Neutron Stars Collide by Award-winning author, adventurer and scientist Mark Kingston Levin PhD
On August 17, 2017, scientists caught two neutron stars in the act of colliding for the first time in history, revealing that these strange smashups are the source of heavy element like gold, platinum, palladium and all other heavy elements including uranium. In addition, LIGO, a form of large-scale laser interferometer, has detected gravity waves predicted by Einstein 100 years ago. This article is a follow-up to Blog 6, which showed how an object more than the mass of the entire Earth can be made of gold and other precious metals.
Figure 1. Artist illustration of radio images (not-to-scale) shows superfast jets blasting from the black hole created by the merger of two neutron stars, a dramatic event observed on August 2017. Credit: D. Berry, O. Gottlieb, K. Mooley, G. Hallinan, NRAO/AUI/NSF
Since this historic event of a neutron-star merger, astronomy power has doubled with the new LIGO means of detecting gravity waves. Also, astronomers detected jets of material that moved near the speed of light.
Study coauthor Adam Deller of Australia’s Swinburne University said, “Based on our analysis, this jet most likely is very narrow, at most 5 degrees wide, and was pointed only 20 degrees away from the Earth’s direction. But to match our observations, the material in the jet also has to be blasting outwards at over 97 percent of the speed of light.” Deller and his colleagues — led by Kunal Mooley, of the California Institute of Technology in Pasadena — used a variety of radio telescopes to study the aftermath of the neutron-star collision. This is a historic event known as GW170817.
GW170817 was the first documented collision of two neutron stars with the LIGO equipment and then 70 electromagnetic observational telescopes. These superdense remnants of massive stars that have died in supernova explosions. GW170817 are neutron stars collisions that are about130 million light years away and from which we are safe.
30th Century: Contact, book 3 of my trilogy, depicts such an event 489 light years away. If this collision was less than one thousand light years from Earth and its jet hit Earth, it would be the end of civilization, but because this collision occurred about 130 million light years from Earth, there were no worries.
We did open up a new era known as “multi-messenger astronomy”: it was the first event ever detected via both gravitational waves (the ripples in space-time first predicted by Albert Einstein a century ago) and electromagnetic radiation.
Figure 2. The neutron star collision made hundreds of times the mass of the Earth in Gold, Palladium, Platinum and Uranium. But it is 130 million light-years from Earth. It is not likely worth a mission to collect it until warp drive is invented. Credit NASA
According to NASA, this represents the first time scientists detected a gravitational-wave event that also produced a gamma ray burst, thanks to two merging neutron stars in the galaxy NGC 4993. These remains and the large fortune of gold is located in the constellation Hydra.
The name GW170817, by the way, is a nod to those gravitational waves, as well as the date astronomers observed the event — Aug. 17, 2017.
“It had been unclear whether these jets broke through the debris shell created by the original explosion. But the observations by Mooley and his team — made 75 days and 230 days after the initial detection of GW170817 — indicate that this did indeed happen,” according to Mooley and others.
At first, the jets interacted with the expelled debris to form a sort of cocoon, which moved much more slowly than the jets themselves. But the jets eventually broke free into interstellar space.
“Our interpretation is that the cocoon dominated the radio emission until about 60 days after the merger, and at later times the emission was jet-dominated,” study co-author Ore Gottlieb, a theorist at Tel Aviv University in Israel, said in the same statement.
Figure 3. Radiation from the pulsar PSR B1509-58, a rapidly spinning neutron star, makes nearby gas glow in X-rays. Credit Wikipedia
A neutron star is the collapsed core of a giant star, which before collapse had a total of between 10 and 29 solar masses. Neutron stars are the smallest and densest stars. Neutron stars have a radius on the order of 10 kilometers (6.2 mi) and a mass between 1.3 and 2.2 solar masses. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core to make the neutron star.
Figure 4. This illustration shows the aftermath of the neutron star merger. Material from the explosion, called ejecta, formed yellow and white rings around the black hole formed from the merger. A jet of material propelled from a disk surrounding the black hole interacted with the ejecta material to create a “cocoon.” Later, the jet broke through to emerge into interstellar space.
Credit: Sophia Dagnello, NRAO/AUI/NSF