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Merging of 14 Galaxies Could Become The Most Massive Structure in Our Universe

Merging of 14 Galaxies Could Become The Most Massive Structure in Our Universe 86

Peering billions of light-years back to when the Universe was just 10 percent of its current age, astronomers have spotted a colossal pile-up: 14 young, starbursting galaxies merging into one of the most massive structures in the Universe.

Using some of the most powerful telescopes in operation today, an international research team discovered the extremely dense concentration of hot galaxies careening towards each other.

Eventually the megamerger will form a cluster of galaxies, gravitationally bound by dark matter and ultimately smooshing together into one ginormous galaxy

This stage of the merger is called a protocluster, and it’s an extraordinary find.

“Having caught a massive galaxy cluster in throes of formation is spectacular in and of itself,” said Scott Chapman, an astrophysicist at Dalhousie University, one of the authors on a new paper published in Nature.

“But the fact that this is happening so early in the history of the Universe poses a formidable challenge to our present-day understanding of the way structures form in the universe.”

All 14 galaxies in SPT2349-56, imaged by ALMA. (ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AUI/NSF))

All 14 galaxies in SPT2349-56, imaged by ALMA. (ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AUI/NSF))

The protocluster, named SPT2349-56, is 12.4 billion light-years away, populated by dusty galaxies that are forming stars at a furious rate – up to 1,000 times faster than the Milky Way. Yet they’re crammed into a space just three times bigger than our whole galaxy.

In itself, the protocluster would be a rare find, but there’s another twist to the story. It’s one of two such recent discoveries.

Publishing in arXiv last September, and their findings accepted into The Astrophysical Journal, a team of researchers announced they’d found a protocluster of 10 dusty starburst galaxies in the early Universe too. They nicknamed it the Dusty Red Core.

You can fully expect to discover all kinds of things forming in the early Universe – stars, galaxies, clusters of galaxies – but the size and composition of these protoclusters is a conundrum.

“The lifetime of dusty starbursts is thought to be relatively short, because they consume their gas at an extraordinary rate,” explained astrophysicist Iván Oteo from the University of Edinburgh, lead author on the arXiv paper.

“At any time, in any corner of the Universe, these galaxies are usually in the minority. So, finding numerous dusty starbursts shining at the same time like this is very puzzling, and something that we still need to understand.”

After the Big Bang, according to our current models of the Universe, everything was still dark for a while. It wasn’t until around 1 billion years later that the Universe became fully ionised and transparent, and we see the first galaxies start appearing.

These clusters appear about 1.4 billion years after the Big Bang. The models of the Universe’s evolution predict that, while these clusters can exist, they ought to have taken much longer than that to evolve.

“How this assembly of galaxies got so big so fast is a mystery,” said Tim Miller, a PhD candidate at Yale University, and lead author on the Nature paper.

“It wasn’t built up gradually over billions of years, as astronomers might expect. This discovery provides a great opportunity to study how massive galaxies came together to build enormous galaxy clusters.”

(ESO/ALMA (ESO/NAOJ/NRAO)/Miller et al.)

(ESO/ALMA (ESO/NAOJ/NRAO)/Miller et al.)

SPT2349-56 was first seen as a faint smudge of light imaged by the South Pole Telescope in 2010, but it was unusual enough to warrant further investigation with something more powerful.

The European Southern Observatory’s (ESO) Atacama Large Millimetre Array (ALMA) and the Atacama Pathfinder Experiment (APEX) telescopes were then used to image the object in higher resolution, showing more detail.

Often objects that early in the Universe are too faint for our telescopes to pick up, but there may be more of these protoclusters out there, the researchers said.

“These discoveries by ALMA are only the tip of the iceberg. Additional observations with the APEX telescope show that the real number of star-forming galaxies is likely even three times higher,” said ESO astronomer Carlos De Breuck.

“Ongoing observations with the MUSE instrument on ESO’s VLT are also identifying additional galaxies.”

The SPT2349-56 paper has been published in the journal Nature, and the Dusty Red Core paper can be read on the preprint resource arXiv.

BONUS: Short video:

MICHELLE STARR
sciencealert.com

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Space

KOI-5Ab, the curious planet that orbits in a system of three suns

KOI-5Ab, the curious planet that orbits in a system of three suns 87
Photo: (Caltech / R. Hurt (IPAC))

To us, the Sun alone seems perfectly normal, but our solar system is actually a strange exception.

Most stars in the Milky Way galaxy have at least one companion star. In a system 1,800 light-years away, astronomers have finally confirmed the existence of a gas giant planet orbiting stars in a triple star system.

Called KOI-5, the system is located in the constellation Cygnus, and the exoplanet was confirmed ten years after it was first detected by the Kepler space telescope.

In fact, the planet – now known as KOI-5Ab – was discovered by Kepler when it began operations back in 2009.

“KOI-5Ab was dropped because it was difficult and we had thousands of other candidates,” astronomer David Siardi of NASA’s Exoplanet Science Institute said.

“There were lighter dives than the KOI-5Ab, and every day we learned something new from Kepler, so the KOI-5 was almost forgotten.”

Exoplanet hunters tend to avoid the complexities of multi-star systems; of the more than 4,300 exoplanets confirmed to date, less than 10 percent are multi-star systems, although such systems dominate the galaxy. As a result, little is known about the properties of exoplanets in multi-star systems compared to those orbiting a lone star.

After Kepler’s discovery, Chardy and other astronomers used ground-based telescopes such as the Palomar Observatory, Keck Observatory, and the Gemini North Telescope to study the system. By 2014, they had identified two companion stars, KOI-5B and KOI-5C.

Scientists were able to establish that the planet KOI-5Ab, is a gas giant that is about half the mass of Saturn and 7 times the size of Earth, and is in a very close five-day orbit around KOI-5A. KOI-5A and KOI-5B, both of roughly the same mass as the Sun, form a relatively close binary system with an orbital period of about 30 years.

KOI-5Ab, the curious planet that orbits in a system of three suns 88

A third star, KOI-5C, orbits the binary system at a much greater distance, with a period of about 400 years – slightly longer than Pluto’s 248-year orbit.

“By studying this system in more detail, perhaps we can understand how planets are created in the universe.”

The discovery was announced at the 237th meeting of the American Astronomical Society.

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Space

Why the universe does not fit into science

Why the universe does not fit into science 89
Photo: YouTube

Science can be compared to an artist painting what he has never seen, or to a writer describing other people’s travels: objects that he has never seen, places where he has never been. Sometimes such scientific “arts” turn out to be beautiful and interesting, but most of them will forever remain only theories, because they are beyond human capabilities.

In fact, science has the right only to speculate: how our universe appeared, how old it is, how many stars and other objects it contains.

Universe model

Why the universe does not fit into science 90

How many stars are there in the sky?

With an unarmed eye, a person can see about nine thousand stars in the sky in one cloudless and moonless night. And armed with binoculars or a telescope, much more – up to several million. However, this is much less than their true number in the universe. Indeed, only in our one galaxy (the Milky Way) there are about 400 billion stars. The exact amount, of course, is not known to science. And the visible universe contains about 170 billion galaxies.

It is worth clarifying that scientists can see the universe 46 billion light years deep in all directions. And the visible (observable) universe includes the space accessible to our eyes from the moment of the Big Explosion. In other words, only this (accessible to human perception) space science refers to our universe. Science does not consider everything that follows.

It is believed that there are supposedly a ceptillion (10 to 24 degrees) stars in our universe. These are theoretical calculations based on the approximate size and age of the universe. The origin of the universe is explained by the Big Bang theory. This is why the universe is constantly expanding and the more time passes, the more complex the universe and its components become.

Why the universe does not fit into science 91

It is not entirely correct to consider and perceive this scientific theory “head-on”. Scientists always claim that that explosion was not exactly an explosion, and the point that exploded was not the only one. After all, it was everywhere, because space did not exist then. And in general – everything happened quite differently from what is described in the Big Bang theory, but all other descriptions of the origin of the universe are even more incredible and inaccurate.

Separate but interconnected

That which is beyond the reach of human perception is usually discarded by science, or recognized as non-existent. Recognizing one thing, science does not want to recognize the existence of the other, although everything in our world is interconnected and is not able to exist separately – by itself.

Each object of the universe is a part of it much more than an independent, separate object.

Any person, like any material object of our world, consists of components: organs, cells, molecules, atoms. And each of its constituent parts can represent the whole world. Separate, and at the same time connected with all the others.

However, science, as a rule, perceives all the components of the universe – people, animals, plants, objects, the Earth, the Sun, other planets and stars – as separate subjects, thereby limiting itself.

Why the universe does not fit into science 92

Even what is considered the visible universe, one of the atoms of which could be called our solar system, is not subject to the boundaries of human perception. But perhaps the atom is an exaggeration, and our solar system is not even an atom, but one of its elements!

How, being so far from the truth, can one reason about something with the degree of probability with which science tries to reason about the origin of the universe?

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Space

An unexplained wobble shifts the poles of Mars

An unexplained wobble shifts the poles of Mars 93

The red planet sways from side to side like a whirligig when it loses speed. The new study allowed scientists to notice that the poles of Mars deviate slightly from the axis of rotation of the planet. On average, they move 10 cm from the center with a period of 200 days.

Such changes are called the Chandler Oscillations  – after the American astronomer Seth Chandler, who discovered them in 1891. Previously, they were only seen on Earth. It is known that the displacement of the poles of rotation of our planet occurs with a period of 433 days, while the amplitude reaches 15 meters. There is no exact answer why this is happening. It is believed that the fluctuations are influenced by processes in the ocean and the Earth’s atmosphere.

Chandler’s wobbles on Mars are equally perplexing. The authors of the study discovered them by comparing data from 18 years of studying the planet. The information was obtained thanks to three spacecraft that orbit the Red Planet: Mars Odyssey, Mars Reconnaissance Orbiter and Mars Global Surveyor. 

Since Mars has no oceans, it is likely that the Red Planet’s wobbly rotation is due to changes in atmospheric pressure. This is the first explanation that researchers have shared. In the future, there should be new details about the fluctuations that have so interested the scientific community.

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