Tag Archives | Physics

A New Look at Newton’s Second Law Could Explain Away the Existence of Dark Matter

From PopSci:

And all it takes to measure is a simple spinning disk here on Earth. When reached for comment, Dark Matter says: “Come on, you almost found me!”

Dark matter’s status as a mysterious and invisible lurker in the universe has frustrated scientists for years. Now, one hopes to solve the puzzle a different way: using a modified version of Newton’s second law that would eliminate the need for dark matter altogether. Researchers in Brazil have devised an experiment that could put the modified Newtonian dynamics (MOND) to the test, New Scientist reports.

Much indirect evidence for dark matter — supposedly 25 percent of the mass in the universe — comes from observing its invisible gravitational effect on visible galaxies and their stars. Deep underground experiments on Earth have attempted to directly detect the weakly interacting particles (WIMPS) that scientists believe constitute dark matter.

But dark matter’s existence is based on the assumption that Newton’s second law of motion holds true at all physical scales.

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The First Test That Proves General Theory of Relativity Wrong

Vlad Tarko writes on Softpedia:
Relativity Is Wrong?According to Einstein’s theory of general relativity, a moving mass should create another field, called gravitomagnetic field, besides its static gravitational field. This field has now been measured for the first time and to the scientists’ astonishment, it proved to be no less than one hundred million trillion times larger than Einstein’s General Relativity predicts.

This gravitomagnetic field is similar to the magnetic field produced by a moving electric charge (hence the name “gravitomagnetic” analogous to “electromagnetic”). For example, the electric charges moving in a coil produce a magnetic field — such a coil behaves like a magnet. Similarly, the gravitomagnetic field can be produced to be a mass moving in a circle. What the electric charge is for electromagnetism, mass is for gravitation theory (the general theory of relativity).

A spinning top weights more than the same top standing still. However, according to Einstein’s theory, the difference is negligible.

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Coast to Coast AM: Time Technology & Research

From the January 31, 2010 show of Coast to Coast AM: TimeControl
Joining Art Bell for the entire 4-hour program, physicist Dr. David Anderson discussed the state of time technology from his research, as well as other labs around the world. He recapped his work from 2002, when he last appeared with Art on the show. At that juncture, his team had created small time warp fields that he said could accelerate time by 300% within the field, as well as reversing time. He described the initiation of a time warp field as quite spectacular to witness, "between the combinations of different chemical reagents and high energy lasers we use to excite or initiate a time warp field...a lot of light, a lot of energy." Since 2002, the effects have increased by "two orders of magnitudes," both in time acceleration and retardation rates, and living organisms have been successfully tested in the warp fields, he detailed. By regenerating "closed timelike curves" (bending spacetime so time loops back on itself) we're finding it "just as easy to move backwards in time as well as forward," Anderson explained.
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What Would You See As You Plummet Into a Black Hole? (Video)

Hazel Muir writes on New Scientist:
A new interactive program reveals the spectacular light show you'd see if you dared to wander close to a black hole. It demonstrates how the extreme gravity of a black hole could appear to shred background constellations of stars, spinning them around as though in a giant black washing machine. The program's creators say it could be an excellent tool to familiarise people with the weird ways that black holes warp light. "It's useful for people to play around with the parameters to study how, for instance, a black hole would distort the constellation Orion," says Thomas Müller of the University of Stuttgart in Germany.
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The Strangest Liquid: Why Water Is So Weird

With a massive blizzard going on in the Northeastern U.S., water (albeit in a frozen form) is on everyone's mind in this part of the world. Very interesting article, whether you are snowed in or not. Edwin Cartlidge writes in New Scientist: Ice

We are confronted by many mysteries, from the nature of dark matter and the origin of the universe to the quest for a theory of everything. These are all puzzles on the grand scale, but you can observe another enduring mystery of the physical world — equally perplexing, if not quite so grand — from the comfort of your kitchen. Simply fill a tall glass with chilled water, throw in an ice cube and leave it to stand.

The fact that the ice cube floats is the first oddity. And the mystery deepens if you take a thermometer and measure the temperature of the water at various depths. At the top, near the ice cube, you'll find it to be around 0 °C, but at the bottom it should be about 4 °C. That's because water is denser at 4°C than it is at any other temperature — another strange trait that sets it apart from other liquids.

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How to Fall 35,000 Feet — And Survive

Parachute On FireDan Koeppel writes in Popular Mechanics:

You’re six miles up, alone and falling without a parachute. Though the odds are long, a small number of people have found themselves in similar situations — and lived to tell the tale.

6:59:00 AM, 35,000 Feet: You have a late night and an early flight. Not long after takeoff, you drift to sleep. Suddenly, you’re wide awake. There’s cold air rushing everywhere, and sound. Intense, horrible sound. Where am I?, you think. Where’s the plane?

You’re 6 miles up. You’re alone. You’re falling.

Things are bad. But now’s the time to focus on the good news. (Yes, it goes beyond surviving the destruction of your aircraft.) Although gravity is against you, another force is working in your favor: time. Believe it or not, you’re better off up here than if you’d slipped from the balcony of your high-rise hotel room after one too many drinks last night.

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They’ve Made Real Lightsabers (Kinda)

RealLightsabersGraeme McMillan writes on io9.com:
An upcoming television show explains why real life lightsabers are a physical impossibility, before building the next best thing. It's like Mythbusters but, surprisingly, made with even more awesome. According to Variety, the show, Sci-Fi Science: Physics of the Impossible, will feature Dr. Michio Kaku looking at the reality behind Star Wars' favored weapon of choice. After explaining that light can't be formed into a solid blade, Jedi-style, he then goes to work looking for alternatives, including plasma swords and carbon nano-tubes, with the help of experts in the field. As you can see from the pic, he apparently succeeds. My mind is almost so blown that I forgot to say that I really, really want to see lightsaber battles as part of the Olympics now.
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Chinese Scientists Create Artificial Black Hole

Popular Science reports on scientists messing around with something that could cause the end of the world: pocket-sized laboratory-made black holes.

Unlike a regular black hole, which traps light using the gravitational pull of the dead star at its core, this simple metal disc uses the geometry of 60 concentric rings of metamaterials to lock up light…bending beams into the center of the disc, and trapping them in the etched maze-like grooves.

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