Perception

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Sun, 26 Feb 2012 00:46:43 -0500

"Love is a matter of chemistry, but Sex is a matter of physics"

Tue, 21 Feb 2012 23:32:41 -0500

“Love is a matter of chemistry, but Sex is a matter of physics”

- anonymous (via fuckyeahelements)

Here is another way to justify how humans are “central” in this...

Tue, 21 Feb 2012 22:34:07 -0500

Here is another way to justify how humans are “central” in this universe.

Consider the range in size of what is physically relevant in our universe. This range spans about 60 orders of magnitude (10⁶⁰) from the size of the visible universe at about 13.7 billion light years (~10²⁸ cm) all the way down to the Planck length, which is the smallest scale in which notions of size and distance essentially breakdown according to standard theories, at ~10^-33 cm.

As humans, at about 10² cm in size, we happen to exist near the middle of this range. This really is no coincidence, nor is it some kind of trickery with units of measurement.

It can be argued that if humans were any smaller our brains wouldn’t have room to develop their complexity allowing for our intelligence, and if we were any bigger our brains would lose their practical efficiency which depends on the brain’s ability to interact with itself. In fact, this must be true for all intelligent life.

So if you ever happen to feel down about your size relative to the rest of the universe, know that you are much more significant than any other structure in this universe exactly the way you are. Even David Deutsch once wrote: “The size of the universe is no more depressing than the size of a cow.”

However, it does seem rather peculiar that we humans exist and are making these observations of size at the point in time when the Universe has expanded to its current size, which just so happens to place us in the middle of this size range. Couldn’t this have been any different?

On the other end of things, one may even be willing to pass the size scale set by the Plank length as being mere coincidence, since the fundamental constants which determine its value could have possibly taken on different values themselves making things very different.

30 Years of the Space Shuttle

Tue, 21 Feb 2012 22:32:17 -0500

30 Years of the Space Shuttle

Stirling Engines Stirling engines are unique heat engines...

Tue, 21 Feb 2012 22:31:51 -0500

Stirling Engines

Stirling engines are unique heat engines because their theoretical efficiency is nearly equal to their theoretical maximum efficiency, known as the Carnot Cycle efficiency. Stirling engines are powered by the expansion of a gas when heated, followed by the compression of the gas when cooled. The Stirling engine contains a fixed amount of gas that is transferred back and forth between a “cold” end (often room temperature) and a “hot” end (often heated by a kerosene or alcohol burner). The “displacer piston” moves the gas between the two ends and the “power piston” changes the internal volume as the gas expands and contracts.

Air in the engine is cyclically heated (by an alcohol burner) and expands to push the power piston (shown in blue) to the right. As the power piston moves to the right, the yellow linkage forces the loose-fitting, red “piston” (on the left half of the machine) to displace air to the cooler side of the engine. The air on the cool side loses heat to the outside world and contracts, pulling the blue piston to the left. The air is again displaced, sending it back to the hotter region of the engine, and the cycle repeats.

The Stirling engine cycle can also be used “in reverse”, to convert rotating motion into a temperature differential (and thus provide refrigeration).

etceterablog: Geometry from the Brockhaus and Efron...

Tue, 21 Feb 2012 22:28:19 -0500

etceterablog:

Geometry from the Brockhaus and Efron Encyclopedic Dictionary, published in Russia,1890-1907.

project-argus: This is useful. So beautiful.

Tue, 21 Feb 2012 22:26:19 -0500

project-argus:

This is useful.

So beautiful.

20 Things You Didn’t Know About The Periodic Table How it...

Tue, 21 Feb 2012 22:25:05 -0500

20 Things You Didn’t Know About The Periodic Table

How it started, how it’s like solitaire, how to fold it, and how it ends.

by Rebecca Coffey

Image above: Periodic Table by Lawrence Berkeley National Lab

1 You may remember the Periodic Table of the Elements as a dreary chart on your classroom wall. If so, you never guessed its real purpose: It’s a giant cheat sheet.

2 The table has served chemistry students since 1869, when it was created by Dmitry Mendeleyev, a cranky professor at the University of St. Petersburg.

3  With a publisher’s deadline looming, Mendeleyev didn’t have time to describe all 63 then-known elements. So he turned to a data set of atomic weights meticulously gathered by others.

4 To determine those weights, scientists had passed currents through various solutions to break them up into their constituent atoms. Responding to a battery’s polarity, the atoms of one element would go thisaway, the atoms of another thataway. The atoms were collected in separate containers and then weighed.

5  From this process, chemists determined relative weights—which were all Mendeleyev needed to establish a useful ranking.

6 Fond of card games, he wrote the weight for each element on a separate index card and sorted them as in solitaire. Elements with similar properties formed a “suit” that he placed in columns ordered by ascending atomic weight.

7 Now he had a new Periodic Law (“Elements arranged according to the value of their atomic weights present a clear periodicity of properties”) that described one pattern for all 63 elements.

8  Where Mendeleyev’s table had blank spaces, he correctly predicted the weights and chemical behaviors of some missing elements—gallium, scandium, and germanium.

9  But when argon was discovered in 1894, it didn’t fit into any of Mendeleyev’s columns, so he denied its existence—as he did for helium, neon, krypton, xenon, and radon.

10 In 1902 he acknowledged he had not anticipated the existence of these overlooked, incredibly unreactive elements—the noble gases—which now constitute the entire eighth group of the table.

11  Now we sort elements by their number of protons, or “atomic number,” which determines an atom’s configuration of oppositely charged electrons and hence its chemical properties.

12  Noble gases (far right on the periodic table) have closed shells of electrons, which is why they are nearly inert.

13 Atomic love: Take a modern periodic table, cut out the complicated middle columns, and fold it once along the middle of the Group 4 elements. The groups that kiss have complementary electron structures and will combine with each other.

14  Sodium touches chlorine—table salt! You can predict other common compounds like potassium chloride, used in very large doses as part of a lethal injection.

15 The Group 4 elements (shown as IVA above) in the middle bond readily with each other and with themselves. Silicon + silicon + silicon ad infinitum links up into crystalline lattices, used to make semiconductors for computers.

16  Carbon atoms—also Group 4—bond in long chains, and voilà: sugars. The chemical flexibility of carbon is what makes it the key molecule of life.

17  Mendeleyev wrongly assumed that all elements are unchanging. But radioactive atoms have unstable nuclei, meaning they can move around the chart. For example, uranium (element 92) gradually decays into a whole series of lighter elements, ending with lead (element 82).

18 Beyond the edge: Atoms with atomic numbers higher than 92 do not exist naturally, but they can be created by bombarding elements with other elements or pieces of them.

19 The two newest members of the periodic table, still-unnamed elements 114 and 116, were officially recognized last June. Number 116 decays and disappears in milliseconds. (Three elements, 110 to 112, were also officially named earlier this month.)

20 Physicist Richard Feynman once predicted that number 137 defines the table’s outer limit; adding any more protons would produce an energy that could be quantified only by an imaginary number, rendering element 138 and higher impossible. Maybe.

Q&BA: How does a gravitational slingshot work? In this...

Tue, 21 Feb 2012 22:24:50 -0500

Q&BA: How does a gravitational slingshot work?

In this episode of Q&BA, I describe how a gravitational slingshot works, and how they are used to get spacecraft to the inner and outer solar system.

by TheBadAstronomer

black-tangled-heart: Google Celebrates Heinrich Rudolf...

Tue, 21 Feb 2012 22:17:42 -0500

black-tangled-heart:

Google Celebrates Heinrich Rudolf Hertz Birthday

One of the pillars of the “Electromagnetic Theory of Light,” German physicist Heinrich Rudolf Hertz is the center of the Google universe today, February 22nd (Australian Time) with his own Google Doodle. According to Google, the new Doodle celebrates the 155th birthday of Heinrich Rudolf Hertz.

spaciousart: Milky Way over Switzerland

Tue, 21 Feb 2012 22:17:39 -0500

spaciousart:

Milky Way over Switzerland

Tue, 21 Feb 2012 22:17:17 -0500

Pulsars: The Universe’s Gift to Physics Astronomers are using...

Tue, 21 Feb 2012 22:16:56 -0500

Pulsars: The Universe’s Gift to Physics

Astronomers are using pulsars throughout the Milky Way Galaxy as a giant scientific instrument to directly detect gravitational waves.

Pulsars, superdense neutron stars, are perhaps the most extraordinary physics laboratories in the universe. Research on these extreme and exotic objects already has produced two Nobel Prizes. Pulsar researchers now are poised to learn otherwise-unavailable details of nuclear physics to test general relativity in conditions of extremely strong gravity, and to directly detect gravitational waves with a “telescope” nearly the size of our galaxy.

Read More

Tue, 21 Feb 2012 22:16:30 -0500

NASA Launches Rocket Into Northern Lights Astronomers recently...

Tue, 21 Feb 2012 22:16:03 -0500

NASA Launches Rocket Into Northern Lights

Astronomers recently sent a 46-foot rocket sailing through the shimmering green band of energy known as aurora borealis, or the northern lights.

The NASA-funded mission launched on the frigid night of Feb. 18 from the Poker Flat Research Range, 30 miles north of Fairbanks, Alaska. The rocket, called the Magnetosphere-Ionosphere Coupling in the Alfvén resonator (MICA), arced 200 miles upward and plunged directly into the lights.

Auroras occur when charged particles emanating from the sun hit Earth’s upper atmosphere, producing light. Instruments aboard MICA probed the electric and magnetic fields that arise from this collision, collecting data for 10 minutes before falling back to Earth.

The recorded information will help researchers understand how the charged particles, collectively known as the solar wind, affect Earth. Such data is important because the sun is currently entering a period of increased activity and electromagnetic storms can affect satellites orbiting the Earth.

Read full article..

Phantom Black Holes of the Milky Way —Could They Pose a Danger...

Tue, 21 Feb 2012 22:12:22 -0500

Phantom Black Holes of the Milky Way —Could They Pose a Danger to Our Solar System?

” The effect of a primordial black hole hitting the Sun ought to be easily observable, say physicists at New York University and Princeton University, noting what we think might be the obvious. But they go on to suggest that such an event wouldn’t be as catastrophic as it sounds.

The likelihood is that a primordial black hole with mass of an asteroid or comet would pass straight through the Sun, generating a small puff of X-rays in the process. The burst would be less even than the background rate of X-rays, so it would be impossible for astronomers to see. Instead, the collision would generate supersonic turbulence that would set the Sun ringing like a bell — sort of a “solar hiccup,” so we might have seen them already.

As we reported previously, the Milky Way may be full of phantom, planet-devouring black holes. A recent computer simulation revealed that there could be literally hundreds of rogue black holes scattered across the Milky Way galaxy. Each one would weigh several thousand times the mass of the sun, so if these bad guys exist — why haven’t we identified them already?

“Rogue black holes like this would be very difficult to spot,” says Vanderbilt astronomer Kelly Holley-Bockelmann. “Unless it’s swallowing a lot of gas, about the only way to detect the approach of such a black hole would be to observe the way in which its super-strength gravitational field bends the light that passes nearby. This produces an effect called gravitational lensing that would make background stars appear to shift and brighten momentarily.”

The research modeled “intermediate mass” black holes —the first of which was just discovered by an international team using the European Space Agency’s XMM-Newton X-ray space telescope (read below). Astronomers have ample evidence that small black holes less than 100 solar masses are produced when giant stars explode. They also have evidence that “super-massive” black holes weighing the equivalent of millions to billions of solar masses sit at the heart of most galaxies, including the Milky Way. “

http:// www.dailygalaxy.com/ my_weblog/2012/02/ weekend-feature-phantom-bla ck-holes-of-milky-way-could-they-pose-a-danger-to-our-solar-system-.html#more

Source: Milky way scientists

‎”As long as there have been humans, we have searched for our...

Tue, 21 Feb 2012 22:09:26 -0500

‎”As long as there have been humans, we have searched for our place in the cosmos. Where are we, who are we? We find that we live on an insignificant planet of a humdrum star, lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people. We make our world significant by the courage of our questions, and by the depth of our answers.”

expose-the-light: beyondnfinity: Sports Level: ASIAN! No...

Tue, 21 Feb 2012 22:07:44 -0500

expose-the-light:

beyondnfinity:

Sports Level: ASIAN!

No doubt.

Photo

Tue, 21 Feb 2012 20:57:14 -0500

Photo

Tue, 21 Feb 2012 20:56:56 -0500