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?

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Finally, an Explanation for the Cold Spot in the Cosmic Microwave Background

Map of the cosmic microwave background (CMB) sky produced by the Planck satellite. The Cold Spot is shown in the inset, with coordinates and the temperature difference in the scale at the bottom. Credit: ESA/Durham University.

According to our current Cosmological models, the Universe began with a Big Bang roughly 13.8 billion years ago. During the earliest periods, the Universe was permeated by an opaque cloud of hot plasma, preventing atoms from forming. About 380,000 years later, the Universe began to cool and much of the energy generated by the Big Bang converted into light. This afterglow is now visible to astronomers as the Cosmic Microwave Background (CMB), first observed during the 1960s.

One peculiar characteristic about the CMB that attracted a lot of attention was the tiny fluctuations in temperature, which could provide information about the early Universe. In particular, there is a rather large spot in the CMB that is cooler than the surrounding afterglow, known as the CMB Cold Spot. After decades of studying the CMB’s temperature fluctuations, a team of scientists recently confirmed the existence of the largest cold spots in the CMB afterglow – the Eridanus Supervoid – might be the explanation for the CMB Cold Spot that astronomers have been looking for!

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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.

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A Particle Physics Experiment Might Have Directly Observed Dark Energy

An illustration of cosmic expansion. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab

About 25 years ago, astrophysicists noticed something very interesting about the Universe. The fact that it was in a state of expansion had been known since the 1920s, thanks to the observation of Edwin Hubble. But thanks to the observations astronomers were making with the space observatory that bore his name (the Hubble Space Telescope), they began to notice how the rate of cosmic expansion was getting faster!

This has led to the theory that the Universe is filled with an invisible and mysterious force, known as Dark Energy (DE). Decades after it was proposed, scientists are still trying to pin down this elusive force that makes up about 70% of the energy budget of the Universe. According to a recent study by an international team of researchers, the XENON1T experiment may have already detected this elusive force, opening new possibilities for future DE research.

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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.

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Astronomy Jargon 101: Standard Candles

This illustration shows three steps astronomers used to measure the universe's expansion rate (Hubble constant) to an unprecedented accuracy, reducing the total uncertainty to 2.3 percent. The measurements streamline and strengthen the construction of the cosmic distance ladder, which is used to measure accurate distances to galaxies near to and far from Earth. The latest Hubble study extends the number of Cepheid variable stars analyzed to distances of up to 10 times farther across our galaxy than previous Hubble results. Credits: NASA, ESA, A. Feild (STScI), and A. Riess (STScI/JHU)

In this series we are exploring the weird and wonderful world of astronomy jargon! If only there was a way to measure the distance to today’s topic: standard candles!

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NASA Continues to Try and Rescue Failing Hubble

Will China's new space telescope out-perform the Hubble? Image:
The Hubble Space Telescope. Image: NASA

Things are not looking very good for the Hubble Space Telescope right now. On Sunday, June 13th, the telescope’s payload computer suddenly stopped working, prompting the main computer to put the telescope into safe mode. While the telescope itself and its science instruments remain in working order, science operations have been suspended until the operations team can figure out how to get the payload computer back online.

While attempting to restart the computer, the operations team has also tried to trace the issue to specific components in the payload computer and switch to their backup modules. As of June 30th, the team began looking into the Command Unit/Science Data Formatter (CU/SDF) and the Power Control Unit (PCU). Meanwhile, NASA is busy preparing and testing procedures to switch to backup hardware if either of these components are the culprit.

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Astronomers saw the Same Supernova Three Times Thanks to Gravitational Lensing. And in Twenty Years They Think They’ll see it one More Time

It is hard for humans to wrap their heads around the fact that there are galaxies so far away that the light coming from them can be warped in a way that they actually experience a type of time delay.  But that is exactly what is happening with extreme forms of gravitational lensing, such as those that give us the beautiful images of Einstein rings.  In fact, the time dilation around some of these galaxies can be so extreme that the light from a single event, such as a supernova, can actually show up on Earth at dramatically different times.  That is exactly what a team led by Dr. Steven Rodney at the University of South Carolina and Dr. Gabriel Brammer of the University of Copenhagen has found. Except three copies of this supernova have already appeared – and the team thinks it will show up again one more time, 20 years from now.

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Dark Energy Survey is out. 29 Papers Covering 226 Million Galaxies Across 7 Billion Light-Years of Space

Cosmology is now stranger to large scale surveys.  The discipline prides itself on data collection, and when the data it is collecting is about galaxies that are billions of years old its easy to see why more data would be better.  Now, with a flurry of 29 new papers, the partial results from the largest cosmological survey ever – the Dark Energy Survey (DES) – have been released.  And it largely confirms what we already knew.

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11-Sigma Detection of Dark Energy Comes From Measuring Over a Million Extremely Distant Galaxies

Exploration of the Universe by the SDSS mission during the past two decades (1998-2019). Credit: eBOSS collaboration

After galaxies began to form in the early universe, the universe continued to expand. The gravitational attraction between galaxies worked to pull galaxies together into superclusters, while dark energy and its resulting cosmic expansion worked to drive these clusters apart. As a result, the universe is filled with tight clusters of galaxies separated by vast voids of mostly empty space.

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