Using a new method to measure the mass of galaxies, astronomers came to very interesting conclusions. It turns out that our nearest neighbor, the Andromeda galaxy, not much larger than our milky Way and not in two or even three times as much as previously thought. In about 4 billion years the two galaxies must face. Previously, scientists believed that the Andromeda will consume the milky Way. However, new data suggest that this event should be called more of a merger.
A study conducted by Prajwala Kaplam and his colleagues from the International centre of radio astronomy in Australia, shows that the mass of the Andromeda galaxy there is no more than 800 billion solar masses. Previously it was believed that this figure is at least $ 1.2 trillion.
To give an accurate assessment of the physical dimensions of our own galaxy, it may be quite difficult, however Kafle and his colleagues came to the same results in 800 billion solar masses, which puts the two galaxies, separated by about 2.5 million light-years on one scale. Report on the work of the team of astronomers prepared for publication in the journal Monthly Notices of the Royal Astronomical Society. You can find it in the online library arXiv.org.
The milky Way and the Andromeda galaxy are the two largest known in the so-called Local group of galaxies, consisting of more than 30 galaxies and covers a space about 10 million light years.
“This completely changes our view of the local group,” said Kafle.
“We thought that there is only one the largest galaxy, and our milky Way is at least two times smaller than her. But our results change everything”.
Scientists gave these assessments, based on observations of fast stars, which due to the casual game gravity got great acceleration and is ready to leave our home galaxy. The necessary “escape velocity” depends on the mass, which continues to attract a star of the galaxy. A few years ago that allowed Kaply and his colleagues to estimate the mass of the milky Way. Then the researchers found that the milky way contains less dark matter than previously thought. According to scientists, the previous sizes concerning the galaxy Andromeda was overstated for the same reason.
“To overcome the gravitational pull and go into space, the rocket after launching it to speeds of 11 km/s. Our galaxy, the milky Way, more than a trillion times heavier than our tiny Earth, so to overcome the gravitational attraction it has to move at a speed of 550 km/s,” says Kafle.
“After a quick observation of orbits of stars, we found that this galaxy has much less dark matter, only a third of what was showing past observations,” — said the scientist.
“It is very exciting that we have used a new method, and immediately a half-century of consonant understanding of the Local group, turn on the head,” — summed up Cafl.