Cosmology Archives

March 25, 2022March 25, 2022 by Evan Gough

NASA’s Roman Mission Might Tell Us if the Universe Will Tear Itself Apart in the Future

The concept of accelerating expansion does get you wondering just how much it can accelerate. Theorists think there still might be a chance of a big crunch, a steady-as-she-goes expansion or a big rip. Or maybe just a little rip?

NASA’s Nancy Gracy Roman Space Telescope won’t launch until 2027, and it won’t start operating until some time after that. But that isn’t stopping excited scientists from dreaming about their new toy and all it will do. Who can blame them?

A new study examines the Roman Space Telescope’s power in detail to see if it can help us answer one of our most significant questions about the Universe. The question?

Will the Universe keep expanding and tear itself apart in a Big Rip?

February 23, 2022February 23, 2022 by Matt Williams

A Detailed Simulation of the Universe Creates Structures Very Similar to the Milky Way and its Surroundings

Simulation of dark matter and gas. Credit: Illustris Collaboration (CC BY-SA 4.0)

In their pursuit of understanding cosmic evolution, scientists rely on a two-pronged approach. Using advanced instruments, astronomical surveys attempt to look farther and farther into space (and back in time) to study the earliest periods of the Universe. At the same time, scientists create simulations that attempt to model how the Universe has evolved based on our understanding of physics. When the two match, astrophysicists and cosmologists know they are on the right track!

In recent years, increasingly-detailed simulations have been made using increasingly sophisticated supercomputers, which have yielded increasingly accurate results. Recently, an international team of researchers led by the University of Helsinki conducted the most accurate simulations to date. Known as SIBELIUS-DARK, these simulations accurately predicted the evolution of our corner of the cosmos from the Big Bang to the present day.

January 14, 2022January 14, 2022 by Evan Gough

Nancy Grace Roman Telescope Will do its Own, Wide-Angle Version of the Hubble Deep Field

This synthetic image visualizes what a Roman ultra-deep field could look like. The 18 squares at the top of this image outline the area Roman can see in a single observation, known as its footprint. The inset at the lower-right zooms into one of the squares of Roman's footprint, and the inset at the lower-left zooms in even further. The image, which contains more than 10 million galaxies, was constructed from a simulation that produced a realistic distribution of the galaxies in the universe. Image Credit: Nicole Drakos, Bruno Villasenor, Brant Robertson, Ryan Hausen, Mark Dickinson, Henry Ferguson, Steven Furlanetto, Jenny Greene, Piero Madau, Alice Shapley, Daniel Stark, Risa Wechsler

Remember the Hubble Space Telescope’s Deep Field and Ultra-Deep Field images?

Those images showed everyone that what appears to be a tiny, empty part of the sky contains thousands of galaxies, some dating back to the Universe’s early days. Each of those galaxies can have hundreds of billions of stars. These early galaxies formed only a few hundred million years after the Big Bang. The images inspired awe in the human minds that took the time to understand them. And they’re part of history now.

The upcoming Nancy Grace Roman Space Telescope (NGRST) will capture its own version of those historical images but in wide-angle. To whet our appetites for the NGRST’s image, a group of astrophysicists have created a simulation to show us what it’ll look like.

November 16, 2021November 16, 2021 by Matt Williams

A new Simulation of the Universe Contains 60 Trillion Particles, the Most Ever

Illustris simulation, showing the distribution of dark matter in 350 million by 300,000 light years. Galaxies are shown as high-density white dots (left) and as normal, baryonic matter (right). Credit: Markus Haider/Illustris

Today, the greatest mysteries facing astronomers and cosmologists are the roles gravitational attraction and cosmic expansion play in the evolution of the Universe. To resolve these mysteries, astronomers and cosmologists are taking a two-pronged approach. These consist of directly observing the cosmos to observe these forces at work while attempting to find theoretical resolutions for observed behaviors – such as Dark Matter and Dark Energy.

In between these two approaches, scientists model cosmic evolution with computer simulations to see if observations align with theoretical predictions. The latest of which is AbacusSummit, a simulation suite created by the Flatiron Institute’s Center for Computational Astrophysics (CCA) and the Harvard-Smithsonian Center for Astrophysics (CfA). Capable of processing nearly 60 trillion particles, this suite is the largest cosmological simulation ever produced.

November 12, 2021November 12, 2021 by Brian Koberlein

Understanding the Early Universe Depends on Estimating the Lifespan of Neutrons

How NASA's Lunar Prospector could study neutron decay. Credit: Johns Hopkins APL/Ben Smith

When we look into the night sky, we see the universe as it once was. We know that in the past the universe was once warmer and denser than it is now. When we look deep enough into the sky, we see the microwave remnant of the big bang known as the cosmic microwave background. That marks the limit of what we can see. It marks the extent of the observable universe from our vantage point.

November 2, 2021November 2, 2021 by Matt Williams

Is the Universe Fine-Tuned for Life?

For decades, various physicists have theorized that even the slightest changes in the fundamental laws of nature would make it impossible for life to exist. This idea, also known as the “Fine-Tuned Universe” argument, suggests that the occurrence of life in the Universe is very sensitive to the values of certain fundamental physics. Alter any of these values (as the logic goes), and life would not exist, meaning we must be very fortunate to be here!

But can this really be the case, or is it possible that life can emerge under different physical constants, and we just don’t know it? This question was recently tackled by Luke A. Barnes, a postdoctoral researcher at the Sidney Institute for Astronomy (SIA) in Australia. In his recent book, A Fortunate Universe: Life in a Finely Tuned Cosmos, he and Sydney astrophysics professor Geraint F. Lewis argued that a fine-tuned Universe makes sense from a physics standpoint.

October 23, 2021October 27, 2021 by Brian Koberlein

Primordial Gravitational Waves Continue to Elude Astronomers

The BICEP telescope in Antarctica during twilight. Credit: Steffen Richter, Harvard University

The standard model of cosmology is a remarkably powerful and accurate description of the universe, tracing its evolution from the big bang to its current state, but it is not without mysteries. One of the biggest unsolved questions of the standard model is known as early cosmic inflation.

October 20, 2021October 21, 2021 by Matt Williams

There are 6×10^80 Bits of Information in the Observable Universe

Since the beginning of the Digital Age (ca. the 1970s), theoretical physicists have speculated about the possible connection between information and the physical Universe. Considering that all matter is made up of information that describes the state of a quantum system (aka. quantum information), and genetic information is coded in our DNA, it’s not farfetched at all to think that physical reality can be expressed in terms of data.

This has led to many thought experiments and paradoxes, where researchers have attempted to estimate the information capacity of the cosmos. In a recent study, Dr. Melvin M. Vopson – a Mathematician and Senior Lecturer at Portsmouth University – offered new estimates of how much information is encoded in all the baryonic matter (aka. ordinary or “luminous” matter) in the Universe.

September 14, 2021September 15, 2021 by Matt Williams

Cosmic Dawn Holds the Answers to Many of Astronomy’s Greatest Questions

A billion years after the big bang, hydrogen atoms were mysteriously torn apart into a soup of ions. Credit: NASA/ESA/A. Felid (STScI)).

Thanks to the most advanced telescopes, astronomers today can see what objects looked like 13 billion years ago, roughly 800 million years after the Big Bang. Unfortunately, they are still unable to pierce the veil of the cosmic Dark Ages, a period that lasted from 370,000 to 1 billion years after the Big Bang, where the Universe was shrowded with light-obscuring neutral hydrogen. Because of this, our telescopes cannot see when the first stars and galaxies formed – ca., 100 to 500 million years after the Big Bang.

This period is known as the Cosmic Dawn and represents the “final frontier” of cosmological surveys to astronomers. This November, NASA’s next-generation James Webb Space Telescope (JWST) will finally launch to space. Thanks to its sensitivity and advanced infrared optics, Webb will be the first observatory capable of witnessing the birth of galaxies. According to a new study from the Université de Genève, Switzerland, the ability to see the Cosmic Dawn will provide answers to today’s greatest cosmological mysteries.

August 25, 2021August 27, 2021 by Matt Williams

This is How a Supermassive Black Hole Feeds

Artist's impression of a quasar and a relativistic jet emanating from the center. Credit: NASA

At the heart of most massive galaxies in our Universe, there are supermassive black holes (SMBH) on the order of millions to billions of times the mass of the Sun. As these behemoths consume gas and dust that’s slowly fed into their maws, they release tremendous amounts of energy. This leads to what is known as an Active Galactic Nucleus (AGN) – aka. a quasar – which can sometimes send hypervelocity jets of material for light-years.

Since they were first discovered, astrophysicists have suspected that SMBHs play an important role in the formation and evolution of galaxies. However, as a result, there has also been considerable research dedicated to how these massive objects form and evolve themselves. Recently, a team of astrophysicists conducted a high-powered simulation that showed exactly how SMBHs feed and determined that a galaxy’s arms play a vital role.