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]

See What Hurricane Florence Looks Like From Space

NASA via Getty Images
NASA via Getty Images

As Hurricane Florence continues to creep its way toward the Carolinas, it’s repeatedly being described as both "the storm of the century” and "the storm of a lifetime” for parts of the coastlines of North and South Carolina. While that may sound like hyperbole to some, Alexander Gerst—an astronaut with the European Space Agency—took to Twitter to prove otherwise with a few amazing photos, and issued a warning to “Watch out, America!”

According to the National Weather Service, “Hurricane Florence will be approaching the Carolina shores as the day progresses on Thursday. Although the exact timing, location, and eventual track of Florence isn't known, local impacts will likely begin in the afternoon hours and only worsen with time throughout the evening and overnight period.”

On Tuesday, Wilmington, North Carolina's National Weather Service took the warning even one step further, writing: "This will likely be the storm of a lifetime for portions of the Carolina coast, and that's saying a lot given the impacts we've seen from Hurricanes Diana, Hugo, Fran, Bonnie, Floyd, and Matthew. I can't emphasize enough the potential for unbelievable damage from wind, storm surge, and inland flooding with this storm.”

Gerst’s photos certainly drive that point home.

Is Pluto a Planet After All? A New Argument Emerges

iStock
iStock

It’s been a tumultuous few years for Pluto. The dwarf planet, first discovered in 1930 by astronomer Clyde Tombaugh, was stripped of its more esteemed planet status in 2006 by the International Astronomical Union (IAU) because its orbit overlapped that of Neptune. A new set of IAU criteria mandated that a planet must orbit the sun, be spherical as a result of gravity, and "clear" the "neighborhood" around its orbit, asserting itself as the dominant presence. Pluto met the first and second edicts but not the third, relegating it to the lesser dwarf planet designation.

That declaration led to an ongoing debate over whether Pluto really earned its demotion. The newest and potentially most compelling argument comes courtesy of a paper from researchers at the University of Central Florida's Space Institute and published in the planetary science journal Icarus. In it, first author Philip Metzger asserts that no one since 1802 has used the cleared-space argument to define a planet. Referring to the IAU's definition as "sloppy," Metzger and his co-authors point out that no one else has separated asteroids from planets by using the clearing mandate. Planets, the paper argues, should not be held to dynamic descriptions of bodies that may change over time.

"We now have a list of well over 100 recent examples of planetary scientists using the word planet in a way that violates the IAU definition, but they are doing it because it's functionally useful," Metzger said in a statement. "It's a sloppy definition. They didn't say what they meant by clearing their orbit. If you take that literally, then there are no planets, because no planet clears its orbit."

Metzger is advocating instead for a planet obtaining its status due to being large enough to achieve a gravity-influenced spherical shape that activates geological changes.

Speaking with CNN, IAU spokesperson Lars Lindberg Christensen indicated a motion could be put forward to have the group reevaluate the classification but that no one had yet done so.

Whatever Pluto is or may one day become, it was a planet to Tombaugh, who wasn't around long enough to experience the reclassification. He died in 1997. In 2015, his ashes, attached to the New Horizons space probe, entered Pluto's orbit after nine years of travel.

[h/t Science Alert]

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