There's a lot we can learn by looking at all those voids making space between galaxies - and now, for the first time, astronomers have used a new method to peer inside these mysterious pockets of nothingness. Voids in space are due to the expansion of the Universe - this results in a web of material with spaces in between the filaments.
Think of pulling apart a
grilled cheese sandwich, if the cheese were made of strings of galaxies. Cosmic
voids can be detected in something called the cosmic microwave background
(CMB), a remnant of electromagnetic radiation left behind by the Epoch of
Recombination around 380,000 years after the Big Bang.
The CMB represents the first
light appearing in the Universe, and in it, cosmic voids seem to correlate with
temperature. Hotter regions are associated with the filaments, and the colder
regions associated with the voids.
Now, for the first time,
researchers have used this CMB map to study the cosmic voids. Led by David
Alonso of Oxford University in the UK, a team of researchers has mapped 774
cosmic voids to the CMB to study the properties of the gas that floats therein.
They used data from
something called the Baryon Oscillation Spectroscopic Survey (BOSS), which
surveyed sound waves that rippled through the early universe like ripples
through a pond, and can still be detected throughout the Universe as regular
fluctuations in the normal matter.
It also revealed the
locations of cosmic voids throughout the Universe, and it was this data that
the team stacked against the CMB. They then compared the energy of the CMB
photons in each void to its modelled electron pressure to deduce the properties
of the gas.
They found that the pressure
inside voids is lower than the cosmic average, which isn't an unexpected
result. There's not a lot of material in voids, and not a lot happening. But
they found something else, too - clues that the gas might be warmer than they
expect it to be.
"If this finding holds
up to scrutiny," Christopher Crocket explained in an article for the
American Physical Society, "it could be a sign that powerful jets from
supermassive black holes are pumping energy into the intergalactic gas and helping
to shape the cosmos."
That would be pretty huge
news - after all, we've only just discovered that winds from supermassive black
holes could be shaping entire galaxies, never mind cosmic voids, which can span
billions of light-years.
We may be waiting for some
time to find out, though. A more in-depth survey, possibly from a more powerful
telescope than the ones currently available, will likely be required to verify
if the data is showing what it seems to be showing. The team's research has
been published in Physical Review D.
Via Sciencealert