ikenbot:

The 4th dimension in our case is where the 3D structures including this very Universe combine and exist within changing time frames. 4D structure can’t exist within a 3D one but a 3D structure can exist in a 4D just like your drawings exist within that flat paper as lines and points but couldn’t exist in our 3D world by itself. Extra dimensions work the same, like a Matryoshka doll that loses and or gains properties the further you go.

Image: 3D projection of a tesseract undergoing a simple rotation in four dimensional space.

In mathematical physics, Minkowski space or Minkowski spacetime (named after the mathematician Hermann Minkowski) is the mathematical space setting in which Einstein’s theory of special relativity is most conveniently formulated. In this setting the three ordinary dimensions of space are combined with a single dimension of time to form a four-dimensional manifold for representing a spacetime. [**]

In physics, spacetime (also space–time, space time or space–time continuum) is any mathematical model that combines space and time into a single continuum. Spacetime is usually interpreted with space as existing in three dimensions and time playing the role of a fourth dimension that is of a different sort from the spatial dimensions. From a Euclidean space perspective, the universe has three dimensions of space and one of time. By combining space and time into a single manifold, physicists have significantly simplified a large number of physical theories, as well as described in a more uniform way the workings of the universe at both the supergalactic and subatomic levels. [**]

But my favorite explanation of extra dimensions in general is Carl Sagan’s version. His version was based on Flatland: A Romance of Many Dimensions which is an 1884 satirical short story by Edwin Abbott Abbott:

The story is about a two-dimensional world referred to as Flatland which is occupied by geometric figures. Women are simple line-segments, while men are polygons with various numbers of sides. The narrator is a humble square, a member of the social caste of gentlemen and professionals in a society of geometric figures, who guides us through some of the implications of life in two dimensions. The Square has a dream about a visit to a one-dimensional world (Lineland) which is inhabited by “lustrous points”.

He attempts to convince the realm’s ignorant monarch of a second dimension but finds that it is essentially impossible to make him see outside of his eternally straight line.

He is then visited by a three-dimensional sphere, which he cannot comprehend until he sees Spaceland for himself. This Sphere (who remains nameless, like all characters in the novella) visits Flatland at the turn of each millennium to introduce a new apostle to the idea of a third dimension in the hopes of eventually educating the population of Flatland of the existence of Spaceland. From the safety of Spaceland, they are able to observe the leaders of Flatland secretly acknowledging the existence of the sphere and prescribing the silencing of anyone found preaching the truth of Spaceland and the third dimension. After this proclamation is made, many witnesses are massacred or imprisoned (according to caste).

After the Square’s mind is opened to new dimensions, he tries to convince the Sphere of the theoretical possibility of the existence of a fourth (and fifth, and sixth …) spatial dimension.

The depiction above is a 4 dimensional figure as represented by 3 dimensional cubes within cubes to visualize how 4th dimensions may work.

Related: Carl Sagan explains extra dimensions

(via scinerds)

Source: ikenbot

howstuffworks: How Grass Works: Grass is the common name for the Gramineae family of plants. With more than 9,000 known species, this family is one of the largest on Earth. Grass is extremely important to most people’s lives, whether they know it or not. For one thing, grass is a major food source all over the world. Rice, corn and oats come from grass plants, for example, and most livestock animals feed primarily on grasses. In some parts of the world, people use grass plants in construction (bamboo is a grass, for example), and wherever it grows, grass plays a vital role in curbing erosion. Grass is also used to make sugar, liquor, bread and plastics, among many other things. Grasses have a very simple structure, and a very simple way of life. Keep reading to learn lots more, including how to get the stuff to actually grow in your lawn….
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howstuffworks:

How Grass Works:

Grass is the common name for the Gramineae family of plants. With more than 9,000 known species, this family is one of the largest on Earth.

Grass is extremely important to most people’s lives, whether they know it or not. For one thing, grass is a major food source all over the world. Rice, corn and oats come from grass plants, for example, and most livestock animals feed primarily on grasses. In some parts of the world, people use grass plants in construction (bamboo is a grass, for example), and wherever it grows, grass plays a vital role in curbing erosion. Grass is also used to make sugar, liquor, bread and plastics, among many other things.

Grasses have a very simple structure, and a very simple way of life. Keep reading to learn lots more, including how to get the stuff to actually grow in your lawn….

(via thescienceofreality)

Source: howstuffworks

the-science-llama:

If Earth Had Rings

First off, they would be really pretty to look at. They would also dominate the sky in both night and day at exactly the same place as they would never rise nor set. And at night you would see the Earth’s shadow swing across the rings, like in the 4th photo here.

However, life would be very different on Earth if this were the case. Nocturnal animals would have a hard time being nocturnal, as the light reflecting from the rings would illuminate the night.

Because we are closer to the Sun than Saturn is, the rings would be more rocky than ice, making them less bright but still pretty bright. In fact, you would see far less stars at night (living anywhere other than the equator or the arctic circle) because of the light pollution and not to mention ruin most meteor showers because of that.

During the day the rings would block sunlight in certain regions of the planet creating wild weather cycles and effecting plant life as well. So basically, they would be definitely pretty to look at but they would also make a whole lot of things screwy.

Illustrations by Ron Miller // io9
— Click the photos for captions

(via scinerds)

Source: the-science-llama

matthen: If a mathematician wants to cross a road, they will think carefully about their optimal path. The total distance of the path should be minimised, but they prefer walking on the sidewalk to the road. If there is no extra discomfort from being on the road, the best path is a straight line, but as it increases it is better to cross the road more directly.  The resulting path is exactly the same as a ray of light refracting through a block of glass [with relative refractive index equal to the ratio of these ‘discomfort levels’]. Fermat’s principle says that light will want to spend less time in the glass (on the road), as it actually travels more slowly in the glass. [video] [code] [more]
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matthen:

If a mathematician wants to cross a road, they will think carefully about their optimal path. The total distance of the path should be minimised, but they prefer walking on the sidewalk to the road. If there is no extra discomfort from being on the road, the best path is a straight line, but as it increases it is better to cross the road more directly.  The resulting path is exactly the same as a ray of light refracting through a block of glass [with relative refractive index equal to the ratio of these ‘discomfort levels’]. Fermat’s principle says that light will want to spend less time in the glass (on the road), as it actually travels more slowly in the glass. [video] [code] [more]

(via scinerds)

Source: matthen

ikenbot: Wild Flower under the Milky Way “This flower is called Primula Denticulata and is located at 1500-3000m above sea level in northern part of Yunnan, China. I had strong desire to take a macro image of these flowers and it took me an hour hour to find them. Putting the camera on the slope, focusing, composition and lightning were all very difficult but the worst thing is shortness of time to moonrise. I had to leave soon.” — Jeff Dai
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ikenbot:

Wild Flower under the Milky Way

“This flower is called Primula Denticulata and is located at 1500-3000m above sea level in northern part of Yunnan, China. I had strong desire to take a macro image of these flowers and it took me an hour hour to find them. Putting the camera on the slope, focusing, composition and lightning were all very difficult but the worst thing is shortness of time to moonrise. I had to leave soon.” — Jeff Dai

(via scinerds)

Source: ikenbot

terra-mater: Weird gravity waves pulse from a tropical cyclone Last Monday, May 13, the Suomi NPP satellite captured a fascinating image of Tropical Cyclone Mahasen as it moved northeast over the Bay of Bengal. The clouds of the storm itself weren’t optically visible in the darkness of a nearly new Moon, but lightning flashes within it were… as well as the eerie ripples of atmospheric gravity waves spreading outwards from its center. Gravity waves are the oscillations of air parcels by the lifting force of bouyancy and the restoring force of gravity. These waves propagate vertically as well as horizontally, and actively transport energy and momentum from the troposphere to the middle and upper atmosphere. Gravity waves are caused by a variety of sources, including the passage of wind across terrestrial landforms, interaction at the velocity shear of the polar jet stream and radiation incident from space. They are found to affect atmospheric tides in the middle atmosphere and terrestrial weather in the lower atmosphere. Atmospheric gravity waves aren’t to be confused with gravitational waves in space, which are created by very dense, massive objects (like white dwarf stars or black holes) orbiting each other closely. When the image was captured, Tropical Cyclone Mahasen was moving north through the Indian Ocean along a track that placed landfall along the Bangladesh coast. As it moved off the coast of India Suomi’s VIIRS Day-Night Band was able to resolve lightning flashes towards the center of the storm, along with mesopheric gravity waves emanating outwards like ripples in a pond. Such gravity waves are of particular interest to air traffic controllers so assist in identifying areas of turbulence. Image credit: NASA/NOAA
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terra-mater:

Weird gravity waves pulse from a tropical cyclone

Last Monday, May 13, the Suomi NPP satellite captured a fascinating image of Tropical Cyclone Mahasen as it moved northeast over the Bay of Bengal. The clouds of the storm itself weren’t optically visible in the darkness of a nearly new Moon, but lightning flashes within it were… as well as the eerie ripples of atmospheric gravity waves spreading outwards from its center.

Gravity waves are the oscillations of air parcels by the lifting force of bouyancy and the restoring force of gravity. These waves propagate vertically as well as horizontally, and actively transport energy and momentum from the troposphere to the middle and upper atmosphere. Gravity waves are caused by a variety of sources, including the passage of wind across terrestrial landforms, interaction at the velocity shear of the polar jet stream and radiation incident from space. They are found to affect atmospheric tides in the middle atmosphere and terrestrial weather in the lower atmosphere.

Atmospheric gravity waves aren’t to be confused with gravitational waves in space, which are created by very dense, massive objects (like white dwarf stars or black holes) orbiting each other closely.

When the image was captured, Tropical Cyclone Mahasen was moving north through the Indian Ocean along a track that placed landfall along the Bangladesh coast. As it moved off the coast of India Suomi’s VIIRS Day-Night Band was able to resolve lightning flashes towards the center of the storm, along with mesopheric gravity waves emanating outwards like ripples in a pond.

Such gravity waves are of particular interest to air traffic controllers so assist in identifying areas of turbulence.

Image credit: NASA/NOAA

(via scinerds)

Source: terra-mater

smarterplanet:

City Forward: An Award-Winning Lesson in the Use of Open Big Data | Citizen IBM Blog

Sponsored by IBM, the City Forward website can be used to compare a selected city’s characteristics and challenges to others around the world. In the process, users can identify trends, pinpoint similarities and get ideas for how a city may be improved. These city stories then can be shared and discussed within the City Forward Community.

Completely free of charge, City Forward connects to the work done by Smarter Cities Challenge teams around the world. The website provides data for more than 100 cities, and offers both city leaders and the public the unique ability to consolidate multiple data sources. The International Academy of Digital Arts and Sciences (IADAS) recently recognized City Forward with its 2013 Corporate Social Responsibility Webby Award.

kidsneedscience: The word epilepsy first entered the English language in the 1570s courtesy William Shakespeare, in his play Julius Caesar, who was known to be epileptic.  It came via the French word epilepsie from the Late Latin transliteration epilepsia of the Ancient Greek word epilepsia meaning a seizure.  The Greeks combined the prefix epi- meaning upon with lepsis (root leps- from the future stem of lambanein, to fall) meaning falling-epilepsy was the falling sickness.   Happy Birthday, William Shakespeare, born April 23, 1564. Image of the bust of Julius Caesar courtesy Andreas Wahra, used with permission under a Creative Commons 3.0 license. 
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kidsneedscience:

The word epilepsy first entered the English language in the 1570s courtesy William Shakespeare, in his play Julius Caesar, who was known to be epileptic.  It came via the French word epilepsie from the Late Latin transliteration epilepsia of the Ancient Greek word epilepsia meaning a seizure.  The Greeks combined the prefix epi- meaning upon with lepsis (root leps- from the future stem of lambanein, to fall) meaning falling-epilepsy was the falling sickness.  

Happy Birthday, William Shakespeare, born April 23, 1564.

Image of the bust of Julius Caesar courtesy Andreas Wahra, used with permission under a Creative Commons 3.0 license. 

(via thescienceofreality)

Source: kidsneedscience