Cosmology Archives

December 7, 2022December 7, 2022 by Matt Williams

“Early Dark Energy” Could Explain the Crisis in Cosmology

A diagram of the evolution of the observable universe. The Dark Ages are the object of study in this new research, and were preceded by the CMB, or Afterglow Light Pattern. By NASA/WMAP Science Team - Original version: NASA; modified by Cherkash, Public Domain, https://commons.wikimedia.org/w/index.php?curid=11885244 — A diagram of the evolution of the observable universe. Credit: NASA/WMAP/Wikimedia

In 1916, Einstein finished his Theory of General Relativity, which describes how gravitational forces alter the curvature of spacetime. Among other things, this theory predicted that the Universe is expanding, which was confirmed by the observations of Edwin Hubble in 1929. Since then, astronomers have looked farther into space (and hence, back in time) to measure how fast the Universe is expanding – aka. the Hubble Constant. These measurements have become increasingly accurate thanks to the discovery of the Cosmic Microwave Background (CMB) and observatories like the Hubble Space Telescope.

Astronomers have traditionally done this in two ways: directly measuring it locally (using variable stars and supernovae) and indirectly based on redshift measurements of the CMB and cosmological models. Unfortunately, these two methods have produced different values over the past decade. As a result, astronomers have been looking for a possible solution to this problem, known as the “Hubble Tension.” According to a new paper by a team of astrophysicists, the existence of “Early Dark Energy” may be the solution cosmologists have been looking for.

December 1, 2022December 1, 2022 by Andy Tomaswick

Sometimes Astronomy isn’t About What you see, but What you don’t see

Constraints are critical in any scientific enterprise. If a hypothesis predicts that there should be an observable phenomenon, and there isn’t any trace of it, that’s a pretty clear indication that the hypothesis is wrong. And even false hypotheses still move science forward. So it is with astronomy and, in particular, explorations of the early universe. A paper authored by researchers at Cambridge and colleagues now puts a particularly useful constraint on the development of early galaxies, which has been a hot topic in astronomy as of late.

November 30, 2022November 30, 2022 by Alan Boyle

Scientists Send Quantum Data Through a Simulated Wormhole

Simulated data wormhole — The wormhole created by researchers exists purely as data. (Illustration credit: Inqnet / A. Mueller / Caltech)

For the first time, scientists have created a quantum computing experiment for studying the dynamics of wormholes — that is, shortcuts through spacetime that could get around relativity’s cosmic speed limits.

Wormholes are traditionally the stuff of science fiction, ranging from Jodie Foster’s wild ride in “Contact” to the time-bending plot twists in “Interstellar.” But the researchers behind the experiment, reported in the Dec. 1 issue of the journal Nature, hope that their work will help physicists study the phenomenon for real.

“We found a quantum system that exhibits key properties of a gravitational wormhole, yet is sufficiently small to implement on today’s quantum hardware,” Caltech physicist Maria Spiropulu said in a news release. Spiropulu, the Nature paper’s senior author, is the principal investigator for a federally funded research program known as Quantum Communication Channels for Fundamental Physics.

Don’t pack your bags for Alpha Centauri just yet: This wormhole simulation is nothing more than a simulation, analogous to a computer-generated black hole or supernova. And physicists still don’t see any conditions under which a traversable wormhole could actually be created. Someone would have to create negative energy first.

November 21, 2022December 10, 2022 by Matt Williams

Einstein's Predictions for Gravity Have Been Tested at the Largest Possible Scale

The first image taken by the James Webb Space Telescope, featuring the galaxy cluster SMACS 0723. Credit: NASA, ESA, CSA, and STScI

According to the Standard Model of Particle Physics, the Universe is governed by four fundamental forces: electromagnetism, the weak nuclear force, the strong nuclear force, and gravity. Whereas the first three are described by Quantum Mechanics, gravity is described by Einstein’s Theory of General Relativity. Surprisingly, gravity is the one that presents the biggest challenges to physicists. While the theory accurately describes how gravity works for planets, stars, galaxies, and clusters, it does not apply perfectly at all scales.

While General Relativity has been validated repeatedly over the past century (starting with the Eddington Eclipse Experiment in 1919), gaps still appear when scientists try to apply it at the quantum scale and to the Universe as a whole. According to a new study led by Simon Fraser University, an international team of researchers tested General Relativity on the largest of scales and concluded that it might need a tweak or two. This method could help scientists to resolve some of the biggest mysteries facing astrophysicists and cosmologists today.

November 20, 2022November 20, 2022 by Laurence Tognetti

Scroll Through the Universe with This Cool Interactive Map

Expansion of the Universe (Credit: NASA/WMAP Science Team)

Johns Hopkins University (JHU) continues to pad its space community résumé with their interactive map, “The map of the observable Universe”, that takes viewers on a 13.7-billion-year-old tour of the cosmos from the present to the moments after the Big Bang. While JHU is responsible for creating the site, additional contributions were made by NASA, the European Space Agency, the National Science Foundation, and the Sloan Foundation.

November 9, 2022November 2, 2022 by Paul M. Sutter

Chipping Away at the Great Attractor Mystery. Another Galaxy Cluster Found Behind the Milky Way’s Disk

At the very centre of the simulation (and our own Universe) is the Milky Way galaxy, and our nearest massive neighbour, the Andromeda galaxy (known as M31). Credit Dr Stuart McAlpine

Something huge lurks in the shadows of the Universe. Known as the Great Attractor, it is causing the Milky Way and all the surrounding galaxies to rush towards it. We would normally have a better understanding of this situation, except for the fact that the Great Attractor happens to lie in the direction behind the galactic bulge, which makes it difficult for us to observe. A team of astronomers have performed a new infrared survey of the region behind the bulge, and they have found yet another large galaxy cluster. Their work is helping to paint a more complete portrait of the environment of the Great Attractor.

October 20, 2022October 20, 2022 by Brian Koberlein

Astronomers Chart the Influence of Dark Matter and Dark Energy on the Universe by Measuring Over 1,500 Supernovae

Artist view of a supernova explosion. Credit: NASA

In 2011, the Nobel Prize in physics was awarded to Perlmutter, Schmidt, and Reiss for their discovery that the universe is not just expanding, it is accelerating. The work supported the idea of a universe filled with dark energy and dark matter, and it was based on observations of distant supernovae. Particularly, Type Ia supernovae, which have consistent light curves we can use as standard candles to measure cosmic distances. Now a new study of more than 1,500 supernovae confirms dark energy and dark matter, but also raises questions about our cosmological models.

October 6, 2022October 6, 2022 by Matt Williams

Astronomers see Tantalizing Evidence for one of the First Stars to Form in the Universe

Astronomers may have discovered the first signs of their ancient chemical remains in the clouds surrounding one of the most distant quasars ever detected. Credit: NOIRLab/NSF

According to the predominant cosmological model, the first stars in the Universe formed roughly 100,000 years after the Big Bang. Known as Population III stars, these early stellar masses were very large, short-lived, and contained virtually no metals or heavier elements. Over time, elements like carbon, nitrogen, oxygen, and iron formed in their interiors through nucleosynthesis. When these stars reached the end of their lifespans, they exploded in a supernova many times greater than anything we see today (a “super-supernova”), causing these elements to be dispersed throughout the cosmos.

For decades, astronomers have been attempting to find evidence of these earliest stars, yet all attempts to date have failed. But thanks to a recent study, a team led by the University of Tokyo thinks they may have finally spotted the first traces of one of the earliest stars in the Universe. While analyzing data previously obtained by the Gemini North telescope of the most distant quasar ever observed, the team noticed a massive cloud of material around it. Based on their analysis, they believe the material came from a first-generation star after it went “super-supernova.”

September 15, 2022September 15, 2022 by Matt Williams

A Galaxy With Ten Times the Mass of the Milky Way is Preparing to Become a Quasar

The massive, hyper-luminous galaxy W0410-0913 and its surroundings, seen 12 billion years back in time. Credit: M. Ginolfi & G. Jones / VLT / ESO.

One of the fundamental questions in astronomy is how galaxies formed over 13 billion years ago and have evolved ever since. A common feature that astronomers have noted is that most galaxies appear to have supermassive black holes (SMBHs) at their center – like Sagittarius A*, the ~4 million solar mass SMBH at the center of the Milky Way. These monster black holes occasionally swallow up nearby gas, dust, and stars and emit excess energy as powerful relativistic jets. This phenomenon, where the center of a galaxy outshines the stars in the disk, is known as an Active Galactic Nucleus (AGN) or quasar.

In a recent study, an international team of astronomers led by the European Southern Observatory (ESO) discovered a galaxy in the early Universe that could reveal more about this evolution. Using the Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, they observed a swarm of galaxies orbiting a very bright and vigorously star-forming galaxy in the early Universe. These observations provide fresh insight into how exceptionally bright galaxies grow and evolve into quasars and emit powerful jets of light across the observable Universe.

August 27, 2022August 27, 2022 by Matt Williams

A New Study Confirms That Gravity has Remained Constant for the Entire age of the Universe

For over a century, astronomers have known that the Universe has been expanding since the Big Bang. For the first eight billion years, the expansion rate was relatively consistent since it was held back by the force of gravitation. However, thanks to missions like the Hubble Space Telescope, astronomers have since learned that roughly five billion years ago, the rate of expansion has been accelerating. This led to the widely-accepted theory that a mysterious force is behind the expansion (known as Dark Energy), while some insist that the force of gravity may have changed over time.

This is a contentious hypothesis since it means that Einstein’s General Theory of Relativity (which has been validated nine ways from Sunday) is wrong. But according to a new study by the international Dark Energy Survey (DES) Collaboration, the nature of gravity has remained the same throughout the entire history of the Universe. These findings come shortly before two next-generation space telescopes (Nancy Grace Roman and Euclid) are sent to space to conduct even more precise measurements of gravity and its role in cosmic evolution.