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]

Tonight, the Lyrid Meteor Shower Peaks on Earth Day

iStock/dmoralesf
iStock/dmoralesf

Tonight, look up and you might see shooting stars streaking across the sky. On the night of Monday, April 22—Earth Day—and the morning of Tuesday, April 23, the Lyrid meteor shower will peak over the Northern Hemisphere. Make some time for the celestial show and you'll probably see meteors zooming across the heavens every few minutes. Here is everything you need to know about this meteor shower.

What is the Lyrid meteor shower?

Every 415.5 years, the comet Thatcher circles the Sun in a highly eccentric orbit shaped almost like a cat's eye. At its farthest from the Sun, it's billions of miles from Pluto; at its nearest, it swings between the Earth and Mars. (The last time it was near the Earth was in 1861, and it won't be that close again until 2280.) That's quite a journey, and more pressingly, quite a variation in temperature. The closer it gets to the Sun, the more debris it sheds. That debris is what you're seeing when you see a meteor shower: dust-sized particles slamming into the Earth's atmosphere at tens of thousands of miles per hour. In a competition between the two, the Earth is going to win, and "shooting stars" are the result of energy released as the particles are vaporized.

The comet was spotted on April 4, 1861 by A.E. Thatcher, an amateur skywatcher in New York City, earning him kudos from the noted astronomer Sir John Herschel. Clues to the comet's discovery are in its astronomical designation, C/1861 G1. The "C" means it's a long-period comet with an orbit of more than 200 years; "G" stands for the first half of April, and the "1" indicates it was the first comet discovered in that timeframe.

Sightings of the Lyrid meteor shower—named after Lyra, the constellation it appears to originate from—are much older; the first record dates to 7th-century BCE China.

How to See the Lyrid Meteor Shower

Monday night marks a waning gibbous Moon (just after the full Moon), which will reflect a significant amount of light. You're going to need to get away from local light pollution and find truly dark skies, and to completely avoid smartphones, flashlights, car headlights, or dome lights. The goal is to let your eyes adjust totally to the darkness: Find your viewing area, lay out your blanket, lay down, look up, and wait. In an hour, you'll be able to see the night sky with great—and if you've never done this before, surprising—clarity. Don't touch the smartphone or you'll undo all your hard ocular work.

Where is the nearest dark sky to where you live? You can find out on the Dark Site Finder map. And because the shower peaks on a Monday night—when you can expect to see 20 meteors per hour—your local astronomy club is very likely going to have an event to celebrate the Lyrid meteor shower. Looking for a local club? Sky & Telescope has you covered.

Other Visible Bodies During the Lyrid meteor shower

You don't need a telescope to see a meteor shower, but if you bring one, aim it south to find Jupiter. It's the bright, unblinking spot in the sky. With a telescope, you should be able to make out its stripes. Those five stars surrounding it are the constellation Libra. You'll notice also four tiny points of light nearby. Those are the Galilean moons: Io, Europa, Ganymede, and Callisto. When Galileo discovered those moons in 1610, he was able to prove the Copernican model of heliocentricity: that the Earth goes around the Sun.

What to Do if There's Bad Weather During the Lyrid Meteor Shower

First: Don't panic. The shower peaks on the early morning of April 23. But it doesn't end that day. You can try again on April 24 and 25, though the numbers of meteors will likely diminish. The Lyrid meteor shower will be back next year, and the year after, and so on. But if you are eager for another show, on May 5, the Eta Aquarids will be at their strongest. The night sky always delivers.

Does the Full Moon Really Make People Act Crazy?

iStock.com/voraorn
iStock.com/voraorn

Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the Moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.

This belief that the Moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the Moon are linked [PDF].

To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

When the researchers compared the time of the visits to the phases of the Moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception—in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

So rest easy (or maybe not): If people seem to act crazy during the full Moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.

This story was updated in 2019.

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