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The Milky Way is said to be much lighter than expected

The Milky Way is said to be much lighter than expected

from Valentine Sattler
New data from the European Space Agency’s Gaia space telescope suggests that the Milky Way contains much less dark matter than previously thought. Therefore, our home galaxy consists of only two-thirds of the invisible mass. At the same time, the data also provides a contrast when compared to other spiral galaxies.

The European Space Agency’s (ESA) Gaia space telescope, launched nearly a decade ago, aims to create a more accurate image of the Milky Way than was possible with previous telescopes. The third data set generated in this way provides an exciting clue: our home galaxy may be much lighter than previously assumed. This is what he’s talking about At least one sheet of paper In the Journal of Astronomy and Astrophysics, published by the French University PSL.

Less amount of dark matter

According to this, it was previously assumed that the Milky Way was about 1.5 trillion times heavier than our Sun. However, new data suggests that it weighs equivalent to “only” 200 billion suns. The new value was calculated using Gaia recordings of 1.8 billion stars: the mass was determined from their motion patterns. Incidentally, the weight reduction only affects dark matter, where the visible mass should still be around 60 billion solar distances.

The study also confirms that stars observed at the edge of the galaxy move slower than those closer to the center Kepler’s third law. However, older observations indicated that the decrease in velocity in spiral galaxies – such as the Milky Way – does not follow this law.

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Two possible reasons are given for this deviation from previous observations. So it is possible that the high edge velocity in other galaxies is caused by collisions that have not occurred in the Milky Way for a long time. The second explanation is the different measurement method used in other galaxies. It is possible that old data on these conclusions is incorrect – or that calculations with the new Gaia data set are incorrect. Additional measurements and calculations will likely show whether this is the case or not.

source: Polish via Golem