Our solar system is about 28 thousand light years away from the center of the Milky Way. At this distance, the new observations indicate, we move at a speed of about one million km/h around the galaxy and not about 800 km/h as previously thought
For many of us, the act of looking closely in the mirror after a vacation provides a surprise. Likewise, the astronomers who closely examined the Milky Way galaxy found that our galaxy is much more massive than previously thought. Extremely precise measurements of the Milky Way revealed that our galaxy rotates about 150 thousand km/h faster than previously thought.
This increase in speed, says Mark Reid of the Harvard-Smithsonian Center for Astrophysics, increases the Milky Way's mass by 50 percent. The greatest mass, in turn, means a greater gravitational push which increases the likelihood to crash into the Andromeda galaxy or with smaller galaxies. So if we are faster we are also heavier and have a greater chance of getting hit.
The scientists used the Very Large Array (VLBA) of radio telescopes to remap the Milky Way. Taking advantage of VLABA's unprecedented ability to take extremely detailed images, they followed a long-term plan to measure distances and motions in our galaxy.
At the American Astronomical Union conference in Long Beach, California, which is taking place these days, Reid said that he used trigonometric parallax (parallax, a simulated change in the position of an object due to a change in the position of the observer) to make the measurements. "This is exactly the same method that surveyors who study the earth use to measure distances." said. "And this is also the gold standard of measurements in astronomy."
Trigonometric parallax was first used in 1838 to measure the first distances to the stars, but with better technology the accuracy is now 10,000 times greater.
Our solar system is about 28 thousand light years away from the center of the Milky Way. At this distance, the new observations indicate, we move at a speed of about one million kilometers per hour around the galaxy and not about 850 kilometers per hour as previously thought.
The scientists observed 19 regions of star formation activity throughout the galaxy. On several islands within this area, the gas molecules are strengthened and naturally emit radio emissions in the same way that lasers amplify light signals. These regions, known as cosmic masers, serve as bright milestones for the VLBA's sharp radio field. By observing these regions separately at times when the Earth is in opposite regions of its orbit around the Sun, astronomers were able to measure the tiny apparent displacement of the position of these objects against the background of the more distant objects.
The astronomers found that their direct measurements differed from previous indirect measurements, sometimes by two orders of magnitude. The star-forming regions where those cosmic misers reside "define the spiral arms of the galaxy," Reid explains. Measuring the distances to these areas will serve as a kind of measuring stick for mapping the spiral structure of the galaxy. The areas where stars are formed are seen in the image above as blue and green dots. The position of the sun (and us) is circled.
The VLBA can adjust to the Earth's rotation rate and thus locate the true image of the objects as they orbit the center of the Milky Way, with greater accuracy. If we add to this the measurements of the movements along the line of sight, which results from the change in the radio emission frequency of the masers, the astronomers are able to determine the three-dimensional movement of the star formation regions. Using this information, Reid reports that most star-forming regions do not follow a circular path as they circle the galaxy. Instead we find them moving more slowly than other regions as they circle the center in an elliptical rather than circular orbit.
The researchers linked this phenomenon with what they call spiral density shock waves, in which the gas initially in a circular orbit is compressed and stars are formed from it, and thus it is pushed into a new orbit - elliptical. It is this phenomenon that continues to maintain the spiral structure of the galaxy.
Reid and his colleagues found more surprises. They measured distances to multiple areas in a single spiral arm and thus were able to calculate the angle of the arm. "These measurements" said Reid, "indicate that our galaxy has four spiral arms of gas and dust in which new stars are formed and not two as was commonly thought until now. Recent surveys using NASA's Spitzer Space Telescope suggest that the oldest stars reside primarily in two spiral arms, raising the question of why the older stars do not appear in all arms. Answering that question, the astronomers say, will require more measurements and a deeper understanding of the way the galaxy works.
So, now that we know we are fatter, how do we compare to other galaxies in the neighborhood? "In the local group of galaxies, Andromeda was considered the older and dominant sister." Reid said. "However, it turns out that we are almost equal in size and mass. We are not identical twins, but more like ordinary twins. It is likely that these galaxies will collide sooner than we thought, but this depends on measuring the lateral motion, something we have not done so far."
The VLBA is a system of 10 radio telescope antennas stretching from Hawaii to New England and south to the Caribbean. They have the greatest observational power than any other astronomical instrument in the world. The VLBA routinely produces images that are sharper and more detailed than those taken by the Hubble Space Telescope. Its ability to distinguish is similar to reading a newspaper in Los Angeles from New York, which allows astronomers to more accurately determine distances.
20 תגובות
: )
Without a problem we reach about 75% of the speed of light, although we only hold this speed for fractions of a second, but with a particle accelerator, even with the tiny one at the Weizmann Institute in Rehovot,
And even with this big one in Geneva, without a problem you reach at least 75 percent of the speed of light...
If you happen to be an electron
Good evening Michael,
Indeed, your corrections are correct. I wanted to simplify and shorten it, and even so the response came out longer than I wanted. In my opinion, the above article is very non-trivial and requires a broad and deep understanding of physics, it is not 'popular science'.
Moshe asked about the relativistic effects as a result of the galaxy moving at a million km/h. I took a relativity equation regarding the change in length as a function of speed and placed the data - it turned out that a spaceship moving at the speed of light to a star 4 light years away would cover the corrected distance in less than 54 seconds (DHA time). It's just for fun, I'm not signing it...
Shabbat Shalom
For the little brother:
Some corrections:
When measuring with the parallax method as you described, it is not possible to recognize the fact that a trapezoid is formed.
After all, the whole idea is to locate the position of the star by the differences between the angles obtained from both sides and determining its position as the apex of the triangle obtained from these two base angles.
There are an infinite number of trapezoids that give exactly the same base angles, so it is not possible to identify a trapezoid in the way you described.
I don't know exactly how they achieved the improvement exactly but two of the ways they used to improve accuracy are mentioned in the article: one is the simultaneous use of 19 areas instead of one area and the other is a large number of measurements. Probably added to this is also better equipment than that used by those who measured in the past.
The issue becomes even more complex if you take into account the fact that not only does the Earth move within the solar system, but the solar system also moves within the galaxy at exactly the speed that you want to measure.
In general - the parallax method is used here - not only to measure the distance to the stars - but to use the distance estimate (obtained while relying on the speed of the movement of the solar system) to calculate the speed of the movement of the solar system (which - as mentioned - was already based on as if it were known).
Therefore, it is probably an iterative calculation process that assumes certain values for all the sizes and repeats and improves its assessment to improve the match between them.
Your description of the arms being a result of the shock wave is correct (and it also appears in the article), but the reason for tracking regions lies, as written in the article, in exactly this fact: they didn't follow regions just like that, but "star formation regions" which are the regions where the maser emission is created. They did not follow individual stars because the source of the maser emission is the star-forming region.
By the way, your answer to Moshe is not clear to me.
He asked about the effect of the movement of the solar system in the galaxy on "our concepts of time and mass" and you tried to answer him about the effect of an unknown thing on the time of our flight to the nearest star.
If we fly to the nearest star at the speed of light, then from the point of view of those flying, the flight will take zero time, and from the point of view of the observers on Earth, a value will be obtained that is a function of the difference between the speed of our movement and the speed of the movement of the nearest star. This difference is apparently almost zero and not a million km/h as you assumed in your calculation.
To Moses,
I did some calculations regarding your question - the speed of the galaxy will have a relative effect but not by much!
Flying at the speed of light to the nearest star (4 years) will save us 54 seconds. With the existing technology that flight would last 80,000 years, but because of the relativistic effect it would last 79,999 years and 11 months and 17 days and 11.5 hours (we saved about 12.5 days) - also something 🙂
And Aliran and me,
I'm afraid the article is a bit confusing, I'll try to clarify simply:
The goal was to follow certain stars in order to estimate the size of the galaxy, its mass and rotation speed. They wanted to use a method that does not depend on the light intensity of the stars (Doppler effect and illuminance) but a method that is based on the position of the observed stars in relation to the Earth. This method is called perilexa and today, because the equipment has improved, it is possible to reach a level of accuracy 10,000 times higher than before.
How do you do that? You look at a star from "one side" of the solar system (the movement of the Earth) and again from the "other side" of the solar system. If the observed star was static then a triangle would be obtained, but it moves and therefore a trapezoid is obtained - and thus the speed of the star can be calculated.
Here there are several "buts" (plural of 'buts'), at these distances and with the disturbances in between it is very difficult to follow a single star. Therefore follow regions/groups of stars, where there is maser emission (a laser is a certain type of maser). From the analysis of the data, they found that there is a significant difference between the measurement in this way and the previous measurements that, as mentioned, relied on the intensity of illumination - sometimes 100 times !!!. The researchers found that stars move faster than they thought. Therefore, in order for the galaxy to be stable, the galaxy needs to be heavier in order to have enough gravity to hold the stars moving faster than previously thought (the balance between gravity and centrifugal force).
It seems to me that you have a basic mistake - the stars do not make up the spiral arms, the stars pass through the spiral arms. The spiral arms are a type of shock/compression/gravity wave that causes dust clouds to compress and ignite new stars - just like you don't see a light beam from a flashlight, but see the dust particles in the light beam. The Earth passes in its rotation in the galaxy every 140 million years through a 'spiral arm'.
Eliran: By and large, as you can see how many toes you have on your feet.
In the small, you look in different directions, see stars, calculate the distance and come to the conclusion that they are part of the galaxy, and slowly it is possible. It's also main arms, there are probably other smaller ones.
And in the end, there are theorists who develop theories on the subject, some are right, some are wrong. As until now they thought there were two arms, now they think differently, and this may certainly change.
How do you know how many arms our galaxy has without seeing it from the outside?
Thanks.
Avi Blizovsky:
As you saw in the article - you do everything at a tremendous speed of a million kilometers per hour - not just the translation.
Moshe:
This has no effect.
The speed of a system only means that those observing it from another system will see that the times and distances in it change as a function of the differences between the observing system and the observed system.
to my father Thanks fixed. This was of course a mistake due to the speed of the translation.
I suggest researchers read the following article for today in science.
Maybe they'll also find a way to add malevolent intent behind the future bleak state of the galaxy.
Has the solar system received a speeding report yet?
Does the fact that we move at such a great speed affect our concepts of time and mass in relation to the theory of relativity?
And if the Milky Way once moved at even greater speeds?
jubilee:
It's billions of years, so you still have some time, but when you pack - don't forget to pack this too:
https://www.hayadan.org.il/mysky-gadegt-0701094/
To understand why - see response number 2 there.
Chen T
To start answering you, I searched the page for the word "hole" because I wanted to see if the article mentioned the subject in any way.
I didn't find it and the search found instead part of the word "girls" in a Google advertisement asking if I'm in love with my friend.
I will take this opportunity to inform that snoozer who keeps asking me this question again and again that it is none of his business and it will not help him if he asks me a thousand times.
As for wormholes, as far as I know no one knows if they exist or if they can be made.
The very use of the word is due to the fact that the equations of the theory of relativity allow their existence, but it must be remembered that these are dynamic equations that actually define how the state of the universe changes from moment to moment. A steady state is a state that the universe can maintain for more than a moment. To date they have not been able to show that a stable state of a wormhole is possible.
All this - from the theory side.
Another side of science is the side of the experiment, but if we continue the word game that is why I repeated the word "side" until now - I must say that science has not yet sided such a hole in the experiment as well.
Lior:
You will be amazed what can be done when the powers of the big bang and dark energy are at your disposal for billions of years.
With such resources it is really easy to reach a million km/h, but these resources are not at the disposal of your spacecraft and it - poor thing - will not be able to escape from the catastrophe using the known technology.
Wrong units!
km/h is a unit of acceleration while km/h is a unit of speed!!
Question: 1. How do we reach a million km/h and can understanding how to reach this speed help us to reach this speed as well.
2. If it is a relative speed, if a spaceship slows down or flies in "reverse" we can reach much more distant locations.
PS: I am not a scientist in the field.
When is a collision expected?
Shall we start packing?
Father, I apologize that the question is not related to the article.
Michael, I'm asking here because this is a new discussion:
What is known today about the possibility of the existence of a wormhole? Is it just an MDB idea or a theory with too many missing persons and too little evidence to substantiate it as serious?
Is a wormhole a technology that can be produced, according to the theory, or a result of nature that can only be used in certain locations in the universe?