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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Searching for Dark Matter Inside the Earth

Dark matter remains one of the greatest mysteries in science.  Despite decades of astronomical evidence for its existence, no one has yet been able to find any sign of it closer to home.  There have been dozens of efforts to do so, and one of the most prominent just hit a milestone – the release and analysis of 8 years of data.  The IceCube Neutrino Observatory will soon be releasing results from those 8 years, but for now let’s dive in to what exactly they are looking for.

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How did Supermassive Black Holes Form? Collapsing Dark Matter Halos can Explain Them

Artist's conception of a supermassive black hole in a galaxy's center. Credit: NASA/JPL-Caltech

We don’t quite understand how the first supermassive black holes formed so quickly in the young universe. So a team of physicists are proposing a radical idea. Instead of forming black holes through the usual death-of-a-massive-start route, instead giant dark matter halos directly collapsed, forming the seeds of the first great black holes.

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The Milky Way’s Central bar Spin-Rate is Slowing Down Thanks to Dark Matter

Credit: Data: ESA/Gaia/DPAC, A. Khalatyan(AIP) & StarHorse team; Galaxy map: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)

If it were’t for an enormous halo of dark matter enveloping our galaxy, the spin-rate of our central bar should stay pretty constant. But researchers have recently inferred that it has slowed down by almost 25% since its formation, a clear sign of the presence of dark matter.

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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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A Dark Matter map of our Local Cosmic Neighborhood

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

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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New All-Sky Map of the Milky Way’s Galactic Halo

The outer reaches of the Milky Way galaxy are a different place.  Stars are much harder to come by, with most of this “galactic halo” being made up of empty space.  But scientists theorize that there is an abundance of one particular thing in this desolate area – dark matter.  Now, a team from Harvard and the University of Arizona (UA) spent some time studying and modeling one of the galaxy’s nearest neighbors to try to tease out more information about that dark matter, and as a result came up with an all new way to look at the halo itself.

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Jupiter Could Make an Ideal Dark Matter Detector

NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill (wikimedia commons)

So, you want to find dark matter, but you don’t know where to look? A giant planet might be exactly the kind of particle detector you need! Luckily, our solar system just happens to have a couple of them available, and the biggest and closest is Jupiter. Researchers Rebecca Leane (Stanford) and Tim Linden (Stockholm) released a paper this week describing how the gas giant just might hold the key to finding the elusive dark matter.

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Is Dark Matter Responsible for Extra Gamma Rays Coming From the Center of the Milky Way?

A Brilliant Star in Milky Way's Core
A Brilliant Star in Milky Way's Core

For years astronomers have puzzled over a strange excess of gamma rays coming from the galactic center. Annihilating dark matter has always been a tantalizing explanation, and new research claims that it’s the best answer.

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