Researchers discover strange behavior in magnetars, ultra-powerful magnetic stars.
- In a new study, scientists describe a magnetar's bizarre behavior.
- Magnetars are neutron stars with extremely powerful magnetic fields.
- The strange space objects also emit radio bursts that reach Earth.
Astronomers recently witnessed very strange behavior from a magnetar, a peculiar kind of rotating neutron star that also happens to be one of the strongest magnets in the universe.
Magnetars are essentially remains of dead stars with amazingly strong magnetic fields that also emit mysterious radio signals. When a star dies, going supernova, about one in ten such explosions result in magnetars. Others end up creating neutron stars, or pulsars.
About 30 magnetars, each up to 20 km (12 mi) in diameter, have been spotted around the Milky Way. Imagine a magnet the size of a town flying by.
According to NASA, the strength of a magnetar's magnetic field could be one thousand trillion times stronger than Earth's. In fact, measured at up to 1 quadrillion gauss, the field is so intense that it heats the magnetar's surface to an extra balmy 18 million degrees Fahrenheit.
To think about the magnetar's power another way, NASA shared if a magnetar appeared about halfway of the distance between the Earth and the moon (238,855 miles), it could wipe out information from the magnetic strips of all credit cards on our planet.
A new study, carried out by scientists from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) and CSIRO in Australia, studied magnetars by largely relying on X-ray telescopes that looked for high-energy outbursts. Some times magnetars also send out radio pulses like pulsars, which are less magnetic. Why this happens and how such pulses change has been the focus of the research.
Here's what might happen if you fell into a magnetar
The scientists studied pulses coming from the magnetar J1818, observing it eight times, and found some very inconsistent behavior. It started out sending pulsar-like signals, then began flickering and going back and forth between emitting like a pulsar or a magnetar.
The study's lead author, Ph.D. student Marcus Lower of Swinburne University/CSIRO, elaborated on why this magnetar turned out to be so fascinating:
"This bizarre behavior has never been seen before in any other radio-loud magnetar," said Lower. "It appears to have only been a short-lived phenomenon, as by our next observation, it had settled permanently into this new magnetar-like state."
What the scientists found was that the magnetic axis of J1818 was not aligned with its rotation axis. Its radio signals come from the magnetic pole in the Southern Hemisphere, from below the equator. Other magnetars tend to have magnetic fields aligning with their spin axis.
Yet, while misaligned, the magnetic arrangement appears to be stable. The researchers concluded that the radio pulses coming from J1818 emanate from loops of magnetic field lines that join the two poles. This is different from most neutron stars.
The findings have bearings on magnetar simulations, leading to deeper knowledge of their creation and evolution. The scientists are looking to catch flips between magnetic poles to be able to map a magnetar's magnetic fields.
Read the new paper, published in the Monthly Notices of the Royal Astronomical Society (MNRAS).
What can cause a ripple in both space and time? Neutron stars colliding. And what can observe that phenomenon? A two-mile-long laser.
Michell Thaller, the Assistant Director of Science Communication at NASA, wanted to talk to us about a heavy subject matter. Specifically, super-dense neutron stars that are so dense that they're only the size of New York City but carry the weight of the sun. And when they circle each other in orbit for long enough, they collide with enough force to send ripples in both space and time. Those ripples alone are strong enough to alter the course of light. In fact, just a few years ago a rare astronomical event occurred where you'd have seen a star "blink" for a few minutes on and off before disappearing for good. Scientists are able to detect these gravitational ripples thanks to a LIGO, or a Laser Interferometric Gravitational-Wave Observatory, which measures the refraction of light based on gravity waves. Oh, and one more thing: Albert Einstein correctly deduced that this phenomenon years before it was ever recorded. If you'd like to know more, visit NASA.
This discovery finally points to the source of Earth's precious heavy elements, also proves Einstein correct in more ways than one.
Last September, scientists at a special observatory announced that they detected a gravitational wave for the first time. The detection took place in September, 2015, but wasn’t announced until last year. The observatory is known as the Laser Interferometer Gravitational-Wave Observatory (LIGO). It registered ripples in space-time formed from the collision of two black holes. Apparently, the fabric of the universe ripples just as water does.
We’ve tired the electromagnetic spectrum when it comes to examining the universe. Now, astronomers are fiddling with a whole new aperture, gravitational waves. A little over 100 years ago, Einstein first predicted gravitational waves as something that would happen throughout space-time as a result of dramatic events. September’s announcement proved him right, although he himself thought we’d never be able to detect them, the results being so slight.
Officials at the National Science Foundation, LIGO, MIT, Caltech, and other institutions have now made a second groundbreaking announcement, the detection of gravitational waves from another astronomical event, the merging of two neutron stars. This latest signal was detected on Aug. 17. A neutron star is the remnant of a larger star whose core has collapsed. Usually, this is followed by a supernova, where the outer layer of the star blows off in a colossal explosion.
The neutron stars that merged were each 1.1 to 1.4 times the mass of our sun. An event of this magnitude only occurs once in 80,000 years, LIGO scientists say. The light emitted by this neutron star collision resulted in a “fireball,” which is an intense burst of gamma radiation. Such a fireball or kilonova creates the heaviest known elements, such as gold, platinum, and lead, and sends them careening throughout the cosmos.
See an animated clip of a neutron star collision here:
These are small, dense stars. One teaspoon worth would weigh more than 10 million tons, more than the entire population of Earth. As the core continues to collapse, the gravity inside gets so strong it fuses protons and electrons together, forming neutrons, hence the name. When two neutron stars merge, one of two things happen. Either an even bigger neutron star is born or a black hole is made. This event, now known as GW170817, created an ultra-dense neutron star.
Though it occurred approximately 130 million years ago, the resulting gravitational waves reached Earth last August, with the ripples arriving one second before the light did. This is the very first time scientists recorded an astronomical event through both light and gravitational waves.
Over 1,200 scientists from 100 institutions around the world work at the LIGO Scientific Collaboration. LIGO is comprised of two observatories, one in Hanford, Washington, and the other in Livingston, Louisiana. Each contains an instrument so sensitive it can detect a single ripple in space-time lasting just a fraction of a second. In addition to the LIGO detectors, the newly launched Virgo observatory in Italy helped to zero-in on the location of the explosion. Other such observatories are in the works for Japan and India, which will further help pinpoint an event’s location.
Each observatory consists of an L-shaped tunnel. Laser light is sent by mirror down each of them. When there are no gravitational fluctuations, the laser bounces back normally. But when there are ripples in space-time, it squeezes and pulls the beam which gives scientists a reading.
Artist concept of neutron star falling into its neighbor. Credit: NASA
Caltech’s David H. Reitze is the executive director of the LIGO Laboratory. In a press release, he explained the importance of the groundbreaking even. “This detection opens the window of a long-awaited ‘multi-messenger’ astronomy. It’s the first time that we’ve observed a cataclysmic astrophysical event in both gravitational waves and electromagnetic waves — our cosmic messengers,” Dr. Reitze said, “Gravitational-wave astronomy offers new opportunities to understand the properties of neutron stars in ways that just can’t be achieved with electromagnetic astronomy alone.”
The event also solidified another of Einstein’s predictions. Not only does it further confirm the existence of gravitational waves but that they travel at the speed of light. Its little wonder that the scientists who put together LIGO won this year’s Nobel Prize in Physics.
See the announcement of this historic event in astronomy here:
LIGO and Virgo reveal a gravitational wave was detected on two different continents. Here's what that means and why it matters.
The twin Laser Interferometer Gravitational-Wave Observatory (LIGO) is a collaborative effort. It’s basically a group of scientists who use specialized equipment to study gravitational waves. There are currently two such observatories in the US, one in Hanford, Washington and the other in Livingston, Louisiana. They use an interferometer, or a laser-based instrument, to detect even the minutest ripples in space-time as it relates to gravitational waves. The instrument is so delicate, it can pick up distortions one proton in width.
LIGO observatories are owned by the National Science Foundation (NSF) and are run by scientists at NASA, MIT, and Caltech. The Europeans now have their own gravitational observatory, known as Virgo, based in Italy. The two collaboratives recently started working together, and they’ve just made an announcement unveiling new results, a noteworthy milestone in gravitational astronomy.
Researchers announced what they called a “new window on the universe,” at the G7 Ministerial Meeting on Science, taking place Sept. 27-28. Back on August 14, Virgo for the first time detected a gravitational wave, made by a binary black hole system. The two LIGO locations picked it up just after. The wave was created when two black holes collided and merged. All three locations registered the resulting gravitational wave.
This was the first time in history such a wave was detected on two different continents. This is more than just a scientific second opinion, it gets us closer to a 3D picture of what Einstein's gravitational waves actually look like. The twin LIGO detectors in the United States mean scientists can detect gravitational waves, but only on one plane. The Virgo detection literally adds a new dimension to the breakthrough discovery of gravitational waves in 2015 (which is a hot favorite to win the Physics Nobel Prize this year). Professor Andreas Freise, a LIGO project scientist at the University of Birmingham, puts it like this: “It’s like if I give you just one slice of apple, you can’t guess what the fruit looks like.” The third detector also means scientists can triangulate the source of the wave to identify exactly where in the universe the signal originated.
National Science Foundation director France Córdova spoke at the press conference. She said, "This is an exciting milestone in the growing international scientific effort to unlock the extraordinary mysteries of our universe."
See a video depicting the recorded black hole merger here:
Gravitational waves were first predicted by Einstein’s general theory of relativity. LIGO’s recording of a black hole collision several months ago confirmed this famous physicists suppositions, first hypothesized in 1916. You can hear a recording of that collision. The most recently detected gravitational waves came from a location 1.8 billion light years away. These were two enormous black holes, the first 31 and the second 25 times the mass of our sun. The resulting black hole was 53 times our sun’s mass.
With three detection locations, scientists can better gauge the distance of the origin of these ripples in space-time. University of Texas astrophysicist J. Craig Wheeler perked the ears of some space heads back in August when he tweeted, “New LIGO. Source with optical counterpart. Blow your sox off!” The optical counterpart he mentioned wasn’t elaborated on until now. Scientists believe they may be able to detect other particles emanating from black hole collisions. But some space geeks took it to mean that LIGO and Virgo had detected the merger of a neutron star.
Aerial view of the Virgo detector. The Virgo collaboration/CCO 1.0
Still, what was announced is no less groundbreaking, according to Georgia Tech professor Laura Cadonati. She’s the deputy spokesperson for LIGO. “This increased precision will allow the entire astrophysical community to eventually make even more exciting discoveries," she said, "including multi-messenger observations." With these detectors, astronomers may also be able to find and study light, x-rays, neutrinos, and other subatomic particles emanating from cosmic events.
LIGO spokesman David Shoemaker, who is also of MIT, said, “This is just the beginning of observations with the network enabled by Virgo and LIGO working together.” He added, “With the next observing run planned for fall 2018, we can expect such detections weekly or even more often.”
More gravitational observatories are in the works in other locations, including one for New Delhi. With an international network, researchers believe they can gain better information, further test Einstein’s theory, and get more accurate location information for black hole and neutron star mergers, among other significant cosmic phenomenon.
Caltech’s David H. Reitze is the executive director of the LIGO Laboratory. He said, “We have taken one step further into the gravitational-wave cosmos. Virgo brings a powerful new capability to detect and better locate gravitational-wave sources, one that will undoubtedly lead to exciting and unanticipated results in the future.”
See the press conference for yourself here:
Scientists create a superfluid with negative mass that accelerates backwards.
Scientists at Washington State University created a fluid with the previously-theorized (and rather counterintuitive) property of negative mass.
This is the first time a negative mass has ever been observed under laboratory conditions and can lead to advancements in our understanding of such hard-to-study topics as black holes, dark matter and neutron stars.
What's unusual about the created fluid is that when you push on it, it doesn't accelerate in the direction where it was pushed, as you would expect. Instead, it accelerates back, towards you. Scientists have previously hypothesized matter could have negative mass the way a particle can have a negative charge. But they have not been able to show it definitively until this study.
“What’s a first here is the exquisite control we have over the nature of this negative mass, without any other complications,” said Michael Forbes, professor of physics and astronomy at WSU and the study’s co-author.
Forbes and the team led by WSU professor Peter Engels used lasers create the conditions for observing negative mass. First, they cooled rubidium atoms to nearly absolute zero. In the resulting state, known as a Bose-Einstein condensate, particles move super slowly, behaving like waves according to the principles of quantum mechanics. What also happens is that particles form what’s called a “superfluid”, moving in unison without loss of energy.
The scientists then used lasers to change the spin of the atoms in the fluid, making them behave like they had negative mass.
“Once you push, it accelerates backwards,” said Forbes. “It looks like the rubidium hits an invisible wall.”
Some scientists have pointed out that what’s created here is “negative effective mass,” with Sabine Hossenfelder of the Frankfurt Institute for Advanced Studies explaining the difference this way:
“Physicists use the preamble ‘effective’ to indicate something that is not fundamental but emergent, and the exact definition of such a term is often a matter of convention. The ‘effective radius’ of a galaxy, for example, is not its radius. The ‘effective nuclear charge’ is not the charge of the nucleus. And the ‘effective negative mass’ – you guessed it – is not a negative mass. The effective mass is merely a handy mathematical quantity to describe the condensate’s behavior,” Hossenfelder said on her blog.
Regardless of the wording, researchers agree that this is a significant advancement in experiments involving supercooling atoms and pave the way for studying complex cosmic phenomena.
You can read the study here, in the journal Physical Review Letters.