Hai Yen Hello everyone
Dear friends, recently scientists have used a range of telescopes around the world,
In order to measure the distance in the universe, they measured the distances of 4 different galaxies.
As a result, it is possible that the previous "standard model of cosmology" needs to be revised,
So what is the true story of this? Let's decode with Top Thu vi in ​​today's video.
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Let's go explore.
Since 1929, scientists have known that,
the universe is expanding at a rate determined by the so-called Hubble constant
It is named after the American astronomer Edwin Hubble. When he and his colleagues realized that,
when we look at distant galaxies, the farther away they are, the faster the galaxies leave the earth.
They did this by measuring the "displacement" of light coming from those galaxies
also known as red shift measurement.
The longer the red shift is
prove that the galaxy is farther away from the earth and therefore it moves faster.
Hubble values ​​are considered to be basic constants,
This is the measurement unit used to describe the expansion of the universe.
According to scientists
our universe has become bigger since the Big Bang explosion about 13.8 billion years ago.
The interesting thing about expansion is not only the speed, but also the implications.
According to Nasa, if the expansion begins to slow down,
that implies that there's something in the universe that's slowing down growth, maybe it's dark matter
However, if growth becomes faster, it is possible that dark energy is pushing for faster expansion.
But recently, a new study was published in the astrophysical journal on February 26, 2020
The researchers said that: We need to reconsider the "standard model of cosmology"
These new measurements are made by many telescopes around the world
emphasizing the difference between previous measurements of a "standard model of cosmology"
In this new study, the scientists fine-tuned measurements of distances to four different galaxies
They are located between 168 and 431 million light-years from the earth.
These are galaxies UGC3789, NGC6264, NGC6323 and NGC5765b
After taking measurements, they discovered that
The universe is expanding at a current velocity of about 73.9 km/s
quite different from 67.4 km/s with "standard model of cosmology"
This is a pretty big difference, so scientists are questioning the  "standard model of cosmology"
The team said that
their job is to use completely independent distance measuring techniques to produce a final result
It is likely that the predictions of the "standard model of cosmology" have problems.
The big difference of Hubble constant not only happened in this work
Back in 2001,
scientists use the Hubble space telescope to measure light from some type IA supernovas
The results also show a 8% difference in the value of the Hubble constant
when compared to the method using CMB measurements.
In other words, the Hubble space telescope
recorded a faster pace of cosmic expansion than the CMB measurements did.
It was these that sparked controversy surrounding Hubble's constant,
They said that for Hubble's constant to be basic, it must be really good and not be altered by any measure
Similar to the speed of light,
it is a defined velocity and it does not seem to change with any measurement method.
But with Hubble's constant going the opposite,
It seems to constantly change over time and different measurements.
That is why it is still one of the most inexplicable things scientists have to do with studying the universe
Scientists are also not sure that the Hubble constant is wrong
Or does the universe have something that continuously changes these measurements?
Some scientists hypothesize that the universe has a new kind of particle unknown to humans
it may be the cause of these erroneous results.
Or maybe there is something that has changed the universe over time such as dark matter
a mysterious matter accounting for about 80% of matter in the universe.
So far, scientists have not had any suitable explanation for these false results.
What about in your opinion? What caused the constant change of the Hubble constant?
Leave your comments below the video to share with everyone.
Clearly, our universe is living they are constantly expanding
if the rate of expansion is known, then scientists can trace back in time,
to be able to determine the age of the universe,
Just as investigators can unravel the initial conditions leading to a traffic accident
So finding the rate of expansion of the universe is very important for determining the age of the universe
Since the early 20, The debate rages on strongly about the size and limits of the universe:
Some people think that the universe is confined to the Milky Way and the nebulae are also in it
they are nothing but relatively close gas clouds illuminated by stars
And then there came a young American who quit his profession as a lawyer to astronomy,
His name was Edwin Hubble and the space telescope was later named after him.
In 1924, he proceeded to measure the distance to the Andromeda Nebula
with a 2.5m diameter telescope just built on top of Wilson.
He measured the distance to this nebula to be 900,000 light-years away
(but according to measurements and calculations now is 2.5 million light years) is beyond our Milky Way galaxy.
Meaning Andromeda becomes a neighbor galaxy with our galaxy.
And at that time, the door of the universe to the galaxy was opened.
The universe suddenly became full of "galaxies and islands".
Now we know that our galaxy is only one of hundreds of billions of galaxies contained in the observable universe
However, Hubble has no intention of stopping there.
He attacked an issue that had puzzled astronomers for years.
A long time ago, although I did not understand the true nature
but when they looked at the nebulae they noticed that their light was all red.
This red color is assigned to teleporting away (this is also called the "Doppler effect"
The faster a galaxy moves away, the redder its light is.
This means that we only need to measure the redness of the light coming from a galaxy to infer its velocity
And Hubble took the measurement, still with the telescope at Mount Wilson
He measured the distance and rate of distance away from other galaxies by using their redshift.
His efforts paid off. In 1929, he published his second major discovery:
if all other galaxies are moved away from the Milky Way, then this motion is not accidental.
And the astronomer declared what is now called the "Hubble law"
The rate of movement of a galaxy is proportional to the distance from it to the Earth
A galaxy more than three times farther away will teleport far away
a galaxy ten times farther away will move away ten times faster.
And this outward movement is the same in all directions.
Although seemingly strange and strange, the conclusion is inevitable: "the universe is expanding"
And that's the way Hubble created the Hubble constant that scientists have used for decades.
Also as we know, speed is proportional to distance,
scientists know that the distances between galaxies are increasing
and they argue that everything had to be closer to each other in the past.
This idea was reviewed in detail
when we go back in time to a very high density of matter and temperature
That's the theory of the beginning of the universe, the Bigbang explosion.
There was a time when the scientific community was divided into two groups
between one that supports the Big Bang theory and one that supports the Stopped State theory
but today most scientists are convinced by the scenario of the Big Bang theory
It is consistent with the measurement observations
after the cosmic microwave background radiation was discovered in 1964,
and especially when its spectrum is detected in accordance with black-body radiation.
Since then, astrophysicists have incorporated large data in observations
and put more theoretical calculations into the Big Bang model,
and its parametric model or Lambda-CDM model
It becomes the theoretical framework for modern studies in cosmology.
But if the Hubble constant wavered, would the big bang theory still be convincing?
This maybe you and I will not be able to answer, because maybe it is far beyond our comprehension.
Hai Yen hopes that in the future when technology becomes more and more developed
Scientists will have more research works to decipher the mysterious phenomena of the universe.
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See you in the next videos, bye guys.
