel Universes? You Can't Just Go 1, 2, 3, ...

Introducing a whole new breed of number, the p-adics.

Cosmologists have been thinking for years that our universe might be just one bubble amid countless bubbles floating in a formless void. And when they say “countless,” they really mean it. Those universes are damned hard to count. Angels on a pin are nothing to this. There’s no unambiguous way to count items in an […]

As If One Giant Black Hole Weren’t Enough, What’s a Galaxy Doing with Three?

Standard formation models can’t account for this triplet.

Last Thursday, my colleague John Matson described a truly amazing galaxy known, somewhat unromantically, as BX442. It has a majestic spiral pattern while hundreds of its galactic contemporaries were gawky and misshapen—a peculiar and special anomaly which suggests to many astronomers that cosmic pinwheels are ephemeral art forms, like Tibetan sand mandalas. John’s piece spurs […]

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 […]

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 […]

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 […]

Is Reality Digital or Analog?

Look for answers in the winning essays of the third Foundational Questions Institute essay contest.

Last week, the Foundation Questions Institute announced the winners of its third essay contest, which Scientific American co-sponsored. (I helped to decide on the question, judge the essays and hand out the awards at the World Science Festival in New York City.) The essay question was, “Is Reality Digital or Analog?” Is nature, at root, […]

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 […]

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, […]

Is Reality Digital or Analog?

Announcing the third Foundational Questions Institute essay contest.

The Foundational Questions Institute announced this week its latest essay contest, “Is Reality Digital or Analog?”, and if it’s anything like the past two contests, we’re in for a real treat: the contest should draw entrants from some of the deepest thinkers of our time. This time around, Scientific American has joined the institute as […]

Are Mars and Titan Geologically Dead?

New evidence suggests yes, but planetary scientists go back and forth.

PASADENA—They say that null results never get published, either in science or in journalism. Well, I’m about to break that rule. Some of the most interesting results to come out of the Division for Planetary Sciences meeting this week concern non-discoveries. In recent years, planetary scientists have gotten excited by the prospect that Mars and […]

Something Slammed Into the Rings of Saturn and Jupiter

And we’re seeing the aftermath years later.

PASADENA—This week I’m here at the annual Division for Planetary Sciences meeting. Much as I enjoy Pasadena, it’s rather a comedown from last year’s meeting place in Puerto Rico. Leave aside the natural attractions: even the freeways in Puerto Rico are in better repair than California’s. Then again, we don’t come here for the earthly […]

In Praise of Small Things

Runty galaxies are as baffling as their bigger brethren. A second dispatch from the American Astronomical Society meeting.

WASHINGTON, D.C.—Most people think of astronomy as the science of big things—”vastly, hugely, mind-bogglingly big,” as Douglas Adams put it. But judging from last week’s American Astronomical Society meeting in Washington, D.C., the most interesting things in astronomy these days are the small(ish) ones. Planet-hunters, having racked up hundreds of Jupiter-size worlds, now seek Earth-size […]

A Galaxy of New Worlds

The diversity of planets outside our solar system is really kind of crazy. A dispatch from the American Astronomical Society meeting.

WASHINGTON, D.C.—The American Astronomical Society meeting, held here this week, was officially the largest congregation of astronomers (3,400 of them) in history—the most extraordinary collection of cosmic knowledge that has ever gathered together with the possible exception of when Isaac Newton dined alone. The breadth of topics was astounding, but the one that stood out […]

What Do We Really Know About the Kuiper Belt?

Kindly explain to me what Quaoar is. A fifth dispatch from the annual planets meeting.

FAJARDO, Puerto Rico—It smacked of a cunning plan. The organizers of last week’s planets conference put one of the best talks in the very last session of the very last day. Most scientists had either left for the airport or the beach. I almost didn’t make it myself—the room and time got switched at the […]

LCROSS Strikes Earth’s Moon As Other Moons Continue to Puzzle

If planet formation is a mystery, satellite formation is a mystery upon a mystery. A fourth dispatch from the annual planets meeting.

FAJARDO, Puerto Rico—”We could have just stayed in bed” was one comment I overheard this morning from planetary scientists who had woken up early to see NASA’s Lunar Crater Observation and Sensing Satellite (LCROSS) crash into the lunar surface. At 7:31 A.M. (Eastern Daylight Time) the spacecraft’s Centaur-class rocket booster slammed (deliberately) into the moon, […]

Planetary Bombardments, Past and Future

Is Mercury the long-lost moon of Venus? What’s our risk for a massive asteroid impact? A third dispatch from the annual planets meeting.

FAJARDO, Puerto Rico—A fascinating idea came up in an informal chat I had yesterday with asteroid expert Erik Asphaug of the University of California, Santa Cruz. The early solar system was a veritable shooting gallery. Our moon is thought to have formed when a Mars-size body hit Earth and threw out a cloud of debris […]

What Caused Saturn to Lurch?

Saturn’s rings are misaligned with the planet’s equator. Sometime in the 1980s, either the ring moved, or the planet did. A second dispatch from the annual planets meeting.

FAJARDO, Puerto Rico—I first heard about Matt Hedman’s talk while going out to dinner on Tuesday night. Best talk of the meeting, I was told. Everywhere I went yesterday, I kept hearing about this guy Matt Hedman. A former professor of mine chided me for missing his presentation. The problem with the Division for Planetary […]

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