незачем мечтать о межгалактических путешествиях - наши лучшие половины явились оттуда
половина наших тел состоит из атомов, занесённых из других галактик!
Half the atoms inside your body came from across the universe
- Large galaxies like our Milky Way amassed half their matter from neighboring star clusters
- up to a million light years away, according to a new simulation.
- “We did not realise how much of the mass in today’s Milky Way-like galaxies was actually ‘stolen’ from the winds of other galaxies”
- says corresponding author Claude-André Faucher-Giguère at Northwestern University in Illinois
The matter theft occurs after a star death
- When some stars reach the end of their life cycle,
- they become massive supernovae, spewing high-speed gas out into the universe
- The matter in these ejections is picked up by galactic winds,
- streams of charged particles powered by the exploding supernovae
It was previously thought that galactic winds couldn’t be the source of much intergalactic matter transfer
- because they weren’t powerful enough to cross the vast distances that separate neighbouring galaxies
- Turns out, they’re stronger than we thought.
- “We assumed that the winds were confined to the galaxies they came from
- that they could recycle by falling back onto the galaxy that ejected them
- but not transfer much mass from one galaxy to another,” says Faucher-Giguère.
- Over a galaxy’s lifetime, it will swap matter continuously with its neighbours and
- the journey between one galaxy and another could take anywhere from several hundred million to 2 billion years, he says.
Across the universe
- Using 3D models of galaxy evolution, authors simulated the path matter inside galaxies would have taken through the universe
- from the big bang through to today
- More accurate simulations of supernovae revealed that the galactic winds were moving matter faster than previously thought.
- They found that in galaxies with 100 billion stars or more, the galactic winds actually ferried in about 50% of the matter present today.
- Galactic winds as a mode of transfer has been underappreciated
- it was found that for larger galaxies like our own, this intergalactic Gulf Stream is the primary contributor to their growth
- allowing them to snatch away matter from their smaller counterparts.
The intergalactic transfer of matter is less crucial for the growth of smaller galaxies
- which rely more on local galactic winds to keep any matter that might be ejected from supernovae within their system
- the Milky Way receives its matter from the nearby small and large Magellanic clouds
- two dwarf galaxies between 160,000 and 200,000 light years away
Tracking the flow of matter from the origin of the universe to present day
- and understanding where the atoms that make up the air we breathe and water we drink
- is one of the fundamental problems in astrophysics
- It’s one of the holy grails of extra galactic cosmology
- Now, we’ve found that half these atoms come from outside our galaxy
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Authors: Faucher-Giguère and his co-author Daniel Anglés-Alcázar
Reported by Aylin Woodward
Journal reference: Monthly Notices of the Royal Astronomical Society, DOI: 10.1093/mnras/stx1517
https://www.newscientist.com/article/2141950
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The original posting was made at http://hojja-nusreddin.dreamwidth.org/4008303.html