The Cosmic Companion January 18, 2020

Dark matter, strange objects near the center of the Milky Way, a new look at the extinction of the dinosaurs, and ancient galaxies reveal secrets of our own family of stars.

Hello everyone!

I hope everybody has had a fabulous week, as The Cosmic Companion continues to bring you stories, news, and special features, all about space and astronomy! I’m really excited about new features coming to The Cosmic Companion, including Astro Pop - a look at the science behind science fiction and fantasy movies and books, Human and Machine which examines the instruments and people helping us understand the Universe, and Cosmic Comics, our own original comics about space and astronomy!

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The Week in Space

Dark Matter Could Shed Light on Glow of Gamma Radiation

By James Maynard

The origins of a faint glow of gamma-ray radiation are unknown, but dark matter may be the cause — or maybe its just the eruption of supermassive black holes at the cores of energetic galaxies.

Blazars — active galaxies with ravenous supermassive black holes near their center — are suspects in the case of the mysterious gamma radiation. Image credit: M. Weiss/CfA

A faint glow of gamma radiation — the unresolved gamma-ray background — fills the sky. This energy is not evenly distributed, as this light (much more energetic than can be seen by the human eye) is concentrated where the greatest amount of matter is found in the early Universe, while regions containing less matter exhibit lower emissions of radiation.

This correlation between matter and the unresolved gamma-ray background, could help astrophysicists better understand the nature of dark matter, a new study suggests.

The energy which makes up this background radiation comes from sources so far away from us that they cannot be resolved by astronomers. However, the fact that this radiation is concentrated in the same regions which were densely packed with matter in the early universe could provide a tantalizing clue to its nature.

Read more:

More Strange Objects Seen Near Black Hole at Center of Milky Way

By James Maynard

Four more unusual objects have been spotted orbiting the supermassive black hole near the center of the Milky Way galaxy. What are they?

The orbits of the newly-discovered G objects are traced over this image of objects near the center of our galaxy. Image credit: Anna Ciurlo, Tuan Do/UCLA Galactic Center Group

Every major galaxy is home to a supermassive black hole, and our own Milky Way is no exception. Astronomers recently found something unexpected near this massive object — four mysterious objects, each similar to a pair of bizarre bodies spotted in recent years in this same region of the galaxy.

Our local supermassive black hole, Sagittarius A* (Sgr A*, pronounced Sag A star), contains roughly four million times as much mass as the Sun. Not far from this black hole, members of a newly-discovered class of objects is caught in a gravitational dance with the massive body.

Read more:

Asteroid, Not Volcanoes, may have Doomed Dinosaurs

By James Maynard

Roughly 66 million years ago, Earth was struck by an asteroid the size of Mount Everest, ending the age of dinosaurs. New simulations suggest volcanoes played a smaller role in their demise than many researchers believe.

The age of dinosaurs came to an end when a massive asteroid slammed into Earth, while earlier periods of massive eruptions in India played a much smaller role than believed, new simulations suggest. Image credit: The Cosmic Companion/8385/Parker West/Pixabay

The age of the dinosaurs came to an end around 66 million years ago, as the Earth was struck by an asteroid as large as Mount Everest. This event radically changed the climate of the Earth, and forever altered the course of life on the planet.

However, for thousands of centuries before impact, supervolcanoes in the Deccan Traps of India were sending vast quantities of dust and carbon dioxide into the atmosphere, changing the global climate. This pair of events have caused to researchers to debate the degree of influence each of these climatic changes had on this global extinction.

Read more:

Cores of Dying Galaxies Formed in Early Universe

By James Maynard

Examination of the most distant dying galaxy known to astronomers suggests the cores of these objects formed earlier in the evolution of the Cosmos than previous theories suggest. How did they develop and what does it mean for our understanding of galaxies?

Dead galaxies tend to remain that way, even if they are able to gather gas from nearby families of stars. Image credit: Kavli/IPMU

The most distant dying galaxy known to astronomers contains nearly one trillion stars, making this family of stars is significantly larger than our own Milky Way galaxy. Analysis of the core of this galaxy shows this object started to form 12 billion years ago — just 1.5 billion years after the Big Bang.

Like humans, galaxies are born, live out their lives, and fall into silence. The first galaxies formed just a couple hundred million years after the Big Bang, as the gravitational pull of both normal matter and dark matter pulled stars together into groups. Now, by studying dying galaxies, astronomers hope to better understand the life cycles of stellar families.

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Coming soon: The First Woman on the Moon: The Past and Future History of Women in Space by James Maynard

Thanks for reading!

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Astronomy - Don’t Leave Home Without It!

- James

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