First observation of merger of two neutron stars

Neutron stars are the remnants of explosions of supernovae. Neutron stars are most dense in the universe so these are quite small in size. For example the size of London. They are so dense that a spoonful of neutrons weighs as much as 100 000 Eiffel towers.

It so happens that when two neutron stars approach each other, they turn faster and faster generating the gravitational waves by modifying the space-time around them. Ultimately they collide and fuse. After this the eject lots of matter.

How such events in occuring in the universe are detected? Electromagnetic rays emitted during such an event in the form of visible and invisible energy waves can be tracked by the modern telescopes and spectrometry.

Another technique has been added and it measures the gravitational waves which are generated in such violent events involving massive bodies. Such instruments has been installed in US. Called LIGO (Laser interferometer Gravitational-Wave Observatory) can record the gravitational waves.

One such event of fusion of two neutron stars happened 130 million years ago. The gravitational ripples were detected by LIGO on August 17 at 1241 GMT for 100 seconds. Then after 2 seconds a Gamma rays burst was observed. After hours and days following the event, X-rays, UV rays and infrared rays were detected.

This is the first successful observation of fusion of two neutron stars through Gravitational Waves and as well as through different kind of rays that are emitted.

It also confirmed the premise that gravitational waves travel with speed equal to that of light. This event was made possible with the collaboration of 3674 scientists from 953 institutions all around the world.

 

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What Color are the Atoms?

Atoms are the smallest units of matter which are independent and have a definite address. Atoms of different elements are different in many aspects but size and atomic weight are the main attributes. I think there is no such thing as color of things. Color exists only when there is light.When the darkness falls, the color of things begins to dissolve and black color takes over everything. Black color thus obliterate all the differences due to colors. May be this is the reason why in Hindu mythology many Gods are dark complexioned. Take for example Rama, Krishna and Draupadi, all of them are dark in complexion. Although it is strange to explain why so many of Hindus prefer the fair color. So how can a thing have red color and black color at two instances of time? Light a bulb and again colors come back but there is different between the colors of things in different kinds of lights.

Sunlight is a mixture of many colors which are different waves. All the waves are the part of what is called light spectrum. Our eyes can see limited spectrum of light called visible spectrum which is from violet to red. Violet and beyond region called ultra violet have higher energy. On the opposite end is the red color and lower energy infra red. Birds and bees are endowed with more complex eyes and are capable of seeing into the infrared and ultra violet ranges also. The plants have exploited this capability and deposit substances on the flower strategically on flowers so that bees reach the target directly.

Our eyes have light receptors called cones and rods. They gather light from the target and send to the brain for generating a composite picture. The rods are more numerous than cones. The rods are meant for collecting the faint lights and operate when the light is dim like the sailors panning the stars in sky or when we are out in remote village on a clear night. Due to the plenty of light during the nights also these days, the services of the rods are seldom impressed upon. Now the main role is played by the cones. It is not known why these rods have not been traded with cones during the evolution.

When the light falls upon a substance, different energy centers in the substance become excited. These centers are electrons, atoms or molecules rotation, vibration of atoms joined with different kinds of bonds like single, double or triple. Depending upon the available spectrum of rays falling on the substance, those matching these centers are absorbed. This match is very much defined depending on the structure of the molecules.

From the visible spectrum, some of the wave length rays are absorbed. Those which does not match any center is not absorbed and reflected back. This is the color which reaches our eye and is responsible for the color which we attribute to the substance.

Most of the optical analytical instruments use monochromatic light beams to shine on the atoms and molecules. Monochromatic light is pure light beam of single energy and generally matches a particular wavelength emitted by an excited atoms of single elements. Thus they are able to determine the concentration of a particular element in a solution.

Darkness

Darkness is a much maligned being. Everyone praises the light, everyone advocates in the favour of light. Especially on the occasion of Diwali, the most common refrain begins with “Let there be light……”, as if we are living in the dark till now.

Importance of light is due to the darkness. In fact they follow each other. It is only for darkness, we admire the light. The truth is that we have been blessed to see only a very narrow spectrum of the reality. It is a very narrow window in comparison to the whole spectrum. We are not able to see beyond the infrared and ultraviolet region. Only a minuscule window is available for us. Birds and bees are better off than us in this regard. Bees for example can see in the ultraviolet region. Birds can see in the lower frequencies than infrared.

In fact, the visible is just an iceberg floating in the sea of hidden or darkness. Dark matter which is counterpart of the visible matter is many times bigger.

Darkness is absolutely necessary for shutting down the process visible inputs to our mind. It forces the humans to sleep and rejuvenate the brain by giving it the necessary respite. Receptors especially eyes & ears are always receiving and feeding the information to the brain. They keep the brain busy. So the darkness helps to shut down these receptors periodically.

Everything exists in pairs in the universe. One is complementary to the other. Matter has antimatter, electron has positron, vice has virtue, Ravana has Rama, Yin has Yang, eggs have sperms, night has day as their complements. Think if everyone were good or everyone were bad, the evolution or progress will come to a grinding halt. Humans thrive on the competition, dominating others is in their blood. If it were not true, life would be so boring. Species will not have to do anything for survival. No one will challenge others as everyone will be satisfied and have no aspiration.

Snell’s Window

How the species under water see the world above? The entire horizon is visible to them through a window, a disc, called Snell’s window named Dutch mathematician Willebrord Snellius. Anything outside this window is not visible. In fact the area outside this window looks dark.

The diameter of disc varies with the depth at which the viewer is located below water. As the depth of eye increases, the disc gets bigger in size.

All this depends upon the strange properties of the light which illuminates this world and which enters our eyes which act as a camera.

We know now that phenomena occurring in the microscopic realm cannot be explained by usual classical science. For example, light is considered as wave as well as discrete bundles called photon. We have to resort to dualism to explain different kinds of observations. This is because assumptions are required to explain when the reality is not known to us. Light may neither be discrete particles or waves which we are unable to fathom as yet.

As we know that light consists of photons which are tiny bundles of light traveling in a stream. This means that light will travel with different speeds in different mediums. In the water for example, the light travels slowly than the air because water molecules offer resistance to the flow of photons. As a viewer, we see the light rays bending towards the normal to the point where light ray strikes the water. This is the other way of saying that light seem to come from a depth which is more than the real depth. This is shown in the following picture.

Rod in Glass of water

This was explained by a law known as Snell’s law which states that the ratio of the sines of the angles of incidence and refraction is equivalent to the ratio of velocities of light in two media, or equivalent to the opposite ratio of the indices of refraction.

Refraction of light has many strange and interesting consequences. One of them is how the living species like fish, dolphins & divers look the world outside the water. From the Snell’s law, it is clear that a ray of light making an angle of 90 degrees incidence, meaning grazing parallel to surface, bends at an angle of 48.7 degrees. This clearly means that rays covering the entire horizon will form a disc of light with apex on the eye and cone angle double the angle of refraction, that is 97.4 degrees. Depending upon the depth at which eyes of the species are located, the disc diameter will adjust itself to enclose the entire horizon above. The calculations show this as follows.

snell1

So, the entire world above surface will become visible through a disc of light. Outside this disc is all darkness.

This disc is essential to negotiate the space in 3-dimensions. Without this, the species will not be able to know which is upside or downside. They will become disoriented. This can happen to the species which live in the rivers carrying large amounts of clay and are muddied. Here, for survivor, the fish has to adapt other means to survive.

I found this beautiful picture of a turtle in the Snell’s window on the Flickr. Please click the link to see this picture. This site contains very stunning photos. So it will be worthwhile to explore this site.