The researchers of European Space Agency’s Planck space observatory tested a series of holographic models against observations of the very early universe. This model depends on the theory of quantum gravity, cosmic inflation, etc.

1. The Holographic Universe
 Name of the Contributor: Jayita Dan
 Department: Physics
 Brainware University
 https://www.brainwareuniversity.ac.in/

2. Summary:
 The researchers of European Space Agency’s
Planck space observatory tested a series of
holographic models against observations of
the very early universe. This model depends
on the theory of quantum gravity, cosmic
inflation, etc.

3. Contents
 "Imagine that everything you see, feel and hear in
three dimensions and your perception of time, in
fact emanates from a flat two-dimensional field,”
says Professor Kostas Skenderis, director of
STAG at the University of Southampton.
 The holographic universe is a model based on a
principle of string theories and a quantum gravity
that states a volume of space(the universe) can
be thought of as encoded on a 2D surface
bounded by a light-like boundary like a
gravitational horizon.

4.  The irregularities in the cosmic microwaves give significant
evidence to support a holographic explanation of the universe.
Theoretical physicists also astrophysicists explain of these
irregularities using the theory of cosmic inflation and the ‘afterglow’
of the Big Bang theory. They believe that our universe is like a big
and complex hologram where a three-dimensional image is
encoded in a two-dimensional surface. The basic principle is similar
to the ordinary hologram. The recorded photograph is known as
hologram. The principle of recording of a hologram includes
superposition of the scattered wave from the object and another
coherent wave known as reference wave of the same wavelength
as scattered wave.
 All the informations contained within a region of space are
reconstructed from the information on the surface. This means that
the volume of space can be represented as a hologram of the two
dimensional surfaces. Rather it can be thought of as like watching a
3D cinema. We see the pictures(3D) having height, width and depth
in a flat 2D screen. The difference is that we can touch the objects
in 3D universe, and the projection is real from our point of view.

5.  The holographic principle extends the idea of black holes to
cosmology. For example, we cannot observe anything within the
interior because the gravity near a black hole is too high and that is
why light cannot escape. The black hole has a surface known as
the event horizon, and we could observe everything outside of that
surface. So we can understand the interior of a black hole from
information near the event horizon.

 In recent decades, the advances of scientific equipments have
allowed scientists to find that some of the simplest quantum field
theories could explain nearly all cosmological observations of the
early universe.
 According to Professor Skenderis holography is a great upsurge in
the way of thinking of early universe. The further understanding of
the early universe is possible by this study. It will open the door to
explain how space and time emerged.

7. References:
 1. Niayesh Afshordi, Claudio Corianò, Luigi
Delle Rose, Elizabeth Gould, Kostas
Skenderis. From Planck Data to Planck Era:
Observational Tests of Holographic
Cosmology. Physical Review Letters, 2017;
118 (4) DOI: 10.1103/PhysRevLett.118.041301
 2. Universe-is-a-hologram.jpg