we-are-star-stuff:

Sir Isaac Newton (25 December 1642 [NS: 4 January 1643] – 20 March 1727 [NS: 31 March 1727]) was an English physicist, mathematician, astronomer, natural philosopher, alchemist and theologian, who has been considered by many to be the greatest and most influential scientist who ever lived. Although his career was long and littered with success, there were four discoveries that were considered to be his most important.

Law of universal gravitation

Thoughts of gravitation entered Newton’s head as result of a certain apple tree and the tree’s falling fruit. In 1666, while Newton was sitting in the manor house garden at Woolsthorpe, he saw an apple fall from a tree. This triggered certain thoughts that he had been having about gravitation. Despite popular belief, the apple did not fall on his head. What actually happened was that he saw an apple fall from an apple tree and he began to wonder why it fell. From there his thoughts broadened to the rotation of the moon. It was already common knowledge that the moon revolved around the Earth and the planets revolved around the sun. This was caused by gravity. What Newton wanted to know was why the moon revolved around the earth instead of simply being pulled into the earth like the apple was. This brainstorm (which some scholars suspect Newton may have invented late in life) ultimately led to his law of universal gravitation. The law says that all particles of matter in the universe attract every other particle, that gravitational attraction is a property of all matter. The law explained many things, from the orbits of the planets around the sun to the influence of the moon and sun on the tides. And it held sway as the accepted description of terrestrial and celestial mechanics for almost 200 years, until Einstein came along and rocked the boat with relativity.

Three laws of motion

Newton’s laws of motion are three physical laws that form the basis for classical mechanics. They describe the relationship between the forces acting on a body and its motion due to those forces. They have been expressed in several different ways over nearly three centuries and can be summarized as follows:

1. First law: If an object experiences no net force, then its velocity is constant: the object is either at rest (if its velocity is zero), or it moves in a straight line with constant speed (if its velocity is nonzero).
2. Second law: The acceleration a of a body is parallel and directly proportional to the net force F acting on the body, is in the direction of the net force, and is inversely proportional to the mass m of the body, i.e., F = ma.
3. Third law: When a first body exerts a force F₁ on a second body, the second body simultaneously exerts a force F₂ = −F₁ on the first body. This means that F₁ and F₂ are equal in magnitude and opposite in direction.

Theory of light and color

Newton became stuck while trying to figure out what the radius of the earth was in order to help him prove his Universal Law of Gravitation. Rather than guess and take a chance that he might be wrong, he decided to put the project on hold and study something else. That something else optics, or the study of color and light. From 1670 to 1672, Newton lectured on optics. During this period he investigated the refraction of light, demonstrating that a prism could decompose white light into a spectrum of colours, and that a lens and a second prism could recompose the multicoloured spectrum into white light. 

He also showed that the coloured light does not change its properties by separating out a coloured beam and shining it on various objects. Newton noted that regardless of whether it was reflected or scattered or transmitted, it stayed the same colour. Thus, he observed that colour is the result of objects interacting with already-coloured light rather than objects generating the colour themselves.

From this work, he concluded that the lens of any refracting telescope would suffer from the dispersion of light into colours (chromatic aberration). As a proof of the concept, he constructed a telescope using a mirror as the objective to bypass that problem. 

Calculus

When Newton began to muse on the problem of the motion of the planets and what kept them in their orbits around the sun, he realized that the mathematics of the day weren’t sufficient to the task. Properties such as direction and speed, by their very nature, were in a continuous state of flux, constantly changing with time and exhibiting varying rates of change. So he invented a new branch of mathematics, which he called the fluxions (later known as calculus). Calculus allowed him to draw tangents to curves, determine the lengths of curves, and solve other problems that classical geometry could not help him solve. Interestingly, Newton’s masterwork, the Principia, doesn’t include the calculus in the form that he’d invented years before, simply because he hadn’t yet published anything about it. But he did combine related methods with a very high level of classical geometry, making no attempt to simplify it for his readers. The reason was, he said, “to avoid being baited by little Smatterers in Mathematicks.”

fyeahuniverse:

Research Team Discerns Atomic Bond Types From Image

A team of researchers at IBM has had astounding success at imaging things on the smallest of scales, and once again they have worked their magic and produced something completely out of this world. After producing an image of a molecule shaped like the Olympic Rings earlier this year, they have published this image and a paper in the journal, Science, in which the detail is so high that they are able to discern the types of atomic bonds present.

Using a technique called atomic force microscopy (AFM), the team was able to create this picture. Atomic force microscopy works through using a carbon monoxide molecule which effectively works as a recording needle (read: record player needle), as to pick up the minute vibrations.

In order to get a clear picture instead of a fuzzy mess, the experiment must be isolated from any vibrations in the lab. This means that too much warmth would lead to distortion also, so the experiment is kept at a chilly -268C.

In the image you can see just how long the atomic bonds are, with the bright and dark spots corresponding to higher and lower densities of electrons respectively.

That we can now see different physical properties of different bonds is really freaking awesome and this new ability will no doubt lend itself to future developments in many areas of science. (x)

(via physicsphysics)

neurosciencestuff:

The empathy machine

…Let’s dwell for a moment on ‘Silver Blaze’ (1892), Arthur Conan Doyle’s story of the gallant racehorse who disappeared, and his trainer who was found dead, just days before a big race. The hapless police are stumped, and Sherlock Holmes is called in to save the day. And save the day he does — by putting himself in the position of both the dead trainer and the missing horse. Holmes speculates that the horse is ‘a very gregarious creature’. Surmising that, in the absence of its trainer, it would have been drawn to the nearest town, he finds horse tracks, and tells Watson which mental faculty led him there. ‘See the value of imagination… We imagined what might have happened, acted upon that supposition, and find ourselves justified.’

Holmes takes an imaginative leap, not only into another human mind, but into the mind of an animal. This perspective-taking, being able to see the world from the point of view of another, is one of the central elements of empathy, and Holmes raises it to the status of an art.

Usually, when we think of empathy, it evokes feelings of warmth and comfort, of being intrinsically an emotional phenomenon. But perhaps our very idea of empathy is flawed. The worth of empathy might lie as much in the ‘value of imagination’ that Holmes employs as it does in the mere feeling of vicarious emotion. Perhaps that cold rationalist Sherlock Holmes can help us reconsider our preconceptions about what empathy is and what it does.

Though the scientific literature on empathy is complex, a recent review in Nature Neuroscience by a team of researchers from Harvard and Columbia including Jamil Zaki and Kevin Ochsner has distilled the phenomenon into three central stages. The first stage is ‘experience sharing’, or feeling someone else’s emotions as if they were your own — scared when they are scared, happy when they are happy, and so on. The second stage is ‘mentalising’, or consciously considering those states and their sources, and trying to work through understanding them. The final stage is ‘prosocial concern’, or being motivated to act — wanting, for example, to reach out to someone in pain. However, you don’t need all three to experience empathy. Instead, you can view these as three points on an empathetic continuum: first, you feel; then, you feel and you understand; and finally, you feel, understand, and are compelled to act on your understanding. It seems that the defining thing here is the feeling that accompanies all those stages.

Full article

neurosciencestuff:

Why Music Moves Us

Universal emotions like anger, sadness and happiness are expressed nearly the same in both music and movement across cultures, according to new research.

The researchers found that when Dartmouth undergraduates and members of a remote Cambodian hill tribe were asked to use sliding bars to adjust traits such as the speed, pitch, or regularity of music, they used the same types of characteristics to express primal emotions. What’s more, the same types of patterns were used to express the same emotions in animations of movement in both cultures.

“The kinds of dynamics you find in movement, you find also in music and they’re used in the same way to provide the same kind of meaning,” said study co-author Thalia Wheatley, a neuroscientist at Dartmouth University.

The findings suggest music’s intense power may lie in the fact it is processed by ancient brain circuitry used to read emotion in our movement.

“The study suggests why music is so fundamental and engaging for us,” said Jonathan Schooler, a professor of brain and psychological sciences at the University of California at Santa Barbara, who was not involved in the study. “It takes advantage of some very, very basic and, in some sense, primitive systems that understand how motion relates to emotion.”

Universal emotions

Why people love music has been an enduring mystery. Scientists have found that animals like different music than humans and that brain regions stimulated by food, sex and love also light up when we listen to music. Musicians even read emotions better than nonmusicians.

Past studies showed that the same brain areas were activated when people read emotion in both music and movement. That made Wheatley wonder how the two were connected.

To find out, Wheatley and her colleagues asked 50 Dartmouth undergraduates to manipulate five slider bars to change characteristics of an animated bouncy ball to make it look happy, sad, angry, peaceful or scared.

“We just say ‘Make Mr. Ball look angry or make Mr. Ball look happy,’” she told LiveScience.

To create different emotions in “Mr. Ball,” the students could use the slider bars to affect how often the ball bounced, how often it made big bounces, whether it went up or down more often and how smoothly it moved.

Another 50 students could use similar slider bars to adjust the pitch trajectory, tempo, consonance (repetition), musical jumps and jitteriness of music to capture those same emotions.

The students tended to put the slider bars in roughly the same positions whether they were creating angry music or angry moving balls.

To see if these trends held across cultures, Wheatley’s team traveled to the remote highlands of Cambodia and asked about 85 members of the Kreung tribe to perform the same task. Kreung music sounds radically different from Western music, with gongs and an instrument called a mem that sounds a bit like an insect buzzing, Wheatley said. None of the tribes’ people had any exposure to Western music or media, she added.

Interestingly, the Kreung tended to put the slider bars in roughly the same positions as Americans did to capture different emotions, and the position of the sliders was very similar for both music and emotions.

The findings suggest that music taps into the brain networks and regions that we use to understand emotion in people’s movements. That may explain why music has such power to move us — it’s activating deep-seated brain regions that are used to process emotion, Wheatley said.

“Emotion is the same thing no matter whether it’s coming in through our eyes or ears,” she said.