Guide to the Cosmos

Making the Wonders of our Universe Accessible to Everyone.

 Newsletter: Gold & Gamma Rays

“With this ring (a remnant of a dead neutron star), I thee wed.”

 

Gamma rays are the highest energy form of light, and gamma ray bursts (GRBs) are our universe’s most spectacular explosions. We believe they are related to collapsed stars, either neutron stars or black holes. We used to think there were only two types: (1) Long GRBs lasting 20 to 50 seconds, possibly originating in the collapse of massive stars, forming black holes; and (2) Short GRBs, often coming and going in 1/5th of a second, with the usual suspects being merging neutron stars or black holes.

 

NASA’s Fermi and Swift space telescopes are detecting about one GRB per day. Below is a full-sky image taken at gamma ray frequencies. For a brief period, one GRB outshines the entire universe.

 

 

Now it seems that a third type of GRB exists. And these cosmic catastrophes may be the origin of almost all the gold and other heavy metals in the universe.

 

My newsletter of Dec. 2011 reported on the spectacular “Christmas GRB” that occurred on Dec. 25, 2010 and lasted 28 minutes. Then, no one knew whether it was naughty or nice. “Nice” meant a modest explosion from an asteroid or comet falling onto a neutron star within our galaxy. “Naughty” meant a very remote but catastrophic collapse of a neutron star and a normal star, forming a black hole. Now we know it was even naughtier, even more remote, and lasted even longer than originally imagined. New observations identified the Christmas GRB’s host galaxy and determined it was 7 billion light-years away, probably powered by the collapse of a star hundreds of times more massive than our Sun. Other data show low-level emissions continued for 2 hours. This GRB was the first of a new and more spectacular class of cosmic explosions: ultra-long GRBs.

 

All cosmic explosions are powered by gravity. Intense beams of high-energy particles are created in the cores of collapsing, extremely massive bodies. These beams emerge as highly collimated jets, blasting outward and creating gamma rays as they pass through the bodies’ outer layers. The thickness of matter that the jets blast through determines the duration of the GRB. For a compact object, such as a single neutron star, jets reach its surface in less than a second, and the GRB is short. For an hours-long GRB, the collapsing body must be as much as 1000 times larger than our Sun. Blue supergiant stars fit the bill, particularly if they were first generation stars devoid of heavy elements.

 

NASA provided this comparison of cosmic explosions, with duration plotted horizontally and energy release plotted vertically.

 

 

The green zone contains long GRBs, powered by massive but compact stars collapsing to form black holes. The purple zone corresponds to entire stars and solar systems falling into supermassive black holes. The orange zone contains supernovae and also the annihilation of smaller bodies falling onto neutron stars or modest-sized black holes. The blue zone contains the ultra-long GRBs, powered by extremely large and massive stars collapsing to form black holes.

 

The ultra-long GRBs are quite rare, as shown in the plot below of the durations of observed GRB’s.

 

 

So where’s the gold?

 

Scientists at the Harvard-Smithsonian Center for Astrophysics now believe that the collision of two neutron stars produces considerable amounts of gold and other heavy elements, in addition to a short GRB. They attribute the slowly fading infrared light seen after short GRBs to radioactive decay of very heavy elements, some of which will become gold.

 

“We estimate that the amount of gold produced and ejected during the merger of the two neutron stars may be as large as 10 moon masses – quite a lot of bling!” said lead author Edo Berger. That’s a billion, trillion tons of gold among the 20 trillion, trillion tons of collision debris.

 

They multiplied their estimate of gold production in a single collision by the number of GRBs estimated to have occurred over the age of the universe. The result, they say, could account for all the gold that we observe in the universe today.

 

The gold in your ring (or your teeth) may have come from colliding neutron stars and the subsequent gamma ray burst.

 

 

Best Regards,
Robert
 
July 23, 2013

 

Note: Previous newsletters can be found on my website.

 

 

eBooks

Below are my latest eBooks in the Everyone’s Guide Series.  They are available for $2.99 each: for Kindle on Amazon.com, for Nook on Barnes&Noble.com, and on Kobo.com & WaveCloud.com.

(Click on each cover for more information.)

 

 

 

Dr. Robert L. Piccioni

Guide to the Cosmos

 

Author of printed books

"Everyone's Guide to Atoms, Einstein & the Universe"

"Can Life be Merely an Accident?"

and

"A World Without Einstein"