As years go by we come across new discoveries that make us understand the Universe better.
Research is the major factor that allows us to discover more and more as the way science
progresses is by pushing limits to even greater extremes.
I think what is fascinating is the fact that we will never reach an end regarding the exploration
of the universe.
We will keep on learning facts that will blow our minds and keep our interest about the
universe.
Join me today as I explain one of the biggest discoveries that needs to be mentioned as
we are going to talk about a very exciting discovery coming from the center of our own
galaxy very close to the supermassive black hole Sagittarius.
Through the years we found out that we are part of the Milky Way Galaxy.
The Milky Way is a barred spiral galaxy, about 100,000 light years across.
The Milky Way also contains two significant minor arms, as well as two smaller spurs.
One of the spurs, known as the Orion Arm, contains the sun and the solar system.
The Orion arm is located between two major arms, Perseus and Sagittarius.
There are many facts that make our galaxy interesting.
One of them is that our Galaxy does not stand still but it is constantly rotating.
The sun and the solar system travel with them.
The solar system travels at an average speed of 515,000 mph (828,000 km/h).
Even at this rapid speed, the solar system would take about 230 million years to travel
all the way around the Milky Way.
What we know for sure about the Milky Way is that contains over 200 billion stars.
There is also enough dust and gas to make billions more and More than half the stars
found in the Milky Way are older than the 4.5-billion-year-old sun.
What if I told you that we have detected the fastest star?
Yes you heard correctly.
We know who the fastest star is!
Unbelievable huh?
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Billions and billions miles away in the center of our galaxy, there is a realm where the
things are so bizarre that it is hard even to imagine.
While peering deep into the heart of the galaxy, astronomers have found the fastest star ever
seen.
What we know is that it is close to Sagittarius A*.
But what is Sagittarius A*?
Sagittarius A is a complex radio source located at the centre of the Milky Way Galaxy and
belongs to the constellation of Sagittarius.
It is known to be of a super massive black hole with millions of times the mass of our
own Sun.
Being so big, its gravitational effects are extreme and they can be detected by looking
at the stars in its immediate vicinity.
Orbiting Sagitarrius A* are a handful of stars moving at mind-melting speeds.
The black hole has hundreds of stars pulled tightly into its orbit, traveling exceedingly
fast from the gravitational boost granted by this close adjacency.
The black hole at the centre of the Milky Way lies at a distance of 26,000 light years
from Earth.
This happens because of relativity.
It might appead to be excessive but in astronomical scale it is nothing.
As we look closer they may emerge stars capable of even greater speeds.It appears motionless,
but there are clouds of dust and gas orbiting it, which provides a clue to the nature of
the object.
Astronomers calculated its mass using Kepler’s laws and measuring the period and semi-major
axis of the orbit of a star that came within 17 light hours of the object.
They arrived at approximately 4 million solar masses.
The only kind of object that can be that massive and have a radius of about 100 astronomical
units is a black hole.
Astronomers have estimated that it contains 4.31 million solar masses.
The space research communities around the globe have theorized that there are stars
orbiting close to the black hole which have been named as 'Squeezars'.
Scientists believe that the stars move so close to the black hole that they accelerate
at incredible force during their orbit around it.
In their research, explorers have been studying a group of stars lose to the black hole, which
have all been named starting with the letter 'S', indicating how close they are to the
black hole.
In the last 10 years, astronomers have also used this data to learn more about other black
holes in our galaxy and check whether their theories and knowledge of black holes are
accurate or not.
One of the brightest members of the ‘S Star’ cluster that orbits Sgr A* is known as S2
star.
This star had a lot of records as it was believed to be closest to the black hole.
It took 16 years for S2 to complete a rotation of Sagittarius A * and when it was closest
to the black hole, it was only 18 billion kilometers from Sagittarius A *, causing the
S2 star to reach 3% of the speed of light.
S2 is one of the most researched stars orbiting around the black hole.
It is a giant blue star which orbits the Sagittarius A*.
every 16 years.
This is the star that allowed us to prove Einstein’s idea and theories because as
it approached the black hole it started to become even more red-shifted in its light
and we were able to observe this pretty easily but since then a lot of scientists have been
trying to find more of these stars and more unusual objects in this region.
Later on,a team of researchers discovered a less bright star, located closer to the
black hole: The S62 star.
With an orbital completion time of 9.9 years and close to the black hole to a distance
of 2.4 billion kilometers, S62 is closer to Sagittarius A * than from Uranus to the Sun.
The speed of S62 reaches 20,000 km / s, about 6.7% of the speed of light.
This star became a new record holder for the fastest star in the galaxy making it the fastest
star to blitz around the Milky Way’s black hole.
Something happened and S62 drop off its record.
On August 11, the astronomers announced the discovery of a set of new stars in the central
cluster of our galaxy.
In particular two stars broke all the records.
They are known as S4711 and S4714.
Both can be seen with today’s telescope and have the opportunity to admire the beauty.
S4711 orbits the Milky Way’s black hole once every 7.6 years and it seems to be the
record holder for the shortest period of time.
Some claim that it is the most spectacular star.
Until the S4714 star appeared.
S4714 gets to be the fastest and most furious star we know of at our galaxy’s center.
It is the fastest among these as of our current knowledge.
Scientists caught a glimpse of the fastest star in our galaxy zooming around a black
hole.
To be more specific, the S4714 star took the record for closest approach to Sgr A*.
It has an extreme orbital eccentricity of 0.985 and the closest approach to Sgr A* is
just 1900 million km.
It then moves with a speed of 24,000 km per second or 15.000 miles per second and that
it is approximately 8% the speed of light.
It is easy to understand that it has the fastest speed.
This star comes closer to the central black hole.
In other words it is just 1.9 billion kilometers away from it.
This star is now the new record holder for the fastest star in the vicinity but the reason
the star moves so fast is because of its extremely eccentric orbit meaning that the ellipse shape
is elongated to put its speed into perspective.
In order to be more understood, imagine that if an aircraft was flying at that speed it
would orbit the entire earth in less than two seconds.
Imagine that we are not even accounting for the time dilation.
Objects travelling at such high speed experience time much slower than we do.
What is fascinating is that its experiences the largest predicted precession of any star
ever measured and the most important thing is that it has the highest maximum velocity.
However its orbital period lasts about 12 years, and its farthest distance to the galactic
center is 250 billion km.
That means that astronomers can observe this effect in real time too.
S4714 is so close to Sagittarius A* and so faint that even the world’s biggest infrared
telescopes have a hard time picking it out of the crowd of stars in that spot in the
sky.
Still it implies that there may be stars even closer still, perhaps just less massive and
too faint to spot.
This new discovery leads to two exciting consequences the first is that this extreme star, the one
that moves fastest and passes closest to our galaxy’s super massive black hole, will
provide us with the strongest test ever performed of Einstein’s General Theory.
In other words with this new star and these new observatories, we will have the greatest
opportunity we have ever had to look for cracks in Einstein’s greatest scientific achievement.
The second consequence is that this verifies and validates a number of theoretical predictions
of stellar populations that ought to exist but had never been discovered until now.
It will be interesting to find out just how close these stars get.
These predictions further indicate that these should be larger numbers of even fainter stars
that ought to approach our central black hole even more closely and that these next-generation
telescopes should reveal them to us.
We may have gigantic telescopes in the future that will have an even better view.
Improved data analysis could yield even further insight into the Space around Sagittarius
A*.
We expect more stars on extremely tight orbits to be discovered in the near future as scientists
may be able to put this theory to use and locate other stars.
Astronomers believe that there may be stars with velocities and speeds that surpass that
of S4714 hiding near Sgr A*.
Although there has been an improvement in figuring out the stars still we are in the
process of understanding how black hole feeding and formation of stars close to a super massive
black hole works.
Also, in the coming decade, we may be able to test our theory of gravity like never before.
If Einstein’s theory doesn’t match with our observations, it might be the start of
the biggest scientific revolution that physics has never seen.
Τhanks for watching everyone!
I would really like to know your opinion regarding S4714 star.
I want to know your feelings about the star.
Did you know about the existence of this star?
Do you think we will find another star approaching better the speed of light than S4714?
Will new telescopes help us detect them?
Let me know, in the comments below, be sure to subscribe, and I’ll see you next time
on the channel!