The Doppler effect is used to calculate the age of the universe

Let me talk about it briefly, the first thing to measure is the star, and the measurement of the star is measured by the infrared radiant on its surface, because in the universe, no matter what object will radiate infrared microwaves, and infrared is the longest wavelength and the least easy to be blocked by objects, so as long as different types of infrared microwaves are detected, stars can be detected.

And the distance at which the star is detected, which is determined by the redshift of the rays.

First of all, tell the landlord some common sense about rays.

As you should know, there are three major categories of radiation, namely infrared light, which has the longest wavelength, and visible light, which is visible to the human eye, that is, ultraviolet light, which has the shortest wavelength.

The redshift judgment method is to judge whether the object is moving away from us or close to us according to the speed of the object itself and the spectral position of the rays it emitts, and according to the frequency of the spectral change, it is judged to be close to us.

This is known as the Doppler effect, which determines the direction and speed of a star's position and speed.

Therefore, according to the theory of the reexpansion of the universe, it can be deduced that the farther away from us is, the farther away from us the star is, the faster he is away from us, therefore, the star that is far away from us at the fastest speed is the farthest star we have observed to stay with us, so it is naturally tentatively designated as the edge of the universe, and the edge of the universe is not fixed, but our current technical level is not enough, and it cannot be observed.

Calculating the age of the universe" is really a fantasy, and it is all guessed, fantasized, and come out by so-called scientists, and no one has corroborated it, and at the same time, anyone can guess and fantasize.

I speculate that the age of the universe is about 10 million years, can you believe it? If you don't believe me, then you can show the evidence!

I wondered, scientists say that the age of the universe is 15 billion years, and the universe that can be observed at present is 93 billion light years away, what do you see in the more than 70 billion years? Isn't it the universe?

The speed of the expansion of the universe can be calculated according to the redshift value, and then the time of ** can be calculated according to the big ** theory, and then the radius of the universe can be calculated.

It's worth saying.

1. The redshift value of the Doppler effect is used to calculate the velocity, not the distance.

2. The calculation of the radius of the universe by red shift is based on the theory of the universe, that is, the premise is the correctness of the theory of the universe.

How old is the universe?

Astronomers estimate it to be 13 billion to 14 billion years.

Washington, April 24 (Xinhua) -- Astronomers said on April 24 that they used the "Hubble" space telescope to observe the oldest white dwarf in the Milky Way discovered so far, which provides a new way to determine the age of the universe. The newly estimated age of the universe is about 13 billion to 14 billion years.

Astronomers told NASA's press conference that the ancient white dwarfs were discovered in a globular cluster called M4, located in the constellation Scorpio, 7,000 light-years from Earth. Analysis shows that these white dwarfs are about 12 billion to 13 billion years old.

White dwarfs are the products of the burn-out of early stars in the universe, and they gradually cool down with age, so they are considered the ideal "clock" to measure the age of the universe. Astronomers have metaphorically said that estimating the age of the universe with the help of white dwarfs is like using embers to guess when a charcoal fire will go out. But the problem is that white dwarfs get fainter and fainter due to constant cooling, which is a difficulty to overcome in actual observations.

In the process of observing the M4 globular cluster, the observation capabilities of the Hubble space telescope have been pushed to the limit. It took the telescope's camera eight days out of 67 days to capture the faintest and hottest white dwarf to date. These white dwarfs are extremely faint and less than 1 billion times brighter than the faintest stars that can be seen by the naked eye.

The newly discovered white dwarfs were the first stars in the universe. Earlier observations by the Hubble space telescope showed that the first stars in the universe may have formed less than 1 billion years after the birth of the universe's "big **". Therefore, taking these 1 billion years into account, combined with the latest white dwarf observations, the age of the universe should be between 13 billion and 14 billion years, which is basically consistent with some of the earlier results.

Previous estimates about the age of the universe were mainly based on the calculation of the rate of expansion of the universe. Astronomers point out that white dwarf observations provide a completely different and independent means that will help to verify and reconcile results obtained by other methods.

People's ** Overseas Edition" (4th edition, 2002-04-26).

Ref. 5

It's an unknown that scientists are working on...

The light waves emitted by distant stars are redshifted (drop in frequency), indicating that the stars are moving away from us. A violet shift (rising frequency) indicates a movement in our direction.

Measure the expansion velocity, red shift measure velocity.

Please clarify the difference between "inertial mass" and "gravitational mass" before "further discussion".

Also, please distinguish the difference between the "cosmological redshift" and the "Doppler effect" and then discuss how "fast" galaxies are.

I don't think so, because as stars continue to emerge from gas, there is less and less gas until it is no longer possible to produce new stars.

After 10 years to the 14th power, all stars lose their brilliance, the universe darkens, and the black hole at the core of galaxies grows larger.

10 years to the 17th power, only black holes and a few scattered dead stars remain. Protons in stars become unstable.

10 years after the 24th power, protons decay into photons and various leptons.

After 10 years to the 32nd power, the decay process ends, and only photons, leptons, and large black holes remain in the universe.

After 10 to the 100th power, the black hole has completely evaporated, which can be called the end of the world!!

This is called opening the universe, and it is more likely.

You're talking about a closed universe, and sooner or later the expansion stops depends on the density of matter in the universe.

Assuming that the density of matter is twice the critical density, this expansion process will stop in 50 billion years, and the radius of the universe will be twice as large as it is now.

Once gravity prevails, a "big explosion" will be formed, which is the opposite of the big **, and then a singularity will be formed, and then a big ** will occur.

The inertial mass is not necessarily equal to the gravitational mass.

I agree, it's great to have that thought!

But the greater the mass, the greater the inertia.

Let the sound source S, the observer l move in the same straight line in the same direction in the stationary medium with velocity vs, vl respectively, and the propagation velocity of the sound wave emitted by the sound source in the medium is V, and VS is less than V, and VL is less than V. When the sound source is not moving, the sound source finds a sound wave with a frequency of f and a wavelength of x, and the observer receives a sound wave with a frequency of :

f'=(v-vl)v/[(v-vs)x]=(v-vl)f/(v-vs)

So get (1) when neither the observer nor the wave source moves, vs=0, vl=0, and f is obtained from the above equation'=f

2) When the observer is not moving and the sound source is close to the observer, the frequency received by the observer is f=vf (v-vs), which is obviously greater than the original frequency.

I see what you mean, you're not asking why the Doppler effect, but why the wonder wave is "compressed", and what is the frequency of the "compressed" wave?

First of all, you have to understand the fact that the wave source is essentially a series of nearby fulcrums that vibrate, and you can think of it as a series of vibrational particles. This makes it clear that the vibration frequency of each particle depends only on the vibration frequency of the wave source that drives it! Therefore, what you said in your supplementary question, "If the frequency of the outgoing wave increases, that is, the period of the up-and-down vibration of the particles in these places becomes shorter", it is obviously a wrong understanding, and the frequency of the up-and-down vibrations of the particles does not change, but is still equal to the frequency of the source.

I think you're confusing the two concepts, the vibrational frequency of a particle, and the frequency of a wave. When the source of the wave is still and the receiver is relatively stationary, the vibrational frequency of the particle is the frequency of the wave. Because of how many full vibrations a particle completes per second, the receiver receives exactly how many peaks (strictly speaking, the number of wavefronts).

But when the wave source is close to the receiver's motion, the receiver receives more crests due to the motion, so that the frequency of the wave becomes larger. However, as each particle of the wave, the frequency does not change because it is still vibrating under the drive of the wave source.

This is what you call a contradiction, but it is not a contradiction. The frequency of the wave is equal to the frequency of the particle vibration when it is at rest with the wave source, but the vibration frequency of the particle is not equal to the frequency of the wave when it has a relative velocity with the wave source. But the vibrational frequency of the particle remains the same!

You can consider a model of waves composed of discrete vibrating particles, when the wave source is stationary, the particles are equally spaced, but after the wave source moves, the distance between the particles becomes denser, so the frequency of the wave naturally looks larger.

You may still be confused, because most books say that the speed of the wave is equal to the speed of the vibration of the particle, and it does not separate it. So the frequency of the wave should depend only on the frequency of the wave source. Therefore, the Doppler effect should be because the frequency of the wave does not change, only the wavelength and speed of the wave change.

But why do many books say that the frequency of the wave has changed?

In fact, strictly speaking, the frequency of the wave should be constant, but the physical phenomena produced by the wave have nothing to do with the vibration of its particle. If you learn the complete wave theory. You'll find that whether you think of frequency as invariant or as invariant, the final mathematical form is exactly the same.

If you think about it in a single draw-out wave, it doesn't matter how you change it.

Hehe, the above two paragraphs are off-topic, if you think it's more winding, don't worry about it, it has nothing to do with your question. In short, just remember that the frequency of the particle depends on the wave source and is constant in the Doppler effect. But the frequency of the wave is due to the fact that the distance between the troughs and the troughs is shortened, so the frequencies become larger (in fact, the wavelength becomes smaller).

I guess I'm going to get a score for this question, hehe.

There are two frequencies in this problem: one is the natural frequency f of the wave emitted by the wave source, which is constant; The second is the acceptance frequency f that the person receives into the wave

Then, when the wave source is close to the person who is not moving, in fact, the position of the wave emitted by the wave source advances, then it is expressed that the wave is compressed, but at this time, the natural frequency f of the wave emitted by the wave source does not change, but because the position of the wave is constantly moving forward, then it receives more waves than when the wave source is not moving, so the acceptance frequency becomes higher.

For example, if the distance between the wave source and the person is 200 m, and the person receives 10 complete waves per second, then the 11th wave emitted when the wave source advances to 20 m can also be received by the person, so the number of waves received by the person in the same time becomes more. (Originally, the eleventh wave should not have arrived, but because the wave source movement moved it forward, it was also accepted).

To put it simply, when the signal source moves relative to the observation point, the observed signal frequency will change with the different speed and angle of the signal source.

The broadening or reduction (frequency change) of this frequency is called a Doppler frequency.

Ultrasound measurement of blood flow rate makes use of the Doppler effect.

There are also examples in life, when the train passes, the closer it is, the thicker the sound of the whistle, and the farther it goes, the sharper the sound, which is due to the movement of the train, which causes the frequency of the whistle sound that we observe to change.