The Space Beyond

The Worlds Beyond

2011-05-15T09:17:00.000-07:00

Since time immemorial, people were fascinated by what they saw in the sky. They mapped the sky,measured time, and prepared calenders based on there observations and recordings ;which led to the birth of of the oldest branch of science-astronomy.As the time moved on many scientists all around the world contributed to it . Today we know a lot more about our universe.And i found it interesting to know about them.
In this blog you can learn about the past,present, the uncertain future,and the unimaginable phenomena taking place in it .I welcome you to the thrilling worlds and spaces beyond.
We will start our tour from within an atom to the extends of the universe

2011-05-15T08:35:00.000-07:00

The contents of this blog is as follows.
Click on the links below to display the posts

The Atom

2011-05-15T08:34:00.000-07:00

To learn about the vast universe we live in ,we must learn about the smallest particles in it -the atom. To put it simply an atom is the fundamental unit of matter. The internal structure of an atom is pretty much interesting. It consists of a dense central nucleus surrounded by negatively charged electrons. These electrons
keep rotating around the nucleus at a fixed velocity.The electrons of a single atom rotate at different distances from the nucleus thus forming different orbits or shells.Hydrogen has only a single shell while carbon has two shells.
The number of electrons each shell can accommodate also varies.The number of electrons in a particular shell is given by the equation 2nsq(ie. 2*n*n)where n is the shell number.
The nucleus of an atom consist of positively charged protons and neutrons which has no charge.They are collectively called nucleons.The radius of a nucleus is approximately equal to , where A is the total number of nucleons.
Generally an atom has equal number of protons and electrons,thus nullifying each others charges. The nucleons are bound together by a short-ranged attractive potential called the residual strong force. At distances smaller than 2.5 fm this force is much more powerful than the electrostatic force that causes positively charged protons to repel each other.

Atoms of the same element have the same number of protons, called the atomic number. Within a single element, the number of neutrons may vary, determining the isotope of that element. The total number of protons and neutrons determine the nuclide. The number of neutrons relative to the protons determines the stability of the nucleus, with certain isotopes undergoing radioactive decay.

The structure of an atom

More About The Nucleons

2011-05-15T08:19:00.000-07:00

Neutrons and protons,which constitutes the atomic nuclei are collectively called nucleons. Until the 1960s, the nucleons were thought to be elementary particles. Now they are known to be composite particles, each made of three quarks bound together by a force called the strong force.Protons and neutrons are most important and best known for constituting atomic nuclei, but they can also be found on their own, not part of a larger nucleus.Both the proton and neutron are made of three quarks. The proton is made of two up quarks and one down quark, while the neutron is one up quark and two down quarks. The quarks are held together by the strong force. It is also said that the quarks are held together by gluon s, but this is just a different way to say the same thing (gluons mediate the strong force).

To know more about the theories related to the beginning of the universe it is necessary to understand the principle of the elementary particles.

The Elementary Particles

2011-05-15T08:18:00.000-07:00

In particle physics, an elementary particle or fundamental particle is a particle believed not to have substructure; that is, it is believed not to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which all other particles are made.

The elementary particles can be divided into two;the bosons and the fermions.Particles which satisfy the Bose-Einstein law are called bosons,those which satisfy the Fermi-Dirac law are called fermions.

Elementary particles of the Standard Model include:

Six "flavors" of quarks: up, down, bottom, top, strange, and charm;

Six types of leptons: electron, electron neutrino, muon, muon neutrino, tau, tau neutrino;

Bosons (force carriers): the graviton of gravity, the photon of electromagnetism, the W and Z bosons of the weak force, and the eight gluons of the strong force.

Out of this leptons, and baryons which include protons and neutrons come under the fermions.
{For more info on the elementary particles and the standard model theory click here}

The Beginning With A Bang-The Big Bang Theory

2011-05-15T08:17:00.000-07:00

How did it all began?

Scientists and most astronomers belive that the Universe was born in a massive explosion,which they call the Big Bang,which is belived to have occoured 14 billion years ago.This theory is an effort to explain what happened at the very begining of of our Universe.Discoveries in astronomy and physics have shown that our Universe did in fact have a beginning.Before that moment of the Big Bang,there was nothing.During, and after that momentthere was something- our Universe,which contained space and time.

According to the Big Bang theory nothing existed before the explosion.The only thing that existed was a tiny point or bubble that was far smaller than an atom,but hotter and denser than anything we can imagine.This state was coined the term’point singularity’.Then suddenly ,this tiny bubble exploded,and the Universe was born.During the explosion,it let loose a huge amount of energy into a small Universe.Inside the Universe,the energy went zipping around all the place.Within seconds,the Universe gerw from smaller than a single atom ,to bigger than a galaxy.Time,space and matter were all formed out of that energy.

And it kept on growing at a fantastic rate;infact it is still expanding today.

What Happened After The Big Bang

2011-05-15T08:16:00.000-07:00

Right after the big bang,the Universe began stretching like a huge balloon Space and time began to expand at an incredible rate,this phenomenon is called the inflation of space.Later,the Universe became cooler and the particles that make up matter began to form out of the energy.

Right after the Big Bang,a tremendous surge of energy was released,and the universe was born.there was a total turmoil as the elementary particles went crazy.The universe at that time existed as a soup of free-roaming fundamental particles that didn't obey the normal rules of physics.This is why the early Universe is sometimes referred to as 'Particle Soup'.

the picture explains the step by step formation of the present universe

As we know the present universe formed as a result of a massive explosion.Only the quarks,leptons and the force particles were present in the Universe just after the Big Bang.But as the universe cooled down(about 1000 billion degree)quarks began to form clusters of quarks with the help of the gluon s and thus form protons and neutrons.(for more info on the structure of protons and neutrons click here)

The Big Bounce Theory

2011-05-15T08:15:00.000-07:00

the bouncing universe

The Big Bounce theory is yet another theory related to the the formation of the known universe.This theory points out that a Universe existed at a point before the Big Bang.According to some oscillatory universe theorists, the Big Bang was simply the beginning of a period of expansion that followed a period of contraction. In this view, one could talk of a Big Crunch followed by a Big Bang, or more simply, a Big Bounce. This suggests that we might be living in the first of all universes, but are equally likely to be living in the 2 billionth universe (or any of an infinite other sequential universes).The theory simply means that the expanding Universe finally meets it maximum size,and the gravity pulls galaxies closer,thus shrinking the Universe itself into a single point,and the Big Bang happens again.This process keeps repeating on and on.
To fully understand the theory of the Big Bounce one must know about the theory of the Big Crunch.

The Big Crunch

2011-05-15T08:14:00.000-07:00

According to this theory, the universe will one day stop expanding. Then, as gravity pulls on the matter, the universe will begin to contract, falling inward until it has collapsed back into a super-hot, super-dense singularity.

The Hubble Constant measures the current state of expansion in the universe, and the strength of the gravitational force depends on the density and pressure of the matter and in the universe, or in other words, the critical density of the universe. If the density of the universe is greater than the critical density, then the strength of the gravitational force will stop the universe from expanding and the universe will collapse back on itself. Conversely, if the density of the universe is less than the critical density, the universe will continue to expand and the gravitational pull will not be enough to stop the universe from expanding. This scenario would result in the 'Big Freeze', where the universe cools as it expands and reaches a state of entropy.Some theorize that the universe could collapse to the state where it began and then initiate another Big Bang, so in this way the universe would last forever, but would pass through phases of expansion (Big Bang) and contraction (Big Crunch)

Stars-The Giant Balls Of Gas

2011-05-15T08:13:00.002-07:00

A star is a gaseous luminous body of plasma held together by gravity.It does not have any solid matter.Stars like our sun,contains elements like hydrogen,helium,iron, calcium,and magnesium.Elements in cooler stars are nearly liquid in form,like boiling iron in a blast furnace.

The total mass of a star is the principal determinant in its evolution and eventual fate. Other characteristics of a star are determined by its evolutionary history, including diameter, rotation, movement and temperature. A plot of the temperature of many stars against their luminosities, known as aHertzsprung-Russell diagram (H–R diagram), allows the age and evolutionary state of a star to be determined.

Stars-Birth

2011-05-15T08:13:00.001-07:00

Stars are born inside huge clouds of gas and dust.Some of these called giant molecular clouds,contain enough materials make a hundred thousand stars.If parts of the cloud are sufficiently dense and ,gravity will cause them to fall together.As an individual clump of gas and dust collapse,it heats up and,in time,becomes hot enough for nuclear reactions to begin.These reactions turn hydrogen into helium and turn mass into energy. Once these reactions have started,the new arrival becomes a fully-fledged (or'main sequence')star.

the orion nebula

The orion Nebula,a glowing cloud of gas,is part of a huge star-forming region.It shines because it contains some very hot stars.Astronomers believe that more new stars are also being born behind the visible nebula.

Stars-Life

2011-05-15T08:12:00.000-07:00

AProjected timeline of the Sun's life.

From the birth of a star,it starts to change.It very gradual and so it has always been difficult for us humans to notice these changes through time.It takes hundreds of years.Nonetheless,the speed of its evolution depends on the process by which nuclear energy is produced inside it.This process further depends on the mass of the star.The death of a star is marked by a massive explosion called the super novae

A star begins as a protostar,a shrinking cloud of gas which eventually becomes hot enough to shine.It is then a 'main sequence star',which continues to shine because of nuclear reactions inits core.Towards the end of its life,it swells up to become a red giant or a red super giant.It soon uses up its remaining fuel,and sheds its outer shell of gases to form a planetary nebula.It then shrinks and fades to become a white dwarf.A star like the sun will take about 10billion years to reach this stage.A white dwarf finally becomes a black dwarf.

Stars-Death

2011-05-15T08:11:00.000-07:00

At the time of a star birth,the giant clouds give birth to mainly three types of stars,which are the Low-mass star,mid sized star and the Massive stars.

The low-mass stars will develop into a red giant , but never fuse helium as the Mid-sized stars do; otherwise, it will simply contract until electron degeneracy pressure halts its collapse, thus directly turning into a white dwarf.

A white dwarf compared with the Earth

At the same time the Mid-sized stars develops helium in its core an when it get close to its end the core becomes hot enough for the helium fusion to take place.After the star has consumed the helium at the core, fusion continues in a shell around a hot core of carbon and oxygen.At this stage more energy is released in the form of powerful stellar winds and violent pulsations

Helium burning reactions are extremely sensitive to temperature, which causes great instability. Huge pulsations build up and eventually give the outer layers of the star enough kinetic energy to be ejected, potentially forming a planetary nebula. At the center of the nebula remains the core of the star, which cools down to become a small but dense white dwarf.

A black hole

The massive stars turn them selves into black holes after the supernova.If a star is 10 times more massive than the sun,no known force can stop the increasing gravity,and it will collapse to a point of infinite density.Before this stage is reached,within a certain radius,light itself becomes trapped,and the object becomes invisible,and becomes a black hole.Black holes are the densest areas in the Universe.

The Black Hole

2011-05-15T08:10:00.000-07:00

A black hole is a region of space from which nothing, not even light, can escape.To see why this happens, imagine throwing a tennis ball into the air. The harder you throw the tennis ball, the faster it is travelling when it leaves your hand and the higher the ball will go before turning back. If you throw it hard enough it will never return, the gravitational attraction will not be able to pull it back down. The velocity the ball must have to escape is known as the escape velocity and for the earth is about 7 miles a second.

As a body is crushed into a smaller and smaller volume, the gravitational attraction increases, and hence the escape velocity gets bigger. Things have to be thrown harder and harder to escape. Eventually a point is reached when even light, which travels at 186 thousand miles a second, is not travelling fast enough to escape. At this point, nothing can get out as nothing can travel faster than light. This is a black hole.

It is impossible to see a black hole directly because no light can escape from them; they are black. But there are good reasons to think they exist.

When a large star has burnt all its fuel it explodes into a supernova. The stuff that is left collapses down to an extremely dense object known as a neutron star. We know that these objects exist because several have been found using radio telescopes.

If the neutron star is too large, the gravitational forces overwhelm the pressure gradients and collapse cannot be halted. The neutron star continues to shrink until it finally becomes a black hole. This mass limit is only a couple of solar masses, that is about twice the mass of our sun, and so we should expect at least a few neutron stars to have this mass. (Our sun is not particularly large; in fact it is quite small.)
A supernova occurs in our galaxy once every 300 years, and in neighbouring galaxies about 500 neutron stars have been identified. Therefore we are quite confident that there should also be some black holes.

Quasars

2011-05-15T08:09:00.000-07:00

At the very end of the visible universe,extremely bright and power full objects called quasars can be seen.They are the most distant objects visible in the universe.Quasars are about the size of the solar system,but produce more light and energy 1000 galaxies.

What are quasars?
They are probably super giant black holes,which are devouring entire stars.These black holes , believed to lie at the center of galaxies,glow brightly as matter funnels into them.
Quasars are important because they show us what the Universe was like,billions of years ago.

Two Quasars with their Host Galaxy

The light from quasars take billions of years to reach us.When we look at a quasar,we see what they looked like in the distant past.