This could change everything we know about the earliest history of the universe.
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Image by NASA |
Scientists at Nagoya University in Japan claim to have
discovered dark matter that dates back 12 billion years ago, which would make
it the earliest observation of the hypothetical substance to date.
Their findings — as detailed in a new paper published in the
journal Physical Review Letters — could potentially offer some tantalizing
answers about the nature of the universe.
Until now, observations of dark matter only went as far back
as ten billion years. Any further than that, and the light was too faint to
observe.
"Look at dark matter around distant galaxies? It was a
crazy idea," said study co-author and University of Tokyo cosmologist
Masami Ouchi, in a statement. "No one realized we could do this."
Dark matter is the mysterious stuff that makes up around 85
percent of the total mass of the universe. It's still one of the biggest
unsolved mysteries in modern physics as it is extremely difficult to detect.
Conventionally, scientists use gravitational lensing to look
across cosmically vast distances, taking advantage of the gravity of objects of
enormous mass, like a galaxy, distorting nearby light into a kind of natural
telescope.
Scientists can look through these "lens galaxies"
to see the light of even older galaxies behind them. And because dark matter
interacts with gravity, the more of it there is in those galaxies, the more
distortion — which is something that scientists can measure.
But since visible light is too faint past ten billion years
for current observatories to detect, the scientists turned to using the cosmic
microwave background (CMB), remnants of the the oldest observable light in the
Universe, to find answers.
The team used the data of 1.5 million lens galaxies in
visible light, and then used the European Space Agency's CMB-observing Planck
satellite to measure exactly how the dark matter in those galaxies distorted
the CMB.
By synthesizing that data, the scientists were able to put
together a picture of the distribution of dark matter just 1.7 billion years
after the Universe was formed. To put that into perspective, scientists believe
the universe is approximately 13.8 billion years old.
They found that the dark matter was significantly less
"clumpy" than predicted in the broadly accepted Lambda Cold Dark
Matter (Lambda-CDM) cosmological model, which posits that as the universe
cooled after the Big Bang, galaxies were formed within these dark matter
clumps, thanks to their gravitational pull.
The team admits a lot more work still needs to be done to
confirm their conclusions.
"Our finding is still uncertain," said Hiranao
Miyatake, the study's leader, in the statement. "But if it is true, it
would suggest that the entire model is flawed as you go further back in
time," adding that a revised new theory could "provide insight into
the nature of dark matter itself."
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