Cosmology Archives

December 12, 2024December 12, 2024 by Mark Thompson

Another Clue About the Ultra-High Energy Cosmic Rays: Magnetic Turbulence

Artist's illustration of ultra-high energy cosmic rays

Space largely seems quite empty! Yet even in the dark voids of the cosmos, ultra-high-energy cosmic rays are streaming through space. The rays contain 10 million times as much energy as the Large Hadron Collider can produce! The origin of the rays though is still the source of many a scientific debate but they are thought to be coming from some of the most energetic events in the universe. A new paper suggests the rays may be linked to magnetic turbulence, coming from regions where magnetic fields get tangled and twisted up.

December 9, 2024December 9, 2024 by Mark Thompson

Has the Universe Been Designed to Support Life? Now We Have a Way to Test it!

NASA's Hubble Space Telescope provided one of the deepest, most detailed visible views of the universe. The field is a very small sample of the heavens and it is observations like this that raise questions like those posed by the anthropic principle. Credit: R. Williams (STScI), the Hubble Deep Field Team and NASA/ESA

The anthropic principle states that the fundamental parameters of the Universe such as the strength of the fundamental forces, have been finely tuned to support life. Whether this is true or not or whether it is even worthy of scientific investigation has been hotly debated. A new paper proposes some ways that this may now be tested and perhaps brings the topic under scientific scrutiny for the first time.

December 9, 2024December 9, 2024 by Evan Gough

Webb Sees a Supercluster of Galaxies Coming Together

Using the NASA/ESA/CSA James Webb Space Telescope, an international team of astronomers have found new galaxies in the Spiderweb protocluster. Because Webb can see infrared light very well, scientists used it to observe regions of the Spiderweb that were previously hidden to us by cosmic dust, and to find out to what degree this dust obscures them. This image shows the Spiderweb protocluster as seen by Webb’s NIRCam (Near-InfraRed Camera). Image Credit: ESA/Webb, NASA & CSA, H. Dannerbauer

As a species, we’ve come to the awareness that we’re a minuscule part of a vast Universe defined by galaxy superclusters and the large-scale structure of the Universe. Driven by a healthy intellectual curiosity, we’re examining our surroundings and facing the question posed by Nature: how did everything get this way?

We only have incremental answers to that huge, almost infinitely-faceted question. And the incremental answers are unearthed by our better instruments, including space telescopes, which get better and more capable as time passes.

Enter the James Webb Space Telescope.

December 8, 2024December 8, 2024 by Brian Koberlein

Observations by DESI Open the Door to Modified Gravity Models

The relations between various approaches of modified gravity. Credit: J. M. Ezquiaga and M. Zumalacárregui (2018)

The standard theory of cosmology is based upon four things: the structure of space and time, matter, dark matter, and dark energy. Of these, dark energy is the one we currently understand the least. Within the standard model, dark energy is part of the structure of space and time as described by general relativity. It is uniform throughout the cosmos and expressed as a parameter known as the cosmological constant. But initial observations from the Dark Energy Spectroscopic Instrument (DESI) suggest the rate of comic expansion may vary over time. If further observations reinforce this, it could open up cosmological models to alternatives to general relativity known as modified gravity.

December 5, 2024December 5, 2024 by Brian Koberlein

Cosmology is at a Crossroads, But New Instruments are Coming to Help

Illustration of the accelerating expansion of the universe. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab

Our understanding of the Universe is profound. Only a century ago, astronomers held a Great Debate to argue over whether our galaxy was an island universe, or whether nebulae such as Andromeda were galaxies in a much larger cosmos. Now we know that the Universe is billions of years old, ever expanding to billions of light-years across, and filled with not just stars and galaxies but with dark energy and cold dark matter. Astronomers summarize this understanding as the LCDM model, which is the standard model of cosmology. While the observational data we have strongly supports this model, it is not without its challenges.

December 3, 2024December 3, 2024 by Evan Gough

Could Primordial Black Holes Be Hiding in Plain Sight?

An artistic take on primordial black holes. Credit: NASA’s Goddard Space Flight Center

Are Primordial Black Holes real? They could’ve formed in the unusual physics that dominated the Universe shortly after the Big Bang. The idea dates back to the 1960s, but so far, the lack of evidence makes them purely hypothetical.

If they do exist, a new paper suggests they may be hiding in places so unlikely that nobody ever thought to look there.

November 29, 2024November 29, 2024 by Evan Gough

A Superfast Supercomputer Creates the Biggest Simulation of the Universe Yet

These images are a small sample from the Frontier supercomputer simulations. They reveal the evolution of the expanding universe in a region containing a massive cluster of galaxies from billions of years ago to present day (left). Red areas show hotter gasses, where temperatures reach 100 million Kelvin or more. The panel on the right is a zoom-in, where star tracer particles track the formation of galaxies and their movement over time. Credit: Argonne National Laboratory, U.S Dept of Energy

Scientists at the Department of Energy’s Argonne National Laboratory have created the largest astrophysical simulation of the Universe ever. They used what was until recently the world’s most powerful supercomputer to simulate the Universe at an unprecedented scale. The simulation’s size corresponds to the largest surveys conducted by powerful telescopes and observatories.

November 25, 2024November 25, 2024 by Brian Koberlein

Einstein Predicted How Gravity Should Work at the Largest Scales. And He Was Right

The sparkling band of the Milky Way Galaxy backdrops the Nicholas U. Mayall 4-meter Telescope, located at Kitt Peak National Observatory. Credit: KPNO/NOIRLab/NSF/AURA/R.T. Sparks

When Albert Einstein introduced his theory of general relativity in 1915, it changed the way we viewed the Universe. His gravitational model showed how Newtonian gravity, which had dominated astronomy and physics for more than three centuries, was merely an approximation of a more subtle and elegant model. Einstein showed us that gravity is not a mere force but is rather the foundation of cosmic structure. Gravity, Einstein said, defined the structure of space and time itself.

November 21, 2024November 14, 2024 by Paul M. Sutter

Here’s How to Weigh Gigantic Filaments of Dark Matter

Artist concept of how a galaxy might accrete mass from rapid, narrow streams of cold gas. These filaments provide the galaxy with continuous flows of raw material to feed its star-forming at a rather leisurely pace. Credit: ESA–AOES Medialab

How do you weigh one of the largest objects in the entire universe? Very carefully, according to new research.

November 17, 2024November 17, 2024 by Mark Thompson

James Webb Confirms Hubble’s Calculation of Hubble’s Constant

Artist impression of the James Webb Space Telescope

We have been spoiled over recent years with first the Hubble Space Telescope (HST) and then the James Webb Space Telescope (JWST.) Both have opened our eyes on the Universe and made amazing discoveries. One subject that has received attention from both is the derivation of the Hubble Constant – a constant relating the velocity of remote galaxies and their distances. A recent paper announces that JWST has just validated the results of previous studies by the Hubble Space Telescope to accurately measure its value.