cosmology

A Universe Aglow - MUSE spectrograph reveals that nearly the entire sky in the early Universe is glowing with Lyman-alpha emission

A Universe Aglow - MUSE spectrograph reveals that nearly the entire sky in the early Universe is glowing with Lyman-alpha emission

Deep observations made with the MUSE spectrograph on ESO’s Very Large Telescope have uncovered vast cosmic reservoirs of atomic hydrogen surrounding distant galaxies. The exquisite sensitivity of MUSE allowed for direct observations of dim clouds of hydrogen glowing with Lyman-alpha emission in the early Universe — revealing that almost the whole night sky is invisibly aglow.

Dance of galaxies challenges current thinking on cosmology

Dance of galaxies challenges current thinking on cosmology

Scientists have a pretty good picture of how the universe formed and evolved – and how it is structured today. This knowledge all fits together nicely as a “standard cosmological model”, which has been able to successfully predict and describe many observational data in the universe. But now and then scientists discover something that threatens to tear down this valuable framework.

How crashing neutron stars killed off some of our best ideas about what ‘dark energy’ is

How crashing neutron stars killed off some of our best ideas about what ‘dark energy’ is

There was much excitement when scientists witnessed the violent collision of two ultra-dense, massive stars more than 100m light years from the Earth earlier this year. Not only did they catch the resulting gravitational waves – ripples in the fabric of spacetime – they also saw a practically instantaneous flash of light. This is exciting in itself and was the first direct evidence for a merger of neutron stars.

Dark matter: The mystery substance physics still can’t identify that makes up the majority of our universe

Dark matter: The mystery substance physics still can’t identify that makes up the majority of our universe

The past few decades have ushered in an amazing era in the science of cosmology. A diverse array of high-precision measurements has allowed us to reconstruct our universe’s history in remarkable detail.

Could cold spot in the sky be a bruise from a collision with a parallel universe?

Could cold spot in the sky be a bruise from a collision with a parallel universe?

Scientists have long tried to explain the origin of a mysterious, large and anomalously cold region of the sky. In 2015, they came close to figuring it out as a study showed it to be a “supervoid” in which the density of galaxies is much lower than it is in the rest of the universe. However, other studies haven’t managed to replicate the result.

Relax, the expansion of the universe is still accelerating

Relax, the expansion of the universe is still accelerating

There’s been a whirlwind of commentary of late speculating that the acceleration of the expanding universe might not be real after all. It follows the publication this month of a new look at supernovae in our universe, which the researchers say give only a “marginal detection” of the acceleration of the universe.

Turns Out There Is No Actual Looking Up

Turns Out There Is No Actual Looking Up

Direction is something we humans are pretty accustomed to. Living in our friendly terrestrial environment, we are used to seeing things in term of up and down, left and right, forwards or backwards. And to us, our frame of reference is fixed and doesn’t change, unless we move or are in the process of moving. But when it comes to cosmology, things get a little more complicated.

Dark matter: hot or not

Dark matter: hot or not

For almost a century, astronomers and cosmologists have postulated that space is filled with an invisible mass known as “dark matter”. Accounting for 27% of the mass and energy in the observable universe, the existence of this matter was intended to explain all the “missing” baryonic matter in cosmological models. Unfortunately, the concept of dark matter has solved one cosmological problem, only to create another.

Hubble finds Universe may be expanding faster than expected

Hubble finds Universe may be expanding faster than expected

Astronomers have used Hubble to measure the distances to stars in nineteen galaxies more accurately than previously possible. They found that the Universe is currently expanding faster than the rate derived from measurements of the Universe shortly after the Big Bang. If confirmed, this apparent inconsistency may be an important clue to understanding three of the Universe’s most elusive components: dark matter, dark energy and neutrinos.