(ORDO NEWS) — The name of our galaxy comes from the ancient Roman via lactea, which means “milk road”. The fact is that the star clusters observed by our distant ancestors confused them.
And in order to somehow understand the reasons why the night sky is dotted with bright lights, people endowed the stars and nebulae with divine power and origin.
So, according to Greek myth, Zeus brought his son Hercules home to Hera to breastfeed him while she slept.
But Hera did not like the demigod and, waking up, pushed him away from her, causing a few drops of milk to spill into the night sky.
In other cultures, the star trail observed from Earth was called differently, and only with time (and the development of technology) did humanity learn what the Milky Way is.
And since we only see the galaxy from the side, it is hardly possible to know what is happening on its other side.
To do this, you need to create a detailed map of the location of the stars of the Milky Way. But scientists, surprisingly, succeeded.
Star clusters in the Milky Way
Like other galaxies in the universe, the Milky Way is a large system of several hundred billion stars, one of which is our Sun.
At the same time, astronomers still do not have a complete understanding of its nature, unlike other outer star systems.
The situation is complicated by a thick layer of interstellar dust, which covers most of the Galaxy from observation by optical telescopes.
For this reason, its large-scale structure can only be determined using radio and infrared telescopes. According to available data, most of the stars in the Milky Way are single stars like our Sun.
Next come binary stars and their clusters, each of which contains from tens to thousands of bright celestial bodies. These objects differ from each other in age, size and number in each individual cluster.
Recall that the largest and most massive star clusters are globular clusters (so named because of their rounded shape).
Astronomers estimate that our Galaxy contains more than 150 such clusters, but their exact number is still unknown. Moreover, it is these clusters that form a spherical halo around the Milky Way.
Their distinguishing feature is their age, which can be determined by comparing the stellar population of globular clusters with models of stellar evolution.
Thus, the age of the very first stars in our Galaxy ranges from 11 to 13 billion years.
Recall also that globular clusters are extremely bright objects, the average luminosity of which is equivalent to about 25,000 Suns, and the most luminous are at least 50 times brighter.
Milky Way from the side
To an outside observer, our Galaxy looks like a huge thin disk – the Milky Way acquired this shape due to rotation.
And if it were not for the force of gravity, then every celestial body in the galaxy would go into outer space, wandering through the expanses of the vast universe.
But since our survey is limited, the number of observed stars does not greatly exceed 6000.
At first glance, it seems that this is a lot, but in fact, these six thousand heavenly bodies are only a small part of our Galaxy.
So, for every visible star, there are more than 20 million invisible ones, and most stars are either too dim, too far away, or hidden behind clouds of cosmic dust.
But is it possible in this case to find out what the Milky Way looks like from the outside?
Some researchers believe that for this it is necessary to establish the exact position of the stars and then plot them on a three-dimensional map.
To do this, you can use the famous astronomical technique invented almost 180 years ago.
The so-called “stellar parallax” was invented in 1838 by the German astronomer Friedrich Bessel (to measure the distance to a star in the constellation Cygnus).
The basics of this method are quite simple: first you need to bring your index finger to your face and close one eye. Then open it and close the other, keeping your finger at a distance.
The apparent change in finger position when you look at it with your right and left eyes depends on how far it is from your face.
The main condition is the possession of trigonometry skills and the presence of the most ordinary optical telescope. And voila – the Universe is in front of you (almost in full view).
Beyond the Galaxy
Remembering the simple method of stellar parallax, researchers from the Max Planck Institute for Radio Astronomy and the Smithsonian Center for Astrophysics decided to find out what the part of the Milky Way hidden from us looks like.
In an analysis published in the journal Monthly Notices of the Royal Astronomical Society, astronomers measured the distance to a group of stars on the other side of the Galaxy at a distance of 66,000 light-years from Earth (almost double the previous record of 36,000 light-years, reached in 2013). year).
It was possible to measure the distance using the VLBA (Very Long Baseline Array) radio interferometer, an antenna array with very long baselines, which consists of ten radio telescopes controlled remotely.
The construction of this astronomical instrument began in 1986 and was completed in 1993. The cost of the project was $85 million. The construction of the VLBA allowed astronomers to detect shifts in the positions of the stars.
So, with the help of VLBA in 2014 and 2015, scientists were able to detect light from a region of space where new stars are born, even despite clouds of gas and dust that block most of the outgoing radiation.
And as progress continues, the VLBA allows researchers to accurately measure the distance from Earth to distant stars and closely observe the Galaxy’s spiral arms and their shapes.
This means that with VLBA we can map the entire galaxy. We believe that it will take at least ten years to create it, the authors of the new analysis report.
In the meantime, scientists will be busy observing and collecting data, you and I will have to hold our breath thinking about which luminaries and their clusters are on the other side of the Milky Way.
In the meantime, researchers are studying the hidden part of the Galaxy, their colleagues have already created a real map of dead stars and their remains.
Needless to say, how difficult it was to create it, because in the Universe nothing stands still.
These complex astronomical models led to the creation of a map of the stellar necropolis – the area in which stars were born and died.
And while we are waiting for the most accurate stellar map of the Milky Way, we suggest that you familiarize yourself with another amazing work – a map of the location of black holes in the observable Universe. Intrigued? Then you are here!
Contact us: [email protected]