The Milky
Way is a barred spiral galaxy that is around 13.6 billion years old and has massive pivoting
arms that reach across the cosmos.
The disc of our galaxy is around 100,000 light-years in diameter and only 1000 light-years thick.
Just as Earth orbits the sun, the solar system orbits the center of the Milky Way.
Despite travelling through space at speeds of over 515,000mph (828,000kmph), our solar
system takes about 250 million years to complete one revolution.
When our planet was in this position the last time, dinosaurs were only emerging, and mammals
had yet to evolve.
Now imagine a distant galaxy with an almost exact duplicate of the Milky Way galaxy, a
very sun-like star, and a very Earth-like planet with an almost exact copy of you.
Galaxies are similar to fingerprints or snowflakes in that there are many of them and they may
have many traits, yet no two are precisely alike.
Or so it was assumed until scientists discovered a Galaxy that was a perfect replica of our
Milky Way, which stunned astronomers.
Stay tuned as we share everything you need to know about this astonishing find!
The Milky Way galaxy is a massive spiral system made up of hundreds of billions of stars,
one of which is the sun.
Milky Way is derived from the shape of the band of stars and gas clouds that can be viewed
across the night sky from Earth.
Despite the fact that Earth is nestled within the Milky Way galaxy, astronomers do not fully
understand its nature as they do other distant star systems.
Astronomers have discovered two distant galaxies that are nearly identical to our own Milky
Way for the first time.
Although spiral galaxies such as the Milky Way are widespread in the universe, the newly
discovered twins share other crucial characteristics.
Both, for example, have satellite galaxies that are very similar to the Milky Way's close
neighbors, the large and small magellanic clouds.
Astronomers have employed computer simulations of how galaxies evolve, and they don't seem
to yield many examples identical to the Milky Way and its surroundings, leading astronomers
to think they are extremely rare.
However, astronomers have not been able to determine how rare they are until now, thanks
to a new survey that examines hundreds of thousands of galaxies.
According to Aaron Robotham of the International Center for Radio Astronomy Research and the
University of Saint Andrews in Scotland, just 3% of galaxies like the Milky Way have companion
galaxies like the magellanic clouds.
They uncovered 14 Galaxy systems that are similar to our own, with two of them practically
identical.
Robotham and his colleagues were sifting through data from the Galaxy and mass assembly survey,
which maps out over 340 000 galaxies in the local universe, and they were not expecting
to find any actual Milky Way twins.
They had never discovered another galaxy system like the Milky Way previously, which is not
unexpected given how difficult they are to find.
This type of analysis, which led Robotham and his team to the discovery, has only lately
been possible.
The study team required telescopes capable of detecting not only galaxies but also their
dim companions.
They needed to look at enormous regions of the sky and, most importantly, ensure that
no galaxies were overlooked in the survey.
The Milky Way is caught in a cosmic dance with huge and small magellanic clouds, which
can be seen in the night sky of the southern hemisphere.
Many galaxies have smaller companions, but few have two as massive as the magellanic
clouds.
The Galaxy we live in is quite common, but the neighboring magellanic clouds are an uncommon
and probably fleeting event that will vanish in a few billion years.
Staring into space is similar to looking into a funhouse mirror because gravity warps the
fabric of space, generating visual illusions.
Many of these optical illusions occur when the light from a distant Galaxy is magnified,
stretched, and brightened when it passes through a huge Galaxy or Galaxy cluster in front of
it.
This phenomenon is known as gravitational lensing, and it was predicted to exist in
the early twentieth century by Albert Einstein's general theory of relativity.
The equations demonstrated that any big celestial object, like a glass lens in a telescope or
microscope, could bend passing light rays.
When a massive volume of stuff, such as a cluster of galaxies, forms a gravitational
field, it bends and magnifies light from distant galaxies that are behind it but in the same
line of sight.
The effect is similar to staring through a magnifying glass, allowing astronomers to
analyze the features of early galaxies that are too far away to be viewed with present
technology and telescopes.
Astronomers using the Hubble Space Telescope discovered one such strange structure while
studying quasars, the blazing source of active galaxies.
They came across two bright linear objects that appeared to be mirror images of one another.
Astronomers were astounded to discover that they had found a duplicate in the universe.
The astronomers had been perplexed by the peculiarities, and it took them several years
to solve the puzzle.
The researchers determined that the three objects were distorted images of a distant
undiscovered galaxy with the help of two gravitational lensing experts, but the biggest surprise
was that the linear objects were exact copies of each other; a rare occurrence caused by
the precise alignment of the background Galaxy and the foreground lensing cluster.
Shawnee State University astronomer Timothy Hamilton and the expanding team led by Richard
Griffiths of the University of Hawaii Hilo ultimately put together all of the clues to
solve the mystery after following dead end theories, asking help from colleagues.
The stretched photos were of a gravitationally lensed distant galaxy located more than 11
billion light years away.
They appeared to be mirror versions of each other, but when Hamilton discovered the peculiar
linear characteristics in 2013, this rare phenomenon was unknown.
Because Hamilton was unable to answer many questions, the object was termed Hamilton's
object.
It was also discovered by chance in data gathered by the Hubble Space Telescope nearly a decade
ago by Hamilton.
He discovered that the two galaxies had the identical form and virtually parallel black
streaks across the galactic bulge; the central area of the Galaxy where most of the stars
reside.
An exact alignment of a background Galaxy and a foreground Galaxy cluster resulted in
twin enlarged replicas of the remote Galaxy's picture.
This unusual occurrence occurred because the backdrop galaxies straddled a ripple in space's
fabric.
This Ripple is a magnified area generated by the gravity of large concentrations of
dark matter; the unseen glue that makes up the majority of the universe's mass.
As light from distant galaxies flows through the cluster along this ripple, two mirror
images are formed, as well as a third image seen to the side.
It wasn't until 2015 that a more reasonable explanation emerged.
After witnessing Hamilton present this object at a meeting, astronomer Richard Griffiths
of the University of Hawaii proposed that the culprit might be a rare phenomenon called
gravitational lensing, which made a lot more sense than two identical galaxies.
While the Hamilton object was the consequence of gravitational lensing, scientists discovered
another galaxy in a faraway universe that looked to be duplicated at least 12 times
in the night sky.
The remarkable picture was taken by NASA's Hubble Space Telescope and may help scientists
better understand the early Universe.
The Galaxy that can be seen numerous times in the photograph has been given the nickname
of the Sunburst Arc; its distance from Earth is about 11 billion light years.
Due to intense gravitational lending, replicas of the Sunburst Arc Galaxy appear numerous
times in the captured image.
The Sunburst Arc has been lensed numerous times in the photograph by light and mass
from the huge cluster of galaxies seen behind it.
Gravitational lensing has produced four distinct light arcs visible in the photograph.
The Galaxy occurs many times within each Arc, with one in the lower left and three in the
upper right.
Hubble employs a cosmic magnifying lens to analyze objects like these, allowing astronomers
to explore distant portions of the universe in incredible detail.
Scientists studying the Sunburst Arc believe it was formed only 150 million years after
the big bang.
When you consider that astronomers believe the universe is 13.8 billion years old, the
Sunburst Arc is quite old.
According to Einstein's notes, if an observer were placed at the proper distance, deflected
light rays from around the celestial object would converge to form a magnified image.
This is is a phenomenon known as strong gravitational lens; for example, to utilize the Sun as a
gravitational lens to generate an image of a more distant astronomical object, an observer
must be at least 550 times further away than the Sun than the Earth.
Light beams are not deflected sufficiently in a weak gravitational lens to enlarge the
image, but instead create minor distortions.
Although the deflection from each cluster of galaxies is almost visible on its own,
the combined effect causes a slight distortion in views of distant galaxies that can only
be deduced from measurements.
Astronomers call this phenomenon Cosmic shear.
By measuring the redshift to each background Galaxy, it is possible to separate the Dark
Matter structures that are located at different redshifts.
With enough background galaxies at different redshifts, we can do a tomography of the Dark
Matter structures.
A very long time ago, in the very early Universe, scientists discovered a galaxy that appears
far too advanced to have formed in the brief period since the Big Bang.
It's known as SPT0418-47, and it's 12.4 billion light-years away - back when the Universe
was only 1.4 billion years old.
The similarities to our own galaxy, the Milky Way, are what make it unique.
SPT0418-47 is a flat, revolving disc that lacks the distinctive curved arms of a spiral
galaxy.
It has the same mass as the Milky Way.
Furthermore, it has a galactic bulge, which is the densely packed concentration of stars
found at the center of most spiral galaxies.
Although earlier rotating disc galaxies have been discovered, SPT0418-47 is the first to
have a galactic bulge, contributing to a growing body of evidence that galaxies develop and
evolve considerably differently than previously assumed.
Recent discoveries are starting to paint a more complex picture.
It's extremely challenging to peer that far into space, but a combination of ever-advancing
technology and the development of new observation techniques is helping astronomers to see what's
in those far and murky reaches.
One of these is gravitational lensing, which is used to investigate the distribution of
matter, galaxies, and clusters of galaxies and allows for views of the distant Universe.
The discovery of galaxies that are identical to our Milky Way opens up a world of possibilities
for what might exist in the universe.
While study continues, our universe and its genesis remain a huge enigma that will be
solved over time.
Let’s hear your thoughts in the comments down below.