Category: Space & Physics

Like GPS? Thank Relativity

By C. Renée James | August 29, 2014 1:42 pm

gps-device

In 1971—16 years after Einstein’s death—the definitive experiment to test Einstein’s relativity was finally carried out. It required not a rocket launch but eight round-the-world plane tickets that cost the United States Naval Observatory, funded by taxpayers, a total of $7,600.

The brainchild of Joseph Hafele (Washington University in St. Louis) and Richard Keating (United States Naval Observatory) were “Mr. Clocks,” passengers on four round-the-world flights. (Since the Mr. Clocks were quite large, they were required to purchase two tickets per flight. The accompanying humans, however, took up only one seat each as they sat next to their attention-getting companions.)

The Mr. Clocks had all been synchronized with the atomic clock standards at the Naval Observatory before flight. They were, in effect, the “twins” (or quadruplets, in this case) from Einstein’s famous twin paradox, wherein one twin leaves Earth and travels nearly at the speed of light. Upon returning home, the traveling twin finds that she is much younger than her earthbound counterpart.

In fact, a twin traveling at 80 percent the speed of light on a round-trip journey to the Sun’s nearest stellar neighbor, Proxima Centauri, would arrive home fully four years younger than her sister. Although it was impossible to make the Mr. Clocks travel at any decent percentage of the speed of light for such a long time, physicists could get them going at jet speeds—about 300 meters (0.2 mile) per second, or a millionth the speed of light—for a couple of days. In addition, they could get the Mr. Clocks out of Earth’s gravitational pit by about ten kilometers (six miles) relative to sea level. And with the accuracy that the Mr. Clocks were known to be capable of, the time differences should be easy to measure.

Hafele and Keating with their Mr. Clock on their initial flight.

Hafele and Keating with two Mr. Clocks on their initial flight.

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CATEGORIZED UNDER: Space & Physics, Technology, Top Posts

The Tale of a Vintage Spacecraft That’ll Never Make it Home

By Sarah Scoles | July 10, 2014 1:26 pm
ISEE-3 before its 1978 launch. Credit: NASA

ISEE-3 before its 1978 launch. Credit: NASA

Your mission, should you choose to accept it: Find and reanimate an ailing spacecraft, prevent it from hurtling into deep space, and guide it back to stable orbit near Earth. This setup could be the plot of a cheesy computer game, but it was actually the summer plan of a team of renegade spacemen.

The group of ambitious volunteer-engineers made contact with a 1970s spacecraft, downloaded its data, and attempted to shift its trajectory homeward. They wanted to resume the craft’s mission and siphon its data back down to Earth. Their initial plan, however, failed on Wednesday when they discovered the thrusters were out of juice—but in the wake of that setback they are altering, rather than abandoning, their plans.

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CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: space exploration

A Century On, This Math Prodigy’s Formulas Are Finally Unravelled

By Amir Aczel | June 6, 2014 11:48 am

math prodigy Srinivasa Ramanujan

A hundred and one years ago, in 1913, the famous British mathematician G. H. Hardy received a letter out of the blue. The Indian (British colonial) stamps and curious handwriting caught his attention, and when he opened it, he was flabbergasted. Its pages were crammed with equations – many of which he had never seen before. There were many kinds of formulas there, and those that first caught his attention had to do with algebraic numbers. Hardy was the leading number theorist in the world – how could he not recognize the identities relating to such numbers, scribbled on the rough paper? Were these new derivations, or were they just nonsensical math scrawls? Later, Hardy would say this about the formulas: “They defeated me completely. I had never seen anything in the least like it before!”

Now, for the first time, mathematicians have identified the mathematics behind these breakthrough scrawls – shedding further light on the genius who made them.

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CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: math

Why Habitable Exoplanets Are Bad News for Humanity’s Future

By Andrew Snyder-Beattie, University of Oxford | April 24, 2014 11:21 am

PIA10363 exoplanetThis article was originally published on The Conversation.

Last week, scientists announced the discovery of Kepler-186f, a planet 492 light years away in the Cygnus constellation. Kepler-186f is special because it marks the first planet almost exactly the same size as Earth orbiting in the “habitable zone” – the distance from a star in which we might expect liquid water, and perhaps life.

What did not make the news, however, is that this discovery also slightly increases how much credence we give to the possibility of near-term human extinction. This because of a concept known as the Great Filter.

The Great Filter is an argument that attempts to resolve the Fermi Paradox: why have we not found aliens, despite the existence of hundreds of billions of solar systems in our galactic neighborhood in which life might evolve? As the namesake physicist Enrico Fermi noted, it seems rather extraordinary that not a single extraterrestrial signal or engineering project has been detected (UFO conspiracy theorists notwithstanding).

This apparent absence of thriving extraterrestrial civilizations suggests that at least one of the steps from humble planet to interstellar civilization is exceedingly unlikely. The absence could be caused because either intelligent life is extremely rare or intelligent life has a tendency to go extinct. This bottleneck for the emergence of alien civilizations from any one of the many billions of planets is referred to as the Great Filter.

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CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: exoplanets

How the “Gooey Universe” Could Shed Light on the Big Bang

By Amir Aczel | April 9, 2014 8:40 am
choc-universe2

Calculations of the density of stars, planets, gas clouds, and empty space indicate that the cosmos has the viscosity of chocolate syrup.

“Interdisciplinary” is a huge buzzword in academia right now. But for science, it has a long history of success. Some of the best science happens when researchers cross-pollinate, applying knowledge from other fields to inform their research.

One of the best such examples in physics was the concept of a Higgs field, which led to the 2013 Nobel Prize in physics. Few people outside the physics community know that the insight to the behavior of the proposed Higgs particle actually came from solid state physics, a branch of study that looks at the processes that take place inside condensed matter such as a superconductor.

Now cosmologists are trying to borrow some ideas of their own. The new discovery of gravitational waves — the biggest news in cosmology this century — focuses fresh attention on a field in which recent progress has otherwise been slow. Cosmologists are now attempting to explore novel ways of trying to understand what happened in the Big Bang, and what, if anything, caused the gargantuan explosion believed to have launched our universe on its way. To do so they’ve turned their attention to areas of physics far removed from outer space: hydrology and turbulence. The idea is pretty clever: to view the universe as an ocean.

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CATEGORIZED UNDER: Space & Physics, Top Posts

Einstein’s Lost Theory Describes a Universe Without a Big Bang

By Amir Aczel | March 7, 2014 10:32 am
einstein

Einstein with Edwin Hubble, in 1931, at the Mount Wilson Observatory in California, looking through the lens of the 100-inch telescope through which Hubble discovered the expansion of the universe in 1929. Courtesy of the Archives, Calif Inst of Technology.

In 1917, a year after Albert Einstein’s general theory of relativity was published—but still two years before he would become the international celebrity we know—Einstein chose to tackle the entire universe. For anyone else, this might seem an exceedingly ambitious task—but this was Einstein.

Einstein began by applying his field equations of gravitation to what he considered to be the entire universe. The field equations were the mathematical essence of his general theory of relativity, which extended Newton’s theory of gravity to realms where speeds approach that of light and masses are very large. But his math was better than he wanted to believe—his equations told him that the universe could not stay static: it had to either expand or contract. Einstein chose to ignore what his mathematics was telling him.

The story of Einstein’s solution to this problem—the maligned “cosmological constant” (also called lambda)—is well known in the history of science. But this story, it turns out, has a different ending than everyone thought: Einstein late in life returned to considering his disgraced lambda. And his conversion foretold lambda’s use in an unexpected new setting, with immense relevance to a key conundrum in modern physics and cosmology: dark energy.

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CATEGORIZED UNDER: Space & Physics, Top Posts

Pilot Dreams of Stamping His One-Way Ticket to Mars

By Carl Engelking | March 6, 2014 9:00 am
Nick Noreus

Nick Noreus prepares to fly an Mi-17 in Ukraine while he was embedded with the Afghan Army for a year.

There’s something rejuvenating about escaping civilization for the quiet isolation of unadulterated wilderness. But could you leave it all behind — forever? That’s the fate that awaits the men and women still in contention for a one-way ticket to the Red Planet.

Pilot, mechanic and inventor Nick Noreus, 33, from Florida, survived the first round of cuts, and he is on the shortlist for the Mars One mission. Read More

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: Mars, space exploration

Mysterious Moon Base Discovered? Not So Fast.

By Ernie Mastroianni | January 30, 2014 1:12 pm

MoonAnamolyGoogle01

Earlier this month, when a few high-traffic news websites reported a strange object or wedge-shaped craft on Google Moon, I was skeptical. Surprised, too, because when I opened the application, there it was, a distinct V-shape of bright lights inside a tiny crater on the moon’s far side. It did not look natural. I marked its location at 142 degrees and 34 minutes east and 22 degrees 42 minutes north, at the edge of Mare Moscoviense.

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CATEGORIZED UNDER: Space & Physics, Top Posts

Seven Things You Didn’t Know About Rosetta

By Sarah Scoles | January 21, 2014 10:22 am
468057main_rosetta_concept_946-710

This artist’s concept represents ESA’s Rosetta spacecraft passing by an asteroid. Courtesy NASA

In case you were asleep yesterday and missed the big news, the European Space Agency’s (ESA) Rosetta spacecraft woke up from its 31-month hibernation. After the robotic equivalent of a drinking a black coffee — warming its navigation systems, pulling out of a spin, and pointing a radio dish toward Earth — Rosetta beamed a message to its home planet: Hello, world. NASA’s Goldstone antenna in California picked up the transmission and sent it to a roomful of scientists, who engaged in some unprecedented fist-pumping at the news that their comet-chronicling craft was alive and well. Rosetta’s Twitter account then said “hello” to the world in 23 different languages.

Rosetta is on its way to Comet 67P/Churyumov-Gerasimenko, a 1.9 by 3.1-mile (3 by 5-kilometer) chunk of dust and ice that’s headed toward the sun. When the spacecraft reaches its destination, it will begin to orbit the comet, spending two months scrutinizing the surface. This is a first: While astronomers have taken fly-by pictures, no one has ever tried to give a comet a satellite.

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CATEGORIZED UNDER: Space & Physics, Top Posts

Time Travel Via Wormhole Breaks the Rules of Quantum Mechanics

By Bill Andrews | January 16, 2014 12:52 pm

time-travel

Science has done it again everybody! Brace yourselves for this groundbreaking news, freshly determined by physicists: Time travel, if it exists, may have some weird consequences. Gosh, who’d have thunk it?

But no, seriously, a recent article suggests that a certain kind of theoretically possible time machine would wreak minor havoc with a firm principle of quantum mechanics, the often-weird science of the smallest bits of the universe. You know what this means: We get to explore the science of time travel!

Time Travel: No, Really

Let’s get this out of the way first: Obviously time travel exists, because it’s already the third week of 2014. We’re all time travelers (chrononauts), technically, moving 1 second per second through time. Certain weird side effects of relativity theory also mean time can travel more quickly under certain conditions, so it’s even possible for you to travel into the future (someone else’s future, at least) faster than the usual rate.

The “useful” kind of time travel, though, for sci-fi authors and dreamers alike, is into the past, Back to the Future style. And, happily, relativity theoretically can make that possible, too, by warping the fabric of reality, space-time, so much that it loops back on itself. A so-called wormhole (again, officially deemed possible by science) could be the bridge that connects two different times.

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CATEGORIZED UNDER: Space & Physics, Top Posts
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