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Understanding the Early Universe Depends on Estimating the Lifespan of Neutrons

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.

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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.

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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.

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

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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This is How a Supermassive Black Hole Feeds

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.

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The Largest Rotating Objects in the Universe: Galactic Filaments Hundreds of Millions of Light-Years Long

We’ve known for a while about the large-scale structure of the Universe. Galaxies reside in filaments hundreds of millions of light-years long, on a backbone of dark matter. And, where those filaments meet, there are galaxy clusters. Between them are massive voids, where galaxies are sparse. Now a team of astronomers in Germany and their colleagues in China and Estonia have made an intriguing discovery.

These massive filaments are rotating, and this kind of rotation on such a massive scale has never been seen before.

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Is the Hubble constant not…Constant?

Cosmologists have been struggling to understand an apparent tension in their measurements of the present-day expansion rate of the universe, known as the Hubble constant. Observations of the early cosmos – mostly the cosmic microwave background – point to a significantly lower Hubble constant than the value obtained through observations of the late universe, primarily from supernovae. A team of astronomers have dug into the data to find that one possible way to relieve this tension is to allow for the Hubble constant to paradoxically evolve with time. This result could point to either new physics…or just a misunderstanding of the data.

“The point is that there seems to be a tension between the larger values for late universe observations and lower values for early universe observation,” said Enrico Rinaldi, a research fellow in the University of Michigan Department of Physics and coauthor on the study. “The question we asked in this paper is: What if the Hubble constant is not constant? What if it actually changes?”

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A Dark Matter map of our Local Cosmic Neighborhood

Since it was first theorized in the 1970s, astrophysicists and cosmologists have done their best to resolve the mystery that is Dark Matter. This invisible mass is believed to make up 85% of the matter in the Universe and accounts for 27% of its mass-energy density. But more than that, it also provides the large-scale skeletal structure of the Universe (the cosmic web), which dictates the motions of galaxies and material because of its gravitational influence.

Unfortunately, the mysterious nature of Dark Matter means that astronomers cannot study it directly, thus prevented them from measuring its distribution. However, it is possible to infer its distribution based on the observable influence its gravity has on local galaxies and other celestial objects. Using cutting-edge machine-learning techniques, a team of Korean-American astrophysicists was able to produce the most detailed map yet of the local Universe that shows what the “cosmic web” looks like.

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