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kottke.org posts about gravity

Gravity is the new light

posted by Tim Carmody   Jun 16, 2016

Gravitational waves from two colliding black holes were first detected last September and announced in February. This week, the same science team announced a second wave detection of two smaller black holes in December.

If the first one confirmed the long-held predictions of general relativity, the new detections are a signal to get started on some all-new science.

A black hole’s gravity is so strong that even light can’t escape, so black holes are essentially impossible to see with telescopes. But they do give off gravitational waves.

“Light’s always been how we do astronomy,” Professor Jo Dunkley, an astrophysicist at Oxford University who didn’t work on the experiment, told BuzzFeed News. “Everything we know about space, we’ve got from light. This can show the stuff you can’t see with light.”

Counting black holes, combining telescope with gravitational measurements to better understand neutron stars, all the usual origin-of-the-universe stuff.

If gravitational waves don’t require cataclysmic collisions between enormous black holes for us to measure them, but can be detected on the regular, we can use them to try to figure out a whole lot more than just whether or not Einstein was totally right. That is a very nice tool to have in your pocket.

We Work Remotely

A final test of relativity

posted by Jason Kottke   Nov 27, 2015

A European Space Agency probe will be launched into space early next month to help test the last major prediction of Einstein’s theory of general relativity: the existence of gravitational waves.

Gravitational waves are thought to be hurled across space when stars start throwing their weight around, for example, when they collapse into black holes or when pairs of super-dense neutron stars start to spin closer and closer to each other. These processes put massive strains on the fabric of space-time, pushing and stretching it so that ripples of gravitational energy radiate across the universe. These are gravitational waves.

The Lisa Pathfinder probe won’t measure gravitational waves directly, but will test equipment that will be used for the final detector.

LISA Pathfinder will pave the way for future missions by testing in flight the very concept of gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. LISA Pathfinder will use the latest technology to minimise the extra forces on the test masses, and to take measurements. The inertial sensors, the laser metrology system, the drag-free control system and an ultra-precise micro-propulsion system make this a highly unusual mission.

(via @daveg)

Aningaaq, a Gravity companion film

posted by Jason Kottke   Nov 21, 2013

[Mild spoilers] During the production of Gravity, Jonas Cuaron (co-writer of the screenplay and Alfonso Cuaron’s son) shot a short film that shows the other side of the conversation that Sandra Bullock’s character had while in the Soyuz capsule. In the film, an Inuit fisherman struggles to communicate with the distressed voice on the other end of his radio.

The short was filmed “guerrilla style” on location on a budget of about $100,000 — most of which went toward the 10-person crew’s travel costs — and Cuaron completed it in time to meld the dialogue into Gravity’s final sound mix. The result is a seamless conversation between Aningaaq and Ryan, stranded 200 miles above him, the twin stories of isolated human survival providing thematic cohesion. Still, Jonas says he was careful “to make it a piece that could stand on its own.” Should both get Oscar noms, an interesting dynamic would emerge: Two films potentially could win for representing different sides of one conversation, to say nothing of having come from father and son.

“Life in Ikea is impossible”

posted by Jason Kottke   Nov 15, 2013

The trailer for Alfonso Cuarón’s “Ikea”, a film about a man and a woman lost in the vast nothingness of Ikea.

(via ★interesting)

Visitors

posted by Jason Kottke   Aug 12, 2013

Here’s the trailer for Visitors, a new film from Koyaanisqatsi collaborators Godfrey Reggio and Philip Glass. Most of the trailer consists of a single two-minute shot.

That shot reminds me of many things: Andy Warhol, long photos, James Nares’ Street, and Robbie Cooper’s work depicting kids playing video games.

Also interesting is that Visitors is comprised of only 74 shots, which with a runtime of 87 minutes means the average shot lasts over a minute. According to a recent investigation by Adam Jameson, an ASL (average shot length) of more than a minute is unusual in contemporary film. Inception, for instance, has a ASL of just 3.1 seconds and even a film like Drive, with many long shots, has an ASL of 7 seconds. But as Jameson notes, Alfonso Cuarón’s upcoming Gravity contains only 156 shots, including a 17-minute-long shot that opens the film. But the Hollywood master of long-running shots? Hitchcock, I presume:

1. Rope (1948, Alfred Hitchcock), ASL = 433.9 [seconds]

OK, this isn’t a recent recent film, but it has to be noted, as it’s most likely the highest ASL in Hollywood. Hitchcock used only 10 shots in making it (the film’s Wikipedia page lists them). (As you probably know, Hitchcock designed those shots, then edited them such that the finished film appeared to be a single take.)

Trailer for Gravity

posted by Jason Kottke   Jul 24, 2013

The latest trailer for Gravity, starring Bullock and Clooney and directed by Alfonso Cuarón (who directed Children of Men).

Holy God, this looks terrifying. Can’t wait. (via ★interesting)

Wringing out a washcloth in space

posted by Jason Kottke   Apr 18, 2013

What happens when you wring a washcloth out in zero gravity? Something cool.

Commander Hadfield is the best. I love when he casually lets go of the wireless mic and it just floats there right in front of his face. (thx, dusty)

The speed of gravity

posted by Jason Kottke   Sep 07, 2010

Newton said the speed of gravity is infinite but according to Einstein (and some nifty interstellar measurements), it most certainly is not.

But in general relativity, things are much more intricate, and incredibly interesting. First off, it isn’t mass, per se, that causes gravity. Rather, all forms of energy (including mass) affect the curvature of space. So for the Sun and the Earth, the incredibly large mass of the Sun dominates the curvature of space, and the Earth travels in an orbit along that curved space.

If you simply took the Sun away, space would go back to being flat, but it wouldn’t do so right away at every point. In fact, just like the surface of a pond when you drop something into it, it snaps back to being flat, and the disturbances send ripples outward!

Hammer vs. feather on the Moon

posted by Ainsley Drew   Oct 02, 2009

Nothing like a little science on the Moon, I always say.

Astronaut David Scott in 1971, from the Apollo 15 Lunar Surface Journal. Scott was part of the Apollo 15 crew, and applied Galileo’s findings about gravity and mass by testing a falcon feather and a hammer. The film, shown in countless high school physics classes, is the nerdy, oft-neglected cousin of Neil Armstrong’s space paces.

That’s no moon, it’s a seamount

posted by Jason Kottke   Mar 05, 2009

There’s a fascinating tidbit in this Google blog post about the non-discovery of Atlantis in Google Earth. It concerns how the depth of the ocean floor is measured.

Now you’re probably wondering where the rest of the depth data comes from if there are such big gaps from echosounding. We do our best to predict what the sea floor looks like based on what we can measure much more easily: the water surface. Above large underwater mountains (seamounts), the surface of the ocean is actually higher than in surrounding areas. These seamounts actually increase gravity in the area, which attracts more water and causes sea level to be slightly higher. The changes in water height are measurable using radar on satellites.

Wow! (via ben fry)

Satellites measuring the earth’s gravity from orbit

posted by Jason Kottke   Aug 10, 2006

Satellites measuring the earth’s gravity from orbit detected a change in gravity from the massive earthquake that caused the tsunami in the Indian Ocean. “The gravity at the earth’s surface decreased by as much as about 0.0000015 percent, meaning that a 150-pound person would experience a weight loss of about one-25,000th of an ounce.”

Physicist Lawrence Krauss sums up his thoughts

posted by Jason Kottke   Jul 11, 2006

Physicist Lawrence Krauss sums up his thoughts from a small conference he organized on the topic of gravity. “There appears to be energy of empty space that isn’t zero! This flies in the face of all conventional wisdom in theoretical particle physics. It is the most profound shift in thinking, perhaps the most profound puzzle, in the latter half of the 20th century.”

I can’t tell if this is a

posted by Jason Kottke   Jun 13, 2006

I can’t tell if this is a joke or not, but someone seems to be quite skeptical about the “theory of gravity” on this Christian Forums site. “are you going to tell me that the gravity of the sun is strong enough to keep PLUTo in orbit but not an airplane or a little bird??????”

A moving mass has been shown to

posted by Jason Kottke   Mar 24, 2006

A moving mass has been shown to generate a gravitomagnetic field (just like a moving electrical charge creates a magnetic field) and “the measured field is a surprising one hundred million trillion times larger than Einstein’s General Relativity predicts”. (via rw)

Lisa Randall and Raman Sundrum have proposed

posted by Jason Kottke   Nov 03, 2005

Lisa Randall and Raman Sundrum have proposed some ideas about gravity, extra dimensionality, and string theory that may be testable when the Large Hadron Collider goes online at CERN in 2007.