BLACK HOLE – An unsolved mystery

Firstly Blackhole is not is hole.
It is a neutron star.

A Black hole formed when a star dies. The dead star firstly expand due to supernova and then squeeze or contract toward its core due to its high gravitational pull.
Due to this high contraction the electrons of atoms come near to protons in nucleus and become neutral. So that it is called neutron star.

This information is based on some famous theories.
According to some theories the size of a black hole can be as small as just one atom and big as 75 billion miles in diameter.

Currently the smallest known black hole is only 20 km in diameter and have mass equivalent approximetely 3.4 solarmass.
(1 solarmass= 1.8×10³⁰kg).

One teaspoonfull of black hole matter has equivalent mass of one earth. Because it is so dense.

The spin of black hole on its axis is nearly 3000 times faster then earth.
The inside temperature of black hole is very low about 1/10¹⁴kelvin while the outside temperature is very high.

The gravitational pull of black hole is very high. So it bends the space. Due to this bend in space, even light can not pass through a black hole (because light has the property to the travel in straight line).

Anything can never be fall in black hole directly. Due to black hole’s high spin, the object that fall in black hole rotate with a very high speed around it.

Even everything not fall in the black hole because due to high spin, and because of this the centrifugal force increases.
Due to increment in centrifugal force some mass can escape the gravitational pull of black hole.

If anything falls in blackhole, the body rotating and start to stretch toward its surface.
The body Stretch because gravity attract it toward the surface and high spin and high centrifugal force oppose this attraction. So both the phenomena of moving and attracting occur at same time and then the body get stretched.
Because of these phenomena, the form of body changes and it cannot remain stable.

If you fall into a blackhole, the time moves slowly for you due to bend in the space.

Mostly every galaxies has black hole in middle. Our galaxy(the milky way) also has a giant black hole in its middle.

Black holes cannot be observe or seen directly because they are black. They are observed by the radiation and stars moving around them.

Nearest found black hole to our solar system is HR 6819 and it is only 1000 light year away.
(Light year is the distance that travelled by light in one year with speed 3 lakh km/sec).

To come out from a black hole as impossible as to climbing on a waterfall from bottom to top by a boat.

to be continue……..


If you find any errors in any of our posts, you can contact us



Current is a flow of electric charge carriers , usually electrons or electron deficient atoms.

the common symbol for current is the uppercase letter I

S.I. unit is ampere

electric current can either be direct or alternating current, means DC or AC


an electric current that reverses its direction many times a second at regular intervals, typically used in power supplies.

AC current can be produced by rotating a coil of wire in magnetic field.


An electric current flowing in one direction only.

a battery is a prime example of DC power

direct current may flow through a conductor such as a wire but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams.

to be continue….

this is brief introduction about electric current, we’ll update more information soon.



MOON – A Brief Introduction

The earth has only one natural satellite called moon. It is also called dead satellite.
Moon’s gravity is just 1/6 of earth’s gravity. It is only 1.62m/s².

A large size terrestrial body collide with earth 4.53 billion years ago and a large piece of earth is separate and revolve in orbit around earth. Now that large piece is our moon.

Due to moon’s less gravity, there is no atmosphere on the moon because the escape velocity of atmospheric particle is greater than the escape velocity of moon and due to this the atmospheric particle escape out of moon’s gravitational pull.

Moon’s escape velocity is only 2.38km/sec while earth’ escape velocity is 11.19km/sec.

Moon complete one revolution of earth in just 29.4 days While earth can complete one revolution of sun in 365.25 days.
Moon can complete one revoution on its axis in 27.3 days.

Earth’s one day time 23 hours and 56 minutes. This is the cause of leap year.

According to some theories if moon does not exist then earth’s day time would be approximately 6 to 10 hours. So moon increase earth’s day time.

Moon’ gravity cause tides in sea.

Thousands of asteroid and comets was collides with moon’s surface and cause craters on its surface. You can see these craters from earth by telescope.

The first living animal land on the moon surface was a dog name Laika on 3 November 1957.
And The man who took the first steps on the moon’s surface on july 20, 1969, was named Neil Armstrong .

Neil Armstrong and aldrin walked on surface of the moon.

Radius of the moon is approximately 1,738 km Earth to moon distance is 384400kms.
Light can take 1.2 second to reach the moon from earth.





Earth – the blue planet

Earth is a Germanic word, and it means “the ground“, and it is at least 1000 years old . but all of the planets were named on greek and roman god and goddess (except earth).

Earth is about 4.5 billion years old and third planet from sun.

you could be spinning through space at just over 1,000 miles per hour.

Earth have different seasons because  Earth is tilted 23.4 degrees on its ‘axis.

The Earth’s diameter is about 12,800km.

Earth’s Core Is as Hot as the Sun’s Surface.

We live on the earth ,not in the earth.

About 70% of the Earth’s Surface is Covered in Water. Earth have only 3% fresh water and other 97% of it is salted.

About 100 lightning bolts strike earth every second.

About 5000 people dies due to drinking polluted water and about 100 million mammals dies by pollutionon earth.

Currently earth has about 3 trillion trees.

The earth’s population is about 7.6 to 7.8 billion.

many claims states that Nicolaus Copernicus was the man who discovered earth.




here you find information about solar system, but it is in brief, we shall update it soon with more information.

There are many planetary systems like ours in the universe, with planets orbiting a host star. our planetary system is named the “solar” sytem because our sun is named Sol , after the latin word for sun, “solis”, and anything related to the sun we call “solar.”

Age 4.568 billion years

our solar system formed about 4.5 billion years ago from a dense cloud collapsed, possibly due to the shockwave of a nearby exploding star, called supernova. when this dust cloud collapsed. it formed a solar nebula – a spinning, swirling disk of material. As is typical of molecular clouds, this one consisted mostly of hydrogen, with some helium, and small amounts of heavier elements fused by previous generations of stars.

The solar system consists of the Sun, planets, dwarf planets, moons, and numerous smaller objects such as comets and asteroids. 194 moons, 3,583 comets and 796,289 asteroids have been found in the solar system. 99.86% of the solar system’s mass is found in the Sun.

The Sun is our nearest star. It is, as all stars are, a hot ball of gas made up mostly of Hydrogen. The Sun is so hot that most of the gas is actually plasma, the fourth state of matter. The sun is classified as a G-type main-sequence star, or G dwarf star, or more imprecisely, a yellow dwarf. The planets in order from the Sun based on their distance are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Approx distance between neptune (8th) planet and sun is 4.476 billion km.
It is 143.73 billion km from the Sun, thus giving the Solar System a diameter of 287.46 billion km approx.

Based on where the planets end, you could say it’s Neptune and the Kuiper Belt. If you measure by edge of the Sun’s magnetic fields, the end is the heliosphere. If you judge by the stopping point of Sun’s gravitational influence, the solar system would end at the Oort Cloud. The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars, that is occupied by a great many solid, irregularly shaped bodies, of many sizes but much smaller than planets, called asteroids or minor planets.
The asteroid belt formed from the primordial solar nebula as a group of planetesimals.
Planetesimals are the smaller precursors of the protoplanets. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitationally perturb each other’s orbits and collide, gradually coalescing into the dominant planets.

The Kuiper belt, occasionally called the Edgeworth–Kuiper belt, is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger – 20 times as wide and 20–200 times
as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed.
The Kuiper belt is home to three officially recognized dwarf planets: Pluto, Haumea and Make make. Kuiper belt contain comets, mostly ice comets with black colour. When the orbit of the comet brings it close to the Sun, the ice evaporates into space, leaving some of the fine dust sitting on the surface. The dust is fine like talcum powder because comets are too small to have
enough gravity to squeeze the dust together into larger particles. The surface is very black.

The sun sends out a constant flow of charged particles called the solar wind, which ultimately travels past all the planets to some three times the distance to Pluto before being impeded by the interstellar medium. This forms a giant bubble around the sun and its planets, known as the heliosphere.

The heliosphere is the vast, bubble-like region of space which surrounds and is
created by the Sun. In plasma physics terms, this is the cavity formed by the Sun in the
surrounding interstellar medium. The “bubble” of the heliosphere is continuously “inflated”
by plasma originating from the Sun, known as the solar wind.
The heliosphere acts as a shield that protects the planets from interstellar radiation.

The Oort Cloud lies far beyond most distant edges of the Kuiper Belt. While the planets of our solar system orbit in a flat plane, the Oort Cloud is believed to be a giant spherical shell surrounding the Sun, planets and Kuiper Belt. The outer limit of the Oort cloud defines the cosmographic boundary of the Solar System and the extent of the Sun’s Hill sphere. The outer Oort cloud is only loosely bound to the Solar System, and thus is easily affected by the gravitational pull both of passing stars and of the Milky Way itself. The Oort Cloud is made up of icy pieces of space debris.
In short, gravity from the planets shoved many icy planetesimals away from the Sun, and gravity from the galaxy likely caused them to settle in the borderlands of the solar system, where the planets couldn’t perturb them anymore. And they became what we now call the Oort Cloud.
The Oort cloud is thought to occupy a vast space from somewhere between 2,000 and 5,000 au .
The outer limit of the Oort cloud defines the cosmographic boundary of the Solar System and
the extent of the Sun’s Hill sphere.

to be continue…



Newton’s first law or law of inertia:

An object at rest remains at rest, or if in motion, remains in
motion at a constant velocity unless acted on by a net external force. An external force is a force
originating from outside an object rather than a force internal to an object. For instance, the
force of gravity that Earth exerts on the moon is an external force on the moon . The property of
a body to remain at rest or to remain in motion with constant velocity is called inertia. Newton’s
first law is often called the law of inertia . The inertia of an object is measured by its mass.
Example-The motion of a ball falling down through the atmosphere,

Newton’s second law of motion

Newton’s second law of motion or law of acceleration is closely related to Newton’s first law of
motion. It mathematically states the cause and effect relationship between force and changes in
motion. Newton’s second law of motion is more quantitative and is used extensively to calculate
what happens in situations involving a force. Newton’s second law states that the acceleration of
an object is directly related to the net force and inversely related to its mass.
Acceleration is a vector quantity that is defined as the rate at which an object changes its
velocity. An object is accelerating if it is changing its velocity.
Riding your bicycle is a good example of this law of motion at work. Your bicycle is the mass.
Your leg muscles pushing pushing on the pedals of your bicycle is the force.

Newton’s third law of motion

Newton third law or The law of action-reaction
His third law states that for every action (force) in nature there is an equal and opposite reaction.
In other words, if object A exerts a force on object B, then object B also exerts an equal and
opposite force on object A.
example, when you jump, your legs apply a force to the ground, and the ground applies and
equal and opposite reaction force that propels you into the air. Engineers apply Newton’s third
law when designing rockets and other projectile devices.


In physics, the fundamental interactions, also known as fundamental forces

Types of forces

  1. Gravitational force (between particles with mass)
  2. electromagnetic (between particles with charge/magnetism)
  3. strong nuclear force (between quarks)
  4. weak nuclear force (that changes quark types)


Gravity or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light are brought toward (or gravitate toward) one another.•

On Earth, gravity gives weight to physical objects, and the Moon’s gravity causes the ocean tides.

•An invisible force that pulls objects toward each other. So, the closer objects are to each other, the stronger their gravitational pull is.

•The gravitational attraction of the original gaseous matter present in the Universe caused it to begin coalescing and forming stars and caused the stars to group together into galaxies, so gravity is responsible for many of the large-scale structures in the Universe.

•Gravity has an infinite range, although its effects become increasingly weaker as objects get further away. •

In SI units, G has the value 6.67 × 10^-11 Newtons kg^-2m².


Difference Between Gravitation and gravity is that Gravitation can be an attractive force or repulsive force but gravity is always an attraction force.


•Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles.

•The electromagnetic force is carried by electromagnetic fields composed of electric fields and magnetic fields, and it is responsible for electromagnetic radiation such as light.

•It is one of the four fundamental interactions (commonly called forces) in nature, together with the strong interaction, the weak interaction, and gravitation.

•Electromagnetic forces are responsible for the chemical bonds between atoms which create molecules.

•All of the light from the Sun and other sources consists of photons which are the electromagnetic force carriers. • Sunspots are temporary phenomena on the Sun’s photosphere that appear as spots darker than the surrounding areas. • They are regions of reduced surface temperature caused by concentrations of magnetic field flux.

Electromagnets are very widely used in electric and electromechanical devices, including

•Motors and generators. •Transformers. •Pickups. •Relays. •Electric bells •Loudspeakers •headphones.etc


•In nuclear physics and particle physics, the strong interaction is the mechanism responsible for the strong nuclear force, and is one of the four known fundamental interactions, with the others being electromagnetism, the weak interaction, and gravitation.

•At the range of 10−15 m. The strong force inherently has such a high strength that hadrons bound by the strong force can produce new massive particles.

•Thus, if hadrons are struck by high-energy particles, they give rise to new hadrons instead of emitting freely moving radiation.

•The strong interaction is mediated by the exchange of massless particles called gluons that act between quarks, antiquarks, and other gluons. As its name suggests,

•the strong force is the strongest—it’s 100 times stronger than the electromagnetic force

•(which binds electrons into atoms), 10,000 times stronger than the weak force (which governs radioactive decay), and a hundred million million million million million million (1039) times stronger than gravity.

Artificially,the energy associated with the nuclear force is partially released in nuclear power and nuclearweapons, both in uranium or plutonium-based fission weapons and in fusion weapons likethe hydrogen bomb.


•The weak interaction, which is also often called the weak force or weak nuclear force, is the mechanism of interaction between subatomic particles that is responsible for the radioactive decay of atoms.

•The weak interaction participates in nuclear fission, and the theory describing it

•in terms of both its behaviour and effects is sometimes called quantum flavourdynamics (QFD).

•The effective range of the weak force is limited to subatomic distances, and is less than the diameter of a proton.

• Beta decay is just one example of the weak force.

•During beta decay a neutron disappears and is replaced by a proton, an electron and a neutrino (anti-electron).

•Without the weak force, the sun would cease to exist. It is the only interaction that can change one kind of quark into another or its flavor.

• A quark is a type of elementary particle and a fundamental constituent of matter. •Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei.

•It is the only interaction that violates P or parity-symmetry.

• A parity transformation (also called parity inversion) is the flip in the sign of one spatial coordinate. In three dimensions, it can also refer to

•the simultaneous flip in the sign of all three spatial coordinates.