Why is the discovery of merging neutron stars important?

Reasons why this is important:

  • It is the first simultaneous detection of a gravitational wave and electromagnetic signal (and the strongest GW signal yet). It spectacularly corroborates the reality of the GW detection technology and analysis. The progenitor has been unambiguously located in a (relatively) nearby galaxy, allowing a host of other telescopes to obtain detailed measurements.
  • It shows that GWs travel at the speed of light, a further verification of Einstein’s General Relativity.
  • It shows that most of the very heavy elements such as gold, platinum, osmium etc. are plausibly produced by merging neutron stars and constrains the rate of such mergers in the local universe.
  • It shows that short gamma ray bursts – some of the most energetic explosions in the universe – can be caused by neutron star mergers.
  • It is the closest detected short gamma ray burst (with a known distance). That the progenitor has also been characterised allows a closer investigation of the interesting physics underlying the ejection and jet mechanisms thought to be responsible for the gamma rays.
  • It provides observational constraints on how matter behaves at extremely high densities, testing our understanding of fundamental physics to its limits – for example, the details of the gravitational wave signal moments before merger are diagnostic of the interior conditions of neutron stars at densities of 1018∼1018 kg/m33.
  • It provides an independent way of measuring the expansion of the universe, because the distance to the GW source pops out of the analysis and can be compared with the redshift of the identified host galaxy. The result agrees with measurements made using the cosmic microwave background and the distance-redshift relation calibrated by other means, verifying our estimation of distances, at least in the local universe.

ESO Telescopes Observe First Light from Gravitational Wave Source

ESO’s fleet of telescopes in Chile have detected the first visible counterpart to a gravitational wave source. These historic observations suggest that this unique object is the result of the merger of two neutron stars. The cataclysmic aftermaths of this kind of merger — long-predicted events called kilonovae — disperse heavy elements such as gold and platinum throughout the Universe. This discovery, published in several papers in the journal Nature and elsewhere, also provides the strongest evidence yet that short-duration gamma-ray bursts are caused by mergers of neutron stars.

.. As night fell in Chile many telescopes peered at this patch of sky, searching for new sources. These included

It appeared very close to NGC 4993, a lenticular galaxy in the constellation of Hydra, and VISTA observations pinpointed this source at infrared wavelengths almost at the same time. As night marched west across the globe,

  • the Hawaiian island telescopes Pan-STARRS and Subaru also picked it up and watched it evolve rapidly.

.. “ESO’s great strength is that it has a wide range of telescopes and instruments to tackle big and complex astronomical projects, and at short notice. We have entered a new era of multi-messenger astronomy!” concludes Andrew Levan, lead author of one of the papers.

A Nobel prize for medicine for the understanding of body clocks

This year, three of the prize-winners may be particularly appreciative of that, for they are some of the scientists who have helped to explain why jet lag exists in the first place.

.. Jeffrey Hall, Michael Rosbash and Michael Young are, between them, responsible for working out how the endogenous clocks of fruit flies—and, by extension, of other organisms—run what is known as the circadian rhythm. This is the internal cycle (circa is the Latin for “about” and dies the Latin for “day”) that matches the body’s physiology to the alternation of light and darkness caused by Earth’s rotation. In human beings it controls, among many other things, sleep patterns.

.. Between them, studying mutated fruit flies, they put together an explanation of what is going on at a molecular level.

..Their first step, in 1984, was the isolation within the fruit-fly genome of a gene called period, which had previously been found to be important in controlling circadian rhythms

.. Dr Hall and Dr Rosbach then went on to measure the concentration in fly brains of the protein this gene encodes. They discovered that the protein’s concentration cycles predictably over the course of 24 hours, peaking at night. They also measured levels of the messenger molecule, produced by period genes, which carries the recipe for the protein to a cell’s protein-making machinery. That, too, cycles daily—peaking a few hours before concentration of the protein itself is at its highest.

.. The crucial part of the story is that the protein inhibits the action of periodgenes. The more of the protein there is, the less active the genes are. That reduces production of the messenger molecule, which reduces production of the protein, which permits the gene to reactivate. And so on.

Want Geniuses? Welcome Immigrants

If immigrants to the United States were considered their own country, Najam wrote, their tally of Nobels would exceed that of every country but the United States.

.. An article about immigrants in The Atlantic just a few years ago noted that the four United States-based physicists who sounded the 1939 warning about nuclear weapons that led to the Manhattan Project were born outside the United States. The article went on to point out that “immigrants or the children of immigrants have founded or co-founded nearly every legendary American technology company, including Google, Intel, Facebook, and of course Apple (you knew that Steve Jobs’s father was named Abdulfattah Jandali, right?).”

.. among graduates of American colleges, immigrants are twice as likely to receive patents as native-born Americans. Her research further suggests that this doesn’t come at the expense of native-born Americans but in fact stimulates their innovation, too. “You’re bouncing ideas off each other,” Hunt told me.

.. if the foundation took into account children of immigrants as well as immigrants themselves, the percentage of its geniuses that reflects the benefits of immigration would be higher than 21.7. It’s also worth noting that for most of the grant’s history, foreign-born people constituted less than 10 percent of the United States population.

.. I asked her what she made of immigrants’ prevalence among MacArthur geniuses. “I think most of us feel very lucky to be here, so we work extremely hard,” she said. “I think maybe trauma is part of what drives us.” She added that in terms of innovation, “Having the different perspectives, having the different life experiences, makes you see things differently.” Fresh ideas and great art are often born that way.

.. They come with a sort of hunger and a kind of gaze that don’t subtract from what those of us already here have but, instead, add to it. They give us insights, inventions, art. Embracing their genius is the genius of America.