THE GHOSTS OF UNIVERSE {DARK MATTER AND DARK ENERGY}

Human civilization has come from the first source of energy i.e. From fire to nuclear through hydroelectricity, wind turbine, chemical energy, solar energy, and many more. But still, we are in generation 1.0. In this whole universe, we cannot say that we are the only ones, who are here as a living being. Can we ever get that form of energy which is an infinite source? Let’s get into that…

In terms of astrophysics, dark matter and dark energy are the hidden part of the universe that affect the universe on a large number.

DARK MATTER

The era started when scientists first observe the anomaly in the universe rotation curve of our nearest galaxy andromeda which is just 2.5 billion years ago from us. According to Newtonian gravitation law in our solar system the more distance we move from the sun the lesser speed we acquire for revolving around the sun. but when we compare the speed between stars of andromeda which are at the edge of the universe and the stars which are near the center of it, we found that there is no difference between them i.e. flat. Not only andromeda but also our own galaxy and also other galaxy have the same type of flat graph. so, there is something that has very much gravitation pull than our sun even more than the red giants because as per calculation even the gravitation pull of all the stars of our neighbour galaxies is not enough to keep its rotation curve flat. So, who is that? As per today, it is denoted by dark matter and we cannot spot it as astronomical clouds or objects as it is not interacting with us but distorting the space-time in a large manner.

Rotation Curve (Speed Vs Distance)

Rotation Curve Of Galaxy

Another example of the dark matter is that you may have seen the picture of some galaxies in a distorted manner, so is this for dark energy or dark matter, and how? So, the answer is gravitational lensing due to the presence of dark matter. we all know that light cannot escape from the gravitational pull, so when there is a high gravitational pull and light rays have to come through this, then distortion of space-time causes the distortion of light which is creating a distorted view. A perfect example of this is the Cheshire cat galaxy, actually, the light comes from this galaxy through a blob of dark matter which causes extreme distortion of the appearance of the galaxy, making it the appearance of a cat.

DARK ENERGY

Whenever we tried to look through a telescope towards 13.7 billion years ago it looks dark, like nothing, actually, there is nothing. The universe started from a big bang which was occurred approximately 13.6 billion years ago. So, before that universe was so small to give birth a star. Hubble space telescope (HST) observations of very distant supernovae that showed that, a long time ago, the universe was actually expanding more slowly than it is today. So, the expansion of the universe has not been slowing due to gravity, as everyone thought, it has been accelerating. No one knows why but it is occurring. At the time of the big bang, the temperature of the universe is very hot but now as it is expanding it is cooling down. Generally, with the help of our astronomical telescopes, we are able to look at the cosmic microwave background, not further than that. So, let’s take an assumption of a grid system and put our stars at some point on that grid then, you can notice the expansion of this universe in that grid points. The star which was some billion light-years ago looked red, what does that mean? Does it only give out red light! No, actually due to the expansion of the universe the distance between the star and us increases, and due to which the wavelength of light also increases and larger the wavelength, redder it is going to be, also the energy of that light also decreases. It is called redshift. So, scientists thought that there was some strange kind of energy-fluid that filled space, which was causing this expansion toward the big rip. Maybe there is something wrong with Einstein’s theory of gravity and a new theory could include some kind of field that creates this cosmic acceleration. Theorists still don’t know what the correct explanation is, but they have given the solution a name. It is called dark energy.

POWER SPECTRUM

So those are the finest examples of the universe about the dark matter and dark energy. Also, if we move toward the energy spectrum of our universe then it indicates that dark energy contributes 68% of the total energy in the present-day observable universe. The mass-energy of dark matter and ordinary (baryonic) matter contributes 27% and 5%, respectively, and other components such as neutrinos and photons contribute a very small amount.

Astronomers, astrophysicists, scientists have been trying since 1930 on this dark matter and also upon the dark energy. In addition to this NASA has sent a satellite named Fermi Gamma-Ray Telescope to detect the dark matter at the time of their collision as they supposed to emit the higher energy form of light that is gamma-ray. the baryonic matter could still be able to create dark matter if it were all tied up in brown dwarfs or in small, dense chunks of heavy elements. So, there is a possibility for dark matter in massive compact halo objects (MACHO), still, we are not pretty sure about it and maybe it is made up of other, more exotic particles like axions or WIMPS (Weakly Interacting Massive Particles).

We have been trying a lot, still the mystery continues and maybe in near future, harnessing energy from dark energy, utilization of dark matter, would be in our hands.

Picture references-

1. pic1-https://fineartamerica.com/art/photographs/galactic+center
2. pic2- Distant Galaxies in the Hubble Ultra Deep Field Hubble Space Telescope . Advanced Camera for SurveysNASA, ESA, R. Bouwens and G. Illingworth (University of California, Santa Cruz)STSCI-PRC06-12
3. pic3-https://www.researchgate.net/figure/Flat-galaxy-rotation-curve-explained-with-fundamental-conservation_fig2_326579825
4. pic4-http://spacetelescope.org/images/heic1106c
5. pic5-https://www.researchgate.net/figure/The-rotation-curve-of-galaxy-NGC-6503-data-from-47-The-dark-matter-halo-contribution_fig2_230779703
6. pic6-https://skyandtelescope.org/astronomy-news/will-radio-bursts-reveal-hidden-baryons/ 

Related links/References-

1. https://bit.ly/3jxV7LN [DARK MATTER]
2. https://en.wikipedia.org/wiki/Dark_energy [DARK ENERGY]
3. https://go.nasa.gov/3jG4ucx [FERMI TELESCOPE DATA]
4. https://go.nasa.gov/31Nb4rf [HUBBLE TELESCOPE DATA]
5. https://www.wikipedia.org