A close-up view of a simulated Milky
Way galaxy, generated from the birth of the universe all the way to the
present.
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A powerful new computer simulation has
provided the clearest-ever picture of how our galactic home, the Milky
Way, came to exist.
The Milky Way is a truly monstrous collection of more than 100 billion stars that stretches more than 100,000 light-years wide.
However, we have company in the form of small neighbors called dwarf
galaxies, which orbit our much-larger spiral galaxy. Some are choking with dark matter — a so-far unexplained gravitational anomaly
that pervades galaxies. Others have been ripped apart into a diffuse
“graveyard” of stars for lurking too close to our spiral galaxy.
Though tiny in relation to the Milky Way (some are comprised of just a
few thousand stars), these dwarf galaxies have vexed astronomers to no
end: Not even the most advanced computer simulations could explain how
they got there.
But in a new study
published in Astrophysical Journal Letters on August 12, a group of
researchers at Caltech say they’ve finally reconciled the existence of
our tiny galactic neighbors.
“[O]ur model simulates a galaxy as similar to the Milky Way as we
can, starting from cosmological initial conditions just after the Big
Bang,” study leader Andrew Wetzel told Business Insider in an email.
Wetzel says the simulation below is not an exact match, in terms of
our galaxy’s spiral arms — it’s a sort of simulated pseudo-Milky Way —
but is possibly the “closest yet” for matching the Milky Way.
It shows what our galaxy might look like from an unfathomable distance of about 300,000 light-years away:
A view of Caltech’s simulated Milky
Way galaxy from 300,000 light-years away.
Hopkins Research Group/Caltech |
Wetzel says of the image above:
The trick to making this highly accurate simulation, Wetzel explained in a Caltech press release, was more detailed modeling of exploding stars called supernovas.
Each cataclysmic explosion spews out powerful winds, which he said can have “dramatic effects” on star-forming gas and dust where dwarf galaxies eventually form.
According to the release:
Once those blasts were properly accounted for, their simulated Big Bang — the birth of the universe — smoothly led to the formation of a Milky Way and its colorful neighborhood of dwarf galaxies.
It also let them create pretty amazing fly-through videos of the simulated Milky Way:
“You can see the Milky Way-like disk in
the center, but also, around it are both the low-mass (dwarf) galaxies,
and the ‘diffuse’ (almost circular) distribution of stars that we call
the ‘stellar halo’. It is the graveyard of dwarf galaxies that have been
destroyed by orbiting too close to the Milky Way. This stellar
distribution is quite diffuse (low density), so it appears really really
faint, but … this is how we think the Milky Way would look from afar if
you could produce a really really deep image of everything around it.”
Each cataclysmic explosion spews out powerful winds, which he said can have “dramatic effects” on star-forming gas and dust where dwarf galaxies eventually form.
According to the release:
“These winds, which reach speeds up to
thousands of kilometers per second, ‘can blow gas and stars out of a
small galaxy,’ says Wetzel. Indeed, the new simulation showed the winds
can blow apart young dwarf galaxies, preventing them from reaching
maturity.”
It also let them create pretty amazing fly-through videos of the simulated Milky Way:
According to the release, the research
team plans to spend another “20 million CPU hours” to predict where
faint, as-yet-undiscovered dwarf galaxies may be lurking.
Wetzel says if you’re looking for the most accurate map of the Milky Way, researchers have previously used Spitzer Space Telescope data to make one.
See if you can find home below:
Wetzel says if you’re looking for the most accurate map of the Milky Way, researchers have previously used Spitzer Space Telescope data to make one.
See if you can find home below:
The most accurate Milky Way galaxy
illustration, showing all of the known spiral arms and star clusters.
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