NASA/JPL-Caltech/L. Cieza (University of Texas at Austin) via Wikimedia Commons // Public Domain
NASA/JPL-Caltech/L. Cieza (University of Texas at Austin) via Wikimedia Commons // Public Domain

Growing Stars Are Tidying the Universe

NASA/JPL-Caltech/L. Cieza (University of Texas at Austin) via Wikimedia Commons // Public Domain
NASA/JPL-Caltech/L. Cieza (University of Texas at Austin) via Wikimedia Commons // Public Domain

The world is kind of a mess these days, but at least our universe is cleaning itself up.* Astronomers say rapidly forming stars are gobbling up more cosmic debris than ever before, effectively cleaning up outer space. They presented their findings at the 2016 National Astronomy Meeting in Nottingham, UK.

This discovery was made possible by the European Space Agency’s Herschel Astrophysical Terahertz Large Area Survey (Herschel ATLAS) project. For four years, the Herschel Space Observatory drifted through the black, bearing the largest and most powerful infrared telescope ever flown in space. Through Herschel ATLAS, astronomers gained access to the observatory’s astonishingly detailed images and insights. 

We are so far away from other objects in space that looking into the universe is also literally looking back in time. To find out if and how the process of star formation has changed, a team of researchers used Herschel data to look 12 billion years into the past.

Cosmic dust is exactly what it sounds like: solid particles hanging in the space between the stars. This dust is the raw material of galaxies. A burgeoning star sucks in nearby debris, growing and absorbing, even as it empties the space around it. While star-gobbled cosmic dust shines, free-floating dust absorbs light, which renders it nearly impossible to see from Earth. Fortunately, Herschel’s telescope could see it. 

Project co-leader Steve Eales researches physics and astronomy at Cardiff University. “We were surprised to find that we didn't need to look far in the past to see signs of galaxy evolution,” he said in a press statement. “Our results show that the reason for this evolution is that galaxies used to contain more dust and gas in the past, and the universe is gradually becoming cleaner as the dust is used up." 

Loretta Dunne is another of the project co-leaders from Cardiff University. "Before Herschel, we only knew of a few hundred such dusty sources in the distant universe, and we could only effectively 'see' them in black and white,” she said. 

“Herschel, with its five filters, has given us the equivalent of technicolour, and the colour of the galaxy tell us about their distances and temperatures," Dunne said. "So we now have half a million galaxies we can use to map out the hidden star formation in the universe."

*We realize this may be small consolation.

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How Often Is 'Once in a Blue Moon'? Let Neil deGrasse Tyson Explain

From “lit” to “I can’t even,” lots of colloquialisms make no sense. But not all confusing phrases stem from Millennial mouths. Take, for example, “once in a blue moon”—an expression you’ve likely heard uttered by teachers, parents, newscasters, and even scientists. This term is often used to describe a rare phenomenon—but why?

Even StarTalk Radio host Neil deGrasse Tyson doesn’t know for sure. “I have no idea why a blue moon is called a blue moon,” he tells Mashable. “There is nothing blue about it at all.”

A blue moon is the second full moon to appear in a single calendar month. Astronomy dictates that two full moons can technically occur in one month, so long as the first moon rises early in the month and the second appears around the 30th or 31st. This type of phenomenon occurs every couple years or so. So taken literally, “Once in a blue moon” must mean "every few years"—even if the term itself is often used to describe something that’s even more rare.

[h/t Mashable]

Neutron Star Collision Sheds Light on the Strange Matter That Weighs a Billion Tons Per Teaspoon
Two neutron stars collide.
Two neutron stars collide.

Neutron stars are among the many mysteries of the universe scientists are working to unravel. The celestial bodies are incredibly dense, and their dramatic deaths are one of the main sources of the universe’s gold. But beyond that, not much is known about neutron stars, not even their size or what they’re made of. A new stellar collision reported earlier this year may shed light on the physics of these unusual objects.

As Science News reports, the collision of two neutron stars—the remaining cores of massive stars that have collapsed—were observed via light from gravitational waves. When the two small stars crossed paths, they merged to create one large object. The new star collapsed shortly after it formed, but exactly how long it took to perish reveals keys details of its size and makeup.

One thing scientists know about neutron stars is that they’re really, really dense. When stars become too big to support their own mass, they collapse, compressing their electrons and protons together into neutrons. The resulting neutron star fits all that matter into a tight space—scientists estimate that one teaspoon of the stuff inside a neutron star would weigh a billion tons.

This type of matter is impossible to recreate and study on Earth, but scientists have come up with a few theories as to its specific properties. One is that neutron stars are soft and yielding like stellar Play-Doh. Another school of thought posits that the stars are rigid and equipped to stand up to extreme pressure.

According to simulations, a soft neutron star would take less time to collapse than a hard star because they’re smaller. During the recently recorded event, astronomers observed a brief flash of light between the neutron stars’ collision and collapse. This indicates that a new spinning star, held together by the speed of its rotation, existed for a few milliseconds rather than collapsing immediately and vanishing into a black hole. This supports the hard neutron star theory.

Armed with a clearer idea of the star’s composition, scientists can now put constraints on their size range. One group of researchers pegged the smallest possible size for a neutron star with 60 percent more mass than our sun at 13.3 miles across. At the other end of the spectrum, scientists are determining that the biggest neutron stars become smaller rather than larger. In the collision, a larger star would have survived hours or potentially days, supported by its own heft, before collapsing. Its short existence suggests it wasn’t so huge.

Astronomers now know more about neutron stars than ever before, but their mysterious nature is still far from being fully understood. The matter at their core, whether free-floating quarks or subatomic particles made from heavier quarks, could change all of the equations that have been written up to this point. Astronomers will continue to search the skies for clues that demystify the strange objects.

[h/t Science News]


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