Astronomers using the Hubble Space Telescope have mapped a huge halo of gas around the Andromeda Galaxy – the largest galaxy closest to our Milky Way galaxy.
The map – the most detailed of its kind – shows that the halo of plasma (electrically charged gas) around this spiral galaxy extends approximately 1.3 million light-years (and about 2 million) light years in some directions towards the galaxy.
The halo is invisible, but researchers say that if it could be seen, it would be three times the width of the ‘plow’, making it the largest feature of the night sky.
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“It’s important to understand the vast accumulation of gas around the galaxy,” said Samantha Barrack, a team member at Yale University in Connecticut, USA.
“This reservoir of gas is the fuel for future star formation inside the galaxy, as well as the flow of events such as supernovae. It is full of links to the galaxy’s past and future evolution, and we have finally been able to study it in detail in our immediate galactic neighborhood. “
The team found that Andromeda’s halo is made up of two different layers. The inner ‘shell’ has a more complex structure than the outer shell, which is probably. The galaxy disk is the result of a supernova. These violent explosions – the death throws of giant stars – also caused heavy elements in space, which were found in large quantities in the halo.
The halo was mapped by studying ultraviolet light from 43 distant quarters – an extremely bright galactic core powered by a black hole – located behind the halo.
Researchers using Hubble’s ‘Cosmic Origins Spectrograph’ to analyze how this background light is absorbed by halo gases in different regions show variations in the composition of the gas.
Andromeda is thought to be similar in size and shape to our galaxy, so these findings also offer insights into our own galactic halo, which is very difficult to map from within the galaxy.
Reader Q&A: If the universe is expanding, why would the Andromeda Galaxy collide with the galaxy?
Asked by: Bezari Total, Taumarmuni, New Zealand
The expansion of the universe is a massive phenomenon: in general, the farther away the galaxy is, the faster it returns from us. But in smaller regions of space, this expansion is negligible compared to the motion of individual galaxies.
The constellations of Andromeda and the Milky Way galaxy are large enough to create gravitational forces that control normal expansion and pull them together. But don’t worry, the collision won’t happen for another four billion years.
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