Cosmology Archives

December 5, 2022December 5, 2022 by Scott Alan Johnston

Construction Begins on the Square Kilometer Array

Artist's Impression of SKA-Low. credit: SKAO/DISR

At twin ground-breaking ceremonies today in South Africa and Australia, project leaders formally marked the start of construction on what will be the largest radio telescope ever built. Dubbed the Square Kilometer Array Observatory (SKAO) – referring to the total area the antennas and dishes will cover when complete – the telescope is not a single detector but rather a collection of them, connected across two continents using a technique known as interferometry (the same technique used by the Event Horizon Telescope, which took the first ever photograph of a black hole in 2019).

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.

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November 7, 2022November 7, 2022 by Brian Koberlein

Can JWST see Galaxies Made of Primordial Stars?

The distance of first generation stars. Credit: STScI

All stars are composed of mostly hydrogen and helium, but most stars also have measurable amounts of heavier elements, which astronomers lump into the category of “metals.” Our Sun has more metals than most stars because the nebula from which it formed was the remnant debris of earlier stars. These were in turn children of even earlier stars, and so on. Generally, each new generation of stars has a bit more metal than the last. The very first stars, those born from the primordial hydrogen and helium of the cosmos, had almost no metal in them. We’ve never seen one of these primordial stars, but with the power of the Webb and a bit of luck, we might catch a glimpse of them soon.

October 28, 2022October 28, 2022 by Brian Koberlein

JWST Sees the Same Galaxy From Three Different Angles Thanks to a Gravitational Lens

This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada

One of the great tragedies of the night sky is that we will never travel to much of what we see. We may eventually travel to nearby stars, and even distant reaches of our galaxy, but the limits of light speed and cosmic expansion make it impossible for us to travel beyond our local group. So we can only observe distant galaxies, and we can only observe them from our home in the universe. You might think that means we can only see one face of those galaxies, but thanks to the James Webb Space Telescope that isn’t entirely true.

August 24, 2022August 24, 2022 by Brian Koberlein

Colliding Black Holes Provide Another way to Measure Distance in the Universe

A simulation of two merging black holes. Credit: Simulating eXtreme Spacetimes (SXS) Project

We know the universe is expanding, and we have a pretty good idea of how fast it’s expanding, but we don’t know the rate exactly. That’s because of the different methods we have to measure the rate of cosmic expansion keep giving us slightly different results. It’s a nagging problem that bugs astronomers, so while they have worked to ensure current methods are accurate, they have also looked to new ways to measure cosmic expansion. One of these new ways involves gravitational waves.

August 13, 2022August 13, 2022 by Brian Koberlein

Primordial Black Holes Could Have Triggered the Formation of Supermassive Black Holes

Artist view of merging black holes in the early universe. Credit: LIGO/Caltech/MIT/R. Hurt (IPAC)

The early moments of the universe were turbulent and filled with hot and dense matter. Fluctuations in the early universe could have been great enough that stellar-mass pockets of matter collapsed under their own weight to create primordial black holes. Although we’ve never detected these small black holes, they could have played a vital role in cosmic evolution, perhaps growing into the supermassive black holes we see today. A new study shows how this could work, but also finds the process is complicated.

August 3, 2022August 3, 2022 by Brian Koberlein

Astronomers Measure the Signal of Dark Matter From 12 Billion Years ago

Visualization of how dark matter lenses distant light. Credit: Reiko Matsushita (Nagoya University)

Although the particles of dark matter continue to allude us, astronomers continue to find evidence of it. In a recent study, they have seen its effect from the edge of visible space, when the universe was just 1.5 billion years old.

August 2, 2022August 3, 2022 by Laurence Tognetti

The Record for the Farthest Galaxy just got Broken Again, now just 250 million years after the Big Bang

Artist's illustration of a protogalaxy. Midjourney AI. — Artist's illustration of a protogalaxy. This is not real, it's just a colorful image generated by Midjourney AI.

In a recent study submitted to MNRAS, a collaborative research team has utilized the first set of data from the James Webb Space Telescope (JWST) discovering a galaxy candidate, CEERS-93316, that formed approximately 250 million years after the Bing Bang, which also set a new redshift record of z = 16.7. This finding is extremely intriguing as it demonstrates the power of JWST, which only started sending back its first set of data a few weeks ago. CEERS stands for Cosmic Evolution Early Release Science Survey, and was specifically created for imaging with JWST.

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.

May 6, 2022May 6, 2022 by Alan Boyle

Why Believing in the Multiverse Isn’t Madness

"Doctor Strange in the Multiverse of Madness" — Doctor Strange is portrayed by Benedict Cumberbatch in "Doctor Strange in the Multiverse of Madness." (Marvel Entertainment)

What is the multiverse? The idea that the universe we inhabit is just one of many parallel universes gets a superhero shout-out in “Doctor Strange in the Multiverse of Madness,” the latest movie based on Marvel comic-book characters.

And in the opinion of Brian Greene, a theoretical physicist at Columbia University, giving some screen time to the multiverse isn’t such a bad thing — even if the plot has some horror-movie twists.

“I think it’s really good if some of these ideas are brought out in a variety of different ways,” Greene says in the latest episode of the Fiction Science podcast, which focuses on the realm where science and technology intersect with fiction and popular culture.