55% off on Cambly! Start speaking English with prices starting from 384 TL per month! cambly.biz/baris 55% discount code: cobe
With the back to school discount at Cambly Kids, 1 lesson starts from 179 TL! Valid for limited time. cambly.biz/bariskids 55% off code: wmap (collaboration)
---
The universe is exactly 13.8 billion years old. Numerous observations have been made to measure this. And by using very independent measurement methods.
All of them led us to this conclusion, 13.8 billion years that is. So for a very long time, scientists have agreed on this issue, the age of the universe. But a strange news came out recently. As you know, after the launch of JWST, the James Webb Space Telescope, we started to get some new observations. These are much better quality and detailed observations than we have obtained so far! Therefore, it also contains new discoveries. And the following article published recently drew attention to an observation by JWST of very distant galaxies. The conclusion was: The universe is not 13.8 billion years old, but 26.7 billion years old! Now, I will give you insight on what is going on in the background, in that lobby when you hear such news.
HOW IS THE AGE OF THE UNIVERSE MEASURED?
How do you measure the age of the universe? We count our own age since the day we were born, it is recorded somewhere, there are people who see it. But what about the beginning of the universe, that's the beginning of everything. There is no one to count it. But we can rewind time! We observe that the universe is expanding, and we can measure the rate of that expansion. It's like watching a car that we know is going at 50 kilometers per hour. If the odometer shows 500 kilometers, then we can say that it has traveled for 10 hours. This is how the simplest calculation of the age of the universe works.
That Hubble constant, which expresses the amount of expansion of the universe, is actually the speed of a car. When we take that and rewind it, we see that the universe will be 14.4 billion years old. Of course, this is a very rough calculation, but it is still very close to its true value of 13.8 billion years! The slight difference says that the universe does not always expand at the same rate, but that it expanded much faster in the beginning.
So the speed is not constant. You know, when cars go out, they start in low gear first, then increase their speed by increasing gears. There are no more gears though…
NUCLOCOSMOCHRONOLOGY
Of course, now we can not say age measurement and talk about radioactive decay. When you hear radioactive, don't think of Hulk immediately! I'm talking about atoms. These atoms decay into another atom after a certain period of time. And thanks to laboratory experiments, we know which will turn into what in how long. This is called half-life. Well, just as it sounds… For example, if we have 100 of these atoms with a half-life of 5 years, when we measure them 5 years from now, we should have half of them left, that is, 50. All right, but how will this information be of use to us when measuring the age of the universe? By measuring the age of the Earth, of course! Since the Earth appeared much later than the formation of the universe, the age of the Earth constitutes a limit to the age of the universe, giving us an idea. For example, if the Earth is 4.6 billion years old, the universe cannot be 3 billion years old, right? If we find it so, we can say that "There must be an error in one of the two calculation". But how do we measure it? Now, bring the oldest thing we can find! Let's race. Let's see who will find the oldest stone in the world! or… We can measure meteors They come from outside. Not far from the outside though, probably from somewhere still in the Solar System. But this is how we can calculate the age of the Solar system as about 4.6 billion years. Of course, that's just the Solar system part of it. In order to go from here to the age of the universe, we need to know what lies before the solar system. From the chemical composition of the Sun, we know that it is not a star formed at the beginning of the universe, but is formed from the supernova remnants of another star. Otherwise we wouldn't be either! All those atoms that make up us were formed from Hydrogen to Helium, fusing together inside the womb of the Sun's mother! Of course, these first stars also have an age limit, when we take this limit into account, what we see is…
Yes, you got it right, it's pretty consistent with 13.8 billion years.
---
Researched and Written by: Ögetay Kayalı
Organized and Presented by Barış Özcan
Edited by: Alperen Çatak
---
The full text of the video and the sources used:
barisozcan.com
11 авг 2023
