Original Post from Inside Science
Signal hints at possible interactions between ordinary hydrogen and dark matter in the early universe, but some scientists remain skeptical.
(Inside Science) — After spending nearly two decades listening to the skies with radio telescopes, astronomers have finally detected a long-sought-after and subtle signal from the early universe. A group of scientists claim to have found a sign of radiation from the very first generation of stars, only about 180 million years after the Big Bang — just a blink of an eye to the cosmos.
“Other than the cosmic microwave background radiation, this is the earliest observation of any kind in the universe. Compare it to Hubble looking at the first galaxies at 400 million years old; we’re looking at a time roughly half that age,” said Judd Bowman, a cosmologist at Arizona State University in Tempe, Arizona and lead author of the research, published today in the journal Nature.
During an era known as the “cosmic dawn,” the first stars were forged from primordial hydrogen and helium gas. Their ultraviolet light reached free hydrogen gas in the surrounding regions, interacting with the atoms in a way that left a key signature in the radio spectrum from the afterglow of the Big Bang. Looking for signatures like this helps astronomers probe the early moments of the universe when it was first beginning to form its structure.
Artist’s rendering of how the first stars in the universe may have looked.
Image credits: N.R. Fuller, National Science Foundation
From Science News
When it comes to the dimensions of spacetime, what you see may be what you get.
Using observations from the collision of two neutron stars that made headlines in 2017 (SN: 11/11/17, p. 6), scientists found no evidence of gravity leaking into hidden dimensions. The number of observed large spatial dimensions — kilometer-scale or bigger — is still limited to the three we know and love, the researchers report January 24 at arXiv.org.
Just as insects floating on a pond may be unaware of what’s above or below the water’s surface, our 3-D world might be part of a higher-dimensional universe that we can’t directly observe. However, says astrophysicist David Spergel of Princeton University, a coauthor of the new study, “gravity might be able to explore those other dimensions.”
Such extra dimensions might explain some conundrums in physics, such as the existence of dark matter (an as-yet-unidentified source of mass in the universe) and dark energy (which causes the universe’s expansion rate to accelerate), says coauthor Daniel Holz, an astrophysicist at the University of Chicago. “That’s why people get excited about these modifications.”
To look for any hint of leaking gravity, scientists turned to the light and gravitational waves emitted in the neutron star smashup detected on August 17, 2017
From Space Academy
For many years, scientists have been very much baffled by a weird anomaly far away in space: a mysterious “Cold Spot” about 1.8 billion light-years across. It is cooler than its surroundings by around 0.00015 degrees Celsius (0.00027 degrees Fahrenheit), a fact astronomers discovered by measuring background radiation throughout the universe.
Previously, astronomers believed that this space could be cooler simply because it had less matter in it than most sections of space. They dubbed it a massive supervoid and estimated that it had 10,000 galaxies fewer than other comparable sections of space.
We’ll let Veritasium explain..