Dark matter and
dark energy
The surroundings we see and the
materials we use contains of matter. The matter as we know is something which
occupies space and has some mass, these matters contains atoms and molecules.
These atoms contain particles such as protons, electrons and neutrons. In other
words, we can call this matter as baryonic matter. But the interesting and
shocking fact is that the matter we see i.e. the visible universe, the sun,
other stars and the galaxies which contains these baryonic matters comprises less
than 5% of the entire mass of the universe. The question which arises here is,
what is that thing which occupies 95% of the mass of the universe?
The answer for this question is, In
the entire universe baryonic matter comprise 5% of mass and the rest of the
universe contains mysterious and invisible substance called dark matter (25%)
and a force which counteracts gravity called dark energy (75%). This is
probably the most shocking discoveries of the 20th century.
Let us
learn about this mysterious and invisible thing in the space which we call it
as dark matter and dark energy.
Dark
matter
Dark matter has no particular
definition, we still don’t know exactly what dark matter is but our scientists
are pretty sure that it does exist because we can see the effects of it on
galaxies. Scientists are not able to directly detect the dark matter as it
doesn’t interact with the light and is invisible. But after a lot of study
scientists have few ideas what dark matter can be, dark matter contains exotic
materials which doesn’t react with the normal matter and light but still exerts
a gravitational pull. The question which haunts us the most is from where do
this dark matter came from, according to Dr. Stephen hawking at the beginning
of the big bang, universe is thought to have zero size but as it started
expanding temperature of the matter or radiation decreased. One second after
big bang temp would have fallen about thousand million degrees. At this time
universe would have contained particles like photons, electrons, neutrinos and
their antiparticles with few protons & neutrons.
As it continued to expand and temp
dropped, the rate at which electrons and anti electrons produced fell and these
both annihilated with each other to form more and more photons leaving behind
only few electrons. The particles which remained after this are
neutrinos/anti neutrinos, these cannot be annihilated with each other as they
don’t interact among themselves and with others very weakly. So, they should be
still around today and it is believed that they may be in the form dark matter.
But is it true or false we don’t know yet.
Now, let me tell you the effect of dark matter on some of galaxies and
its stars. According to standard physics stars near edges of the spinning
galaxies should move much slower than the stars near the center of the galaxy
but according to recent observations stars which are present near the edges
have more or less equal speed as the stars near the center of the galaxy.
This
result shows that stars near the edges are getting affected by gravitational
field by unknown mass i.e. dark matter. Now, let us move on to learn about dark
energy.
Dark
energy
Dark energy is even more strange and
mysterious, as of dark matter even dark energy has no particular definition for
itself. it cant be detected, it cant be measured and it cant be tasted but we can see its effects clearly. All we know is it’s a repulsive energy which counteracts gravitational
force.
In 1929 Edwin Hubble said that light emitted from distant galaxies shifted to the red end of electromagnetic spectrum, this shift is what we call as red shift. It usually occurs because universe is expanding and wavelength of the light goes on decreasing. According to recent studies it has been seen that universe is expanding at a faster rate than what scientists expected, which is really a shocking news for them, because earlier it was believed that pull of gravity would slow down the expansion or even retract at some point and collapse on itself. The increase in the speed of expansion is due to a repulsive force present in the empty space and the interesting fact about it is, it increases as the universe expands. this invisible force is governing the expansion of the universe and is called as dark energy. sounds bit scary, right?
The idea of dark energy dates back to 1917 when Einstein gave a cosmological constant as a mathematical aid for his static universe theory after applying general theory of relativity to it. According to Albert Einstein universe is static i.e. its not expanding and has uniform distribution of matter across the universe and is spherical in shape, to support this he gave a equation called Einstein field equation which is λ = 1/R2 = κρ/2 where k is called as cosmological constant. It is a force which counteracts gravitational force, which controls or stops the collapsing of universe on itself. But later he discarded it as experiments showed that universe is continuously expanding.
In 1929 Edwin Hubble said that light emitted from distant galaxies shifted to the red end of electromagnetic spectrum, this shift is what we call as red shift. It usually occurs because universe is expanding and wavelength of the light goes on decreasing. According to recent studies it has been seen that universe is expanding at a faster rate than what scientists expected, which is really a shocking news for them, because earlier it was believed that pull of gravity would slow down the expansion or even retract at some point and collapse on itself. The increase in the speed of expansion is due to a repulsive force present in the empty space and the interesting fact about it is, it increases as the universe expands. this invisible force is governing the expansion of the universe and is called as dark energy. sounds bit scary, right?
The idea of dark energy dates back to 1917 when Einstein gave a cosmological constant as a mathematical aid for his static universe theory after applying general theory of relativity to it. According to Albert Einstein universe is static i.e. its not expanding and has uniform distribution of matter across the universe and is spherical in shape, to support this he gave a equation called Einstein field equation which is λ = 1/R2 = κρ/2 where k is called as cosmological constant. It is a force which counteracts gravitational force, which controls or stops the collapsing of universe on itself. But later he discarded it as experiments showed that universe is continuously expanding.
It is very interesting how ‘cosmological constant’ was
called one of the biggest blunders of Einstein is now called as dark energy.
Dark energy is something which is mainly found in empty space and this energy
is stronger than any energy in the world. Therefore, empty space is not really empty but contains more
energy than everything else combined in the universe. Till today we are unable to know what exactly dark matter and dark energy are and what are its properties. I hope we discover about it sooner and solve the mystery of it.
We think that we know everything about
this universe but we are still apes holding smartphones in the tiny island
called as earth in the ocean of universe.
Amazing🔥🔥🔥🔥
ReplyDeleteGood bro u can go still deep ....as far as I concern...about the matter😊😊
ReplyDeleteyes, but information about this is still not available. scientists are yet to discover more about this matter. thank you for your suggestion bro..
DeleteGood work honey bushy, one day you are going to explore the concept of whole universe and probably be the walking dictionary of space
ReplyDeleteAnd next time we are expecting you to work on Cosmic Rays and the relationship between Cosmic Rays and spirituality
kadri
ya,sure brother and i hope you will be joining me for this next project..
DeleteVery interesting and a true facts. .!! Thanks broda for the blog...!!
ReplyDeleteTq brother..
Delete