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quantumaniac:

Uncertainty Principle 

In 1927, Werner Heisenberg revolutionized our understanding of the physical world when he announced his Uncertainty Principle. As Heisenberg himself summed it up in his paper: “The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa.” 

The momentum of a particle is its mass times velocity, and its position is, of course, where it is located. According to this principle, the very act of measuring a particles mass, velocity or position causes the other two values to blur! This is not because of a lack of proper technology or our misunderstanding of particles - this is a fundamental property of nature! Quantum Mechanics is simply very counterintuitive at times. There is no way around the simple fact that one cannot exactly know the position and its momentum at the same time. 

In this video, Professor Walter Lewin explains it very well by using this example. If you shine a simple laser through a rectangular slit in a piece of paper - the laser beam, will, of course, pass through and you will see exactly the same beam on the wall behind it. However, as you make the slit smaller and smaller, the Uncertainty Principle begins to take effect. Once the slit is extremely small, say one-hundredth of an inch - you begin to know the laser’s position too precisely. Since you already know the speed of the laser to be the speed of light, you cannot precisely know the position as well. So the beam begins to spread out like this: 

This is Heisenberg’s Uncertainty Principle at work. 

Black Holes & Pulsars Could Reveal Extra Dimensions

Making a black hole let go of anything is a tall order. But their grip may slowly weaken if the universe has extra dimensions, something that pulsars could help us to test.

String theory, which attempts to unify all the known forces, calls for extra spatial dimensions beyond the three we experience. Testing the theory has proved difficult, however.

Now John Simonetti of Virginia Tech in Blacksburg and colleagues say black holes orbited by neutron stars called pulsars could do just that - if cosmic surveys can locate such pairings. “The universe contains ‘experimental’ setups we cannot produce on Earth,” he says.

Black holes are predicted to fritter away their mass over time by emitting particles, a phenomenon called Hawking radiation. Without extra dimensions, this process is predicted to be agonisingly slow for run-of-the-mill black holes weighing a few times as much as the sun, making it impossible to measure.

Extra dimensions would give the particles more ways to escape, speeding up the process. This rapid weight loss would loosen a black hole’s gravitational grip on any orbiting objects, causing them to spiral outwards by a few metres per year, the team calculates (The Astrophysical Journal, DOI: 10.1088/2041-8205/737/2/l28).

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(via theaxiomofchoice)

danielholter:

“Diamond” Planet Found; May Be Stripped Star

The odd planet was discovered orbiting what’s known as a millisecond pulsar—a tiny, fast-spinning corpse of a massive star that died in a supernova.

(via smoot)

scienceisbeauty:

Supernova Modelling. Entropy, Single time step, 340x340x340 voxels.

Simultaneous visualization of two variables of a turbulent combustion simulation. Images were generated by Hongfeng Yu at UC Davis. Simulation was performed by Dr. Jackie Chen at the Sandia National Laboratories.

Source: Turbulent Combustion Simulations, UC Davis Department of Computer Science

(via harpy-in-trousers)

sayitwithscience:

Have you ever looked out on a starry night and wondered what else is out there? Perhaps, who else? And if there were to be someone, something there— would they be looking out for you, too?

Don’t worry, you’re not alone. Others have theorized about it: Frank Drake (an American Radio astronomer who wrote the famous Arecibo message) made an entire equation. Behold, The Drake Equation.

N = R* × f_p × n_e × f_l × f_i × f_c × L

The Drake Equation is an equation for predicting the number of civilizations in the Milky Way Galaxy capable of interstellar communication.

Short descriptions of what the variables of the equation represent can be found here.

The variables represent the average rate of star formation per year in our galaxy, the fraction of those stars which have planets, the average number of planets that can potentially support life per star which has planets, the fraction of those which actually go on to develop life in the future, the fraction of those which go on to develop intelligent life, the fraction of those which can release detectable signals of their existence, and (finally) the length of time for which these civilizations release signals.

That all seems like a mess, but you get the idea.

According to Drake’s parameters:

• 50% of new stars develop planets
• 0.4 planets will be habitable
• 90% of habitable planets develop life
• 10% of new instances of life develop intelligence
• 10% of such life develops interstellar communications
• These civilizations, might, on average, last 10,000 years.

To be fair, we are not sure on the actual figures. Drake’s values gives an answer of 10, meaning that 10 of these theoretical civilizations would be able to communicate.

But the importance of Drake’s equations is not necessarily the numerical value. It lies in all the questions that the equation led him to. Who knows exactly how many stars there are and what not? These figures are yet to be discovered.

So next time you look above, remember to always question. You’re not alone in questioning and you don’t know where these questions can lead you. Like Drake, you might be led to discover companions from different worlds.

Plateaus and Gaps

This fantastic close-up of Saturn’s outer C ring shows large and sharp changes in brightness across the rings, owing to the extreme variations in ring particle concentrations at different distances from the planet. The dark gap running through the center contains the Maxwell ringlet, as well as a faint, narrow ringlet discovered in Cassini images. Another very dark region to the right of the Maxwell gap is also a narrow gap.

The image was taken in visible light with the Cassini spacecraft narrow angle camera on Oct. 29, 2004, at a distance of about 836,000 kilometers (519,000 miles) from Saturn. The image scale is 4.6 kilometers (2.9 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

courtesy NASA/JPL/Space Science Instituteimage id: PIA06540

(via likeaphysicist)