We already know that there are many galaxies in our Universe and one thing is for sure
that the deeper we look into the cosmos, the more galaxies we see.
Join me as I explain the collision that is going to happen between the Milky Way and
Andromeda Galaxy! Galaxies are sprawling systems of dust, gas,
dark matter, and anywhere from a million to a trillion stars that are held together by
gravity. It has been estimated that the observable universe contains almost two trillion galaxies.
Imagine how infinite our Universe is! Some of those distant galaxies are similar to our
own Milky Way, while others are quite different. From all these Galaxies we have discovered
through years of research that Andromeda Galaxy is coming closer to
our own.
It is important to mention some information about The Andromeda Galaxy that makes it so
important. First and foremost, The Andromeda Galaxy is
the closest large galaxy to our Milky Way. At 2.5 million light-years, it’s the most
distant thing visible we can see with the naked eye in the Northern Hemisphere especially
on the dark sky. It is the brightest galaxy we can see and it is also named as M31. Although
there are several dozen minor galaxies closer to our Milky Way, the Andromeda galaxy is
the closest large spiral galaxy to ours. A spiral galaxy has a flat, spinning disk
with a central bulge surrounded by spiral arms. That spinning motion, at speeds of hundreds
of kilometers a second, may cause matter in the disk to take on a distinctive spiral shape,
like a cosmic pinwheel. There has been a speculation by a team of astronomers who believe that
M31 or Andromeda Galaxy was formed between five and nine billion years ago when two smaller
galaxies collided and merged creating this one. The Andromeda galaxy and our Milky Way
galaxy reign as the two most massive and dominant galaxies within the Local Group of Galaxies.
Local group is a collection of more than 54 galaxies including the Milky Way, the Triangulum
galaxy and many smaller dwarf galaxies. If it wasn’t for the Andromeda Galaxy we
wouldn’t be able to extent our knowledge about the outer space. In other words the
Andromeda Galaxy has contributed to the knowledge we have gained about the Universe, as it was
the first clue that there existed a universe outside the Milky Way. So we should be grateful
for its existence. Both the Milky Way and the Andromeda galaxy
claim to have about a dozen satellite galaxies. Both are some 100,000 light-years across,
containing enough mass to make billions of stars. Andromeda has also a diameter of 200,000
of light years which is twice the diameter of our galaxy. The mass of either galaxy is
difficult to estimate with any accuracy, but it is considered that the Andromeda Galaxy
is more massive than the Milky Way by a margin of some 25% to 50%.
In recent years, scientists have done detailed studies of black holes, stars and other objects
within the galaxy. This included a stunning mosaic of Andromeda galaxy images taken by
the Hubble Space Telescope in 2015. Andromeda contains a concentrated bulge of matter in
the middle, surrounded by a disk of gas, dust, and stars and an immense halo.
I think we get to know Andromeda galaxy better, but what if I told you that Andromeda draws
our attention also for another reason. Yes that is what we are going to analyze in the
following lines. So join me to this journey. Studies have shown that the Andromeda Galaxy
has probably started collision with our galaxy. And it is not a speculation but years and
years of research with the necessary tools to discover it. But let’s get deeper into
it to have a better understanding. We do know that Andromeda is racing towards
our galaxy. Approximately in four billions years, anyone left in our solar system will
witness the most spectacular event to take place in the history of the night sky as the
Andromeda will collide with our galaxy, The Milky Way.. Something we need to know is that
galaxy collisions are a normal part of the universe's evolution as across the universe,
galaxies are colliding with each other. Astronomers see galactic collisions through their telescopes.
In some ways, when a galactic merger takes place, the two galaxies are like ghosts; they
simply pass through each other. That’s because stars inside galaxies are separated by such
great distances. Thus the stars themselves typically don’t collide when galaxies merge.
Let’s see some of the consequences. This collision will change the structure of the
two galaxies forever as both galaxies will be utterly disrupted The stars in both the
Andromeda galaxy and our Milky Way will be affected by the merger. The Andromeda galaxy
contains about a trillion stars. The Milky Way has about 300 billion stars. Stars from
both galaxies will be thrown into new orbits around the newly merged galactic center. Although
the galaxies will plow into each other, stars inside each galaxy are so far apart that they
will not collide with other stars during the encounter. However, the stars will be thrown
into different orbits around the new galactic center.
The monster collision between our Milky Way and fellow spiral galaxy Andromeda will occur,
as we mentioned, in almost 4 billion years from now, according to the new research, which
is based on observations made by Europe's Gaia spacecraft. Some prominent previous estimates
had predicted the crash would happen significantly sooner, in about 3.9 billion years. Astronomers
have reached to this conclusion after years of research and observation and this finding
is crucial to our understanding of how galaxies evolve and interact. In general it contributes
to learn how the universe works and its laws of nature.
So we do know for a fact that the Milky Way and Andromeda are heading toward each other.
Indeed It is approaching us, by about 250 miles per hour and the two galaxies will merge
a few billion years from now. That is fast enough to travel from here to the moon in
one hour. The measurement was made using the Doppler effect, which is a change in frequency
and wavelength of waves produced by a moving source relative to an observer, to measure
how starlight in the galaxy has been compressed by Andromeda's motion toward us. This is normal
due to the fact that Neighboring galaxies are bound into clusters by their mutual gravitational
attraction. All galaxies have a big spherical halo which
is an envelopment of gases covering the entire galaxy. Andromeda also has a very large Halo
which can stretch up to 2 million light-years. It's so faint it's hard to see, though. Even
nearby galaxies have halos so faint you can't really see them directly. However, astronomers
are clever, and have found ways to measure them indirectly. Using such a technique, aided
by observations with Hubble Space Telescope, new research shows that the nearby Andromeda
galaxy has a layered halo, two nested spherical shells, with the outer one reaching out to
a staggering two million light years. Our own Milky Way has a halo, too, and it reaches
out to about one million light years. But….Andromeda is about 2.5 million light years away. That
means that the halos of these two galaxies are already colliding!
The descriptions that are about to be mentioned, are based on painstaking Hubble Space Telescope
measurements of the motion of the Andromeda galaxy, followed by computer modeling of the
inevitable future collision between the two galaxies. Astronomers can predict with certainty
the next major cosmic event to affect our galaxy, sun, and solar system: the titanic
collision of our Milky Way galaxy with the neighboring Andromeda galaxy.
So let’s pay attention now as there is an illustration about what is going to happen
and in the exact same order that the incidents are going to take place. This series of illustrations
shows the predicted merger between our Milky Way galaxy and the neighboring Andromeda galaxy.
Astronomers can illustrate as an animation what is about to happen with the collision
and demonstrate the predictions of this simulation. We are to the Present day and then in 2 billion
years the disk of the approaching Andromeda galaxy is noticeably larger.In 3.75 billion
years Andromeda fills the field of view. In 3.85 billion years the sky is ablaze with
new star formation. What we say is that such interactions can also trigger a small amount
of star formation. When the galaxies collide, it causes vast clouds of hydrogen to collect
and become compressed, which can trigger a series of gravitational collapses. A galaxy
collision also causes a galaxy to age prematurely, since much of its gas is converted into stars.
After this period of rampant star formation, galaxies run out of fuel. The youngest hottest
stars detonate as supernovae, and all that's left are the older, cooler red stars with
much longer lives. This is why giant elliptical galaxies, the results of galaxy collisions,
have so many old red stars and very little active star formation. In 3.9 billion years,
star formation continues. In 4 billion years Andromeda is tidally stretched and the Milky
Way becomes warped. That is when the giant spiral galaxies fall together. The first impact
in around 4 billion years completely disrupts the spiral structure of both galaxies creating
amazing tidal tails.In 5.1 billion years the cores of the Milky Way and Andromeda appear
as a pair of bright lobes.In 7 billion years the merged galaxies form a huge elliptical
galaxy, its bright core dominating the nighttime sky. Both galaxies contain a super massive
black hole which will fall towards the center of the new merged galaxy. They do that through
a process called dynamical friction. To sum up we could claim that, The Hubble
Space Telescope observations indicate that the two galaxies, pulled together by their
mutual gravity, will crash together about 4 billion years from now. Around 6 billion
years from now, the two galaxies will merge to form a single galaxy.
But something that we need to take into consideration is…What is going to happen with the Sun
and the earth?
The galaxies as we know them will not survive. In fact, our solar system is going to outlive
our galaxy. At that point, the sun will not yet be a red giant star – but it will have
grown bright enough to roast Earth’s surface. Then, the solar system will have a new cosmic
address: A giant elliptical galaxy, formed by the collision and merger of the Milky Way
and Andromeda.It’s a real, scientific prediction.
How about life on Earth? What is going to happen? What the results will be of this collision?
Will earthly life survive the merger? Will life on earth still exist? Astronomers say
that the luminosity, or intrinsic brightness, of our sun is about to increase steadily over
the next 4 billion years. As the sun’s luminosity increases, the amount of solar radiation reaching
the Earth will also increase. It’s possible that by 4 billion years from now the increase
in the Earth’s surface temperature will have caused a runaway greenhouse effect, perhaps
similar to that going on now on the planet next door, Venus, whose surface is hot enough
to melt lead. No one expects to find life on Venus. Likewise, it seems likely life on
Earth will not exist 4 billion years from now. What’s more, our sun is evolving, too.
It’s expected to become a red giant star eventually. The sun’s outer layers will
swell into the space of the solar system so that Earth itself is swallowed by the sun’s
outer layers. That’s expected to happen about 7.5 billion years from now. Perhaps
by that time we’ll have left Earth, and even our solar system.
Thanks for watching everyone! I would really like to know your opinion on this video. What
do you think of this collision? Do you think that it is going to happen? If so, would you
like to be part of this change and witness it?Let me know in the comments below, be sure
to subscribe, and I’ll see you next time on the channel!