Cosmology Archives

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

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

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.

August 23, 2022August 23, 2022 by Brian Koberlein

The Latest Webb Observations Don’t Disprove The Big Bang, But They Are Interesting

Diagram showing the Lambda-CBR universe, from the Big Bang to the the current era. Credit: Alex Mittelmann/Coldcreation

Okay, so let’s start with the obvious. The big bang is not dead. Recent observations by the James Webb Space Telescope have not disproven the big bang, despite certain popular articles claiming otherwise. If that’s all you needed to hear, then have a great day. That said, the latest Webb observations do reveal some strange and unexpected things about the universe, and if you’d like to know more, keep reading.

August 11, 2022August 11, 2022 by Brian Koberlein

Even a Cyclical Universe Needed to Come From Somewhere

*Could our Universe be part of a wider Multiverse? And could these other Universes support life? Credit: Jaime Salcido/EAGLE Collaboration*

In the beginning…

The first words of the book of Genesis make a declarative statement. God created Heaven and Earth, and thus begins the cosmic story. While not all creation myths have an act of beginning, most do. Humans are storytellers, and we like stories with a beginning. This origin need is deep within us and is even part of our scientific worldview. As is so often said in science, effects have causes. This cause and effect process is a powerful tool for understanding the world around us, but it’s not without its problems, particularly with the origin of the universe.

July 29, 2022July 30, 2022 by Matt Williams

The James Webb is Measuring Distant Galaxies 5-10 Times Better Than any Other Telescope

Artist conception of the James Webb Space Telescope. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez

On December 25th, 2021, after many years of waiting, the James Webb Space Telescope (JWST) finally launched to space. In the sixth-month period that followed, this next-generation observatory unfurled its Sunshield, deployed its primary and secondary mirrors, aligned its mirror segments, and flew to its current position at the Earth-Sun Lagrange 2 (L2) Point. On July 12th, 2022, the first images were released and presented the most-detailed views of the Universe. Shortly thereafter, NASA released an image of the most distant galaxy ever observed (which existed just 300 million years after the Big Bang).

According to a new study by an international team of scientists, the JWST will allow astronomers to obtain accurate mass measurements of early galaxies. Using data from James Webb’s Near-Infrared Camera (NIRCam), which was provided through the GLASS-JWST-Early Release Science (GLASS-ERT) program, the team obtained mass estimates from some of the distant galaxies that were many times more accurate than previous measurements. Their findings illustrate how Webb will revolutionize our understanding of how the earliest galaxies in the Universe grew and evolved.

July 23, 2022July 23, 2022 by Brian Koberlein

Gamma-ray Bursts can Help Astronomers Measure Vast Distances Across the Universe

An illustration of a powerful gamma ray burst. Credit: NAOJ

Now that the James Webb Space Telescope is operational, astronomers can study some of the most faint and distant galaxies ever seen. By some accounts, we may have already captured the image of a galaxy from when the universe was just 300 million years old. But we can’t be entirely sure of its distance, and that is a big problem for astronomers.

July 21, 2022July 22, 2022 by Carolyn Collins Petersen

JWST Sees the Most Distant Galaxy Ever, Just 300 Million Years After the Big Bang

By now, almost everyone has seen the first-release images from JWST and marveled at these amazing views of the infrared universe the telescope was launched to explore. The view of SMACS 0723 seen above illustrates the promise JWST holds. While there are many more early-release images in the observation pipeline, we’re starting to see the first research papers come out. As expected, studies of distant galaxies are grabbing headlines already.

Wow, are these findings amazing! In the last couple of days, websites and social media have been alive with images of a blob that, in reality, is one of the oldest (earliest) galaxies ever seen. It’s one of two—GL-z11 and GL-z13—that show us what they looked like when the Universe was extremely young, about 300 million years after the Big Bang. When confirmed, they’ll mark a milestone in studies of the infant Universe.

June 23, 2022June 23, 2022 by Evan Gough

Plenty of Examples That Giant Galaxies Like the Milky Way Formed Through Mergers

The Universe’s giant galaxies pose a thorny problem for astronomers. The galaxies have grown large somehow, and the only things that can make a galaxy giant are probably other galaxies. So mergers must have played an important role.

Astronomers have known about galaxy mergers for a long time, but the process is still mysterious. A new study based on ten years of work presents observations and direct measurements of the galaxy merger process that remove some of the mystery.

June 7, 2022June 7, 2022 by Laurence Tognetti

These Galaxies are Definitely Living in a Simulation

Studying the universe is hard. Really hard. Like insanely, ridiculously hard. Think of the hardest thing you’ve ever done in your life, because studying the universe is quite literally exponentially way harder than whatever you came up with. Studying the universe is hard for two reasons: space and time. When we look at an object in the night sky, we’re looking back in time, as it has taken a finite amount of time for the light from that object to reach your eyes. The star Sirius is one of the brightest objects in the night sky and is located approximately 8.6 light-years from Earth. This means that when you look at it, you’re seeing what it looked like 8.6 years ago, as the speed of light is finite at 186,000 miles per second and a light year is the time it takes for light to travel in one year. Now think of something way farther away than Sirius, like the Big Bang, which supposedly took place 13.8 billion years ago. This means when scientists study the Big Bang, they’re attempting to look back in time 13.8 billion years. Even with all our advanced scientific instruments, it’s extremely hard to look back that far in time. It’s so hard that the Hubble Space Telescope has been in space since 1990 and just recently spotted the most distant single star ever detected in outer space at 12.9 billion light-years away. That’s 30 years of scanning the heavens, which is a testament to the vastness of the universe, and hence why studying the universe is hard. Because studying the universe is so hard, scientists often turn to computer simulations, or models, to help speed up the science aspect and ultimately give us a better understanding of how the universe works without waiting 30 years for the next big discovery.